Nanoscale gold catalysts, activating agents, support media, and related methodologies useful for making such catalyst systems especially when the gold is deposited onto the support media using physical vapor deposition

European).

Description

The invention relates to gold-based catalyst systems, and particularly to gold-based catalyst systems in which nanoscale gold particles are immobilized on nanoporous supports.

It is known that ultra-fine nanoscale gold particles have specific physical and chemical properties different from those of ordinary coarse gold (Ultrafine Particles, published by the Agne Publishing Center in 1986). In particular, such ultra-fine gold is catalytically active and can be used as a catalyst for the carbon monoxide oxidation reaction to form carbon dioxide. The use of catalytically active gold has also been proposed for the catalysis of other oxidation reactions, such as carbon black oxidation in exhaust gas streams from a diesel engine, oxidation of unsaturated and saturated hydrocarbons, etc.

In general, ultra-fine gold particles are very mobile and have high surface energies, so they tend to coagulate easily. In fact, it is difficult to prevent such coagulation, which makes ultra-fine gold hard to touch. Such mobility is undesirable because the catalytic activity of gold tends to decrease with increasing particle size. This problem is relatively characteristic of gold and is much less common with other precious metals such as Pt and Pd. Thus, it is desirable to develop methods for deposition and immobilization of ultra-fine gold particles on a carrier in a state of evenly dispersed.

Previously known basic methods of depositing catalytically active gold on various supports have recently been collected by Bond and Thompson (GC Bond and David T. Thompson, Gold Bulletin, 2000, 33 (2) 41) and include: (i) co-precipitation in which the carrier and gold precursors are precipitated from solution, probably as hydroxides, by the addition of a base such as sodium carbonate; (ii) precipitation precipitation in which the gold precursor is precipitated into a slurry of the pre-formed support by increasing the pH, and (iii) the Iwasawa method in which the phosphine gold complex is prepared (e.g. [Au (PPh₃)]WELL₃) to react with freshly precipitated carrier precursor. Other methods were also used with varying degrees of success, such as the use of colloidal systems, grafting and vapor deposition.

However, there are serious difficulties associated with these methods, resulting in a situation aptly described by

Wolf and Schuth (Applied Catalysis A; General 226 (2002) 2): (presented below as an article by Wolf et al.). "Although rarely expressed in publications, it is also well known that the reproducibility of high activity gold catalysts is typically very low." The reasons for such serious reproducibility problems include: difficulty in controlling the size of gold particles, poisoning the catalyst by ions such as Cl, the inability of these methods to control the deposition of nano-sized gold particles, loss of active gold in the pores of the substrate, in some cases the need for thermal treatments to activate the catalysts, inactivation of certain catalytic sites as a result of treatment thermal, no control of gold oxidation and non-homogeneous hydrolysis properties of gold solutions after adding the base.

In a review, Haruta (Catalysis Today 36 (1997) 153-166) describes Au catalysts for various catalytic reactions, predominantly oxidation reactions. It discloses, inter alia, PVD methods for depositing Au on a support, in particular by cathode sputtering. The disclosed carriers are known as porous (e.g., Y-Al 2 O 3, Si, Ti, Fe or Co oxides). The article emphasizes the importance of the deposited Au particle size (should be less than 10 nm to catalyze the CO oxidation reaction) and the importance of the support (it should tightly bind Au and provide maximum boundary space of the gold-support interface) The article then describes the microscopic equality of catalysts obtained by precipitation-precipitation, CVD and PVD methods, i.e. in all, Au is predominantly present on the catalyst surface in the form of semicircular particles.

German Patent DE 10030637 A1 describes the use of PVD techniques for depositing gold on supports. However, the carriers exemplified in the working examples are only ceramic titanates prepared as described under conditions in which the resulting carriers may be insufficiently nanoporous. Thus, these documents underestimate the importance of using nanoporous supports of catalytically active gold deposited using PVD techniques. International patent applications WO 99/47726 and WO 97/43042 provide lists of supports, catalytically active metals, and / or methods for introducing catalytically active metals into carriers. However, these two documents also underestimate the benefits of using nanoporous supports for catalytically active PVD deposited gold. Indeed, International Patent Application WO 99/47726 lists many carriers as preferred carriers that lack nanoporosity.

In short, gold offers great potential as a catalyst, but the difficulties associated with the treatment of catalytically active gold severely limit the development of commercially viable, gold-based, catalytic systems.

In patent pending St. Ser. America No.

US 4046712 A discloses PVD deposition (preferably, ion beam sputtering) of Pt group metals on low porous ceramic or carbon substrate particles (preferably, Al₂ABOUT₃) to provide a product that is useful as an oxidation catalyst, especially as disclosed in a CO oxidation reaction. The solution described as particularly advantageous (cf. Example 3) requires adherence of fine (1-5 μm) alumina particles sputtered Pt to larger (100 μm, i.e. about 140 mesh) non-sputtered alumina particles. The PVD sputtering method is described as a better method than the usual vapor deposition to coat porous or non-porous substrates, moreover porous substrates (actually less mechanically and thermally stable) are not required when using sputtering.

British Patent Application GB 1486108 A discloses composite particles obtainable by sputtering onto small particles (preferred materials are oxide carriers such as Y-AI2O3), among others Au, and then coating macroscopic units such as fibers, wool or ceramic granules.

It has been found that the use of physical vapor deposition methodology for the deposition of nanoscale gold on activating nanoporous supports definitely facilitates the use of catalytically active gold and opens up opportunities for significant improvements associated with the development, production and use of gold-based catalytic systems. Thus, the invention relates to new properties, components and methods for making gold-based heterogeneous catalyst systems, generally containing nanoscale gold deposited on a nanoporous support. In many aspects, the invention provides significant improvements in methods of depositing catalyst on supports (particularly, the deposition of catalytically active gold on a nanoporous support as defined in the appended claims), catalyst support construction, catalyst system design, catalyst activating agents and methods of using activating agents to enhance performance of catalytic systems.

The gold-based catalyst systems of the invention exhibit excellent catalytic performance. These systems can be used in rooms with limited CO content in the form of personal protection, vehicle and building, as catalysts and catalyst carriers for cleaning exhaust gas from internal combustion engines, for removing CO from fuel cell input materials and for catalyzing other oxidation reactions such like oxidation of carbon black in exhaust gas streams from a diesel engine and selective oxidation of organic compounds. For example, gold-based catalyst systems may be suitable as catalyst systems for the catalytic oxidation of unsaturated and saturated hydrocarbons. The term hydrocarbon means unsaturated or saturated hydrocarbons such as olefins or alkanes. The hydrocarbon may also contain heteroatoms such as N, O, P, S or halogen. The organic compounds intended for oxidation may be acyclic, monocyclic, bicyclic or polycyclic and may be mono-olefinic, di-olefinic or poly-olefinic. Double bonds in compounds containing two or more double bonds can be conjugated or unconjugated.

Generally, one aspect of the invention includes the use of physical vapor deposition (PVD) methodologies as defined in the appended claims for depositing catalytically active gold, optionally together with other catalytically active metals, on a nanoporous support. In some embodiments, nanoporous supports have a very large surface area per volume of support, and typical methodologies include saturation of such supports with their largest possible volume of catalyst. Indeed, the technical literature reports that such "full volume" impregnation may be required to achieve acceptable catalytic performance. However, the PVD method tends to be the line of sight for the coating technique, all the more so because the PVD method deposits the catalyst mainly on and very close (there will be some slight surface penetration, such as due to diffusion) of the surface of nanoporous supports. From a typical perspective, nanoporous carriers appear to be under-utilized, giving the impression that PVD is an inappropriate technique for use in this context. However, surface deposition / coating of catalytically active metal nanoscale nanoporous support topography has been found to provide catalytic systems with excellent performance despite conventional knowledge. In the case of gold, e.g., it appears that these nanoscale properties help to immobilize gold, prevent gold accumulation that could result in reduced performance. In brief, the invention recognizes that nanoporous supports have more to offer catalytically than just a large surface area per volume of support.

In certain aspects of the invention, PVD is performed by catalytically active metal by unique methods. In one embodiment, the carriers are both drum mixed (or otherwise fluidized) and comminuted (e.g.

ground or ground) to some extent during at least part of the PVD treatment. It was found that the comminution of carriers during PVD increases the efficiency of the resulting catalyst system.

In accordance with other aspects, PVD is used to deposit catalytically active gold separately and after saturating the supports with an activating agent. Briefly, preferred types of procedures include PVD gold deposition only after saturating the supports with one or more activating agents, drying and optionally roasting. This significantly expands the range of activating agents that can be used in combination with a catalytically active metal. Ingredients that may otherwise react or be too soluble in solution may be used when using wet methods to deposit gold. For example, the method of the invention allows gold to be deposited, optionally together with other metals, on supports containing very basic or water-soluble materials. This opened up the possibility of testing and using water-soluble metal salts as activating agents, since they do not leach out during subsequent PVD gold deposition. It is not very practical to try to use such salts as activating agents when gold is introduced into the carriers as a result of treatment with the solution as gold solutions may elute water-soluble material and / or may be chemically incompatible with activating agents (e.g. gold solutions are often strongly acidic, e.g. HAuCl₄).

Water-soluble salts, such as alkali and / or alkaline earth metal salts are inexpensive, readily available and easily incorporated into the catalytic systems during the practice of the invention. Importantly, these salts have been found to be strong activators for gold-based catalysts, especially when used to activate nanoporous carbon supports. Separating the PVD deposition process of catalytically active gold from earlier activation of the supports was key to helping enable the use of this improvement in the use of carbon supports with activating salts for gold-based catalysis.

The invention offers many other properties and advantages. First, it has been observed that catalytically active gold is active immediately after PVD deposition. There is no need for thermal treatment of the system after gold deposition, as with some other methodologies.

This, of course, does not mean that a heating step is not possible if desired. The scope of the invention includes the subsequent heating step. In addition, gold is very catalytically active for relatively long periods in terms of CO oxidation, even if it tends to deposit only closer to the surface of the support when PVD is used to deposit gold. Catalytic systems are also effective in humid environments and operate over a wide range of temperatures, including room temperature (e.g., about 22 ° C to about 27 ° C) and significantly lower temperatures (e.g., below 5 ° C).

The physical vapor deposition process is very clean, i.e. no pollutants are introduced into the system, as is the case with solution processes. In particular, the process may be free of chlorides, so there is no need to carry out washing steps to remove chlorides or other undesirable ions, particles or reaction by-products, as with most solution deposition processes.

Using this process, very low levels of metal are required for high activity. While in most research in this field at least 1% by weight of gold was used to obtain activity, and often much more than 1% by weight of gold for high activity, very high activity was achieved in this work at 0.05% by weight of gold or less . Such a reduction in the amount of precious metal required to achieve high activity gives a very significant cost saving.

The catalytic system is strong and compatible. For example, two identical solutions of this system were produced and tested over a period of about one month. Despite the fact that the two solutions were separately manufactured, the relevant data for each of them was identical for practical purposes. This type of compliance is not typical for gold-based catalyst systems. See the article by Wolf et al.

As a result of this process, a very homogeneous product is obtained in relation to the concentration of valuable metal per particle and the size of the metal nanoparticle and size distribution. TEM studies have shown that gold can be deposited in the process in forms comprising separate nanoparticles and small clusters, or in the form of a more continuous thin film, depending on what is desired. In general, desirable forms include gold in the form of nanoparticles / gold in the form of small clusters.

By using this method of catalyst preparation, catalyst metals can be deposited evenly on non-uniform or non-homogeneous surfaces. This is not possible with solution deposition processes in which the solution used for deposition promotes deposition on surfaces having a charge opposite to the deposited metal ion, leaving other surfaces uncovered or, at best, poorly coated.

The PVD method can be used to deposit other metals simultaneously or sequentially, or to deposit a mixture of metals using multiphase objects in such a way that catalyst particles can be formed that contain multiphase nanoparticles, e.g. nanoparticles containing mixtures of atoms, e.g. M₁ them₂ (Where's m₁ them₂ are different metals), or which contain combinations of metal nanoparticles for multifunctional catalysts, e.g. mixtures of nanoparticles containing mixtures of separate M particles₁ and separate particles M₂. In this way, catalyst particles can be produced that can catalyze more than one reaction and these functions can be simultaneously implemented in practice. Thus, catalyst particles can be produced that will effectively oxidize CO and simultaneously oxidize NO_X.

Using this method, it is possible to effectively deposit catalytically active metals on a larger range of carriers, e.g. on fibers or meshes. While the fibers can be coated using solution coating processes, shears used to grind and disperse the fibers generally result in dust formation and inefficient coating due to fiber abrasion during the coating process. Catalytic fibers can be used to produce new, highly catalytically active felt, fabric and mesh nets.

This new process enables the creation of new families of active metals on carbon and other oxidation sensitive substrates. In processes known in the art that require a heating step to attach and activate the catalyst particles, carbon in the presence of an oxidizing medium may react at elevated temperatures, which are often required. Thus, the carbon particles must be treated with a reducing atmosphere because they could be attacked by oxygen atoms during this heating step. Such a reduction step may undesirably reduce other catalyst components (e.g., as in the case of iron oxide supported on carbon or on porous carbon). According to the invention, the carbon particles and other non-oxide particles can be coated with catalyst nanoparticles and no heating or subsequent reduction step is required. In this way, a large specific carbon surface can be converted into a catalytic surface for CO oxidation, without losing the adsorptive properties of the porous carbon to remove other impurities from the gas phase.

In one aspect, the invention relates to a method for producing a heterogeneous catalyst system. The method includes introducing smaller nanoporous particles (i.e. guest particles) into a larger particle (i.e. host particle). The method includes depositing catalytically active metal on the improved specific surface of the support, and includes gold as the active metal and physical vapor deposition as the method of depositing said metal. The ratio of average size of host particles to guest particles is preferably from 10,000: 1 to 10: 1.

According to another aspect, the invention provides a heterogeneous catalyst system obtainable by this method. The system contains a nanoporous support. The nanoporous support may contain at least one water-soluble salt, which is a saturated support. The nanoporous support also contains catalytically active gold deposited on the support, wherein the catalytically active gold can be deposited at a penetration depth ratio of about 1 x 10^-9to about 0.1.

In another preferred method of the invention, a heterogeneous catalyst system is provided that comprises a nanoporous composite support, an alkali metal salt that is a saturated support, and catalytically active gold supported on the support.

According to an aspect, the invention also relates to a method for producing a catalytic system. Another preferred method includes the step of saturating the water-soluble salt of the catalyst support and the step of heat treatment of the saturated support at a temperature above about 200 ° C. In addition, the method includes the step of physically depositing the gas phase catalyst on the heat treated support.

In another preferred aspect of the invention, the method includes the step of physically depositing the gas phase catalyst onto the catalyst support, and the step of mixing and comminuting the support during at least a portion of the physical vapor deposition.

In another preferred aspect, the method comprises the step of hydrolyzing a metal alkoxide on a catalyst support. The method includes the step of depositing catalytically active metal on an activated support surface and includes gold as the active metal and physical vapor deposition as a method of depositing said metal.

Fig. 1 is a picture obtained by TERM of the cross section of a surface of a nanoporous support containing gold nanoparticles for use for reference purposes (material according to example 3).

Fig. 2 schematically illustrates a side view of an apparatus for performing a PVD process for depositing catalytically active gold on a support.

Fig. 3 is a schematic perspective view of the device of fig. 2.

Figure 4 shows a test system that was used to test samples for CO conversion to assess the catalytic properties of the CO oxidation reaction.

Fig. 5 schematically illustrates the system used for chromatographic analysis of the catalytic properties of samples.

Fig. 6 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the containing stream

CO in the air is a function of time.

Fig. 7 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 8 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 9 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 10 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 11 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 12 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the containing stream

CO in the air is a function of time.

Fig. 13 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the containing stream

CO in the air is a function of time.

Fig. 14 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 15 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 16 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 17 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 18 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 19 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the containing stream

CO in the air is a function of time.

Fig. 20 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the containing stream

CO in the air is a function of time.

Fig. 21 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 22 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 23 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 24 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 25 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 26 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the containing stream

CO in the air is a function of time.

Fig. 27 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the containing stream

CO in the air is a function of time.

Fig. 28 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 29 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 30 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 31 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 32 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 33 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the containing stream

CO in the air is a function of time.

Fig. 34 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the containing stream

CO in the air is a function of time.

Fig. 35 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 36 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 37 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 38 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 39 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 40 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the containing stream

CO in the air is a function of time.

Fig. 41 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the containing stream

CO in the air is a function of time.

Fig. 42 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 43 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 44 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 45 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 46 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 47 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the containing stream

CO in the air is a function of time.

Fig. 48 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the containing stream

CO in the air is a function of time.

Fig. 49 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 50 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 51 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 52 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 53 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 54 is a graph showing catalytic characteristics of samples, wherein the ability of each sample to catalytically oxidize CO to CO₂ in the containing stream

CO in the air is a function of time.

Fig. 55 is a graph showing catalytic characteristics of a sample, wherein the ability of each sample to catalytically oxidize CO to CO₂ in the containing stream

CO in the air is a function of time.

Fig. 56 is a graph showing catalytic characteristics of samples, wherein the ability of each sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 57 is a graph showing catalytic characteristics of samples, in which the ability of each sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Fig. 58 is a graph showing catalytic characteristics of a sample, wherein the ability of the sample to catalytically oxidize CO to CO₂ in the stream containing CO in the air it is presented as a function of time.

Detailed description

During the practice of the invention, the catalytically active gold is deposited onto the desired support (s) using physical vapor deposition. Physical vapor deposition refers to the physical transfer of gold from a gold source or a target metal to a support. Physical vapor deposition can be considered a process involving atom-on-atom deposition, although in fact, gold can be transferred in the form of very small clusters containing more than one atom per cluster. Upon approaching the surface, gold can interact with the surface physically, chemically, ionically and / or otherwise.

Physical vapor deposition typically occurs under temperature and vacuum conditions in which gold is very mobile. Consequently, gold is quite mobile and will tend to migrate on the surface of the substrate until it is immobilized in a certain manner, e.g. by adhering to a location on or very close to the surface of the support. It is understood that the adhesion sites may contain defects such as surface gaps, structural gaps such as faults and dislocations, interphase boundary areas between phases or crystals or other gold clusters such as small gold clusters. A clear advantage of the invention is that the deposited gold is effectively immobilized in such a way that it retains a high level of catalytic activity. This contrasts with typical methodologies in which gold accumulates in such large clusters that catalytic activity is excessively impaired or even lost.

There are various solutions for performing physical vapor deposition. Representative solutions include sputtering, evaporation and cathodic arc deposition. Any of these solutions or other PVD solutions may be used, although the properties of the PVD technique used may affect the catalytic activity. For example, the energy of the physical vapor deposition technique used may affect mobility, and thus the tendency to accumulate gold. Higher energy is often responsible for gold's increased tendency to accumulate. Increased accumulation, in turn, leads to a decrease in catalytic activity. Generally, the energy of particle deposition is the lowest for evaporation, higher for sputtering (these particles may have a certain ion content in which a small fraction of colliding metal particles are ionized) and the highest for the cathode arc (where the particles may contain tens of percent ion content). Accordingly, if deposited gold is obtained by using a particular PVD technique that is more mobile than may be desirable, it may be useful to use a lower energy PVD technique instead.

Physical vapor deposition is generally a technique of coating the targeting line / surface between the gold source and the support. This means that only the exposed outer surfaces of the support, and not the inner pores in the substrate, are directly coated. Internal surfaces that are not directly at the source's aiming line will often not be directly coated with gold. However, it was found using TEM analysis that after deposition on the surface of the porous substrate, gold atoms can migrate through diffusion or other mechanism over a moderate distance to the catalyst surface to form nanoparticles and gold clusters in the pores of the substrate in the area immediately adjacent to the surface prior to immobilization . The average penetration of porous substrates can be up to 50 nanometers deep or sometimes more, e.g. from about 70 to about 90 nm deep. However, the penetration depth is generally less than 50 nm and may be less than 30 nm. Gold penetration is very shallow compared to the typical dimension of the support.

Total thickness of gold, or C._t, are equal to the depth of gold penetration plus the thickness of gold that is deposited on the surface of the substrate and which is not penetrated by diffusion. Such overall thickness is generally less than 50 nm and can often be less than 30 nm or even less than 20 nm. For materials containing surface pores, whose depth is greater than about 10 nm to 20 nm, the total thickness of gold may be above 50 nm, because the gold layer adheres to the surface contours and the contour of the actual surface is a reflection of the structure of the pores. It is most preferred if the active gold particles are collected in the outermost part of the catalyst particle, because it is the surface of the catalyst that interacts most easily with the gaseous reagents.

The thickness of the gold coating area relative to the particle size of the catalyst support is quantified by the formula

PDR = C_t/ UST in which PDR is the ratio of penetration depth, UST is essentially the support thickness or particle size and C_tis the total thickness of gold as defined above. The principal support thickness means the support dimension measured perpendicular to the catalyst surface and usually indicates the particle size. The basic thickness of the support can be determined by microscopic methods such as optical microscopy or scanning electron microscopy. C value_tcan be determined by transmission electron microscopy (TEM) for thin films and by high resolution scanning electron microscopy for thicker films. Total Thickness C_t it is very easy to see the TEM data by visual examination. Due to the uniformity with which gold is coated, a single representative TEM image can be effectively used to characterize the coating. In practice, the sample can be effectively characterized by testing a number of TEM images of cross sections of the catalyst surface (see below). In preferred embodiments, the PDR is from about 1 X 10^-9 to 0.1, preferably from 1 X 10^-6 up to 1 X 10^-4, indicating that the range of gold coating is indeed very thin relative to the total thickness of the support. As indicated above, this usually corresponds to a penetration depth of up to about 50 nm, preferably about 30 nm on preferred supports.

Characterization of the surface area and gold clusters is carried out using transmission electron microscopy, as this is a method well known in the field of catalysts. One method suitable for characterizing catalytic surfaces is as follows: catalyst particles are deposited in 3M Scotchcast ™ Electrical Resin # 5 (epoxy; 3M Company, St. Paul, MN) in disposable embedded capsules; wherein the resin is allowed to cure at room temperature for 24 hours.

For each sample, a randomly selected, embedded granule is cut (using a stainless steel razor blade previously cleaned with isopropyl alcohol) down to the central surface area of ​​the granule so that most of the granule is cut off and is on one side, leaving the epoxy resin on the other side . A small trapezoidal face (less than half a millimeter per side) is selected and cut so that the epoxy resin / granule interface remains intact. The long direction of this interface is also the cutting direction. Leica Ultracut UCT (Leica Microchip Inc., Bannockburn, II) is used for transverse cutting of the frontal surface. Initially, the front surface is oriented so that the granule surface is perpendicular to the edge of the knife. Sections approximately 70 nm thick are cut at a speed of 0.08 mm / second. The obtained cross-sections are separated by floating on the surface of deionized water and collected using a microtome fiber tool, then taken using "Perfect Loop" (loop distributed by Electron Microscopy Sciences, Fort Washington, Pa). The samples are transferred using this loop to a 3 mm diameter copper TEM mesh, mesh size 300, with a substrate containing a lace carbon / formvar system. Interesting areas (intact, smoothly cut fragments representing interphase areas) that lie on the holes in the ground are mapped and analyzed.

Images are taken at various magnifications (50,000 X and 100,000 X) using a Hitachi H-9000 transmission electron microscope (TEM; Hitachi High Technologies America,

Pleasanton, Ca) at an accelerating voltage of 300 KV, using a Gatan CCD camera (Gatan Inc., Warrenton, Pa) and Digital software representative areas

Micrograph. They are imaged (selected areas in which the surface of the catalytic separation of the surface is clearly examined in a manner perpendicular to the surface of the sample). Calibrated markers and sample markings are placed on each image. Numerous (> 10) interfacial areas were examined.

An example of a TEM image of a cross-section of a representative surface of the inventive catalyst (material according to Example 3) is shown in Fig. 1. Gold nanoparticles can be seen both on the support surface and in the support sub-area. The area containing the gold nanoparticles is very thin and it can be seen that the deposition of gold follows the contours of the support surface.

As a consequence of coating according to the aiming line, the obtained catalytically active material according to the invention can, from one perspective, be considered as nanoporous catalytic supports containing relatively thin coatings of discontinuous, catalytic gold and close to their outer surfaces. This means that the resulting catalytically active material contains a gold-enriched surface area close to the surface and an internal area containing a small amount of gold. In preferred embodiments, this gold-enriched coating region comprises small (generally less than 10 nm, most preferably less than 5 nm) separate gold clusters.

According to the invention, the solution for producing a catalytically active coating region only on the surface of the nanoporous support is opposed to typical knowledge of the development of new catalytic materials, therefore the fact that the resulting material is so catalytically active is unexpected. Specifically, the invention places the catalytic functionality only close to the surface of the highly porous support. Internal porosity is intentionally unused. From a typical perspective, this incomplete use of the nanoporous support seems pointless. Knowing that the catalytically active metal is to be deposited only on the surface of the support, a typical tendency would be to use a non-porous substrate for depositing catalytically active gold on the support. This is especially the case when the PVD method cannot access the interior of the porous support under any circumstances. The invention overcomes these trends by combining the recognition that (1) gold mobility is very limited on the surface of nanoporous supports, and (2) gold is still catalytically active, even at very low weight loads resulting from the surface coating solution. Consequently, the use of such supports is highly and extremely advantageous in the context of gold deposition on the surface area of ​​the nanoporous support, even when the total catalytic performance of the support is not utilized.

In general, physical vapor deposition is preferably performed while the carrier to be treated is subjected to thorough mixing (e.g., by drum, fluidized or similar mixing), which helps ensure that the surfaces of the particles are properly treated. Methods of drum-mixing particles for PVD deposition are summarized in US Pat. Ser. U.S. Patent No. 4,615,825. Methods specific to catalysts were described by Wise: "High Dispersion Platinum Catalyst by RF Sputtering," Journal of Catalysis, vol. 83, pp. 477-479 (1983) and Cairns et al. in the patent description Ser. US 4046712. More preferably, the support is either tumbler mixed or otherwise fluidized and comminuted (e.g., triturated or ground to some extent) during at least part of the PVD process. This achieves a certain degree of mechanical abrasion of the particle surface and the production of specific finely ground material during gold deposition. The data suggest that catalytic activity is enhanced when deposition is carried out using comminution. We believe that these processes, i.e. the production of finely ground material and the mechanical interaction of abrasive grains with others, increases the activity of the resulting catalyst materials. Without wishing to be bound by theory, it is believed that finely ground material provides a larger surface area for greater activity. Freshly prepared support surfaces are also exposed, which may also enhance catalyst performance.

The influence of such comminution on the surface properties of the catalytic system obtained was examined by TEM analysis. In the case of gold on carbon containing the activating agents of the invention, TEM analyzes revealed the presence of a unique, two-phase structure that is believed to contain nanoparticles and gold clusters and carbonaceous material on the surface of gold-coated particles. It is possible that the mechanical action is the reason for obtaining such a unique structure, because the carbonaceous material from one granule is transferred to the gold-coated surface of the other granule by wiping. Such a gold / activating nanocomposite and carbon have very high CO catalytic oxidation activity.

Device 10 for carrying out the preferred PVD process is shown in Figures 2 and 3. Device 10 consists of a housing 12 defining a vacuum chamber 14 containing a particle mixer 16. The housing 12, which if desired can be made of aluminum alloy, is vertically oriented hollow cylinder (45 cm high and 50 cm in diameter). The base 18 includes a through hole 20 of the high vacuum gate valve 22 followed by a six-inch diffusion pump 24 as well as a support 26 for the particle mixer 16. The chamber 14 can be emptied to a background pressure of 10^-6 Torah.

The upper part of the housing 12 includes a removable L-gasket 28 rubber sealing plate which is provided with an external magnetron dc with a diameter of 3 inches as a source of sputter deposition 30 (US Gun II, US, INC., San Jose, CA). A sputter of 32 (7.6 cm (3.0 inches) diameter x 0.48 cm (3/16 inches) thickness is attached to source 30. yeast³sputtering 30 is powered by MDX-10 Magnetron Drive (Advanced Energy Industries, Inc., Fort Collins, CO) equipped with Sparc-le 20 arc breaker (Advanced Energy Industries, Inc., Fort Collins, CO).

Particle mixer 16 is a hollow cylinder (12 cm x 9.5 cm horizontal diameter) with a rectangular hole 34 (6.5 cm x 7.5 cm) in the upper part 36. The hole 34 is located 7 cm just below the surface 36 of the element sputtering gold 32 so that the sputtered gold atoms can enter the volume of the mixer 38. The mixer 16 is provided with a shaft 40 aligned with its axis. Shaft 40 has a rectangular cross-section (1 cm x 1 cm) to which four rectangular blades 42 are bolted to form a mixing mechanism or paddle wheel for drum-mixed carrier particles. Each blade 42 has two holes 44 (2 cm in diameter) to promote communication between the partial volumes contained in each of the four quadrants formed by the blades 42 and the mixer cylinder 16. The dimensions of the blades 42 are selected so as to provide slots with the walls of the mixer 48 on the side and end of sizes of either 2.7 mm or 1.7 mm. Preferred methods for using this device are described below in the examples.

The size of the gap between the mixer 16 and the walls of the housing 12 affects the performance of the resulting catalyst. If the resulting gap is smaller, the carrier particles will have a greater tendency to grind to a certain degree. Since it is assumed that such milling is preferred, the gap is adjusted to a suitable distance to ensure that such milling occurs. In one preferred method, the gap was set to a size about the diameter of the carrier particles to be coated.

Physical vapor deposition can be carried out at any desired temperature (s) in a very wide range. However, deposited gold may be more catalytically active if it is deposited at relatively low temperatures, e.g., at a temperature less than about 150 ° C, preferably less than about 50 ° C, more preferably at ambient temperature (e.g., about 20 ° C to about 27 ° C) or lower. Work in ambient conditions is beneficial as efficient and economical because no heating or cooling is required during the deposition process.

Without wishing to be bound by theory, it is assumed that deposition at lower temperatures produces more catalytically active gold for at least two reasons. First of all, at lower temperatures, gold with larger defects is obtained in terms of geometric dimension and / or shape (angularity, elbows, faults, etc.). It is assumed that such defects are significant in many catalytic processes (see ZP Liu and P. Hu, J. Am. Chem. Soc, 2003, 125, 1958). On the other hand, deposition at higher temperatures often leads to the production of gold, which has a more ordered and defect-free crystal structure and is therefore less active. In addition, the deposition temperature may also affect gold mobility. Gold tends to be more mobile at higher temperatures and therefore accumulation and loss of catalytic activity are more likely.

The invention provides catalytically active gold on the desired support (s) in the form of heterogeneous catalyst systems according to the invention. Gold is commonly known as a noble, relatively inert yellowish metal. However, the properties of gold change substantially under nanoscale conditions in which gold becomes highly catalytically active. The high reactivity of gold as a catalyst compared to other metal catalysts is illustrated by reactions such as oxidation of CO at ambient conditions and reduction of NO, as well as epoxidation and hydrochlorination of unsaturated hydrocarbons.

Catalytically active gold can be identified by one or more of the required properties, such as size, color and / or electrical properties. Generally, if a gold sample has one or more of these required properties, and preferably two or more of these properties, then it will be considered to be catalytically active during the practice of the invention. The nanoscale dimension is a key requirement for catalytically active gold, in that the catalytic activity of gold largely depends on whether the gold sample has a nanoscale thickness (e.g. particle diameter, fiber diameter, film thickness or the like). Clusters (also called clusters in literature) with smaller dimensions tend to have greater catalytic activity. As the dimension increases, the catalytic properties decrease rapidly. Accordingly, in preferred embodiments, the catalytically active gold can have a wide scale nanoscale dimension, with smaller dimensions being more preferred when greater activity is desired. Catalytically active gold clusters as such, in the context of the present invention relate to particles or clusters with dimensions ranging from 0.5 nm to 50 nm, preferably 1 nm to 10 nm. Preferably, the gold has a size of not more than 2 nm to 5 nm in any dimension. Technical literature reports that catalytic activity may be maximum with dimensions in the range of 2 nm to 3 nm. The dimension of individual gold nanoparticles can be determined using TEM analysis, which is well known in the art and is described herein.

When it comes to coloration, larger dimensions of gold have a yellowish coloration. However, under nanoscale dimensional conditions in which gold is catalytically active, the color of gold becomes reddish pink when observed under white light, although very small gold clusters and gold surface particles may be colorless. Such colorless particles can have completely catalytic properties, and the presence of such colorless particles is usually accompanied by some colored gold nanoparticles. Consequently, determining whether the color of the gold sample includes a discernible reddish pink component and / or is colorless, indicates the possibility that the sample is catalytically active.

The amount of catalytically active gold provided on the support can vary widely. However, from a practical point of view, it is helpful to consider and compare many factors when choosing the desired weight load. For example, catalytically active gold is very active when provided on nanoporous supports in accordance with an embodiment of the present invention. Thus, only very low weight loads are needed to achieve good catalytic performance. This is beneficial because gold is expensive. Thus, for economic reasons, it is not desirable to use more gold than is justified to obtain the desired degree of catalytic activity. In addition, because nanoscale gold is very mobile during PVD deposition, catalytic activity can be impaired if too much gold is used due to the accumulation of gold in large clusters. Considering such factors and using them as a general guideline, the weight load of gold on the support is preferably from 0.005 to 10% by weight, preferably from 0.005 to 2% by weight, and most preferably from 0.005 to 1.5% by weight based on the total weight of the support and gold .

Deposition of catalytically active gold on a support is very compatible with PVD techniques. Gold is naturally sprayed to form catalytically active nanoscale particles and clusters on the surface of the nanoporous support. It is assumed that gold is deposited mainly in elemental form, although it may also occur in other oxidation states. Although gold is mobile and will tend to accumulate at low energy surface locations, the nanoporous support properties and the beneficial use of activating agents during the implementation of the invention assist the immobilization of gold, helping to maintain deposited gold clusters in an isolated and preferably discontinuous form. This helps to maintain catalytic activity that could otherwise be compromised if gold accumulates in larger clusters. Alternatively, if desired, very thin nanoscale gold films can also be formed on some or all surfaces of the support, keeping in mind that catalytic activity decreases as the thickness of the film increases. Even if such films with catalytic activity can be formed, discontinuous, isolated gold clusters tend to have much more catalytic activity and are preferred for most applications.

Optionally, if desired, the heterogeneous catalyst system may be heat treated after gold deposition. Some typical methods may require such heat treatment to obtain catalytically active gold. However, gold deposited by the process of the invention is very active after deposition without any need for thermal treatment. Indeed, such gold can very effectively catalytically oxidize CO to form CO₂ at room temperature or even at a much lower temperature. In addition, depending on factors such as the properties of the support, activating agents, the amount of gold or the like, catalytic activity may be impaired to some extent if the heat treatment is carried out at too high a temperature. Indeed, for some types of solutions in which the heterogeneous catalytic system is intended for use in a heated environment, e.g. in an environment with a temperature greater than about 200 ° C, the catalytic activity of the system should be confirmed at such temperatures. Embodiments of the invention that show good catalytic performance of CO oxidation reactions under such high temperature conditions are described below in the examples. These solutions include systems in which the carrier contains one or more substances such as alumina, titanium dioxide, silica, and / or the like.

It is also assumed that gold with a low coordination number is preferred in catalytic nanoparticles. Gold with a small coordination number refers to Au_n, for which n is on average from 1 to 100, preferably from about 2 to 20. Without wishing to be bound by theory, it has been proposed that the catalytic activity of very small gold clusters is associated at least to some extent with a small number of coordination defects, and that these defects can create storage areas for loads that can be transferred from the subsoil carriers and / or other sources. Accordingly, in view of such defects and mechanism, it is preferred that the heterogeneous catalysts of the invention have one or more of the following characteristics: (a) gold, and therefore defects, are mainly found on the surface of the underlying support; (b) the average value for n is greater than about 2, and (c) as much as practically possible, gold clusters are isolated but still close to each other (at a distance of about 1-2 nm or less), ( d) although such features may be associated with smaller gold clusters, it is possible that such properties can be found mainly at faults or the edges of larger clusters.

In addition to gold, one or more other catalyst metals may also be deposited on the same supports and / or on other supports mixed with gold-containing supports. Examples of such catalysts include one or more metals such as silver, palladium, platinum, rhodium, ruthenium, osmium, copper, iridium or the like. If used, they may be co-deposited onto a support from a target source that is the same or different from the target gold source. Alternatively, such catalysts may be supported on the support either before or after the gold is deposited. Other catalysts requiring heat treatment for activation may advantageously be supported and heat treated prior to gold deposition.

During the implementation of the invention, catalytically active gold is deposited on one or more nanoporous supports, thereby forming a heterogeneous catalytic system. Nanoporous means that the total volume of nanopores for pores between 1 and 10 nm is above 20% (i.e., above about 0.20, using the formula below) of the total pore volume of the carrier material in the range from 1 to 100 nm, as calculated, using the following formula

NPC =

CPV₁ - CPv₁₀^CPVand ^{- CPV}100

NPC - volume of nanopores

CPV_n - the total pore volume for the pore radius 'n' (MM³/_G) x10^-3 n - pore radius (in nanometers).

Data for calculating the volume of nanopores by the above method can be obtained using the technique described in ASTM Standard Practice D 4641-49, in which nitrogen desorption isotherms are used to calculate the pore size distribution of catalysts and catalyst supports in the range from about

1.5 to 100 nm. Alternatively, nanopores can be observed and their size can also be measured by transmission electron microscopy (TEM), so that relevant data can also be obtained by TEM.

Nanoporous support properties help to immobilize gold clusters on the support surface. This stabilization of very small gold particles and clusters has been proven both as a result of direct observation of smaller gold particles in TEM studies of materials with nanoporous surfaces, and in increasing the catalytic activity that was measured as the catalyst's ability to convert CO to CO₂ in the presence of air.

Nanoporous support properties help to immobilize gold clusters on the support surface. This stabilization of very small gold particles and clusters has been proven both as a result of direct observation of smaller gold particles in TEM studies of materials with nanoporous surfaces, and in increasing the catalytic activity that was measured as the catalyst's ability to convert CO to CO₂ in the presence of air. Nanoporous substrate particles may optionally additionally have microporous, mesoporous and / or macroporous properties, which are defined in the relevant IUPAC Compendium of Chemical Technology standards, 2nd edition (1997). A typical population of activated carbon or alumina support particles will often contain a combination of nanoporous, microporous, mesoporous and macroporous properties.

It should be noted that the support materials need only be nanoporous in the outer surface area of ​​the support, to a depth equal to or greater than the depth of penetration of the gold atoms according to the invention. Thus, the invention includes methods by which non-nanoporous materials normally having a small specific surface area can be transformed to have external surfaces characterized by nanoporosity. These methods include the adsorption of nanoporous materials, such as gels and colloidal systems with nanoparticle dimensions on the surface of the material to form the nanoporous material; hydrolysis of metal alkoxides or metal salts on the surface of the material to form nanoporous materials; and oxidizing a thin coating of metal, such as, e.g., aluminum, titanium, tin, antimony or the like, on the surface of the material to form a nanoporous material. In the second case, thin metal films can be deposited by physical vapor deposition, while oxidation can be carried out with dry or moist air to form a film of nanoparticles on the substrate.

For the hydrolysis of metal alkoxides, as exemplified herein, water hydrolysis in gaseous form is generally more effective in the production of active nanoporous films than hydrolysis in liquid form or aqueous solutions.

The support is made by adsorbing or adhering fine (less than 100 microns, preferably less than 50 microns, and most preferably less than 10 microns) nanoporous particles on coarse (over 30 mesh) particles. Such a "small particle on a larger particle" composite structure provides a significant increase in total external specific surface area while maintaining the desired gas permeability properties, ie, a small pressure drop across larger particles. In addition, by using nanoporous, smaller particles in the construction of such composite particles, cheap, non-porous, coarse particles can be used. In this way, very cheap, highly active catalyst particles can be produced, because the basis of the volume of the catalyst bed are cheap, coarse particles constituting the substrate. Examples of nanoporous small particles that can be used in this way include small sol-gel particles and airgel particles with a high specific surface area.

When constructing composite carrier particles, small particles can be adhered to larger particles using partially hydrolyzed alcoholate solutions, basic metal salt solutions or colloidal metal oxides and nanopartic oxyhydroxides as adhesive. Partially hydrolyzed alkoxide solutions are prepared by a method well known in the art for the sol-gel method. Useful metal alkoxides include alkoxides of titanium, aluminum, silicon, tin, vanadium and admixtures of these alkoxides. Basic metal salts include titanium and aluminum nitrate and carboxylate. Colloidal materials with nanoparticle dimensions include colloidal systems of aluminum, titanium oxides and oxyhydroxides as well as silicon, tin and vanadium oxides. The adhesive is in the form of a solution and is generally contained in an amount of from 2 to about 50% by weight of the oxide of the nanoporous material with small particle sizes to be glued.

To construct composite carrier particles, generally one of two preferred methods can be used. In one method, nanoporous material with small particle sizes is mixed with the selected adhesive in solution, after which the resulting mixture is combined with coarse particles. If the coarse particle is porous, a mixture of small particles and adhesive solution may be introduced by initially wetting the porous larger particles. If the larger particle is not porous, then the mixture of small particles and adhesive solution may be admixed to coarse particles and the liquid solution may be removed during mixing or after mixing. In any case, after combining a nanoporous material with small particles, with an adhesive agent and coarse particles, and after removing the liquid from the solution, the mixture is dried and roasted to form a composite particle containing smaller, nanoporous particles adhered to the surface of a larger particle. The roasting temperature is selected so that it is lower than the temperature at which nanoporous particles lose porosity. Generally, the roasting temperature will be between 200 ° C and 800 ° C.

In addition to nanoporosity, the carriers of the invention preferably have one or more additional properties. For example, preferred carrier solutions are characterized by multiphase e.g. biphasic surfaces. A multiphase surface means that the surface has more than one phase. The data obtained indicates that the catalytic activity increases when gold is deposited on a multiphase surface. Without wishing to be bound by theory, it is assumed that the surface boundaries obtained help stabilize gold. TEM studies described herein and well known in the art can be used to assess whether a surface is biphasic. It is assumed that these phase boundaries are very finely dispersed at the nanoscale, helping to create effective border areas to immobilize gold.

Multiphase properties can be provided by treating the carrier with one or more activating agents. For example, Ba (NO₃)₂ is one type of activating agent that can be added to a support prior to gold deposition using solution saturation followed by calcination. Considering the solution in which barium nitrate is used as the activating agent for the carrier, which is gamma alumina, when the obtained materials are tested using X-ray diffraction, no separate barium phase is detected. Without wishing to be bound by theory, it is assumed that barium reacts on the surface of the support, which is alumina, thus modifying the surface. Consequently, it is assumed that the surface contains areas enriched in aluminum constituting one phase and an area enriched in bar constituting the second phase. Each phase has different properties and different affinity for gold. Thus, the phase boundaries, according to one view, perform a function in a way analogous to fencing, aimed at preventing gold migration and accumulation. Activating agents are further described below.

A wide variety of materials can serve as suitable carriers for carrying out the invention.

Representative examples include carbon materials, silica materials (such as silica), metal compounds such as metal oxides or sulfides, and combinations of the foregoing, etc. Representative metal oxides (or sulfides) include oxides (or sulfides) of one or more metals, such as magnesium, aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, strontium, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, cadmium, indium, iron, tin, antimony, barium, lanthanum, hafnium, thallium, tungsten, rhenium, osmium, iridium and platinum.

Examples of carbonaceous substances include activated carbon and graphite. Suitable types of activated carbon may be derived from a variety of sources, such as carbon, coconut, peat, any activated carbon (activated carbons) from any source (s), combinations of at least two such carbons and / or the like.

Preferred carrier solutions can be selected from alumina, titanium dioxide, titanium dioxide-alumina, activated carbon, double oxides such as hopcalite (CuMnO₂), molecular sieves and / or similar. Of these, alumina, titanium dioxide and activated carbon are particularly preferred support materials. Activated carbon, titanium dioxide and alumina occur in forms characterized by nanoporosity, and therefore these forms are preferred carrier materials. Activated carbon is beneficial because, in addition to being a carrier for catalytic activity, carbon also acts as an absorbent for harmful gases. Activated alumina is also a preferred support material because it is very resistant to aging and heat. Heterogeneous catalyst systems are preferably made of alumina-containing components as a carrier when the catalyst system will be used at elevated temperatures and / or a longer service life is desired.

Heterogeneous catalyst systems of the invention may optionally contain one or more activating agents to enhance the catalytic performance of the system. The term activating agent, as used herein, generally refers to any component that itself generally does not have catalytic properties but may increase the performance of the catalyst when the activating agent (s) and the catalyst are introduced into the system together.

One preferred class of activating agents of the invention includes one or more metal salts. Clearly, the use of such a metal salt enhances the catalytic effect, but the exact mechanism of such reinforcement is unknown. Not wanting to be bound by theory, it is assumed that the metal cation reacts with the surface of the support in a way that supports the immobilization of gold (e.g. by providing a multiphase surface) and / or that the metal cation acts as an electron acceptor or participates in a specific manner in the sequence of catalytic reactions.

Examples of metal salts include alkali or alkaline earth metal salts such as lithium, sodium, magnesium, calcium and / or barium. Other metals include Cs, Ru, etc. Combinations of any of the metal salts listed may be used. In some embodiments, the activating agent comprises at least one alkali metal salt and at least one alkaline earth metal salt, wherein the weight ratio of the alkali metal salt to the alkaline earth metal salt is from about 1:19 to about 19: 1, preferably from about 1 : 3 to about 3: 1. For example, the catalytic effect of a system comprising potassium and barium salts on nanoporous alumina as a support with gold as a catalyst is surprising as shown in the examples below. Briefly, this system catalytically oxidizes almost the entire CO content in a test stream containing 1500 ppm CO at ambient temperature for a longer period of time.

Metal salts may include any suitable counterion - anion (s). Examples include nitrate, hydroxide, acetate, carbonate, combinations of the mentioned anions, etc. Carbonate is a particularly preferred anion because it appears to have activating properties independently. Carbonate is even more effective when used in combination with an alkali metal or alkaline earth metal. Accordingly, preferred activating agents of the invention include carbonate, and more preferably, an alkali metal carbonate or alkaline earth metal carbonate.

Potassium carbonate is very effective, e.g. especially when used on activated carbon with gold as a catalyst, but is also effective in systems with other types of support, such as e.g. alumina. The fact that potassium carbonate activates the carbon-gold system is completely unexpected. First, gold deposition on K₂WHAT₃ without the presence of carbon or other nanoporous support, it provides a system with very little, if any, catalytic activity. In addition, gold deposition on activated carbon without K₂WHAT₃ also provides a system with very little, if any, catalytic activity. However, when these three components are combined, a very effective catalyst system is obtained, the results of which are shown in the examples below. Indeed, the discovery of such a simple and effective method of producing activated carbon as a support for catalytically active gold is a significant achievement. The advantages of using carbonate are highlighted by data showing that potassium sulfate is a weak activating agent, although it is assumed that its effect can be improved if the carrier saturated with potassium sulfate is subjected to thermal treatment before gold deposition.

Furthermore, potassium carbonate and many other salts mentioned here are very soluble in aqueous solution. Deposition of gold on the substrate by the PVD method makes it easy to obtain systems containing both gold and such activating materials. Water-soluble activators such as K₂WHAT₃, cannot be used in typical methods of saturation with aqueous solution or precipitation. This is because such activators could be dissolved in solutions and washed out of the carrier by aqueous solvents.

Another preferred class of activating agents includes alcoholates, especially those described above, due to the properties of forming nanoporous surfaces on less porous host particles. Preferred alcoholates include Ti and Al alcoholates. Alkoxide materials are preferably used in combination with one or more of the water-soluble salts described above. In the case where two types of materials are used together, they may be introduced into the carrier simultaneously or sequentially in any order, although it is preferred that the alcoholate (alcoholates) is introduced into the carrier after it has been saturated with salt (s). In a representative process, the water-soluble salt is introduced into the carrier, after which the carrier is dried and optionally calcined. Then, the alcoholate is introduced into the carrier, the product is hydrolysed, dried and possibly subjected to roasting. And gold is deposited on the activated substrate.

It turns out that the use of alkoxide as the impregnating agent / activating agent changes the crystal structure of the support in TEM studies. Specifically, the structure of the support grain near the support surface appears to be much finer than in the core area and much finer than in identical systems made without alkoxide. Structure modification in most cases reaches deeper into the support rather than gold, e.g. up to 50 nm or more. In some cases, the boundary between the modified surface area and the unmodified core area can be easily observed.

Not all alcoholates can work in all conditions. For example, Ti and Al alcoholates have been found to enhance catalytic performance when incorporated into catalyst systems as shown in the examples. However, by exchanging the mentioned alcoholates for the Zr alcoholate in these preparations, no increase in the ability of the system to oxidize CO was obtained.

Similarly, some water-soluble activating agents that are salts, especially such as sulfates, oxalates and phosphates, do not have an activating effect in some studies, although it is believed that roasting a saturated carrier may improve the effects of at least sulfates and oxalates. Without wishing to be bound by theory, it is assumed that those types of anions that tend to coordinate affect the surface charges of the carrier in a way that weakens the ability of the surface to immobilize gold. Furthermore, the sulphate and oxalate anions are easily degraded at reasonable roasting temperatures, which may explain why roasting is thought to enhance the activating properties of these materials.

Iron salts are also weak candidates for use as the only activating agent using PVD techniques for gold deposition. This is unexpected because iron salts are effective activators when gold is deposited on particles as a result of treatment with a solution. This indicates that components that readily work in one context, e.g., during solution treatment, may not work the same in another context, e.g., during PVD treatment.

Similarly, not all porous supports are easily activated under the same conditions that work for other supports.

The amount of activating agent used in a heterogeneous catalyst system can vary widely and will depend on various factors including the properties of the activating agent, the amount of gold to be introduced into the system, the properties of the support, etc. Generally, if too much little activating agent, you may not get the full potential benefits of using the activating agent. On the other hand, the use of an additional amount of activating agent above a certain point may not provide significant additional benefits, and may attenuate the catalytic effect to some extent. Accordingly, as indicated in the guidelines, representative embodiments of the invention may contain from 0.25 to 15, preferably from 1 to 5%, by weight of the activating agent based on the total weight of the activating agent and carrier. In the case where one or more water-soluble salts and one or more alkoxides are used in combination, the molar ratio of salt (salt) to alcoholate component (s) is from 1: 100 to 100: 1, preferably from 1: 5 to 5: 1.

The activating agent can be introduced into the heterogeneous catalyst system in a variety of ways. In some cases, the carrier to be used may as such contain a suitable activating agent. For example, activated carbon obtained from a coconut shell naturally contains potassium carbonate as an ingredient. This type of activated carbon is an excellent support for the gold catalyst, as it requires no additional activating ingredients.

The benefit of using activated carbon from coconut shells has been demonstrated, as well as the benefit of using potassium carbonate as the activating agent. Kuraray GC and Kuraray GG are both derived from coconut shells. Kuraray GG carbon is a naturally obtained carbon that contains potassium carbonate. Kuraray GC carbon is similar except that it was washed with acid and then rinsed thoroughly with water to remove potassium carbonate and other acids, and water-soluble ingredients. When gold is deposited on these two coals using the method

PVD, a system derived from Kuraray GG carbon (contains potassium carbonate) is a very good catalyst for CO oxidation, especially in wetter conditions. On the other hand, the system derived from Kuraray GC carbon (essentially without potassium carbonate) has low CO oxidation activity in a dry or humid environment. In addition, if Kuraray GG carbon is washed to remove the potassium salt, the catalytic functionality of the resulting system is significantly impaired. Catalytic activity can be recovered if the washed Kuraray GG carbon is saturated with the activating agent before gold deposition, especially if the saturated carbon will be subjected to thermal treatment (hereinafter described) before gold deposition.

TEM (transmission electron microscopy) examination of gold deposited on Kuraray GG carbon particles by physical vapor deposition showed the presence of nanoparticles and protodots both on the direct surface of the support and in the pores immediately adjacent to the support surface. As can be seen from transmission electron microscopy, gold is found in both nanoparticles and very small clusters. Gold particles were formed preferentially in small grooves and cracks like pores in coal, as evidenced by the orientation of gold particles in linear systems resembling necklace on the surface of carbon. A shaded image of the same area showed clearly streaked gold. The homogeneity of gold deposition can be clearly seen in TEM images. The gold clusters observed by the TEM method were as small as 1 nm or smaller and as large as about 5 nm. The gold-enriched grooves or striations had a width of about 7 nm and a length of about 50 to 100 nm. There were also gold-enriched domains containing extremely fine gold systems that would appear as if the veil of light areas in a dark field of the image. It is not known why these areas, although quite crystalline in nature, did not merge into single gold crystals.

Without being bound by theory, a possible explanation for potassium carbonate is that potassium carbonate provides places where water can adsorb. Indeed, in some cases gold catalysts have been found to be more active in the presence of moisture.

Unlike Kuraray GG carbon, many other desirable carriers do not naturally include an activating agent. Consequently, in some cases, it may be desirable to incorporate an activating agent containing one or more ingredients into the desired support. This can be done in any desired way. Impregnation of the first humidity is one suitable technique, and examples of the use of solution impregnation are described in the examples below. Briefly, the method of impregnating the first humidity involves slowly adding, with stirring, a solution containing the desired activating agent to the dry carrier particles. The solution is generally added until saturation and it is preferable to avoid the addition of excess solution. Typically, these are aqueous solutions and the concentration of each of the activating agents in the solution is generally from about 0.2 M to about 2.5 M. If more than one type of activating agent is to be added, they can be added together, separately or overlapped. After saturation, the particles are dried and possibly roasted (heat treatment).

Gold deposition is preferably carried out by PVD after saturation, drying and optionally roasting. Separation of saturation and gold deposition is clearly advantageous for many reasons. First, if gold is added to the particles by solution saturation, the types of activating agents that can be used will be limited. For example, HAuCl₄, i.e. gold particles commonly used in methods with a solution due to its relatively low cost, is very acidic, which makes it incompatible with activating alkaline agents, such as preferred alkali and alkaline earth metal salts. In cases where basic gold particles are used, saturation with an aqueous solution may tend to elute some of the desired activating ions. Thus, the subsequent deposition of gold by PVD (no-solution process) separated from saturation with activating agents is a significant process feature that allows much easier use of gold in combination with these highly effective activating agents. An additional benefit of this method is that gold can be deposited on the support with the activating agent already in place. It is believed that this is one of the reasons why the gold deposited according to the invention is as active as gold deposited without requiring subsequent heat treatment.

However, heat treatment (roasting) of the activated support prior to gold deposition can be very beneficial.

In some cases, the activating agent may not function as desired before roasting. For example, roasting provides clear improvements when the activating agent is nitrate. In other cases, the effect of an effective activating agent would be further enhanced. For example, the action of generally effective carbonates can be enhanced to some extent by roasting. In addition, salts such as potassium carbonate tend to already exist in active form after saturation, and the resulting activated carriers are preferably dried, e.g. at a temperature of up to about 200 ° C, with no real need for roasting.

Generally, the heat treatment involves heating the saturated support at a temperature in the range of 125 ° C to about 1000 ° C for a period of time in the range of 1 second to 40 hours, preferably 1 minute to 6 hours, in any suitable atmosphere, such as air; an inert atmosphere such as nitrogen; carbon dioxide; argon; or a reducing atmosphere such as hydrogen; e.t.c. The particular thermal conditions used will depend on factors including the properties of the support and the properties of the impregnating agent (s). Generally, the heat treatment should be at a temperature lower than that at which the ingredients of the saturated carrier may decompose, degrade or otherwise undesirably heat. The following examples describe many saturated media roasting operations.

Although the activating agent can be provided as a salt or similar compound, the resulting salt form or ionic components thereof after introduction into the heterogeneous catalyst system is not known with certainty. X-ray diffraction analysis does not clearly indicate a metal oxide or carbonate phase, although some carbonate is shown per se. Therefore, it is assumed that the metal ions have reacted and modified the surface of the support.

The catalysts of the invention can be used in a wide range. It is believed that these catalysts will find application in the field of automotive exhaust gas treatment, catalyzed hydrogenation, as hydrocarbon oxidation catalysts and as catalysts for the removal of nitrogen oxides, and in sensors for detecting and determining gases and vapors, and for removing CO from residential areas. In respiratory protection devices, such as anti-smoke masks or engine gas masks, the catalysts of the invention may preferably be used to remove hazardous CO or other gases from breathing air.

The invention will now be described in more detail in the following illustrative examples.

Test method 1: CO conversion test procedure

Fig. 4 shows the test system 50 used for the subject samples for testing CO transformations to assess the catalytic properties of the CO oxidation reaction. The compressed air pressure from the supply line 52 decreases, regulates and filters through the regulator 54 (3M

Model W-2806 Air Filtration and Regulation Panel, 3M Company, St. Paul, MN) to remove solids and oils. The regulator is set to obtain an inlet pressure between 40 and 60 psi. Valve 56 (Hoke Inc., Spartanburg, SC) is used to set the desired main air flow rate measured by flow meter 58 (Gilmont®, Barnant Co, Barrington, IL) in the range of 0 to 77 liters per minute. The flow meter 58 was calibrated using a Gilibrator® bubble flow meter (Sensidyne, Inc., Clearwater, FL; not shown). Unless otherwise indicated, 64 liters per minute air flow rates were used in all catalyst tests.

The main air flow passes through the upper space 60 above the heated distilled water bath 62 in vessel 64 and then passes through lines 57 and 75 to a 1000 ml flask with mixing 66. Relative humidity in the flask with mixing is monitored using a sensor RH 68 (Type 850252, General Eastern, Wilmington, MA). The RH 68 sensor provides an electrical signal to the humidity controller 70 (Omega Engineering PID controller series CN1200 from Omega Engineering Inc., Stamford, CT), which supplies energy through wire 71 to the submerged heater 72 to maintain the RH humidity at a set level. Unless otherwise indicated, relative humidity is regulated at 85%.

A carbon monoxide cylinder 74 provided with a regulator 76 suitable for handling CO provides an adjustable CO gas flow through line 73. A very fine stainless steel 78 metering valve (Swagelok Co, Solon, OH) is used to set the desired CO flow rate. Unless otherwise indicated, a CO flow rate of 96 ml / minute is used to achieve a CO concentration of 1500 ppm in the air stream. The measured amount of CO is combined with the humidified air in the flask with mixing 66.

The combined stream then flows to the test chamber 80 with the box 81 as inverted, 13 quart stainless steel bucket tightly engaging the support pedestal 83. Inside the test chamber 80 there is a fixed test element 82. The test chamber 80 is sealed with the support pedestal 83 using foam seal (not shown). Two clamps (not shown) provide an accurate seal to support pedestal 83. The box 81 can be removed, allowing the catalyst elements to be placed inside to be tested and removed after the test. Support pedestal 83 is provided with an internally converging fitting 29/42 (not shown) on which the element 82 containing the catalyst to be tested is attached.

CO and CO concentrations₂ and dew point temperature are measured at the outlet of the test chamber using a Bruel & Kjaer Multi-gas Monitor Type 1302 sensor (Bruel & Kjaer, Naerum, Denmark; not shown) equipped with optical filters # 982 for CO detection₂ and # 984 for CO detection. Multi-gas Monitor was calibrated using 10,000 ppm CO gas standards₂ and 3000 ppm CO, according to the procedure recommended by the manufacturers. Data from the Multi-gas Monitor comes to a data collection device, such as a chart recorder or laptop PC with Hyperterminal Software (Hilgraeve, Monroe, MI). The text files are delivered to the Mikrosoft® Excel software (Mikrosoft Corp., Redmond, WA) for data analysis. Before starting, the test system 50 is allowed to equilibrate to a constant nominal concentration of 1500 ppm CO. The variation in initial CO concentration was ± 5% for samples tested at 1500 ppm and ± 3% for samples tested at 3600 ppm CO. The air flow temperature is monitored in the direction behind the fixed test element using a K-type thermocouple (not shown) and a digital readout (not shown) (Fluke 51 K / J Thermometer, Fluke Corporation, Everett, WA).

Before the test, the catalyst samples are sieved to remove small parts. Unless otherwise specified, samples were screened to remove particles smaller than 20 mesh, using standard US sieves (ASTM E-11 specification; The Murdock Co., Mundelein, IL). A specified volume of catalyst, typically 100 ml, is introduced into the aluminum solid test element 82 with an internal diameter of 8.9 cm (3.5 inches) and provided with an external 29/42 tapered fit using a delivery column (as described in British Application 606876 with one modification, i.e. removal of the upward cone). Typical bed depth is approximately 1.6 cm (0.6 inches). The screens mounted inside the solid test element 82 prevent loss of catalyst particles during the test. When the measured CO concentration stabilizes, the pipe 85 carrying the air / CO mixture is disconnected from the top of the test chamber 80 via a conical fit (not shown), the box 81 is removed and the solid test element 82 containing the catalyst is placed on the fit 29/42 on base pedestal 81. The box 81 is replaced and sealed to the support pedestal 83. Measurements of CO and CO concentration₂ begins when the air / CO 85 transfer tube is attached to the tapered component on the top of test chamber 80. Measurements are continued for a specified period of time, typically 30 minutes.

For tests carried out at 64 liters per minute and 3600 ppm CO, valve 78 has been replaced with a more accurate metering double stainless steel valve (Swagelok Co., Solon, OH) to allow adjustment at higher CO flow rates.

Test method 2: Chromatographic test procedure and apparatus

Fig. 5 shows the system 100 used for the chromatographic analysis of the catalytic properties of the samples. System 100 includes a tank 102 with a high CO pressure in the air (1.9% by volume) and also coupled to a source 104 of increasingly compressed air supplied through line 106. A pressure regulator and shut-off valve 101 and a fine-needle valve 103 help regulate CO flow in the air through the line 105. The flow of CO in the air is measured by a rotameter 107 (Alphagaz (Air Liquide) 3502 flow tube, Morrisville, PA).

The flow of increasing compressed air through line 106 has a reduced pressure, is subject to regulation and filtration in a 110 regulator (3M Model W-2806 Air Filtration and Regulation Panel, 3M Company, St. Paul, MN). The regulator is set to obtain an inlet pressure between 40 and 60 psi. Fine needle valve 112 is used to set the desired air flow rate through line 106.

The streams of CO in the air with increasing compressed air combine at 108, giving a mixture of CO in the air at the desired concentration of the flow rate.

Rotameter 114 (Aalborg Instruments 112-02 flowtube,

Orangeburg, NY) on line 116 measures the total flow of combined streams. Rotameters are calibrated using a Gilibrator® bubble flow meter (not shown) located at the catalyst bed (no catalyst). The two rotameters 107 and 114 were selected to obtain concentrations from about 1000 to 20,000 ppm CO at flow rates from about 100 ml / minute to about 500 ml / minute under laboratory ambient conditions.

The diluted CO mixture in the air in line 116 is then humidified to the desired RH value by passing the air mixture or through the inner tube pipe in the shell of the Nafion® 118 dryer as shown (Perma Pure MD 110-12P; Toms River, New Jersey) working as a humidifier or by passing the air mixture through a pressure vessel containing water (not shown). Moist air is introduced into dryer 118 through line 120 and exits through line 122. In this latter embodiment, an RH of about 70% was obtained at a flow rate of 200 ml / minute. Moist air is passed through the dryer casing to moisten dry CO in a stream of air flowing through the inner tube. Humid air is obtained by bubbling compressed air through a glass frit into a water flask, maintained at a controlled temperature in a cooled water bath. If a lower RH is desired, the bath water temperature is lowered until the CO mixture in the air reaches the desired RH. This is measured using a General Eastern Hygro-M1 refrigerated dew point hygrometer (GE General Eastern Instruments, Wilmington MA). The air at room temperature saturated with water vapor, with a flow of about 3 l / min through the dryer cover moistens the CO / air stream at a flow of 100 ml / minute to> 90% RH.

A sample of the catalyst (usually about 1-2 cm deep) is made into flakes in a thick-walled polyethylene pipe 124 with an internal diameter of 4 mm and a length of about 8 cm to form a catalyst bed 125. A cotton plug 127 seals one end of the pipe 124. The CO mixture in the air passes through the catalyst bed and then through the 126 particle filter cartridge ((Balston DFU sample filter grade BQ, Parker Hannifin Corporation, Tewksbury, MA)) to the gas chromatograph 128 gas sampling valve (SRI model 8610C gas chromatograph with gas sampling valve and thermal conductivity and helium ionization detectors, Torrance, CA). The filter particles 126 protect the GC valve from being destroyed by particles leaving the catalyst bed.

The gas sampling valve periodically injects the outgoing stream from the catalyst bed into a 5-foot 5 L molecular sieve column. This causes separation

CO from air. The CO concentration is determined either using a thermal conductivity detector (CO detection limit around 500 ppm) or a helium ionization detector (CO detection limit <10 ppm). CO concentration is measured approximately every four minutes during the test, displayed and recorded data file.

These detectors are calibrated by diluting a known Scott certified CO stream (99.3%) with a known air stream to obtain a known CO concentration (flow calibration: Sensidyne Gilibrator flow calibrator, Clearwater, FL). Based on this data, a calibration curve is obtained.

Gold deposition method: Method of depositing gold nanoparticles on substrate particles:

The apparatus described in detail and shown in Figs. 2 and 3 is used to prepare catalytic substances according to the following procedure, unless explicitly indicated otherwise. 300 cm³ the substrate particles are first heated to about 200 ° C in air overnight (120 ° C for carbon substrates) to remove residual water. They are then placed when they are hot in the particle mixing apparatus 10 and the chamber 14 is evacuated. As soon as the chamber pressure reaches 10^-5 rail, argon is supplied to the chamber 14 as sputtering gas at a pressure of about 10 millitres. Then the process of gold deposition begins by applying 0.03 kilowatts to the cathode. During the gold deposition process, the shaft of the particle mixer 40 rotates at a rate of about 4 revolutions per minute. The energy supply stops after minutes. The chamber 14 is refilled with air and the gold-coated particles are removed from the apparatus 10. The gold sputter 32 is weighed before and after coating to determine the amount of gold deposited. For carbon particles, the amount of gold deposited, determined by elemental plasma ion source analysis, on the treated carbon particles was 0.05% by weight.

During the deposition process, the gap between the blades 42 and the chamber wall was maintained at 1.7 mm (deposition condition 1) or 2.7 mm (deposition condition 2).

Preparation of alumina gamma particles:

Deionized water at room temperature (2600 ml), 48g 16 N nitric acid (dda) and 800 g powdered alpha alumina monohydrate sold under the trade name DISPERAL was placed in a 18.9 liter polyethylene lined steel vessel. The batch was dispersed at high speed for five minutes using a Gifford-Wood Homogenizer Mixer (Greeco Corp., Hydson, NH). The resulting sol was poured into an aluminum tray lined with polyester 46 cm X 66 cm X 5 cm, in which it was dried in an oven with air at 100 ° C to a brittle solid.

The resulting dried substance was crushed using a "Braun" UD pulverizing apparatus having a 1.1 mm gap between the steel plates. The crushed substance was sieved and a 0.125 mm to about 1 mm screen material was retained and introduced at the end of the roasting apparatus, which was a 23 cm diameter stainless steel pipe with a length of 4.3 meters, having a 2.9 meter hot zone, the tube was inclined by 2.4 degrees to the horizontal and rotated at 7 rpm, providing a residence time of about 15-20 minutes. The roasting apparatus had a hot zone feed temperature of around 350 ° C and an outlet temperature of around 800 ° C. The gas above the alumina particles at the hot end of the roasting apparatus was measured at about 380 ° C during roasting. The pre-fired material was then screened to a size above 20 mesh but below 16 mesh using standard USA screens (ASTM B-11 specification; The Murdock Co., Mundelein, IL). The fraction with this dimension was designated as "A" alumina particles. An additional sample of pre-fired material was sieved to a size above about 20 mesh but below 14 mesh, using standard US sieves (ASTM B-11 specification; The Murdock Co., Mundelein, IL). Samples with a particle size of 14 to 20 mesh were designated as "B" alumina particles. These materials were used to prepare the following catalyst supports.

Example 1 (references). Type A gamma alumina particles:

Type A gamma alumina particles were treated with gold by plasma spraying as previously described using the deposition condition 2. The performance of the CO oxidation catalyst of Example 1 in CO oxidation during gas flow through a bed was measured using test method 1. The CO conversion was 3600 ppm CO and total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Figure 6.

Fig. 6 and other similar graphs in these examples show the measured gas concentrations in ppm versus testing time after passing the test gas mixture through a 100 ml test bed. The elapsed time is specified in minutes: seconds: tenths of a second.

Example 2 (references). Unmodified B-type gamma alumina particles:

Type B gamma alumina particles were treated with gold by plasma spraying as described previously using the deposition condition 2. The performance of the catalyst for the CO oxidation reaction according to example 2 in the oxidation of CO during gas flow through the bed was measured using test method 1. The CO conversion was 3600 ppm CO and total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Figure 7.

Saturation of gamma alumina particles:

A saturation liquid solution was prepared by mixing a sufficiently soluble saturating metal salt with deionized water in an amount sufficient to make a solution of the desired concentration. For example, to prepare a 0.5 M potassium carbonate solution (FW = 138.21 g / mol), 69.11 g of potassium carbonate were dissolved in sufficient deionized water to give a final volume of 1 liter.

The particles were saturated by the method of impregnation of the first humidity. The technique of impregnating the first humidity is to slowly add the saturation solution to the dry gamma alumina particles, while mixing the particles with a spatula or spatula, until the pores of the gamma alumina particles are completely saturated with the solution by introducing the solution into the pores of the gamma alumina particles. An excess of saturation solution is avoided, as demonstrated by visual observation, of the liquid phase on or between the particles. When the particles are completely saturated, they are dried in an oven with forced air flow at 130 ° C and subjected to roasting as described for each sample.

Example 3 (references). Preparation of gamma alumina particles saturated with potassium carbonate - sample heated to 130 ° C:

710 g of gamma alumina A particles (volume - 950 ml of gamma alumina particles) were saturated by impregnation with the first humidity using 0.5M solution K₂WHAT₃(Merck KgaA, Darmstadt, Germany). After adding 469 ml 0.5 MK₂WHAT₃ full saturation achieved. As a result, about 2.5% by weight of potassium is present in the catalyst support after drying. The particles were dried at 130 ° C and a portion of 300 ml of this sample was treated with gold (deposition condition 2).

The weight percentage of gold on this sample was determined by Inductively Coupled Argon Plasma Spectroscopic Analysis (ICP). The results for the replicated samples were 0.0486% by weight of gold and 0.0521% by weight of gold.

The sample of Example 3 was examined by TEM as previously described. The approximate size range of Au particles in the wavelength area, which turned out to be representative of the sample, was 2.1 to 6.6 nm. The average Au particle size in this area was 3.0 nm and the approximate depth range in the substrate was 38 to 60 mm. In the flat region of the sample, the approximate size range of Au particles was 2.4 to 11.4 nm. The average size of Au particles in this region was 8.6 nm and it was found that the gold particles were completely on the particle surface and low penetration was observed.

The performance of the catalyst of example 3 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Figure 8. These results illustrate the better catalytic properties of the support modified with a potassium source.

Example 4 (references). Preparation of potassium carbonate saturated gamma alumina particles - sample heated to 300 ° C:

300 ml of the dried sample of example 3 was calcined to 300 ° C by heating in air in a chest furnace and the sample was kept at 300 ° C for 1 hour. After cooling, this calcined sample was treated with gold (deposition condition 2).

The performance of the catalyst of example 4 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Figure 9.

Example 5 (references). Preparation of potassium carbonate saturated gamma alumina particles - sample heated to 600 ° C:

300 ml of the dried sample of example 3 was calcined to 600 ° C by heating in air in a chest furnace and the sample was kept at 600 ° C for 1 hour. After cooling, this calcined sample was treated with gold (deposition condition 2).

The performance of the catalyst of example 5 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Figure 10.

Example 6 (references). Preparation of potassium carbonate saturated gamma alumina particles - influence of potassium carbonate content:

A potassium carbonate solution was prepared by dissolution

6.91 g K₂WHAT₃ ((Merck KGAA, Darmstadt, Germany)) in deionized water sufficient to reach a volume of 200 ml. A sample of gamma alumina B particles (particle volume 300 ml, 224.14 g) was impregnated by the first humidity impregnation method, using about 150 ml 0.4 MK₂SO₄. After saturation, the particles were dried in an oven at 130 ° C. After drying, the saturated particles were treated with gold by plasma spraying (deposition condition 2)

The performance of the catalyst of example 6 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 3600 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Figure 11.

Example 7 (references). Preparation of potassium carbonate saturated gamma alumina particles - influence of potassium carbonate content:

Saturated potassium carbonate particles of gamma alumina were prepared and tested exactly as described in Example 6, except that instead of 13.82 g of potassium carbonate

6.91 g potassium carbonate. The test results are shown in Figure 12.

Examples 8 (references). Preparation of potassium carbonate saturated gamma alumina particles - influence of potassium carbonate content:

Saturated potassium carbonate particles of gamma alumina were prepared and tested exactly as described in Example 6, except that instead of 20.72 g of potassium carbonate,

6.91 g potassium carbonate. The test results are shown in Figure 13.

Example 9 (references). Preparation of ammonium carbonate saturated gamma alumina particles:

A 0.5 M ammonium carbonate solution (Fisher Scientific Co., Fair Lawn, NJ) was prepared by dissolving 11.41 g of ammonium carbonate hydrate in deionized water in an amount sufficient to reach a volume of 200 ml. A sample of gamma alumina A particles (particle volume 300 ml, 224.14 g sample) was impregnated by impregnation of the first humidity, using about

150 ml 0.5 M ammonium carbonate solution. After saturation, the particles were dried in an oven at 100 ° C. After drying, the saturated particles were treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 9 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Figure 14.

Example 10 (references). Preparation of potassium hydroxide saturated gamma alumina particles:

A 0.4 M potassium hydroxide solution was prepared by dissolving 4.49 g KOH (Merck KgaA, Darmstadt, Germany) in deionized water sufficient to reach a volume of 200 ml. A sample of gamma alumina A particles (particle volume 300 ml, 224.14 g) was impregnated by first humidity impregnation using about 150 ml 0.4 M KOH. After saturation, the particles were dried in an oven at 100 ° C. After drying, saturated treatment with gold by plasma sputtering deposition 2).

The performance of the catalyst of example 10 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Figure 15.

condition particles

Example 11 (references). Preparation of gamma alumina particles saturated with potassium acetate:

A 0.4 M potassium acetate solution was prepared by dissolving 7.85 g KCH₃ABOUT₂ (Fisher Scientific Co., Fair Lawn, NJ) in deionized water sufficient to give a volume of 200 ml. A sample of gamma alumina A particles (300 ml particle size, 224.14 g) was impregnated by the first humidity impregnation method, using about 150 ml 0.4 M KCH₃ABOUT₂. After saturation, the particles were dried in an oven at 100 ° C. After drying, saturated treatment with gold by plasma sputtering deposition 2).

The performance of the catalyst of example 11 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Figure 16.

Example 12 (references). Preparation of gamma alumina saturated potassium sulfate particles:

A potassium sulfate solution was prepared by dissolving 13.94 g K₂SO₄ (JT Baker Chemical Co., Phillipsburg, NJ) in deionized water sufficient to reach a volume of 200 ml. A sample of gamma alumina A particles (particle volume 300 ml, 224.14 g) was impregnated by the first moisture impregnation method, using about 150 ml 0.4 MK₂SO₄. After saturation, the particles were dried in an oven in particles condition at 100 ° C.

After drying, the saturated particles were treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 12 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Figure 17.

Example 13 (references). Preparation of gamma alumina particles saturated with potassium oxalate:

A potassium oxalate solution was prepared by dissolving 14.74 g K₂C₂ABOUT₄ (Mallinkrodt Chemical Works, St. Louis, Mo.) In deionized water sufficient to reach a volume of 200 ml. A sample of gamma alumina A particles (particle volume 300 ml, 224.14 g) was impregnated by first moisture impregnation using approximately 150 ml 0.4 MK₂C₂ABOUT₄. After saturation, the particles were dried in an oven at 100 ° C. After drying, saturated treatment with gold by plasma sputtering deposition 2).

The performance of the catalyst of example 13 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Figure 18.

Example 14 (references). Preparation of potassium phosphate saturated gamma alumina particles:

condition particles

A potassium phosphate solution was prepared by dissolving 13.93 g K₂HPO₄. (Aldrich Chemical Co., Milwaukee, WI) in deionized water sufficient to reach a volume of 200 ml. A sample of gamma alumina A particles (particle volume 300 ml, 224.14 g) was impregnated by first moisture impregnation using approximately 150 ml 0.4 MK₂HPO₄. After saturation, the particles were dried in an oven at 100 ° C. After drying, the saturated particles were treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 14 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Figure 19.

Example 15 (references). Preparation of barium-saturated gamma alumina particles - dried at 130 ° C:

The first moisture impregnation technique was used to saturate Type A gamma alumina particles using a 0.4 M barium nitrate solution (ACS certified, Fisher Scientific Co., Fair Lawn, NJ) as the loading solution. Such saturation requires the use of 224.1 g of gamma alumina in 148 ml of a solution prepared by dissolving 20.9 g of barium nitrate in deionized water to obtain a final volume of 200 ml. After drying at 130 ° C, the sample was treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 15 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 20.

Example 16 (references). Preparation of barium-saturated gamma alumina particles - roasting to 300 ° C:

The first humidity impregnation technique was used to saturate the A-type gamma alumina particles using a 0.4 M barium nitrate solution (ACS certified, Fisher Scientific Co., Fair Lawn, NJ) as a loading solution, exactly as described in Example 12. After drying at 130 ° C, some of the sample was calcined to 300 ° C and kept at 300 ° C for 1 hour before cooling in the oven. After cooling, the sample was treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 16 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Figure 21.

Example 17 (references). Preparation of barium-saturated gamma alumina particles - roasting to 600 ° C:

The first humidity impregnation technique was used to saturate A-type gamma alumina particles using

0.4 M barium nitrate solution (with ACS certification,

Fisher

Scientific Co., Fair Lawn, NJ) as a loading solution exactly as described in Example 12. After drying at 130 ° C, part of the sample was calcined to 600 ° C and kept at 600 ° C for one hour. After cooling, the sample was treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 17 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Figure 22.

Comparison of the results of example 17 with the results of example 16 and example 15 shows that the activating effect of barium nitrate is strongly manifested after heating the saturated support to a temperature of 600 ° C.

Example 18 (references). Manufacture of potassium carbonate treated - barium-saturated gamma alumina particles - roasting to 600 ° C:

The first humidity impregnation technique was used to saturate the A-type gamma alumina particles using a 0.4 M barium nitrate solution (ACS certified, Fisher Scientific Co., Fair Lawn, NJ) as a loading solution exactly as described in Example 12. After drying at 130 ° C, part of the sample calcined to 600 ° C and kept at 600 ° C for one hour. After cooling, this sample was saturated with 0.5 MK₂WHAT₃ method of impregnation of the first humidity. The sample was dried at 130 ° C and treated with gold according to deposition condition 2.

The performance of the catalyst of example 18 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 23.

Comparison of the results of testing the material of example 18 with the results of testing the material of example 17 indicates that an improvement in catalytic performance can be achieved using a combination of activating agents.

Example 19 (references). Preparation of magnesium saturated gamma alumina particles - dried at 130 ° C:

The first humidity impregnation technique was used to saturate A-type gamma alumina particles with a 0.4 M magnesium nitrate hexahydrate solution (Alfa Aesar, Ward Hill; MA). A saturation solution was prepared by dissolving 20.51 g of magnesium nitrate hexahydrate in deionized water to obtain a final volume of 200 ml. 148 ml of this solution was used to saturate 224.14 g alumina particles. After drying at 130 ° C, the sample was treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 19 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 24.

Example 20 (references). Preparation of magnesium saturated gamma alumina particles - roasting to temperature

300 ° C:

The first humidity impregnation technique was used to saturate Type A gamma alumina particles with a 0.4 M magnesium nitrate solution (Alfa Aesar, Ward Hill, MA) as described in Example 16. After drying at 130 ° C, part of the sample was calcined to 300 ° C and held at 300 ° C for 1 hour before cooling in the oven. After cooling, the sample was treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 20 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Figure 25.

Example 21 (references). Preparation of magnesium saturated gamma alumina particles - roasting to temperature

600 ° C:

The first humidity impregnation technique was used to saturate Type A gamma alumina particles with a 0.4 M magnesium nitrate solution (Alfa Aesar, Ward Hill, MA) as described in Example 16. After drying at 130 ° C, part of the sample was calcined to 600 ° C and held at 600 ° C for one hour. After cooling, the sample was treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 21 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Figure 26.

Comparison of the results of example 21 with the results of example 20 and example 19 show that the activating effect of magnesium nitrate is strongly manifested after heating the saturated support to a temperature of 600 ° C.

Example 22 (references). Preparation of calcium saturated gamma alumina particles - dried at 130 ° C:

The first humidity impregnation technique was used to saturate A-type gamma alumina particles with a 0.4 M calcium nitrate solution. To prepare a loading solution, 18.89 g of calcium nitrate tetrahydrate (BAKER ANALYSED®, JT Baker, Co., Phillipsburg, NJ) was dissolved in deionized water to give a volume of 200 ml. 148 ml of this solution was used to saturate 224.14 g of gamma alumina particles. After drying at 130 ° C, the sample was treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 22 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Figure 27.

Example 23 (references). Preparation of calcium saturated gamma alumina particles - roasting to 300 ° C:

The first humidity impregnation technique was used to saturate Type A gamma alumina particles with a 0.4 M calcium nitrate solution (calcium nitrate tetrahydrate, BAKER ANALYSED®, JT Baker, Co., Phillipsburg, NJ) as described in Example 19. After drying in at 130 ° C, part of the sample was calcined to 300 ° C and kept at 300 ° C for 1 hour before cooling in the oven. After cooling, the sample was treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 23 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 28.

Example 24 (references). Preparation of calcium-saturated gamma alumina particles - roasting to 600 ° C:

The first humidity impregnation technique was used to saturate A-type gamma alumina particles with a 0.4 M calcium nitrate solution (calcium nitrate tetrahydrate,

BAKER ANALYSED®, JT Baker, Co., Phillipsburg, NJ) as described in Example 19. After drying at 130 ° C, part of the sample was calcined to 600 ° C and kept at 600 ° C for one hour. After cooling, the sample was treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 24 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 29.

Comparison of the results of example 24 with the results of example 23 and example 22 shows that the activating effect of calcium nitrate is manifested after heating the saturated support to a temperature of 600 ° C.

Example 25 (references). Manufacture of potassium carbonate treated - calcium saturated gamma alumina particles - calcining to 600 ° C:

The first humidity impregnation technique was used to saturate A-type gamma alumina particles with a 0.4 M calcium nitrate solution (calcium nitrate tetrahydrate,

BAKER ANALYSED®, JT Baker, Co., Phillipsburg, NJ) as described in Example 19. After drying at 130 ° C, part of the sample was calcined to 600 ° C and kept at 600 ° C for one hour. After cooling, the sample was saturated by first humidity impregnation using a 0.5 M potassium carbonate solution. The resulting particles treated with calcium and potassium were dried at 135 ° C overnight and treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 25 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 30.

Example 26 (references). Preparation of iron-saturated gamma alumina particles:

The first humidity impregnation technique was used to saturate A-type gamma alumina particles using a 0.4 M solution of iron nitrate nonahydrate. To produce iron nitrate solution, 32.32 g Fe (NO₃)₃ 9H₂O (ACS certified, Fisher Scientific Co., Fair Lawn, NJ) was dissolved in deionized water to give a final volume of 200 ml. 224.14 g of gamma alumina A particles were saturated with iron nitrate solution. After drying at 130 ° C, the sample was calcined to 600 ° C and kept at 600 ° C for 1 hour. After calcining, the saturated particles were treated with gold by sputtering (deposition condition 2).

The performance of the catalyst of example 26 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 31.

Example 27 (references). Preparation of manganese saturated gamma alumina particles:

The first moisture impregnation technique was used to saturate Type A gamma alumina particles with 148 ml of a 50% manganese nitrate solution (Fisher Scientific Co., Fair Lawn, NJ). 224.14 g of gamma alumina A particles were saturated with manganese nitrate solution. After drying at 130 ° C, the sample was calcined to 600 ° C and kept at 600 ° C for 1 hour. After calcining, the saturated particles were treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 27 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 32.

Example 28 (references). Preparation of cobalt-saturated gamma alumina particles:

The first humidity impregnation technique was used to saturate A-type gamma alumina particles using a 0.4 M solution of cobalt nitrate hexahydrate. To produce a cobalt nitrate solution, 23.28 g Co (NO₃)₂ 6H₂O (cz., Mallinkrodt Inc., Paris, Ky) was dissolved in deionized water to give a final volume of 200 ml. 224.14 g of gamma alumina A particles were saturated with cobalt nitrate solution. After drying the saturated particles at 130 ° C, part of the sample was calcined to 600 ° C and kept at 600 ° C for 1 hour. After calcining, the saturated particles were treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 28 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 33.

Example 29 (references). Preparation of copper-saturated gamma alumina particles:

The first humidity impregnation technique was used to saturate Type A gamma alumina particles with a 0.4 M solution of 2.5 copper (II) nitrate hydrate. To make a copper nitrate solution, 18.61 g Cu (NO₃)₂ 2,5^.H₂O (BAKER ANALYSED®, JT Baker, Co., Phillipsburg, NJ) was dissolved in deionized water to give a final volume of 200 ml. 224.14 g of gamma alumina A particles were saturated with a copper nitrate solution. After drying the saturated particles at 130 ° C, part of the sample was calcined to 600 ° C and kept at 600 ° C for 1 hour. After calcining, the saturated particles were treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 29 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 34.

Example 30 (references). Preparation of nickel-saturated gamma alumina particles:

The first moisture impregnation technique was used to saturate Type A gamma alumina particles with a 0.4 M nickel nitrate hexahydrate solution. To produce a nickel nitrate solution, 23.26 g Ni (NO₃)₂ 6H₂O (Cobalt low, certified, Fisher Scientific Company, Fair Lawn, NJ) was dissolved in deionized water to give a final volume of 200 ml. 224.14 g of gamma alumina A particles were saturated with nickel nitrate solution. After drying the saturated particles at 130 ° C, part of the sample was calcined to 600 ° C and kept at 600 ° C for 1 hour. After calcining, the saturated particles were treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 30 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 35.

Example 31 (references). Preparation of chromium-saturated gamma alumina particles:

The first humidity impregnation technique was used to saturate Type A gamma alumina particles with a 0.4 M solution of chromium nitrate onahydrate. To make a chromium nitrate solution, 32.01 g Cr (NO₃)₃ 9H2O (reagent purity, Matheson, Coleman and Bell, Norwood, Ohio) was dissolved in deionized water to give a final volume of 200 ml. 224.14 g of gamma alumina A particles were saturated with chromium nitrate solution. After drying the saturated particles at 130 ° C, part of the sample was calcined to 600 ° C and kept at 600 ° C for 1 hour. After calcining, the saturated particles were treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 31 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 36.

Example 32 (references). Preparation of zinc saturated gamma alumina particles:

The first humidity impregnation technique was used to saturate A-type gamma alumina particles with a 0.4 M solution of zinc nitrate hexahydrate. To produce a zinc nitrate solution, 23.80 g Zn (NO₃)₂ 6H₂O (BAKER ANALYSED Reagent, ® Mallinkrodt Baker, Inc., Phillipsburg, NJ) was dissolved in deionized water to give a final volume of 200 ml. 224.14 g of gamma alumina A particles were saturated with zinc nitrate solution. After drying the saturated particles at 130 ° C, part of the sample was calcined to 600 ° C and kept at 600 ° C for one hour. After calcining, the saturated particles were treated with gold by plasma spraying (deposition condition 2).

The performance of the catalyst of example 32 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 37.

Example 33 (references). Preparation of titanium and potassium saturated alumina gamma particles:

The first moisture impregnation technique was used to saturate Type A gamma alumina particles with a Tyzor LA ™ solution of titanium lactate containing potassium carbonate. To produce a titanium lactate / potassium carbonate solution, 6.91 g K₂WHAT₃ dissolved in 200 ml Tyzor LA titanium lactate (E. L Du Pont de Nemours Co., Willmington, DE: Tyzor LA corresponds nominally to 13.7% by weight TiO₂). 224.14 g of gamma alumina A particles were saturated with about 148 ml of Tyzor LA / potassium carbonate solution. After drying the saturated particles at 130 ° C, part of the sample was calcined to 600 ° C and kept at 600 ° C for 1 hour. After calcining, the saturated particles were treated with gold by plasma spraying (deposition condition 2).

The sample was tested by TEM as previously described. The approximate size range of Au particles in a representative region of the sample was 3.2 to 32 nm. The average particle size Au was 9 nm and the approximate depth range in the substrate was 33 to 60 nm. The performance of the catalyst of the example was examined for its catalytic activity in oxidizing CO during gas flow through a bed using a test method

1. The CO conversion was 3600 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 38.

Metal oxide coated substrates

Example 34 (references). Manufacture of titanium oxide coated alumina particles:

<td>Solution</td><td>titanate</td><td>tetraisopropyl (TPT)</td><td>in</td><td>alcohol</td>

<td>isopropyl</td><td>is prepared</td><td>by mixing 30</td><td>ml</td><td>titanate</td>

<td colspan="2">tetraisopropyl (Gelest,</td><td>Inc., Tullytown, PA)</td><td>from</td><td>alcohol</td>

isopropyl in an amount sufficient to give a final volume of 148 ml. This solution was impregnated by first humidity impregnation with 224.14 g of B type alumina particles. After saturation, the particles were spread on an aluminum tray 30X21 cm and allowed to hydrolyze in air for about 2 hours. During this period of time, the particles were gently mixed every 10 minutes using a spatula. The tray with air hydrolyzed TPT treated particles was transferred to an oven and dried at about 150 ° C overnight. After drying, the titanium oxide coated particles were calcined at 500 ° C (at this temperature for 1 hour, heating rate from room temperature to 500 ° C = 1.6 ° C / minute). After cooling, these particles were treated with gold by sputtering (deposition condition 2).

The performance of the catalyst of example 34 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 3600 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 39.

Manufacture of aluminum oxide coated with particles

Example 35 (reference titanium oxide alumina hydrolysis liquid water:

Titanium oxide coated was prepared as described in Example 31 except that, rather than allowing air hydrolysis of tetraisopropyl titanate prior to drying, after treatment with a TPT-isopropyl alcohol mixture, the particles were washed twice with 500 ml of deionized water. The particles were then dried at 150 ° C overnight. After drying, the titanium oxide coated particles were calcined at 500 ° C (at this temperature for 1 hour, heating rate from room temperature to 500 ° C = 1.6 ° C / minute). After cooling, these particles were treated with gold by sputtering (deposition condition 2).

The performance of the catalyst of example 35 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 3600 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 40.

Example 36 (references). Manufacture of titanium oxide coated potassium carbonate alumina particles:

Potassium carbonate treated alumina particles were prepared by saturation of type A alumina particles using a 0.5 MK solution₂WHAT₃ (Merck KGaA, Darmstadt, Germany) in deionized water. This material was dried overnight at 135 ° C in a forced air oven. A solution of tetraisopropyl titanate (TPT) in isopropyl alcohol was prepared by mixing 30 ml tetraisopropyl titanate (Gelest, Inc., Tullytown, PA) with isopropyl alcohol in an amount sufficient to give a final volume of 148 ml. This solution was impregnated by impregnation of a first humidity of 224.14 g of potassium carbonate A-type alumina particles. After saturation, the particles were spread on an aluminum tray 30X21 cm and allowed to hydrolyze in air for about 2 hours. During this period of time, the particles were gently mixed every 10 minutes using a spatula. The tray with air hydrolyzed TPT treated particles was transferred to an oven and dried at about 150 ° C overnight. After drying, the titanium oxide coated particles were calcined at 500 ° C (at this temperature for 1 hour, heating rate from room temperature to 500 ° C = 1.6 ° C / minute). After cooling, these particles were treated with gold by sputtering (deposition condition 2).

The performance of the catalyst of example 36 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 3600 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 41

The results of testing the material of Example 36 demonstrate that high activity can be achieved by using nanoporous metal oxide coating in combination with an activating agent.

Example 37 (references). Manufacture of zirconia-coated gamma alumina particles:

30.0 g of zirconium n-propoxide (Johnson Matthey Elektronics, Ward Hill, MA) was diluted with isopropyl alcohol to a final total volume of 148 ml. 224.14 g of the B-type gamma alumina particles were saturated by impregnation with first humidity using this solution. The resulting material was hydrolyzed in air for about 5 hours and dried in an oven at 135 ° C overnight. After drying, the titanium oxide coated particles were calcined at 500 ° C (at this temperature for 1 hour, heating rate from room temperature to 500 ° C = 1.6 ° C / minute). After cooling, these particles were treated with gold by sputtering (deposition condition 2).

The performance of the catalyst of example 37 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 3600 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 42.

The particles of Example 37 were placed in a copper ring 1/2 mm high and 3 mm in diameter on a microscope slide and immobilized using Buehler conductive epoxy resin. Conductive epoxy resin was made by mixing 5 g Buehler epoxy base (Epoxy Base No. 20-8130-037, Buehler Inc., Lake Bluff, IL), 1 g Buehler epoxy hardener (No 20-8132-003) and 1 g colloidal carbon glue (Catalog number 16053, Ted Pella, Inc., Redding, CA). The epoxy mix was deaerated under a vacuum of 5 mm for 2 minutes, poured into the ring and into particles. The samples were cured for 1 hour at 70 ° C and the copper ring holding the samples immobilized in epoxy resin was removed from the microscope slide. The immobilized sample was polished flat on one side using 600 grit sandpaper. The flat side was attached to the SouthBay 515 (South Bay

Technology, Inc., San Clemente, CA) and milled using a diamond suspension to a thickness of 15 [mu] m.

The sample was placed in a Gatan ion etching device (Gatan Duo Mill Model 600, Gatan, Inc., Warrendale, PA) and milled using double guns using argon at 5KV and 0.5 mA per gun until the sample was perforated in the correct surface . Samples were tested on a JEOL JSL 200CX (JEOL USA Inc., Peabody, MA) at 200 Kv. Samples were positioned to allow viewing of the outer surface of the gold particle at a viewing angle perpendicular to the surface of the catalyst.

The microstructure and coating conditions of the core on the interface and crystalline core-interface surfaces were determined. The core is alumina, the coating is zirconia, and Au has not penetrated perceptibly into the core. The zirconia phase was discontinuous and gold was generally found on the outer edge of the deposited zirconia. The selected diffraction surface was used to identify major crystalline phases. Crystalline gold, gamma alumina and crystalline zirconia were identified. The zirconia phase was identified as zirconia in the monoclinical structure. Zirconia crystals were clusters of 0.1-03 microns, consisting of basic crystallites of 50-100 nm. Although some small gold crystallites were observed in the 30-100 nm dimension range, the major portion of gold was found in the larger 30-100 nm dimension range.

This example indicates that zirconium dioxide does not work to stabilize gold in the form of nanoparticles and nanoclusters. It has been found that these larger gold particles are essentially inactive as a catalyst for the CO oxidation reaction.

Example 38 (references). Manufacture of alumina coated gamma alumina particles:

30.0 g of aluminum sec-butoxide (Johnson Matthey Elektronics, Ward Hill, MA) was diluted with sec-butanol to a final total volume of 148 ml. 224.14 g of the B-type gamma alumina particles were saturated by impregnation with first humidity using this solution. The resulting material was hydrolyzed in air for about 5 hours and dried in an oven at 135 ° C overnight. After drying, the alumina-coated particles were treated with gold by sputtering (deposition condition 2).

The sample was tested by TEM as previously described. The approximate size range of Au particles in a representative region of the sample was 2.6 to 9.7 nm. The average length of Au particles in this region was 4.4 nm and the approximate depth range in the substrate was 40 to 57 nm.

The performance of the catalyst of example 38 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 43.

The results of testing the material according to example 38 indicate the high performance of the catalyst utilizing the support material, the surface of which has been altered by the hydrolysis of metal alkoxide (aluminum alkoxide) on this surface of nanoporous alumina).

Example 39 (references). Glass beads treated with gold:

in this case (in this case

280 gram of solid glass beads, 170 x 325 mesh, obtained from Potters Industries Inc. (Valley Forge, PA), treated with gold using deposition condition 1. The cathode power was 0.03 kW, the stirrer speed was about 4 rpm, the argon pressure was about 4 mT and the treatment time was 2 hours. The sample was tested as described in Test Method 2 using 5400 ppm CO in air with humidity above 70% RH and a flow rate of 200 ml / minute. the bed was about 1 inch. The results are shown in Fig. Example 40 (reference). Manufacture of titanium oxide treated with potassium carbonate of alumina - Effect of sequential addition:

Depth 44.

topped with steak

<td>Solution</td><td>titanate</td><td>tetraisopropyl (TPT)</td><td>in</td><td>alcohol</td>

<td>isopropyl</td><td>is prepared</td><td>by mixing 30</td><td>ml</td><td>titanate</td>

<td colspan="2">tetraisopropyl (Gelest,</td><td>Inc., Tullytown, PA)</td><td>from</td><td>alcohol</td>

isopropyl in an amount sufficient to give a final volume of 148 ml. This solution was impregnated by first humidity impregnation with 224.14 g of B type alumina particles. After saturation, the particles were spread on an aluminum tray 30X21 cm and allowed to hydrolyze in air for about 2 hours. During this time period, the particles were gently mixed every 20 minutes using a spatula. The tray with air hydrolyzed TPT treated particles was transferred to an oven and dried at about 150 ° C overnight. After drying, the titanium oxide coated particles were calcined at 500 ° C (at this temperature for 1 hour, heating rate from room temperature to 500 ° C = 1.6 ° C / minute). After cooling, these particles were saturated by first humidity impregnation with a 0.5 M potassium carbonate solution (Merck KGaA, Darmstadt, Germany). This material was dried overnight at 135 ° C in a forced air oven. After drying, the potassium carbonate-coated, titanium oxide-coated particles were treated with gold by sputtering (deposition condition 2).

The performance of the catalyst of example 40 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 3600 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 45.

Example 41 (references). Gold treatment of acid washed carbon granules:

1000 12 x 20 mesh Kuraray GC (Kuraray Chemical Company, Ltd., Osaka, Japan) was washed using a solution of 2000 ml deionized water containing 4 ml concentrated NH₄OH (EM Industries, Incorporated, Gibbstown, New Jersey), followed by washing with deionized water to neutral pH. The washed sample was dried at 120 ° C for 24 hours. This material was treated with gold by sputtering (deposition condition 1).

The performance of the catalyst of example 41 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 3600 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 46.

Example 42 (references). Gold treatment of treated carbon granules: the effect of potassium saturation:

123.80 g Kuraray GC (Kuraray Chemical Company, Ltd., Osaka, Japan) with a dimension of 12 X 20 mesh was saturated by impregnation with first humidity using a potassium acetate solution. A potassium acetate solution was prepared by dissolving 7.50 g of potassium acetate (Fisher Scientific, Fair Lawn, New Jersey) in 142.50 g of deionized water). After saturation, the sample was dried in an oven at 130 ° C overnight and then calcined in a flow of nitrogen gas according to a heating schedule: room temperature to 950 ° C 3 ° C / minute and then maintaining 950 ° C for 1 hour. After cooling, this material was treated with gold by sputtering (deposition condition 1).

The performance of the catalyst of example 42 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 32 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 47.

Example 43 (references). Gold treatment of treated carbon granules: the effect of saturation with sodium compound

123.80 g Kuraray GC (Kuraray Chemical Company, Ltd., Osaka Japan) with a dimension of 12 x 20 mesh was saturated by impregnation with first humidity using a sodium acetate solution. A sodium acetate solution was prepared by dissolving 7.50 g of sodium acetate (Mallinkrodt Incorporated, St. Louis, Mo) in 142.50 g of deionized water. After saturation, the sample was dried in an oven at 130 ° C overnight and then calcined in a flow of nitrogen gas according to a heating schedule: room temperature to 950 ° C 3 ° C / minute and then held at 950 ° C for 1 hour. After cooling, this material was treated with gold by sputtering (deposition condition 1). The performance of the catalyst of example 43 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 32 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 48.

Example 44 (references). Gold treatment of unwashed carbon granules:

12X20 mesh Kuraray GG was treated with gold by sputtering (deposition condition 1).

The performance of the catalyst of example 44 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 32 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 49.

Example 45 (references). Gold treatment of carbon granules: the impact of changes in deposition conditions

12 x 20 mesh Kuraray GG was treated with gold by sputtering (deposition condition 1) except that the particle mixer rotated at 10 rpm during the deposition process. The performance of the catalyst of example 45 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 32 liters / minute.

100

The gas had 85% relative humidity. The results are shown in Fig. 50.

Example 46 Preparation of particles with increased specific surface area: fine particles associated with coarser particles:

A 10% bemite sol was prepared by dispersing 20.0 g of alpha alumina monohydrate powder (bemite) sold under the trade name Disperal (Condea Chimie, GMBH), in 188.5 g of deionized water using 1.25 ml concentrated nitric acid as dispersant. To disperse the booze, it was first added to deionized water, while stirring vigorously while sewing the OMNI GLH lab mixer (Omni International, Warrenton, Virginia). The acid was added to the dispersion dropwise while stirring rapidly to form a homogeneous dispersion. To 135.11 g of this sol was added 15.01 g of fine (40200 mesh) gamma alumina particles (gamma alumina was prepared by calcining the bite particles as described previously). This mixture was thoroughly mixed to disperse gamma alumina particles into a boehm sol. This bemit-gamma alumina particle mixture was then added to 230.8 g of the A-type gamma alumina particles while mixing the A-type gamma alumina particles with a spatula to achieve a homogeneous treatment of the A-type gamma alumina particles by the mixture of bemit-gamma oxide particles aluminum. As a result of this process, the finer gamma alumina particles adhered to the surface of the thicker gamma alumina particles. The mixture was transferred to a shallow aluminum tray and

101 dried in an oven at 125 ° C. The dried particles were calcined to 600 ° C according to the schedule: room temperature up to 600^aboutC - 4.8 ° C / minute, held at 600 ° C for 1 hour, and then cooled in an oven. After cooling the particles, they were treated with gold according to deposition condition 2.

The performance of the catalyst of example 46 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 32 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 51.

Example 47 Preparation of particles with an increased specific surface: the effect of a surface modified by creating an uneven and porous surface:

The bohemite sol was prepared as described in Example 46 using 358.52 g of Disperal ™ boho, 592 g of deionized water and 13 mL of concentrated nitric acid. In a separate step, fine size gamma alumina particles were prepared by calcining a Disperal ™ boiling sample to a temperature of 600 ° C in a fused silica tray (heating rate 4.8 ° C / minute, kept at 600 ° C for 2 hours). 58.61 g of these fine-size gamma alumina particles were added to the boiling liquor with rapid mixing using an OMNI GLH lab mixer. 200 g of this mixture was diluted with 900 g of deionized water. To this dispersion, 50.0 g of fine (40-200 mesh) gamma alumina particles were added along with 30.0 g of carbon (Darco Activated Carbon, ICI United States; Inc.,

102

Willmington, DE) and the mixture was thoroughly mixed. 150 ml of this mixture was added in small drops to 224.1 g of type B gamma alumina particles while stirring the particles with a spatula. The resulting particles were evenly colored black (black from the carbon particles in the dispersion). The treated particles were transferred to a shallow aluminum tray and dried in an oven overnight at 120 ° C. The dried particles were calcined to 600 ° C according to the schedule: room temperature to 600 ° C - 2.4 ° C / minute, kept at 600 ° C for 1 hour, cooled in an oven. After cooling the particles, they were saturated with 0.5 M potassium carbonate solution by impregnation of the first humidity. The particles were again dried at 120 ° C overnight, calcined to 600 ° C (4.8 ° C / minute to 600 ° C, kept at 600 ° C for 1 hour, cooled in an oven) and, after cooling, the particles treated with gold according to deposition condition 2.

The performance of the catalyst of example 47 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 3600 ppm CO and the total gas flow rate was 64 liters / minute. The gas had 85% relative humidity. The results are shown in Fig.

Examples. 48 (references). Activation with molecular sieves during gold treatment:

300 ml 14-30 mesh Sigma molecular sieve particles (M2760. 4 A molecular sieves; Sigma Aldrich, St. Louis, Mo) were treated with gold using deposition condition 2.

103

The performance of the catalyst of example 48 was examined for its catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 32 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 53.

Examples 49-54 (references). Impact of changes in deposition conditions on the activity of carbon catalysts:

According to examples 49-54, gold treatment of 300 ml 12 X 20 mesh Kuraray GG carbon particle samples was performed using the deposition conditions indicated in Table 1 below. In this table, "power" means the power of the cathode during the gold deposition process; "Current" means the measured current during this process; "Time" means the time of treatment with gold; "Pressure" means the pressure in the chamber during the deposition process; "Sum of revolutions" means the number of all mixer revolutions in the chamber during deposition; "Gap" indicates the gap between the shoulder blades and the chamber wall, "&lt;20 mesh" indicates the percentage by weight of the sample that passes through the 20 mesh screen after gold treatment; "&lt;60 mesh" indicates the content by weight of the sample, passing through a 60 mesh screen after gold treatment; and "% effect." is a measure of the catalytic activity measured as the percentage of CO removed during the first 15 minutes of the test depending on the amount of CO introduced into the bed of the catalyst tested during the test.

104

Table 1

<td>A sample</td><td>Power</td><td>Electricity</td><td>Time</td><td>Speed</td><td>Ciśni-</td><td>Sum</td><td>Particular</td><td> &lt;2 0</td><td> &lt;60</td><td> %</td>

<td></td><td></td><td></td><td></td><td></td><td>up</td><td>rpm.</td><td>-rope</td><td>mesh</td><td>mesh</td><td>effect.</td>

<td>At-</td><td>(KW)</td><td>(Amp)</td><td>(H)</td><td>(Rev / min)</td><td>(milliliter</td><td>generally em</td><td>(Mm)</td><td> (%)</td><td> (%)</td><td> (%)</td>

<td>Quad</td><td></td><td></td><td></td><td></td><td>track)</td><td></td><td></td><td></td><td></td><td></td>

<td> 49</td><td> 0,03</td><td> 0,06</td><td> 1</td><td> 4</td><td> 10</td><td> 240</td><td> 1,7</td><td> 21,4</td><td> 1,0</td><td> 97</td>

<td> 50</td><td> 0,03</td><td> 0,06</td><td> 1</td><td> 4</td><td> 10</td><td> 240</td><td> 1,7</td><td> 21,1</td><td> 1,3</td><td> 98</td>

<td> 51</td><td> 0,03</td><td> 0,06</td><td> 1</td><td> 10</td><td> 10</td><td> 600</td><td> 1,7</td><td> 22,6</td><td> 1,8</td><td> 95</td>

<td> 52</td><td> 0,03</td><td> 0,06</td><td> 1</td><td> 10</td><td> 3</td><td> 600</td><td> 1,7</td><td> 28,0</td><td> 2,4</td><td> 97</td>

<td> 53</td><td> 0,06</td><td> 0,12</td><td> 0,5</td><td> 4</td><td> 10</td><td> 120</td><td> 1,7</td><td> 10,3</td><td> 0,7</td><td> 90</td>

<td> 54</td><td> 0,03</td><td> 0,06</td><td> 1</td><td> 4</td><td> 10</td><td> 240</td><td> 2,7</td><td> 5,1</td><td> 0,5</td><td> 75</td>

The gold weight percentage measured by ICP for these samples is indicated in the following table. Replica samples of Examples 49 and 53 were measured by the same technique.

Table 2

<td>Example</td><td colspan="2">% by weight of gold</td>

<td> 49</td><td> 0,0657</td><td> 0,0659</td>

<td> 51</td><td> 0,0939</td><td>_-</td>

<td> 52</td><td> 0,0995</td><td>_-</td>

<td> 53</td><td> 0,0962</td><td> 0,0923</td>

<td> 54</td><td> 0,0933</td><td>_-</td>

The behavior of the catalyst materials of Examples 4954 was examined for their catalytic activity in oxidizing CO during gas flow through the bed using a test method

1. The CO conversion was 1500 ppm CO and the total gas flow rate was 32 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 54.

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Examples 55-60 (references). Impact of power changes on the gold level on a carbon catalyst. Activity:

According to examples 55-60, gold treatment with 300 ml samples of 12 X Kuraray GG carbon particles was carried out

twenty mesh, using the deposition conditions indicated in Table 2 below. In these examples, "thickness" means the relative thickness of the gold coating, measured by plasma current, "shaft. rev. "means the rotational speed of the particle mixer shaft," distance "means the length between the sample and the sputtering element and other determinations have been previously determined.

Table 3

<td>At-</td><td>thicker</td><td>Power</td><td>Electricity</td><td>Time</td><td>Shaft.</td><td>Particular</td><td>Odle-</td><td>ABOUT. %</td>

<td>Quad</td><td>bone</td><td></td><td></td><td></td><td>rpm.</td><td>rope</td><td>the phone</td><td>effect.</td>

<td></td><td>(centi</td><td>(KW)</td><td>(Amp)</td><td>(H)</td><td>(R /</td><td>(Mm)</td><td>(Cm)</td><td> (%)</td>

<td></td><td>amps)</td><td></td><td></td><td></td><td>min)</td><td></td><td></td><td></td>

<td> 55</td><td> 15</td><td> 0,09</td><td> 0,15</td><td> 1,00</td><td> 2</td><td> 27</td><td> 8,6</td><td> 80</td>

<td> 56</td><td> 12</td><td> 0,06</td><td> 0,12</td><td> 1,00</td><td> 2</td><td> 2,7</td><td> 8,6</td><td> 72</td>

<td> 57</td><td> 3</td><td> 0,01</td><td> 0,03</td><td> 1,00</td><td> 2</td><td> 2,7</td><td> 8,6</td><td> 59</td>

<td> 58</td><td> 9</td><td> 0,04</td><td> 0,09</td><td> 1,00</td><td> 2</td><td> 2,7</td><td> 8,6</td><td> 77</td>

<td> 59</td><td>std</td><td> 0,03</td><td> 0,06</td><td> 1,00</td><td> 4</td><td> 2,7</td><td> 4,6</td><td> 82</td>

<td> 60</td><td> 6</td><td> 0,02</td><td> 0,06</td><td> 1,00</td><td> 2</td><td> 2,7</td><td> 8,6</td><td> 65</td>

The behavior of the catalyst materials of Examples 5560 was examined for their catalytic activity in oxidizing CO during gas flow through a bed using test method 1. The CO challenge was 1500 ppm CO and the total gas flow rate was 32 liters / minute. The gas had 85% relative humidity. The results are shown in Fig. 55.

106

Examples 61-65 (references). Impact of saturation and heat treatment on catalyst performance:

Samples prepared as described in Examples 1, 3, 4, 5, and 17 and Examples 61, 62, 63, 64, 65 indicated respectively, were screened to retain particles above 40 mesh and smaller than 30 mesh, using standard US sieves (ASTM E-11 specification; The Murdock Co., Mundelein, IL). Retained samples were tested as described in Test Method 2, using 16,000 ppm CO in air at humidity above 85% RH and a flow rate of 100 ml / minute. The weight of the catalyst tested was 435 mg for examples 61, 62 and 65 and 438 mg for examples 63 and 64. The results are shown in Figure 56.

Examples 66-70 (references). Impact of silica carrier and gold coating thickness:

According to examples 66-70, gold treatment of silica substrates with different chromatographic purity (S2509, S4883, S9258 was obtained from Sigma Aldrich Co, St. Louis, MO) was performed as described in Table 3 below. S2509 consists of 70 to 230 particles mesh (63 to 200 μη) with an average pore diameter of 60 A. S4883 consists of 20 to 200 mesh particles (74 to 840 pm) with an average pore diameter of 22 A. S9258 consists of 15 to 40 pm particles with an average pore diameter of 60 A. A distance of 4.6 cm was maintained between the samples and the sputtering element. A 1.7 mm gap was set. "Catalyst mass" refers to the mass of material tested for its catalytic activity. "Drying temp." Refers to the temperature at which the sample was dried overnight before gold treatment.

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Table 4

<td>Example</td><td>substratum</td><td>Catalyst mass</td><td>temp drying</td><td>Power</td><td>Electricity</td><td>Time</td><td>Speed rotary</td>

<td></td><td></td><td>mg</td><td>° C</td><td>kW</td><td>Amp</td><td>h</td><td>rev / min</td>

<td> 66</td><td>S2509</td><td> 98</td><td> 200</td><td> 0,03</td><td> 0,07</td><td> 2</td><td> 4</td>

<td> 67</td><td> 54883</td><td> 105</td><td> 200</td><td> 0,02</td><td> 0,06</td><td> 1</td><td> 4</td>

<td> 68</td><td>S9258</td><td> 98</td><td> 600</td><td> 0,02</td><td> 0,1</td><td> 6</td><td> 4</td>

<td> 69</td><td>S9258</td><td> 105</td><td>_-</td><td>_-</td><td>_-</td><td>_-</td><td>_-</td>

<td> 70</td><td>S2509</td><td> 214</td><td> 200</td><td> 0,03</td><td> 0,07</td><td> 2</td><td> 4</td>

The performance of the catalytic materials according to examples 66 to 70 was tested as described in Test Method 2.

The CO concentration was 1800 ppm CO in air, the relative humidity was> 90% and the gas flow rate was

100 ml / min. The results are shown in Fig. 57.

Example 71 (references). Impact of long-term CO treatment on catalyst performance:

The sample prepared as described in example 38 was sieved to retain particles smaller than 140-mesh using standard USA sieves (ASTM E-11 specification; The Murdock Co., Mundelein, IL). The resulting sample was tested as described in Test Method 2, using 18,900 ppm CO in air with humidity above 85% RH and a flow rate of 100 ml / minute. The catalyst mass was determined to be 119 mg. The test was continued for 28 hours. The results are shown in Fig. 58.

108