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Silica stabilized panatase titania, Vanadia ultrafine catalysts and their production methods

Silica-Stabilized Ultrafine Anatase Titania Vanadia Catalysts and, Methods of Production thereof

Full description

Background of the invention

Selective catalytic reduction (SCR) of nitrogen oxides produced during combustion processes using reductants, for example NH3, has been commercially and technically successful for more than 30 years. They have been used primarily to control NOx emissions in exhaust gases from stationary power plants and other industrial facilities. Recently, interest in the technology has expanded as a result of taking advantage of it to address emissions from mobile energy sources such as marine vessels, cars, trucks and machinery. This increased interest is driven largely by regulations governing emissions from mobile sources. For example, US and European regulations that will be effective in 2010 for mobile diesel engine sets set low levels of NOx emissions, making effective exhaust after-treatment essential, and selective catalytic reduction represents a prominent technical option.

In stationary applications, the requirements on the catalyst are not very high. For example, stationary engines typically operate in close to steady state, constant temperature conditions and with a relatively low gas space velocity. Also the volume requirements for the catalyst will not be so demanding. In on-road applications, however, catalyst requirements are very stringent. In this case, the motors are not operated at a steady state or at a constant temperature but instead rotate through wide variations in load (and thus temperature). In one possible system configuration, the SCR catalyst is positioned upstream of the diesel particulate filter (DPF) and regenerating the soot-laden diesel particulate filter may cause a high-temperature pulse of hot gas to pass through Through the downstream SCR catalyst. Furthermore, mobile applications typically contribute to higher gas space velocities and catalyst volumetric requirements are stringent. For example in early use heavy-duty diesel engines, the size of the catalyst is many times larger than the replacement of the motor. For these reasons it is necessary to develop improved catalysts that have higher thermal stability and improved volumetric activity so that cost-effective technical solutions can be discovered to comply with increasingly stringent regulations.

1. The technology, which has been used for many years in established applications, includes catalysts based primarily on metal oxides, specifically those based primarily on TiO2 as a catalyst support, and the active catalytic activity is primarily based on vanadia. V2O5. Thus mixtures of TiO2 (80 95%) and WO3 (3 10%) and optionally with a balance including SiO2 (e.g. DT-52 (brand) and DT-58 (brand)) were in use as catalyst support. The active vanadia component is typically present at 0.1% by weight. In these catalysts, titania exists primarily with a relatively high surface area in the form of anatase. Review the use and limitations of vanadia-based catalysts for mobile urea SCR systems in Studies in Surface Science and Catalysis, Granger, P and Parvulescu, VI, ed, Volume 171, Chapter 9. There are two considerations that depend on the greater stability of the catalyst. catalyst based mainly on vanadia. Firstly, catalysts may be used in mobile applications in the composition where the diesel particulate filter is placed against the direction of the SCR-vanadia catalyst. In this configuration the vanadia catalyst may be excessively exposed to temperatures associated with exothermic reconstitution of the diesel particulate filter. The second consideration is that required for a catalyst based primarily on vanadia to maintain its catalytic activity at high temperatures (for example, greater than 550 °C, where it competes better with the base metal exchanged with the zeolite cofactors, which display a high degree of Stability and activity at high temperatures DT - 58 contains 10% SiO2, 9 wt% WO3 and 81% TiO2 and has a surface area of approximately 90 m2/g. It is well known, however, that catalysts based mainly on titania and vanadia are not particularly thermally stable. There are many reasons for this lack of thermal stability. First, titania itself tends to sinter at high temperatures with an accompanying loss of surface area. Second, titania also tolerates the transformation of the crystalline form into rutile at high temperatures, and this form is generally believed to be a less active support material than the anatase form. Third, unsupported vanadia has a boiling point of about 675 degrees Celsius, and even when supported on titania, at high temperatures it tends to move somewhat and can eventually accumulate to form vanadia crystals with a lower surface area (and less activity).

For these reasons, it is necessary to improve the thermal stability of the final catalyst and at the same time maintain or increase the catalytic activity for selective catalytic reduction of nitrogen oxides (SCR-DeNOx) from weak-burning motors. Achieving both goals simultaneously represents an important challenge, since it can often be improved at the disadvantage of others. For example, it is mentioned that silica and/or rare earth metals are incorporated into titania in order to increase stability, but again gain both the necessary stability and activity.

Amorphous silica-stabilized ultrafine anatase titania was previously used for catalytic uses. It is known that amorphous silica improves the anatase phase stability and retains the surface area of ultrafine anatase titania. Hence, amorphous silica is an additive in commercial products, for example DT-58 and DT- S10 and these materials can be used commercially in the catalyst for selective catalytic control of diesel emissions, in particular for DeNOx applications.

An early patent describes the use of silicic acid to stabilize anatase titania to DeNOx (US Patent No. 4,725,572). However, a careful reading of this patent shows that the silica source is in fact particulate silica. Also, a very recent US patent (US Patent No. 0956006B1) describes the use of colloidal silica to affect anatase titania with thermal stability and improved hydrothermal stability. A recently published US patent application (US Patent No. 2007/0129241A1) describes DeNOx catalysts based primarily on vanadia/titania with improved stability. Also, the source of silica used here is colloidal silica. However, titania catalysts based mainly on colloidal silica, as noted, lack acceptable stability and activity after exposure to excessively high temperatures. Titania catalysts reduce these defects which will be more usable and beneficial.

While the previously mentioned DT-58 support material is the support material for diesel emission catalysts, as in the case of the field, the improved titanium support would be, in general.

(1) It is more thermally stable, and so it can be placed close to the engine

(2) The most catalytically active, and thus enables the use of a smaller can (i.e. 10 liters versus 12 liters) to contain the catalyst, thus improving (reducing) the size of the emission control system.

The base materials for titania must be produced supported by these improved silica and the synthetic catalysts which guide the present invention.

General description of the invention

This invention discusses silica-stabilized ultrafine anatase titania catalysts, vanadia catalysts, and silica-stabilized catalysts, and methods for preparing them.

The present disclosure describes compositions and processes for producing very fine and stable anatase titania for use, for example, as a support material for a vanadia catalyst, preferably for use in a catalytic emitter control system. Stability contributes to the treatment of titania in the dissolved low molecular weight form and/or the small nanoparticle form (less than 5 nanometres) of silica, as in the preferred representation, tetra (alkyl)ammonium silicate. For example, tetramethylammonium silicate or silicic acid, which helps to effectively maintain the anatase phase and prevent sintering (crystal growth) under thermal conditions and Intense hydrothermal activity, and even in the presence of vanadia, the new stable silica titania materials combined with vanadia have equal or improved catalytic activity for the selective catalytic reaction to NOx compared to the vanadia catalysts that are primarily based on silica and titanias currently available.

In these aspects, the invention is a catalyst support material comprising anatase titania particles comprising greater than or equal to 85% by dry weight of TiO2 and less than or equal to 10% by dry weight of SiO2, wherein the SiO2 is essentially in a low-weight form Low molecular weight and/or small nanoparticle. The catalyst support material may also include, for example, 3 10% WO3 and may have a surface area BET of at least 80 m2/g. The catalyst support material may include greater than or equal to 85% dry weight TiO2, 3.9% SiO2, and 3.9% dry weight WO3, for example. SiO2 may exist at a fractional monolayer value of less than 1.0 before the catalyst support material sinters. The gravimetric form of SiO2 may have a molecular weight of less than 10,000. SiO2 may include silicon atoms that are substantially (eg greater than 50%) in coordination environments Q3, Q2, Q1 and Q0. SiO2 may include batches that essentially drop to less than or equal to 5 nm after redistribution as imaged by scanning electron microscopy or transmission electron microscopy. Optionally used TiO2 may not be present in the presence of urea.

In another aspect, the invention may be a vanadia catalyst including a silica-stabilized titania catalyst support material as described herein which includes V2O5 placed herein. The vanadia catalyst may include, for example, 0.5 5% by dry weight of V2O5 (or better yet 1.0 3%). V2O5 may exist at a fractional monolayer value of less than 1.0 before sintering. Vanadia catalyst may sinter at greater than or equal to 650°C, for example. In another aspect, the invention may be a diesel-emitting catalytic device including a vanadia catalyst as described herein. In another aspect of the invention the diesel emission catalytic system may include the previously described diesel emission catalytic device and a diesel particulate filter, wherein the diesel emission catalytic device is placed upstream or downstream of the diesel particulate filter. particulate filter.

In another aspect, the invention is a method of catalyzing the conversion of nitrogen oxides into N2 gas including exposure of engine emissions including NOx to a vanadia catalyst as described herein with added reductants to produce nitrogen and water. The reducing agent may, for example, be ammonia and/or urea. In the method the vanadia catalyst may include a vanadia catalyst of 0.5 5% by dry weight of V2O5 (much better than 1.0 3%). For example. Engine emissions may pass through the diesel particulate filter before or after being exposed to the vanadia catalyst.

In another aspect, the invention is a method of producing a catalyst support material including supplying a thin slurry including TiO2 and combining the thin slurry of TiO2 with (1) a silica precursor solution comprising primarily SiO2 of low molecular weight. weight and/or SiO2 including small nano-sized particles comprising small nanoparticles and with (2) WO3 to be a mixture of TiO2 WO3 SiO2 TiO2-WO3-SiO2 in which the silica precursor solution is combined solution with TiO2 thin slurry before, after combining WO3 with TiO2 thin slurry and then washing and sintering a mixture of TiO2 WO3 SiO2 to be the silica-stabilized titania support material. In the method, the silica-stabilized titania support material may include, for example, 86 94% dry weight of TiO2, 3 9% dry weight SiO2 and 3 7% dry weight WO3. Titania support material initially has a surface area of less than 80 m2/g before sintering. The TiO2 for thin-texture slurry may include, for example, preformed titanium hydroxide, titanium oxy-hydroxide or titanium dioxide particles. Optionally TiO2 may not produce a thin slurry in the presence of urea. The small nano particle form of SiO2 for a silica precursor solution may essentially include a diameter of less than 5 nm. The low molecular weight form of SiO2, a silica precursor solution, may include a molecular weight of less than 100,000. The SiO2 of a silica precursor solution may include silicon atoms that are primarily in coordination environments Q3 , Q2, Q1 and Q0. The starting solution for silica may include a tetra(alkyl)ammonium silicate solution or silicic acid. SiO2 may include batches that are greater than or equal to 5 nm in depth after redistribution as imaged by scanning electron microscopy or transmission electron microscopy. The method may also include combining a mixture with TiO2 WO3 SiO2 with V2O5 to form a vanadia catalyst. Thus it may include a vanadia catalyst consisting of, for example, 0.5% by dry weight of V2O5. Therefore, the V2O5 of the vanadia catalyst may exist at a fractional monolayer value of less than 1.0 before sintering. Vanadia catalyst may sinter at greater than or equal to 650°C, for example.

In another aspect, the invention refers to a method of producing silica-stabilized titania support material by providing a slurry comprising TiO2 particles, providing a particulate silica source, combining the TiO2 slurry with a silica source. The molecular silica mixture is modified to form a mixture of TiO2 - SiO2, and the mixture of TiO2 and SiO2 is adjusted to a pH of less than 8.5 and a temperature of less than 80 degrees Celsius, where the molecular silica source is melted and re-deposited on TiO2 particles to be a stable titania support material. Silica-stabilized titania support material. The method may also include the step of combining the silica-stabilized titania support material with WO3 to form the silica-stabilized titania catalyst support material. The method may also include washing and sintering the silica-stabilized titania tungsten catalyst support material. The tungsten catalyst support material may include, for example, 86 94% dry weight of TiO2, 3 9% dry weight SiO2 and 3 7% dry weight WO3, where The titania support material initially has a surface area of less than 80 m2/g before sintering. TiO2 particles for thin-textured slurries may include, for example, preformed titanium hydroxide, titanium oxy-hydroxide, or titanium dioxide particles. Thin mortar TiO2 particles do not selectively produce TiO2 in the presence of urea. The SiO2 of a dissolving TiO2-SiO2 mixture may include silicon atoms that are primarily (eg > 50%) in coordination environments Q3, Q2, Q1 and Q0. SiO2 may include TiO2 particles for a method primarily of batches less than or equal to 5 nm in depth after redistribution into SiO2 as imaged by scanning electron microscopy or by transmission electron microscopy. The method may also include combining a mixture with TiO2 WO3 SiO2 with V2O5 to form a vanadia catalyst. In the method the vanadia catalyst may comprise, for example, 0.5-3% dry weight V2O5. The V2O5 of the vanadia catalyst may be present at a fractional monolayer value of less than 1.0 before sintering, and the vanadia catalyst may floccinate at Less than or equal to 650 degrees Celsius.

Other aspects of the invention will become apparent when considering the description below.

Brief explanation of the drawings

Figure 1 is a graph showing the effect of calcination temperature on the surface area of vanadia catalyst.

Figure 2 is a graph displaying the effect of calcination treatment temperature on the percentage of anatase phase of titania in vanadia catalysts.

Figure 3 is a graph displaying the effect of calcination temperature on the activity of DeNOx to 1% for vanadia catalysts.

Figure 4 is a graph displaying the effect of calcination temperature on the conversion of DeNOx to 3% vanadia catalysts.

Figure 5 is a graph displaying the effect of temperature on the DeNOx activity of various vanadia catalysts.

Figure No. 6 is a graph displaying the effect of temperature on the surface area of the catalyst support material of the current invention versus the conventional catalyst support material.

Figure 7 is a transmission electron micrograph (TEM) of a silica-tungsta-titania catalyst, as in Example 6 showing two-dimensional batches of silica less than 2 nanometers deep on the titania surface.

Figure 8 is a scanning electron micrograph of the vanadia-titania catalyst, as in Example 10, showing colloidal silica particles of approximately 20 nanometers placed in it.

Figure 9 is a transmission electron micrograph (TEM) of a catalyst displaying approximately 20 nm colloidal silica particles on the outside of the vanadia-titania catalyst according to Example 10.

Figure 10 is a transmission electron micrograph (TEM) of a catalytic molecule for Example 11. Showing anatase crystals with a batch, the two-dimensional silica layer is exposed on the outer crystal surface. In this image there are no observable silica particles.

Figure 11 is a transmission electron micrograph (TEM) of a catalytic molecule. According to Example 11, showing anatase crystals with a push, a two-dimensional silica layer is exposed on the outer crystal surface. In this image, one remaining silica particle can be seen, which is less than 5 nanometers in diameter.

Figure 12 is a transmission electron micrograph (TEM) of a catalytic molecule. According to Example 12, small 2D batches of silica are shown on anatase crystallites.

Figure No. 13 is a transmission electron micrograph of silica patches present on the surface of catalytic molecules, silica patches present on anatase titania, according to Example No. 13.

Figure No. 14 is a transmission electron micrograph of silica patches present on the surface of catalytic molecules, silica patches present on anatase titania, according to Example No. 13.

Figure 15 is a transmission electron micrograph (TEM) of the catalyst support material before adding and sintering vanadium. The image shows the lattice ridges associated with anatase titania. Silica is present in 1-3 nanometer bursts on the titania surface (Example 14).

Figure 16 is a transmission electron micrograph (TEM) of a vanadia catalyst that shows three three-dimensional silica nodes (larger than 20 nm) (see arrows) that are not well dispersed on the titania surface (e.g., Example 15). ).

Figure 17 is another transmission electron micrograph (TEM) of a vanadia catalyst that displays three three-dimensional silica nodes (larger than 20 nm) (see arrows) that are not well dispersed on the titania surface (e.g. Example No. 16).

Figure 18 is a graph displaying the effect of various calcination (activation) temperatures on catalytic activities (DeNOx) for types of titania-supported vanadium catalysts.

Detailed description

The primary objective of the present invention is to produce a high-surface-area, stable titania support material in the anatase crystal form. A primary form may be used as a support material for vanadia V2O5 in catalyst uses to control diesel emission. Stability is facilitated by treating titania with silica in a low molecular weight form and/or a small nanoparticle form such as tetra(alkyl)ammonium silicate for a dissolved initiator (i.e. tetramethylammonium silicate). silicate) or tetraethylorthosilicate (TEOS). Other examples of silica initiators include low molecular weight silica which may be used in the present invention but are not limited to aqueous solutions of silicon halides (i.e. non-aqueous SiX4 where X = fluorine F, chlorine Cl, bromine Br or iodine I ), silicon alkoxides (i.e. Si(OR)4 where R = methyl, ethyl, isopropyl, propyl, butyl, iso-butyl, sec-butyl, tert-butyl, pentyls , hexyls, octyls, nonyls, decyls, undecyls and dodecyls, for example), other organic silicates such as hexamethyldisilazane, fluoro-silicic acid salts such as ammonium hexafluorosilicates xafluorosilicate [(NH4)2SiF6], and quaternary ammonium silicate solutions (such as for example (NR4)n, (Si02), where R = hydrogen or alkyls as mentioned above Above and when n = 0,. 1 2 For example), sodium silicate and aqueous potassium silicate solutions (Na2Si03, K2Si03, and MSi03, where M is sodium or potassium in various amounts relative to the silicon), cyclic acid (Si(OH)4). Formed by ion-exchange of any of the cationic forms of silica mentioned here using an acidic ion-exchange resin (for example, ion-exchange of alkali-silicate solutions solutions or quaternary ammonium silicate solutions).

The term low molecular weight form of silica refers to silica with a molecular weight of less than about 100,000. The term small nanoparticle form refers to silica particles with diameters larger than 5 nanometers.

The emphasis on thermal stability improvement of catalysts based primarily on vanadia is relatively new, given that this segment of the automotive emission control market is barely developed. It was only after a comprehensive description by the inventor of conventional catalysts that were known to improve the catalyst based mainly on vanadia that (1) the necessary general silica level be reduced and (2) the dissolved molecular weight form and/or molecular size be reduced. Nanoparticles are small, low molecular weight and/or small nanoparticle form, and the silica form was more effective in providing the required stability and activity.

The catalytic support materials of the present invention have exceptional retention of anatase phase titania and surface area after severe thermal and hydrothermal treatments even in the presence of vanadia. The compositions and methods of making the invention utilize low molecular weight and/or small nano particle forms of silica to obtain an exceptionally smooth and stable surface area anatase phase of titania, while the vanadia catalyst exhibits equal or improved catalytic activity. Optional based mainly on vanadia to NOx after accelerating aging. These formulations and methods were previously unknown in the field.

Two main aspects of the present invention differ from the previous method by the nature of the amorphous silica and the method of incorporating it into titania.

Regarding the nature of amorphous silica, it is first necessary to make a distinction between the particulate molecular forms of amorphous silica and the solution or gas-phase forms that consist of low molecular weight amorphous silicate monomers or clusters that It is not considered to be in molecular form or contains very small nano-sized particles. Suitable forms of silica are described according to the present invention and are referred to as low molecular weight silica and/or clearly (less than 5 nanometers) small nanoparticle silica. For example, the two references that describe the types of non-crystalline silica are (Ullman Encyclopedia of Industrial Chemistry, 5th edition, vol. 23a, pp. 583-660, (1993) and Chemistry of Silica, RKIler, 1979). For example, this form of molecular silica is Non-crystalline is colloidal silica or Sol silica. This type of silica consists of suspensions of dense, separated amorphous silica particles that have diameters in a size range between about 5 nanometers and 100 nanometers. In this size range, molecules typically transmit visible light and thus form a turbidity of dark molecules. These molecules can typically be analyzed by visible-light methods using commonly available commercial instruments. As will be seen from the examples below, without further modification, colloidal silica in molecular form (larger than 5 nm) will not be a suitable form of silica according to the present invention. It is not for this reason that the form of silica required (without subsequent modification) according to the present invention is that most of the mass of silica in the molecule is in the inner part and is not available at the interaction surface with the underlying titania. Thus, according to Iler (op cit. Page 8), a non-crystalline silica molecule with a diameter of 5 nm has 1,500 silicate atoms, and 37% of these silicate atoms are on the surface of the molecule, whereas a 1 nm molecule has approximately every silicate atoms on the surface. Thus, for the following purposes, it is required to use silica sources that mainly include molecules that have diameters of less than 5 nm and/or that have low molecular weights, for example a molecular weight of less than 100,000, and thus are available for reaction with Titania. The exception, which will be described later, is the subsequent modification of the amorphous silica using pH and temperature conditions whereby the amorphous silica is dissolved and redistributed on the titania surface.

Where used here, the term “essentially” means that more than 50% of the process or material in question has a special characteristic or the condition to which it is referred.

For example, as noted above, in the present invention the catalyst support material in the preferred embodiment includes silica which is essentially in a low molecular weight form and/or a small nanoparticle form. By this we mean that more than 50% of the silica is either in the low molecular weight form (molecular weight greater than 100,000) or in the small nano-sized molecular form (diameter less than 5 nanometers) or in a combination of both. In the much preferred version silica includes greater than 60% by weight low molecular weight and/or small nanoparticle form. The much preferred version still includes silica greater than 70% by weight of low molecular weight and/or nano-sized molecular forms. The much-preferred version still includes more than 80% silica, and so far it is still preferable to have more than 90% low molecular weight and/or small nanoparticle forms of silica.

Moreover, low molecular weight and small nano-sized forms preferably have surface areas greater than 450 m2/g.

Molecular forms of silica (i.e., where the diameter is larger than 5 nanometers) include silica gel, precipitated silica, and fumed silica. While the primary particles of dense amorphous silica in these molecular forms can be very small (e.g. 2.5 nm), the primary particles irreversibly accumulate together to form much larger secondary particles that can range in size from hundreds of nanometers. Up to many microns in diameter. These secondary molecules do not have a significant fraction of the near-surface silicate molecules available for interaction with titania. Of course, these secondary molecules are easily analyzed using visible light transmittance methods, and when kept in suspension, the molecules are completely opaque. Amorphous silica in none of these forms is also suitable without subsequent modification according to the present invention.

This category of silica initiator which is suitable for the present invention consists of highly alkaline solutions referred to as water soluble silicates. It is described in Iler (op cit, chapter 2). These solutions are typically transparent because silica particles, if present, are generally too small to transmit to visible light. However, depending on the consistency of the silica, small alkali molecules of silica can form in these solutions. Iler (op cite, page 133) estimates that the NaO2:SiO2 mole ratio is 3:1. The average number of SO2 units per molecule in dilution solutions is about 900, which is less than the 1,500 silicate units at 5 nm for the molecule described above. This silicate starter, although it may contain some nano-sized particles above approximately 5 nm, is suitable for the present invention since most of the silica mass is in the form of smaller, low molecular weight species. Alkali siliceous materials are not often in the preferred form of the present invention, however, because residual alkali ions such as sodium have a severe effect on the effective catalytic toxicity of SCR catalysts based primarily on vanadia.

Recently, the nano-sized nature of amorphous silica nanoparticles in alkaline solutions has been examined in great detail by Fedeyko and others (Langmuir 2005, 21, 5197-5206). These authors use a variety of techniques including small-angle X-ray transmittance (SAXS) and small-angle neutron transmittance (SANS). These methods are able to detect the presence of nano-sized particles under about 2-3 nanometers in size. The authors show that when dilution [hydroxide]/[SiO2] is less than about 1, silica forms small nano-sized particles while for [hydroxide]/[SiO2] greater than 1, silica exists as monomers and oligomers that They are too small to be detected in permeability experiments. The next type of amorphous silica, often too small to be easily detected by visible light and X-ray transmittance methods, is referred to as low molecular weight and/or small nanoparticle amorphous silica in the present invention. There are preferred forms of silica of the present invention.

A useful means of characterizing silica monomers and oligomers in solution is Si29 nuclear magnetic resonance (see, for example, Chapter 3 in High-magnification Solid-State NMR of Silicates and Zeolites by G. Engelhardt and D. Michel 1987). The method can provide information on the tetrahedral symmetry perimeter around silicon, in particular whether or not the silicon contains one or more nearest-neighbor groups (bridging oxygens). The notation generally used to describe this consistency is as follows: Q0 refers to central silicon with no adjacent silocon group closer after that, i.e. Si(OH)4, Q1 refers to central silicones with one adjacent silocon group closer after that, i.e. Si(OH)3(OSi)1. Q2 refers to the central silicon with two silicon groups next to each other closer together, i.e. Si(OH)2(OSi)2, Q3 refers to the central silicon with three silicon groups next to each other closer together, i.e. Si(OH)1(OSi)3. Q4 refers to the central silicon with four silicon groups The silicates are next closest neighbors, i.e. Si(OSi)4.

Without linking to any theory, it is believed that for direct use (without subsequent treatment to change the form of silica) it is required to use silicate solutions consisting predominantly of oligomers Q0 to Q3. On the other hand, in solutions of silicate oligomers, which often consist entirely of Q4 species, they are not required for the present invention. Figuratively, it causes this to occur in subsequent species of silicate oligomers, much of the silica being completely surrounded by other silica species and thus unavailable for interaction with the titania surface where it is often needed for anatase to stabilize.

The form of silica that is suitable for use in the present invention is a commercially available alkaline solution tetramethylammonium silicate. A deep understanding of the nature of this solution can be gained based primarily on previous research. Engelhardt and Michel (op cit page 92) described nuclear magnetic resonance Si29 for a 1 M solution of SiO2 (~6 wt%) with TMA/silicates = 1.0 which is roughly equivalent to a TMAOH concentration of 9 wt%. In this solution, the silica is primarily in the form of a cubic octamer, which contains 8 silicon atoms and has a Q3 symmetry. These small species represent about 90% of the silica mass. The actual TMA silicates solution used in the examples of the present invention has a higher concentration of silica (9% by weight) and a lower concentration of TMAOH (7% by weight), and the distribution of the types of silicates is somewhat different from the report mentioned above, as shown in Table 6. Down.

Another form of silica that is suitable for the present invention is silicic acid. This type of silica is described in Iler (op cit chapter 3). The detailed description of silicic acid is accomplished using Si29 NMR as described in G. Engelhardt and D. Michel (op cite page 100). This form of silica can be made by acidifying alkaline silicate solutions, for example by ion-exchange used for acidic ion exchange resins.

Fractional Monolayer Concept

It is important to show that the compositions and methods of the present invention are different from the previous method examples and the means of doing so include the idea of fractional monolayer coverage of the surface of the base material with added oxide. In the definitions below, the written X indicates the added oxide of interest, for example silica.

Cx = the amount of basic surface area of added oxide for excellent monolayer coverage, g/m2.

SA = surface area of mixed oxide

mx = the basic amount of mass of added oxide for excellent monolayer coverage, g/g mixed oxide.

Lx = actual load of added oxide per mixed oxide, g/g

FMX = monomolecular layer of added oxide on aged mixed oxide

TFM = fractional monolayer on aged mixed oxide

Mx = SA *Cx (Equation 1)

FMX = Mx / Lx (Equation 2)

TFM = Total (FMX) (Equation 3)

First, it is necessary to establish the best estimate of monolayer coverage for the added oxides that are very well dispersed on the basic titania or similar oxides, Cx. For vanadium, the reported monolayer coverage value for the supported oxide is 7 8 vanadium atoms/nm2, which corresponds to 1100 µg V2O5/m2. (See for example I.E. Wachs et al., 2003). For tungsta, the written value of 4.5 W atoms/nm2 was used (the I value of 600 µg SiO2/m2 was obtained (Iler, p. 36, op cit). Thus, as an example, mixed oxide consisting of 10 wt% SiO2 (0.10 g/g), 9 wt% WO3 (0.09 g/g) and 2 wt% V2O5 (0.02 g/g) with TiO2 balance, have a measured BET surface area for nitrogen of 250 m2/g. The TFM of this material is TFM = (1 / 250) * ((0.10 / 600E6) + (0.09 / 1700E6) + (0.02 / 1100E6)) = 0.95. This figure indicates that the oxides of SiO2, WO3 and V2O5 are very well dispersed on the titania surface. The surface coverage of the final mixed oxide would be 0.95 the thickness of single layers with added oxides. For silica only, the fractional monolayer coverage specifically would be 0.67, or two-thirds of the surface would be covered by a perfectly dispersed silica coating. The compositions of the present invention when prepared fresh (i.e. after addition of added oxides but before aging or sintering) typically have surface areas greater than about 100 m2/g and a total amount of added oxides of 15% by weight or less and a coverage of Fractional monolayer coverage specifically is about 1.0 or less, and fractional monolayer coverage specifically for silica is about 0.80 or less.

Methods of incorporating silica according to the present invention

Surface coating of titania using alkali silicates or silicic acid as previously described has been practiced industrially for many years in industrial coatings and coatings. See for example Review Chapters 52 and 53 in Colloidal Silica, Fundamentals and Uses (Surfactants Science Series Vol. 131, HE Bergna, WORoberts, eds). As described in Chapter 52 by Bergna and Roberts, one method of coating the titania surface with silica involves exposing the underlying titania particles to silica under alkaline conditions with a silica concentration that is below the dissolution limit for amorphous silica. As described in Chapter 53 by Bergna and Roberts, another method involves exposing the surface of basic titania to monosilicicic acid at a low pH at a concentration of silica that gives a very low dissolution limit again and below. While the methods for incorporating silica previously refer to appropriate representative methods for incorporating silica according to the present invention, there are several important differences. In contrast to the previous method, the titania phase used as the base material is rutile (due to its higher scanning energy than anatase) and there is no suggestion that silica can be added by these methods to prevent the anatase phase from converting to rutile. The second important difference is that the titania particles are the base particles for the paints and coatings of the previous method, regardless of whether there is anatase or rutile, and there are base materials with low surface area, with the BET surface area of nitrogen for the surface of the base material being typically less. From about 15 m2/g. Third, the main difference is in the surface coverage of added oxide such as silica. With the aforementioned definition of monolayer coverage, the compositions of the present invention if prepared on a low-surface support material of 15 m2/g will have a total monolayer coverage of about 5 or higher and fractional monolayer coverage specifically for silica will be Approximately greater than or equal to 3. Thus, in the previous method, there is a silica cover over the entire titania molecule, with a thickness exceeding the thickness of the monolayer. When necessary, the silica coating is positioned to fully indicate the photocatalytic activity of the titania surface. Finally in a preferred embodiment of the present invention, titania is covered with silica under conditions where the added silica is above the good dissolution limit of a few hundred parts per million. As seen later, in the present invention silica, when initially deposited, does not completely cover the titania surface so that the required catalytic fractionation of the titania surface for the SCR reaction is still available. Then the object of the present invention can be met to increase the catalytic activity of a surface while maintaining the stability of the support material.

There is more than one reason why particulate silicas are not preferred to the forms of silica of the present invention, including the forms of particulate silicas with internal porosity and therefore high hole volume. It is well known from what has been written on the subject (e.g. Wachs et al. J. Cat 161, 211-221 (1996)) that silica itself is not a good support material for Vanadia SCR catalysts, while titania and tungsta-doped titania are. It is a good reinforced material. Hence in the present invention, it is desired to reduce the amount of silica surface area that is available to react reversibly with vanadia while increasing the amount of TiO2/WO3 surface area to create a very active catalyst. Thus, only sufficient silica is used to stabilize titania and is used in a form (molecularly distributed on the titania surface) that has a minimal adverse effect on the vanadia catalyst.

Finally another method of making materials of the present invention, wherein the molecular forms of silica previously described can now be used. It is well known that particulate amorphous silica is soluble to a extent that depends on pH and temperature, see for example Iler (op cit page 42). Above about pH 9 and at temperatures above ambient temperature, amorphous silica will be estimated to dissolve hence amorphous silica. The soluble silica can then be deposited again, for example on the titania surface by subsequently lowering the temperature and/or pH to the region of lower silica solubility. In this method, finely mixed particulate silicas can be melted with anatase titania and redistributed in a highly dispersed manner on the titania surface by hydrothermal treatment. However, this post-processing method is not preferred for making the compositions of the present invention, since this step adds processing time and cost during the manufacture of mixed oxide. It is much preferable to use an appropriate silica primer and treat titania directly.

Examples

Titania starting material

In this representation of the present invention, a sulfated titania slurry is used (see Table 1). Sulfated titania slurry can be obtained as an intermediate product in the production process of making titanium dioxide using the sulfuric acid process, for example as produced by the MIC production facility in Thann, France. This thin slurry contains about 27% of the high surface area, hydrous anatase titania, TiO2. TiO2 has primary crystalline particles with sizes less than 5 nm and corresponding BET surface areas of nitrogen in excess of 250 m2/g. The thin slurry has a viscosity of 0.5 3 Pos, a density of 1275 kg/m3, and a low pH of about 1.5 2.0, which in fact results in the thin slurry containing about 6.6 wt% SO3. However, the present invention does not limit the use of this thin mortar. Any composition containing aqueous titania anatase may be used here. When necessary, it is not necessary to use sulfated titania slurry as a primer. A low-sulfate dry anatase titania starter may be used instead.

Type

method

Unit

the description

Remaining after the calcination process

TiO2

Drying and then calcination at 1000 degrees Celsius

% ( the weight )

27+ 1

Iron

TiO2. 15 Fluorescence X-rays

mg/kg

Less than or equal to 80

SO3

G 1.3 Analyze/dry at 105°C

% ( the weight )

6.6 +

P2O5

TiO2. 16 Flou Scanning rays

% ( the weight )

< 0.4

Sodium sodium

TiO2. 47 Atomic Absorption

% ( the weight )

< 0.05

Potassium

TiO2. 5 Fluorescence

% ( the weight )

< 0.01

Pb

TiO2. 13 Fluorescence

% ( the weight )

< 0.01

Peak height

G 1.2 Diffraction X

degree

>

Rutile

TiO2. 48 Diffraction X

Undetected

Private space

G 1.1 BET

m2/g

> 250

* Statistical values

Table No. 1: Composition of Sulfated Titania Slurry treated with sulfur

It is preferable, however, that the titania slurry used here be produced with titania, which is not produced in the presence of urea.

In an embodiment of the invention, the TiO2 component of the catalyst used herein essentially has a surface area of less than 400 m2/g and a pore volume of less than 0.40 cm3/g.

Experimental methods: The composition and stability of catalysts based mainly on titania and the changes that occur during exposure to high temperatures were examined through various means. The methods used consist of X-ray differential analysis (XRD), transmission electron microscopy (TEM), SEM (scanning electron microscopy), and high-magnification resolution solid-state nuclear magnetic resonance spectroscopy (SEM). NMR), nitrogen porosity (nitrogen nitrogen BET / BJH) and catalytic evaluation of the activity of the reaction of NO with ammonia (DeNOx)

XRD: Samples are evaluated for crystal phase composition and crystallite size in the following manner. Samples were prepared for XRD by spherical XRD. PW 1812/00 holders and then analyzed using the Panalytical Instrument conditions were set at 45 kV, 40 mA, 0.0080 2θ/step and 50 s residence time. Phase features enable search matching of empirical models with both the ICCD and ICSD databases. The Rietveld method was used for quantitative phase analysis by X-ray differential. Crystal size was measured on individual peaks using the Scherrer formula as used in the Panalytical High Targets program. Scherrer's formula is actually based on crystal size, which is inversely related to the full width at half maximum (FWHM) of the individual peak - the more narrow, and the crystallite size. The machine expansion value used for the calculation was from the LaB6 standard (NIST profile standard material). In addition to the complete profile method, such as the Rietveld Analysis discovered in the Plus program, the high target X'Pert, in addition to using it to calculate the granular size in addition to that.

TEM: Samples were prepared for TEM analysis by completely dipping the carbon-coated copper TEM grid directly into the powder provided. The mesh was then viewed in TEM at magnifications ranging from 50 to 400,000 times. Analysis was performed using a JEOL 2000FX II TEM operating at 200 kV. During the imaging process, pay special attention to describing the phase size and distribution. Images were calculated with a Gatan MultiScan CCD camera and are in jpeg format.

SEM: Samples were prepared for SEM analysis by spreading the powder provided on the SEM butts of aluminum Al covered with colloidal graphitic carbon. SEM analysis was performed using JEOL 7401 at 2 kV without conductive coating.

Description of the NMR Si29 spectral field of the samples:

Magic angle spinning nuclear magnetic resonance spectroscopy Si29 (SIMASNMR) is a useful method for describing the consistency of silica in solid samples containing silica (see, for example, Engelhardt and Michel, 1987 (op cit,)). As described above. The problem with the Si MASNMR29 spectral range, however, is that nuclear Si29 exists at a naturally low abundance (4.7%), where the method is not very sensitive. The general method for increasing sensitivity is a polar humoral method (see for example Colloid Chemistry of Silica, H. Bergna, ed. ACS Series 234, p. 270 (1994)). In this technique, the polarization spin from a very abundant spin that has a large nuclear magnetic moment (see in the case of H1) is transferred by double resonance to a less abundant spin (Si29). This method has the effect of greatly increasing the sensitivity of the Si29 NMR signal when the silicon silicate has a hydroxide group attached to it. It is known that in silicates, silicon has a tetrahedral arrangement and is surrounded by four oxygen nearest-neighbors and then either hydrogen or silicon next. Isolated tetrahedral silicates placed on the titania surface would be expected to have at least one adjacent nearby hydrogen group, silicon hydroxide, and this proton should increase the sensitivity of the method to bind to silicon silicates. NMR Si29 spectroscopy can also be performed on liquid samples containing low molecular weight dissolved silicates, as also described in Engelhardt and Michel (op cit,).

Nitrogen porosity: Samples were evaluated for nitrogen porosity using Micromeretics TriStar units. The samples were degassed overnight at 150°C under a flow of nitrogen. Then it was cooled to room temperature for adsorption meter. Desorption curves were measured at liquid nitrogen temperature. The surface area was determined using the BET method, and the hole sizes were measured using the BJH method on the adsorption branch.

Vanadia was added by inoculating it with either an alkaline solution (such as, for example, monoethanolamine) or an acidic solution (such as, for example, oxalic acid). Then the inoculated materials were aged at a high temperature in a hydrothermal environment (750 °C for 16 hours in 10% water) (or at 600-900°C for 6 hours in atmospheric air) to cause accelerated aging. It is required to have 100% anatase with a high surface area (associated with very small catalyst crystals), and non-crystalline tungsten after aging treatments.

Examples from No. 1 3: Measuring chemicals:

In the following three examples, we wanted to measure the efficiency of several commercial SCR precursor materials, DT-52TM (Example 1), DT-58TM (Example 2) and DT-S10TM (Example 3). The properties of these three materials are listed in Table 2. It is seen that the DT-52TM contains added tungsta (but not silica), the DT-S10TM contains added silica (but not tungsta), and the DT-58TM contains both tungsta. Tungsta and silica added.

Subject

Property

Unit

DT-52

DT-58

WO3

% by weight

10.0

9.0

0.0

SiO2

% by weight

0.0

10.0

10.0

TiO2

% by weight

balance (90)

balance (81)

balance (90)

Surface area

m2/g

110

110

Crystal Phase

Anatase

Anatase

Anatase

Table 2. Target characteristics of commercial items

For each of the examples from No. 1 and 3, the base materials were used as received and vanadia was loaded onto them in the following manner. A solution of monoethanolamine (MEA) was prepared in ionized water which was 0.4 M (24.4 g/L MEA). To this solution, 10.9 g/liter of V2O5 (0.06 molar) was added. In order to prepare the catalyst with the final vanadia loading 1% by weight, approximately 13.7 g of the solution mentioned above was mixed with 15.8 g of titania support material (loss on ignition = 5% by weight), and the mixture was heated in a rotary evaporator under Vacuum at 75°C until dry. The resulting product was then calcinated in a static blast furnace at a temperature of 600°C, 700°C or 800°C. Similarly, catalysts with a final vanadia loading of 3 wt% were prepared using 41.2 g of MEA/vanadia solution and 15.8 titania.

Then the prepared materials were evaluated for porosity nitrogen, phase composition and crystal size by XRD and for DeNOx activity (refer to the results in Table 3). For DeNOx activity, 0.1 g of sample for each vanadium-loaded catalyst sample was pelleted, mated to a 20/+40 lens, and loaded into the reactor to determine NO conversion in the presence of ammonia. The effluent containing 5%, 02, 1000 ppm ammonia, 1000 ppm NO and 3% water was passed through the catalyst at a space speed of 650 l/g catalytic agent/hour.

the description

Nitrogen porosity

XRD

DeNOx

Example

Supporting material

%V2O5

Temperature, degrees Celsius

surface area (

m2/g)

hole size(

cm2 g)

%anatase

Anatase crystal size (A)

%rutile

Rutile crystal size (a)

%WO3

Tungsta crystal size (A)

% conversion at 325°C

DT-52

600

0.29

100.0

212

0.0

0.0

DT-52

700

0.27

100.0

291

0.0

0.0

DT-52

800

0.04

90.7

1084

0.0

9.3

185

DT-52

600

0.25

97.8

275

0.0

2.2

DT-52

700

0.03

83.9

1380

6.9

2044

9.2

286

DT-52

800

0.01

56.6

1898

34.9

2044

8.9

340

DT-85

600

0.29

100.0

146

0.0

0.0

DT-85

700

0.33

100.0

168

0.0

0.0

DT-85

800

0.31

100.0

249

0.0

0.0

DT-85

600

0.32

100.0

165

0.0

0.0

DT-85

700

0.24

97.8

284

0.0

2.2

DT-85

800

0.06

83.7

1217

8.8

1952

7.6

669

600

0.40

100.0

165

0.0

0.0

DT-S10

700

0.40

100.0

171

0.0

0.0

DT-S10

800

0.38

100.0

192

0.0

0.0

DT-S10

600

0.37

100.0

169

0.0

0.0

DT-S10

700

0.31

100.0

254

0.0

0.0

DT-S10

800

0.14

93.8

1170

6.2

2014

0.0

Table No. 3: Distinguishing comparative examples of commercial materials

An external examination of Table No. 3 confirms that the trends mentioned in what were written and that higher vanadia loadings and higher temperatures are accompanied by a loss of surface area, the conversion of the anatase phase to rutile, crystallization to tungsten, and an increase in crystal size (sintering). ). Individual subjects, however, respond differently from one to another. For example, data for 3% vanadia samples, aged, are plotted in Figures 1 (BET surface area) and Figure 2 (% anatase phase), which have thermal stability indicators for the catalysts crystals.

It can also be clearly seen from these tables No. 1 and 2 and Figures No. 1 and 2 that DT-S10TM (with silica) has a higher thermal stability, followed by DT-58TM (with silica and tungsta), attached by DT-52TM. (With tungsta only). If thermal stability is only a requirement for good vanadia catalyst support then the DT-S10TM would be an obvious choice.

Shown in the following figures (Figures 3 and 4) are DeNOx conversions at 325 °C for materials loaded with 1% and 3% vanadium, respectively. It is clearly seen that the sample with only silica DT-S10TM has a lower conversion for most aging temperatures, while only the sample with 3% vanadia and aged at 800°C has an activity equal to that of DT-58TM.

Thus, based primarily on the efficiency of these commercial samples, there is a clear need to develop a catalyst with both improved stability and activity.

Examples from 4 to 5, the following examples reveal the efficiency of two additional commercial pre-method materials (DT MIC-60TM and Taika ITAC 115 GSTM) with respect to DT-58TM. Samples of these materials were analyzed for composition using x-ray fluorescence analysis, with the results shown in Table 4.

Oxide,% by weight

DT-58

MIC DT-60

Taika

TiO2

80.5

84.2

WO3

9.1

5.3

5.2

SiO2

9.8

10.3

10.2

SiO3

0.4

0.2

0.2

Table No. 4: Material compositions

The results show that the DT-60TM and Tayca TM samples contain negligible amounts of approximately 10 wt% SiO2 and approximately 5 wt% WO3. All three types of materials were loaded with 0.9 wt% V2O5 using precipitation from a MEA solution as in examples 1-3. The products were then aged at 800 °C for 6 hours in a static blast furnace and the products were analyzed using the nitrogen BET method. For DeNOx activity (very small reactor), 0.1 g of sample for each catalyst sample loaded with vanadia was pelleted and crosslinked to a 20/+40 lens and then loaded into the reactor to determine the conversion to NO in the presence of ammonia. The stream containing 5% oxygen, 1000 ppm ammonia, 1000 ppm NO and 3% water was passed through the catalyst at a spatial speed of 650 l/g catalyst/h.

The stability of the surface area for underwater samples is compared to Table 5.

the sample

Surface area (m2/g)

DT-58TM

45.9

DT-60TM

53.3

Taika TM

51.5

Table No. 5: Surface areas of commercial samples

The data shows that samples with a lower tungsta level have slightly greater stability than DT-58TM. However, the DeNOx activities of the catalysts are shown as shown in Figure 5. The activity of the DT-60TM and Tayca TM samples is lower than that of the DT-58TM sample. Thus, as in Examples 1 and 3, Examples 4 and 5 illustrate the need for greater stability and activity of the new materials of the present invention.

Example No. 6: Stability of the silica surface

As noted elsewhere, the present invention directs the provision of ultra-fine titania using a minimal amount and ultra-stable titania using a minimal amount of silica additive. As noted above, particulate silicas (such as, for example, colloidal, fumed, and precipitated) are not ideal sources of silica for use in vanadium-supported titania catalysts because most of the silica is unavailable to react with the titania surface. . The aim of the present invention was to find another form of silica that could be used to attach more efficiently to the surface of titania, but to have less adverse effect on the catalytic activity 10184734 of vanadium supported on the titania surface.

Consideration was given to using silica in a low molecular weight and/or small nanoparticle form instead of the molecular form found in the conventional non-crystalline silica materials described above. The low molecular weight form of silica in aqueous solution is silicic acid, Si(OH)4. However, this chemical quinone has very low solubility in water, so concentrations are limited to a few hundredths of a ppm. (Discussions of the aqueous chemistry of silica in water are found for example in Iler (op cit) and Brinker, C.J. and Scherer, G.W., 1990, Chapter 3.)

From the standpoint of low solubility to Si(OH)4, we have turned to experimenting with tetra(alkyl)ammonium silicate solutions (including but not limited to tetramethylammonium, TMA). These reagents contain silica in low molecular weight forms (see Engelhardt and Michel, op cit). Furthermore, silica is present in these solutions in fairly high concentrations (such as, for example, 9 wt% SiO2). Thus, we consider whether or not the molecular quinones in these solutions may be small enough to selectively interact with the titania surface, while not providing a buffer space for vanadium to bind, which would reduce their catalytic activity.

Si29 NMR spectral domain of a liquid sample of dissolved silicate.

In order to determine the types of silicate in the commercially available TMA silicate solution, the commercial source of the TMA silicate used in these examples (TMA alpha silicate, 9% SiO2) was evaluated using Si29 NMR spectroscopy at 400 MHz by Spectral Data Services Company Limited, shown in Table No. 6 for results.

the description

Q0

Q1

Q2

Q3

Q4

TMA Alpha Silicate (Liquid)

Example No. 6 (solid)

Example No. 14 (solid)

Table No. 6: Q-shapes of silicate solutions (TMA) and Titania solids

It is seen that the TMA silicate solution contains mostly silica species with a conductivity of Q3 or less. However, there is some silica with conductivity of Q4, as the solution does not contain all the silica in an ideal form (conductivity of Q3 or less). However, as will be shown here, we have made the new discovery that soluble silica sources such as tetra(alkyl)ammonium silicate are used to make catalysts based primarily on exceptionally stable vanadia (the anatase phase, space High surface area) that shows excellent catalytic activity for selective catalytic reduction of NOx reactions.

Improved stability by new silica treatment

Examples from No. 1 5 demonstrate the stability and catalytic efficiency of commercial materials loaded with vanadia and exposed to accelerated aging conditions. Example No. 6 illustrates the improvement in thermal stability that can be achieved using the new silica treatment method in accordance with the present invention. The thin slurry of vulcanized titania hydrogel made was diluted to yield a TiO2 content of 21.6 wt%. 112.5 g of this thin slurry was added to the round-bottom flask that was installed with the top stirrer. This thin slurry is heated to a temperature of 60°C via a temperature-controlled temperature shielding jacket and is maintained at that temperature through preparation. To this thin slurry was added 33.3 g of tetramethylammonium silicate (TMA SiO2, Alpha Aesar, 9% SiO2, TMA/SiO2 = 0.5). This mixture was left to react for 20 minutes. Then the pH was adjusted to 6.0 by adding concentrated ammonium hydroxide (29%). Then 3.07 ammonium paratungstate (APT) was added and the pH was adjusted to 6.5 with the addition of more concentrated ammonium hydroxide. This mixture was left to react for an additional 30 minutes, then it was filtered, rinsed with ionic water, and dried. The final trace composition of this oxide basis product was 81 wt% TiO2, 10 wt% SiO2, and 9 wt% WO3. It is then divided into two parts which are calcined over a temperature range of 600-900°C for 6 hours in air using a static blast furnace. The production sample DT-58TM of the same composition was also aged under similar conditions. Both samples were evaluated for surface area retention using the BET method and with the data shown in Figure 6.

The data in Figure 6 clearly show that while the compositions of the two products are only slightly similar, the sample prepared using the low molecular weight and/or small nanoparticle form according to the present invention is much more thermally stable (retains surface area With a larger range than the previous method material (DT-58TM).

MASNMR Si29 spectral field description of solid samples

The following analysis of the material TMA - SiO2 of the invention and the conventional material DT-58TM shows that silica exists in an external form very different from the materials of the present invention. Two samples in their new condition (before adding vanadia but after calcination at 500°C) were analyzed in detail by Spectral Data Services Company Limited using a MASNMR Si29 spectrometer at 270 MHz. I made an attempt to run the DT-58TM sample with mixed polarity but no signal was observed after 1 hour. Under these conditions, no significant signal would be seen if there were any hydroxide groups close to the silicates as would be expected for good silica diffusion on the titania surface. titania surface. This sample was then run for 4 hours using the MASNMR method only. A weak signal was observed at 111 ppm for tetramethylsilane. This signal is constant with silicones in the vicinity of Q4 or Si(OSi)4. Then both observations (lack of the mixed polarity signal and the presence of the Q4 signal) in the NMR experiment are consistent with amorphous silica, where most of the silicones are in the inner molecule of the silica molecule and there are not many groups on Si(OH) on the silica surface. .

The new catalyst support material sample was run under the same minimally invasive NMR conditions and this sample also contained 10 wt% SiO2. However, the source of the silica was TMA SiO2 which contains low molecular weight forms and/ Or a small nano-sized particle of silica. In this case, a strong signal was observed in the H1 Si29 mixture polarity experiment, which shows that there are hydroxyl groups attached to the silicon silicates. This supports the idea that silica is well dispersed on the titania surface in the present invention. Moreover, it is untwisted in the four peaks with the following positions and relative densities 110 ppm, 30% - 100 ppm, 50% - 90 ppm, 16% and -82 ppm (4%) and these peaks know the symmetries Q4, Q3, Q2 and Q1, respectively, as shown in Table 6. It can then be seen that about 70% of the silica is in the symmetry vicinity (Q3, Q2 and Q1) with the hydroxyl groups being the next closest group. This supports the idea that the silica is well dispersed on the titania surface. Thus, we conclude that the use of low molecular weight silica precursor and/or small nanoparticle form such as TMA-SiO2 or other compositions described here gives rise to silica that is well dispersed on the titania surface. In particular, the preferred coordination contour of the silicon atoms of the titania support material of the present invention has essentially (at least 50%) Q3, Q2, Q1 and Q0 symmetries as determined by MASNMR - CP Si29. One major explanation for this difference in the nature of silica is that well-dispersed silica has a greater influence on the mass basis, on the stabilization of titania. Therefore, silica is less necessary for titania to stabilize when silica is widely spread on the titania surface.

In order to also evaluate the nature of the silica coating on the new sample, it was subjected to TEM analysis as shown in Figure 7, which shows the silica present as isolated batches on the surface of anatase titania. The thrusts exhibit a two-dimensional characteristic in that their length is typically less than 5 nm and the depth is typically less than 2 nm (distance from titania surface method).

Example No. 7: The benefit of stability and activity to 90:4:6 of TiO2: SiO2: WO3.

The following example of the invention illustrates the benefit of stability and activity of materials produced according to the methods of the present invention. The thin slurry of a production-made sulfated titania hydrogel was diluted to produce a TiO2 content of 21.6 wt%. 208.3 g of this thin slurry was added to the round-bottom flask that was installed with the top stirrer. This thin slurry is heated to a temperature of 60°C via a temperature-controlled heat shield and is maintained at that temperature through preparation. (In an embodiment of the invention, the titania slurry and the silica component used herein may be mixed at a temperature greater than 80°C and a pH greater than 8.5. Alternatively, the titania slurry silica slurry and the silica component used herein may be mixed at a greater temperature From 70 degrees Celsius and at a pH greater than 7.0). Then 3.4 g of ammonium paratungstate (APT, 88% WO3) was added and left to react for 30 minutes. To this mixture, 22.2 g of tetramethylammonium silicate was added, for Example No. 6, and the mixture was left to react for 10 minutes. Then the pH was adjusted to 6.5 by adding concentrated ammonium hydroxide (NH40H) (29%). This mixture was left to react for an additional 20 minutes, then filtered, rinsed with non-ionic water, dried at 105°C, and then calcinated at 500°C for 6 hours. The final trace composition of this oxide basis product was 90 wt% TiO2, 4 wt% SiO2, and 6 wt% WO3. This vanadia powder was deposited from a MEA solution as in examples 1-3 above, where the final load was 2 wt% V2O5 on the total oxide basis. A portion of the dried powder was then heated to 750°C and held at that temperature for 16 hours in atmospheric air containing 10% by weight water.

Example No. 8: The benefit of stability and activity to 90:5:5 of TiO2: SiO2: WO3.

This further example illustrates the benefit of stability and activity of materials according to the methods of the present invention. The production-made sulfated titania hydrogel thin slurry was thinned to a TiO2 content of 21.6 wt%. 208.3 g of this thin slurry was added to the round-bottom flask that was installed with the top stirrer. This thin slurry is heated to a temperature of 60 degrees Celsius through a temperature-controlled heat shield and is maintained at that temperature through preparation. Then 2.8 g of ammonium paratungstate (APT, 88% WO3) was added and left to react for 30 minutes. To this mixture, 27.8 g of tetramethylammonium silicate (TMA - SiO2, 9% SiO2) were added and the mixture was left to react for 10 minutes. Then the pH was adjusted to 6.5 by adding concentrated ammonium hydroxide (NH40H) (29%). This mixture was left to react for an additional 20 minutes, then filtered, rinsed with non-ionic water, dried at 105°C, and then calcinated at 500°C for 6 hours. The final trace composition of this oxide basis product was 90 wt% TiO2, 5 wt% SiO2, and 5 wt% WO3. This vanadium powder was precipitated from a MEA solution as in examples 1 and 3 above, where the final load was 2 wt% V2O5 on the total oxide basis. A portion of the dried powder was then heated to 750°C and held at that temperature for 16 hours in atmospheric air containing 10% by weight water.

To serve as a base set for comparison, 4 different samples of DT-58TM were loaded with 2 wt% vanadia as above, and hydrothermally aged under sample conditions. Then the results of these four samples were averaged.

The materials from Examples No. 7 and 8 were analyzed together with the reference material DT-58TM by XRD, nitrogen porosity and DeNOx activity with the results shown in Table 7 below. To evaluate the materials for DeNOx applications, 0.1 g of sample for each catalyst loaded sample was pelleted, aged with vanadia to a 20/+40 lens and then loaded into the reactor to determine the conversion to NO in the presence of ammonia. The effluent containing 5% oxygen, 500 ppm ammonia, 500 ppm NO, and 10% water was passed through the catalyst at a spatial speed of 650 l/g catalyst/h. For both example materials 7 and 8, two DeNOx runs were performed. A total of 10 runs were obtained on four DT-58TM reference materials. The results were reported in two ways, the first mentions the conversion of NO and the second method contributes to calculating the reaction rate. When people of ordinary skill realize that an SCR reaction generally must be first order with respect to NO and zero with respect to ammonia, under these conditions the reaction rate is relative to ln (lx), where x is a fractional conversion (% conversion/ 100). Average is the best way to compare samples with high conversions. Basic statistical operations were calculated from the data and analysis of variance showed that the materials of the present invention gave a significant difference (p-value for the null theoretical assumption greater than 0.05) and higher activity than the reference samples.

DT-58*

Example No. 7

Example No. 8

XRD phase

%anatase

95.4

100.0

100.0

%rutile

2.3

0.0

0.0

%WO3

2.3

0.0

0.0

Crystal size (A)

Anatez

391

233

333

Rutile

WO3

498

PSD nitrogen nitrogen

BET surface area (m2/g)

34.9

47.5

30.6

BJH hole size (cm2/g)

0.25

0.29

0.24

% Conversion NO

250 Celsius

19.4

26.7

31.5

three hundred fifty Celsius

64.0

72.6

78.8

450 Celsius

73.1

80.2

82.4

% rate NO

250 Celsius

0.22

0.31

0.38

three hundred fifty Celsius

1.04

1.30

1.57

450 Celsius

1.34

1.62

1.75

* Average of four samples

Table 7, description of samples by nitrogen XRD porosity and DeNOx activity

Figure No. 7 clearly shows that the samples made in accordance with the present invention (Examples Nos. 7 and 8) retain the largest part of the anatase phase, withstand the crystallization of tungsta, and withstand the increase in crystallinity (i.e., showing less sintering) than the basic materials. . Furthermore, the materials of the present invention maintain a higher surface area and hole volume than the reference materials. Finally, the materials made according to the present invention show higher catalytically active activity for the SCR reaction.

The following two examples (Nos. 9 and 10) illustrate the dramatic difference in stability and activity between crystal catalysts made with amorphous silica versus the invented materials.

Example No. 9: The new material of the present invention was prepared in the following manner: A thin slurry of particulate (colloidal) silica versus sulfurized titania hydrogel (comprising 27% TiO2, 7% sulfate, and water) was diluted with water to give 21.7% TiO2. diffuse. 207.7 g of the dispersed material was heated with stirring for 20 minutes to 60°C, and then 2.3 g of ammonium paratungstate (APT, 88% WO3) was added at a low pH. The APT will leave you to react for 20 minutes. Then 44.4 g of a dissolved low molecular weight form of silica tetramethylammonium (TMA) silicate (Alpha Aesar 9 wt% SiO2) was added and left to react for another 20 minutes. Then the pH was adjusted to approximately 6.5 by adding concentrated ammonium hydroxide NH40H (this step must be completed before adding WO3). Then the thin slurry was filtered and rinsed without ammonium sulfate, then dried and calcinated at 500 degrees Celsius for 6 hours in air. The trace composition of this base material was 88 wt% TiO2, 8 wt% SiO2, and 4 wt% WO3 (TiO2 : SiO2 : WO3 = 88 : 8 : 4).

Example No. 10: The comparison sample was made using conventional molecular colloidal silica in the following manner: The thin slurry of production-made sulfated titania hydrogel made to produce (27% TiO2) was diluted with water to give 21.6% TiO2 dispersion. 203.7 g of the dispersed material was heated with stirring at 60°C, and then 2.3 g of ammonium paratungstate (APT, 88% WO3) was added. APT was left to react for 20 minutes. Then 13.3 g of AS-30 colloidal silica (WRGrace 30 wt% SiO2) was added and left to react for another 20 minutes. As will be realized by a person of ordinary skill in the art, this form of colloidal silica is stabilized with the ammonium ion rather than the sodium ion, since the later is the catalyst poison for the SCR reaction. Then the pH of the mixture was adjusted to 6.5 by adding concentrated ammonium hydroxide NH40H. Then the thin slurry was filtered, washed, dried and calcinated at 500°C for 6 hours in air. The trace composition of this base material was 88 wt% TiO2, 8 wt% SiO2, and 4 wt% WO3. Thus, the materials of both examples No. 9 and 10 have slightly the same general composition (TiO2: SiO2: WO3 = 88: 8: 4) on an oxide basis.

Materials comprising titania, silica and tungsten vanadia were added to these base materials to target 2% by weight V2O5. Vanadia was added by impregnation with alkaline MEA solution. Then the inoculants were aged at high temperatures in a hydrothermal environment (750°C for 16 hours in 10% water) to cause accelerated aging. The mature samples were evaluated by X-ray diffraction analysis, and the different patterns observed were analyzed by Rietveld analysis. In order to evaluate the materials of Example No. 9 and 10 for DeNOx uses, 0.1 g of a vanadium-loaded catalyst sample was pelleted, denatured, attached to the 20/+40 lens, and loaded into the reactor in order to determine the NO conversion in the presence of ammonia. The effluent containing 5% oxygen, 500 ppm ammonia, 500 ppm NO and 10% water was passed through the catalyst at a speed of 650 l/g catalyst/h. No conversion or rate data is specified as described above

DT-58*

Example No. 9

Example No. 10

XRD phase

% Anatase

95.4

100.0

91.2

%rutile

2.3

0.0

6.1

%WO3

2.3

0.0

2.7

XRD crystal size (a)

Anatase

391

200

1863

Rutile

89

0

NM

WO3

498

0

268

PSD nitrogen nitrogen

BET surface area (m2/g)

34.9

54.2

8.1

Hole size BJH (cm2/g)

0.25

0.26

0.04

% Conversion NO

250 Celsius

19.4

20.1

8.4

three hundred fifty Celsius

64.0

64.6

34.0

450 Celsius

73.1

70.8

33.2

% rate NO

250 Celsius

0.22

0.22

0.09

three hundred fifty Celsius

1.04

1.04

0.42

450 Celsius

1.34

1.23

0.40

Table No. 8 Description of samples

The results of Table No. 8 show the significant benefit in the stability of the anatase phase (and resistance to sintering) provided by the materials of the present invention, the benefit related to the surface area associated with the innovative materials, and the benefit of the activity associated with the present invention (Example No. 9) relative to the manufactured sample. With colloidal silica (Example No. 10).

The vanadia-loaded catalyst and the shedding from Example 10 were evaluated using SEM microscopy (Figure 8) and TEM (Figure 9). The images clearly show the presence of macromolecular colloidal silica particles with diameters of approximately 20 nm for the subsurface and approximately 100-200 nm for the diameter of vanadia-anatase titania particles.

Example No. 11: This example shows another representation of the present invention, which contributes to the dissolution of amorphous silica attached to the re-deposition of the surface coating of silica on titania through hydrothermal treatment at a high pH. The production-made sulfated titania hydrogel thin slurry was diluted with a 21.6% TiO2 content. 833.3 g of this thin slurry was added to the round-bottom flask that was installed with the top stirrer. This thin slurry was heated to a temperature of 60°C via a temperature-controlled heat shield and was maintained at that temperature through preparation. To this thin slurry, 13.6 g of ammonium paratungstate (APT, 88% WO3) was added and left to react for 20 minutes. Then the pH was adjusted to 6.0 by adding concentrated ammonium hydroxide (NH40H) (29%). To this mixture, 80 g of evaporated silica dispersant (Cabot MS, 10% SiO2 in non-ionized water (SiO2 in DI water)) was added and the mixture was left to react for 20 minutes. Then the pH was adjusted to 9.0 by adding concentrated ammonium hydroxide (NH40H) (29%), and this thin slurry was heated to reflow for 6 hours. Then it was cooled slowly to precipitate the soluble silica, filtered and rinsed with non-ionized water (DI water), dried at 105 degrees Celsius, and then calcinated at 500 degrees Celsius for 6 hours. The final trace composition of this product on an oxide basis was 90 wt% TiO2, 4 wt% SiO2, and 6 wt% WO3 (90:4:6). Under these conditions, the fractional monolayer coverage specifically of silica on titania is less than 1.0. Vanadia was added to this powder from the MEA solution, as in examples No. 1 and 3 above, where the final loading was 2% by weight V2O5 on a total oxide basis. Then a portion of the dried powder was heated to 750°C and held at that temperature for 16 hours in atmospheric air containing 10% air.

The catalyst material from Example 11 was analyzed by XRD, nitrogen porosity, DeNOx activity, and TEM. In order to evaluate a material for DeNOx applications, 0.1 g of sample for each vanadium-loaded catalyst sample and denaturant was pelleted, coupled to a 20/+40 lens, and loaded into the reactor to determine the NO conversion in the presence of ammonia. The flow stream containing 5% oxygen, 500 ppm ammonia, 500 ppm NO and 10% water was passed through the catalyst at a speed of 650 l/g catalyst/h. The results are presented in Table 9.

DT-58*

Example No. 11

XRD phase

%anatase

95.4

100.0

%rutile

2.3

0.0

%WO3

2.3

0.0

XRD crystal size

( a )

Anatez

391

309

Rutile

89

0

WO3

498

0

PSD nitrogen nitrogen

BET surface area (m2/g)

34.9

30.6

Hole size BJH (cm2/g)

0.25

0.21

No rate %

250 Celsius

19.4

30.6

three hundred fifty Celsius

64.0

77.6

450 Celsius

73.1

83.5

No rate %

250 Celsius

0.22

0.36

three hundred fifty Celsius

1.04

1.50

450 Celsius

1.34

1.80

* Average of four samples

Table 9. Description of samples

TEM analyzes as shown in Figures 10 and 11 indicate that while there are a few remaining spherical silica particles that are not completely dissolved and redeposited, they are typically less than 5 nanometers in size. Mostly, the fumed silica has been extensively dissolved and redeposited on the anatase surface as a hard coating, which is more effective in modifying the surface properties of the underlying titania below the line.

These results demonstrate the significant benefit in anatase phase stability (and resistance to sintering) provided by the material of the present invention, the benefit of surface area retention associated with the inventive materials, and the benefit of activity associated with the present invention when silica is dissolved and redistributed in molecular form to molecular form. Nano-particulate in order to provide a uniform covering on the titania surface.

Example 12: The example is another illustration of the beneficial effect of redistributing silica via hydrothermal treatment, only if the starting source is colloidal silica. The production-made sulfated titania hydrogel thin slurry was diluted to produce a 21.6% TiO2 content. 208.3 g of this thin slurry was added to the round-bottom flask that was installed with the top stirrer. This thin slurry was heated to a temperature of 60°C via a temperature-controlled heat shield and was maintained at that temperature through preparation. To this mixture, 6.7 g of colloidal silica AS 30 (WRGrace 30% by weight SiO2) was added and the mixture was left to react for 30 minutes. Then 3.4 g of ammonium paratungstate (APT, 88% WO3) was added and left to react for 10 minutes. Then the pH was adjusted to 6.5 by adding concentrated ammonium hydroxide (NH40H) (29%). Then the pH was adjusted to 9.0 by adding concentrated ammonium hydroxide (NH40H) (29%), and this thin slurry was heated to reflow for 6 hours. Then it was filtered, rinsed with non-ionized water (DI), dried at 105 degrees Celsius, and then calcinated at 500 degrees Celsius for 6 hours. The final trace composition of this product on an oxide basis was 90 wt% TiO2, 4 wt% SiO2, and 6 wt% WO3 (90:4:6). Under these conditions, the fractional monolayer coverage specifically of silica on titania is less than 1.0. Deposited vanadia was added to this powder from the MEA solution, as in examples No. 1 and 3 above, where the final load was 2% by weight V2O5 on a total oxide basis. Then a portion of the dried powder was heated to 750 °C and held at that temperature for 16 hours in atmospheric air containing 10% water.

The catalyst material from Example 12 was analyzed by nitrogen porosity XRD, DeNOx activity, and TEM. In order to evaluate the material in Example No. 12 for DeNOx uses, 0.1 g of sample for each catalyst sample loaded with vanadia and denaturant was pelleted and attached to the 20/+40 lens, and loaded into the reactor in order to determine the NO conversion in the presence of ammonia. The effluent containing 5% oxygen, 500 ppm ammonia, 500 ppm NO and 10% water was passed through the catalyst at a spatial speed of 650 l/g catalyst/h.

The results are presented in Table No. 10 compared to the preparation with colloidal silica (but not hydrothermal treatment, Example No. 10). DeNOx and BET nitrogen analyzes show that Example Material No. 12 has improved anatase phase stability and resistance to sintering, while the catalytic results show that Example Material No. 12 also has improved catalytically active activity associated with hydrothermal redistribution of silica.

Example No. 12

Example No. 10

XRD phase

%anatase

91.6

91.2

%rutile

6.6

6.1

%WO3

1.8

2.7

XRD crystal size (a)

Anatez

562

1863

Rutile

40

NM

WO3

694

268

PSD nitrogen nitrogen

BET surface area (m2/g)

23.3

8.1

Hole size BJH (cm2/g)

0.15

0.04

No conversion%

250 Celsius

31.0

8.4

three hundred fifty Celsius

76.4

34.0

450 Celsius

79.9

33.2

No rate %

250 Celsius

0.37

0.09

three hundred fifty Celsius

1.40

0.42

450 Celsius

1.40

0.40

* Average of four samples

Table No. 10 Description of samples

The TEM image of example material No. 12 is shown below in Figure No. 12. The analysis indicates that while there are a few remaining spherical silica particles that do not dissolve completely and are re-deposited (approximately 10 nanometers in size or less) for most of the fraction, the Mainly colloidal silica and re-deposited on the anatase surface as a rough, discontinuous cover, which is more effective in modifying the surface properties of titania.

Example No. 13: Silicic acid: This example provides another representation of the invention, where low molecular weight silica is in the form of silicic acid generated by ion-exchange of sodium silicate. First, a dilution solution (3 wt% SiO2) of sodium silicate was prepared by adding 569 g of nonionic ion-exchange water to 71 g of Philadelphia Quartz N sodium silicate, 28.7 wt% SiO2. 650.7 g of the portion of strong acid ion-exchange resin (as received) was weighed (format H Dowex 650 °C). Separately, a thin slurry of production-made sulfated titania hydrogel was diluted to produce a 21.6% TiO2 content. 1666.7 g of this thin slurry was added to the round-bottom flask that was installed with the top agitator. This thin slurry was heated to a temperature of 60 degrees Celsius using a temperature-controlled heat shield and was maintained at that temperature through preparation. Then, the ion exchange resin was added to the diluted sodium silicate solution, mixing well and monitoring the temperature. Acidity. When the pH indicated that the ion-exchange reaction had continued to completion (pH greater than 3.0), the resin was filtered and 533 g of silicic acid was added to the titania slurry. This mixture was left to react for 20 minutes. 27.3 g of ammonium paratungstate (APT, 88% WO3) was added and left to react for 20 minutes. Then the pH was adjusted to 6.5 by adding concentrated ammonium hydroxide NH40H (29%). The mixture was then filtered, rinsed with de-ionized water (DI), dried at 105°C, and then calcinated at 500°C for 6 hours. The final trace composition of this product on an oxide basis was 90 wt% TiO2, 4 wt% SiO2, and 6 wt% WO3 (90:4:6). Under these conditions, the fractional monolayer coverage specifically of silica on titania is less than 1.0. Vanadia powder was added from the MEA solution as in examples No. 1-3 above, where the final load was 2% by weight V2O5 on a total oxide basis. Then a portion of the dried powder was heated to 750°C and held at that temperature for 16 hours in atmospheric air containing 10% water. In order to evaluate the materials of Example 13 for DeNOx applications, 0.1 g of sample for each vanadium-loaded catalyst sample and denaturant was pelleted, attached to a 20/+40 lens, and loaded into the reactor in order to determine the NO conversion in the presence of ammonia. The effluent containing 5% oxygen, 500 ppm ammonia, 500 ppm NO and 10% water was passed through the catalyst at a spatial speed of 650 l/g catalyst/h. Then, the mature samples were evaluated by XRD, PSD, nitrogen, and DeNOx conversion and compared against DT-58 as shown in Table 11.

DT-58*

Example No. 13

XRD phase

%anatase

95.4

100.0

%rutile

2.3

0.0

%WO3

2.3

0.0

XRD crystal size (a)

Anatez

391

286

Rutile

89

0

WO3

498

0

PSD nitrogen nitrogen

BET surface area (m2/g)

34.9

40.8

Hole size BJH (cm2/g)

0.25

0.27

No conversion%

250 Celsius

19.4

29.6

three hundred fifty Celsius

64.0

76.7

450 Celsius

73.1

83.0

* Average of four samples

Table 11 Description of samples

It is clearly seen that the materials prepared according to the present invention have anatase phase stability, better surface area retention (sintering resistance), and higher DeNOx activity compared to DT-58. TEM analysis was performed for example material No. 13, and the prominent results in Figures No. 13 and 14 show that silica exists as two-dimensional batches that are also distributed on the titania surface. There are a few rare three-dimensional molecules that can be identified as the presence of silica in some images, but most of the molecules are less than approximately 5 nanometers in size.

Example No. 14: This example provides another representation of the invention where low molecular weight silica is in the form of silicic acid formed by ion-exchange of sodium silicate. First, a dilution solution (3% SiO2) of sodium silicate was prepared by adding 59.7 g of non-ionized water DI water to 7.0 g of sodium silicate for Philadelphia Quartz N sodium silicate, 28.7% by weight of SiO2. A 13.5 g portion of strong acid ion-exchange resin (as received) was weighed (format H Dowex 650°C) and added to the column during flow. Separately a thin slurry of production-made sulfated titania hydrogel was diluted to produce a 21.6% TiO2 content. 208.3 g of this thin slurry was added to the round-bottom flask that was installed with the top stirrer. This thin slurry was heated to a temperature of 60°C via a temperature-controlled heat shield and was maintained at that temperature through preparation. Then 66.7 g of diluted sodium silicate solution was passed through the column to remove sodium. The mixture was left to react for 20 minutes. Then 3.4 g of ammonium paratungstate (APT, 88% WO3) was added and left to react for 20 minutes. Then the pH was adjusted to 6.5 by adding concentrated ammonium hydroxide (NH40H) (29%). Then the mixture was filtered, rinsed with non-ionized water (DI water), dried at 105 degrees Celsius, and then calcinated at 500 degrees Celsius for 6 hours. The final trace composition of this product on an oxide basis was 90 wt% TiO2, 4 wt% SiO2, and 6 wt% WO3 (90:4:6). This composition, before adding vanadia, had a BET surface area of nitrogen of 221 m2/g, where silica is found when covering a molecular monolayer. Fractional monolayer value of 0.30 is known below 1 monolayer. This sample was evaluated using TEM. The identical sample was prepared, except for the spectral domain. The NMR results presented in Table 6 show that most of the silica present in the sample has a consistency of Q3 or less, as would be expected for silica distributed in two dimensional batches on the titania surface. The TEM image shown in Figure 15 shows that the silica exists as a discontinuous covering of 1.3 nm on the anatase titania crystallite surface and there is no distinction, and three-dimensional particles on the silica can be seen larger than 5 nm in diameter.

A solution of MEA was added to this powder, as in examples No. 1 and 3 above, where the final loading was 2% by weight V2O5 on a total oxide basis. A portion of the dried powder was then heated to 750°C and held at that temperature for 16 hours in atmospheric air containing 10% water. In order to evaluate the materials of Example 14 for DeNOx uses, 0.1 g of sample for each vanadium- and denaturant-loaded catalyst sample was pelleted, attached to a 20/+40 lens, and loaded into the reactor in order to determine the NO conversion in the presence of ammonia. The effluent containing 5% oxygen, 500 ppm ammonia, 500 ppm NO and 10% water was passed through the catalyst at a spatial speed of 650 l/g catalyst/h. Then the mature samples were evaluated by XRD, PSD nitrogen, DeNOx and compared against DT-58 as shown in Table 12.

DT-58*

Example No. 14

XRD phase

%anatase

95.4

100.0

%Rutile

2.3

0.0

%WO3

2.3

01.0

XRD crystal size

( a )

Anatez

391

336

Rutile

89

0

WO3

498

0

PSD nitrogen nitrogen

BET surface area (m2/g)

34.9

31.9

BJH hole size (cm2/g)

0.25

0.25

No conversion rate

250 Celsius

19.4

0.41

three hundred fifty Celsius

64.0

1.67

450 Celsius

73.1

1.99

Table No. 12 Description of samples

It is clearly seen that the materials prepared according to the present invention have anatase phase stability, better surface area retention (sintering resistance), and higher DeNOx activity compared to DT-58.

Example No. 15: This example is intended to show that the various materials of the previous method are different from those of the present invention. Specifically make reference to US Patent No. 4,221,768, column 3, 4 (line 3), Example No. 1 and US Patent No. 2007/0129241 (paragraph 0026). In this example, particulate colloidal silica is incorporated into titania during the deposition of titania. First, 1169 g of water was added to 4 liters of a glass cup and this was placed in a refrigerator bath to cool. Then 330 g of TiOCl2 solution (25.9% TiO2) was added slowly with stirring to the cooled water, so that the temperature of the solution did not rise above 30 °C, to make a 5.7% TiO2 solution. Then 544.6 g of this solution was placed in a 1-liter glass beaker and then stirred vigorously. To this mixture was slowly added 4.33 g of colloidal silica AS 30 Ludox (WRGrace 30 wt% SiO2). Then, concentrated ammonium hydroxide (29%) was added to this suspension until the pH reached 7. The thin deposited slurry was aged for two hours. It was filtered, rinsed with non-ionic DI water, and then dried at 105°C. The oxide basis composition of this powder was 4 wt% SiO2 and 96 wt% TiO2. Then the thin slurry was treated with 27 g of dried powder (84.5% solids) in 100 g of de-ionized DI water and heated to 60°C, then 1.7 g of APT was added and left to react for a period of time. 20 minutes. Then the pH was adjusted to 7, the final mixture was filtered, dried at 105°C, and then calcinated at 500°C for 6 hours. The final trace composition of this oxide basis product was 90 wt% TiO2, 4 wt% SiO2, and 6 wt% WO3. Vanadia was added to this powder from the MEA solution, as in examples 1 and 3 above, where the final loading was 2% by weight V2O5 on a total oxide basis. Then a portion of the dried powder was heated to 750°C and held at that temperature for 16 hours in atmospheric air containing 10% water. In order to evaluate the materials of Example 15 for DeNOx applications, 0.1 g of sample for each vanadium-loaded catalyst sample and denaturant was pelleted, threaded to a 20/+40 lens, and loaded into the reactor in order to determine the NO conversion in the presence of ammonia. The effluent containing 5% oxygen, 500 ppm ammonia, 500 ppm NO and 10% water was passed through the catalyst at a spatial speed of 650 l/g catalyst/h. Then, the mature samples were evaluated by XRD, PSD nitrogen, DeNOx and compared against DT-58 as shown in Table 13 and Figure 16.

DT-58*

Example No. 15

XRD phase

%anatase

95.4

90.0

%rutile

2.3

9.0

%WO3

2.3

1.0

XRD crystal size

( a )

Anatez

391

935

Rutile

89

1567

WO3

498

190

PSD nitrogen nitrogen

BET surface area (m2/g)

34.9

10.2

Hole size BJH (cm2/g)

0.25

0.07

No conversion%

250 Celsius

19.4

13.2

three hundred fifty Celsius

64.0

46.3

450 Celsius

73.1

57.9

* Average of four samples

Table 13 Description of samples

The results clearly show that the comparison material for Example No. 15 (which is not composed of low molecular weight silica and/or small nanoparticle silica clearly) has a clearly lower stability and activity than in the reference DT-58 samples. In addition, TEM analysis (Figure 16 shows that silica exists as large three-dimensional nodes (such as, for example, less than 20 nanometers to 50 nanometers or larger in size).

Example No. 16: This representation is similar to the representations of the previous method, where silica is incorporated in a dissolved form in the precipitation (see, for example, US Patent No. 4221768, column 3, line 36, except in this example TMA silica is used for the present invention as in Example No. 7 , 8 and 9. In this example, the material is prepared by incorporating silica again during the deposition of titania. However, in this case, TMA silicate is used as a source of silica, and titanyl sulfate solution is used as a source of titania. First, 990 g of titanyl sulfate solution (10.1% TiO2, approximately 29% sulfuric acid H2SO4) was added to a 1-liter beaker. In the separate beaker, 26.5% of TMA silicate (9 wt% SiO2, Alpha Aesar) was diluted with 350 ml deionized water. In the third bowl with a continuous flow of removing the deposited flake slurry, 150 g of water was added and then this bowl was stirred. The titanyl sulfate solution was pumped to vessel 3 at a rate of 20 ml/min, and the TMA silicate solution was also pumped to vessel 3 at a rate of 10 ml/min. Also, ammonium hydroxide (NH40H) in concentration (29%) was pumped to vessel 3 in order to keep the pH of the oxide precipitation at 6.0. The total flow from vessel 3 was taken into the other beaker. It is known to a person of ordinary skill in the art that vessel 3 is a continuous flow, stirred vacuum reactor. When the precipitation of oxides was complete, the precipitate was filtered, rinsed with non-ionic water, and then dried at 105°C. The oxide basis composition of this powder was 2.5 wt% SiO2, 97.5 wt% TiO2.

Then the thin slurry was treated with 51.2 g of dried powder (73% solids) in 122 g of deionized DI water and heated to 60°C, then 1.8 g of APT was added and left to react for a period of time. 20 minutes. Then the pH was adjusted to 6.5 and left to react for 20 minutes. The final mixture was filtered, dried at 105°C, and calcinated at 500°C for 6 hours. The final trace composition of this product on an oxide basis was 93.5 wt% TiO2, 2.5 wt% SiO2, and 4 wt% WO3 (93.5:2.5:4). Vanadia was added to this powder from the MEA solution, as in examples No. 1 and 3 above, where the final load was 2% by weight V2O5 on a total oxide basis. Then a portion of the dried powder was heated to 750 °C and held at that temperature for 16 hours in atmospheric air containing 10% water. In order to evaluate the materials of Example No. 16 for DeNOx uses, 0.1 g of sample for each catalyst sample loaded with vanadia and denaturant was pelleted, attached to a 20/+40 lens, and loaded into the reactor in order to determine the NO conversion in the presence of ammonia. The effluent containing 5% oxygen, 500 ppm ammonia, 500 ppm NO and 10% water was passed through the catalyst at a spatial speed of 650 l/g catalyst/h. Then, the mature samples were evaluated by XRD, PSD, nitrogen, and DeNOx conversion and compared against DT-58 as shown in Table 14.

The results clearly show that the vector material under conditions where low molecular weight silica and/or small nanoparticle form is incorporated during titania deposition has low anatase phase stability, sintering resistance, and low DeNOx activity for these ground state materials. . Shown in Figure 17 is a very small electron transmission TEM (TEM) of the vanadia catalyst, which displays large nodes of three-dimensional silica that are not well distributed on the titania surface.

DT-58*

Example No. 16

XRD phase

%anatase

95.4

82.3

%rutile

2.3

14.8

%WO3

2.3

2.9

XRD crystal size (a)

Anatez

391

1456

Rutile

89

1994

WO3

498

353

PSD nitrogen nitrogen

BET surface area (m2/g)

34.9

12.0

Hole size BJH (cm2/g)

0.25

0.05

No conversion%

250 Celsius

19.4

12.2

three hundred fifty Celsius

64.0

50.0

450 Celsius

73.1

55.8

* Average of four samples

Table No. 14 Description of samples

Example No. 17: This representation is similar to Example No. 16, only the final composition is (90:4:6 TiO2:SiO2:WO3 before adding vanadia. In this example, the material is prepared by melting the silica again during the deposition of titania. First, the titania is added. 891 g of titanyl sulfate solution (10.1% TiO2, approximately 29% sulfuric acid H2SO4) to a 1 liter beaker. In the separate beaker, 44.4% of TMA silicate (9 wt% SiO2, Alpha Aesar) was diluted with 400 ml of water. Non-ionizing. In the third bowl with a continuous removal flow of the deposited thin slurry, 150 g of water was added and then this bowl was stirred. The titanyl sulfate solution was pumped into vessel 3 at a rate of 20 ml/min, and the TMA silicate solution was also pumped into vessel 3 at a rate of 10 ml/min. Also, concentrated ammonium hydroxide (NH40H) (29%) was pumped into vessel 3 in order to keep the pH of the oxide precipitation at 6.0. The total flow from vessel 3 was taken into the other beaker. It is known to a person of ordinary skill in the art that Vessel 3 is a continuous flow, stirred vacuum reactor. When the precipitation of oxides was complete, the precipitate was filtered, rinsed with non-ionic water, and then dried at 105°C. The oxide basis composition of this powder was 4.3 wt% SiO2, 96.7 wt% TiO2.

Then, all the dried powder was treated with a thin slurry in approximately 150 g of non-ionized DI water and heated to 60 degrees Celsius, then 6.8 g of APT was added and left to react for 20 minutes. Then the pH was adjusted to 6.5 and left to react for 20 minutes. The final mixture was filtered and dried at 105°C and calcinated at 500°C for 6 hours. The final trace composition of this product on an oxide basis was 90 wt% TiO2, 4 wt% SiO2, and 6 wt% WO3. Vanadia was added to this powder from the MEA solution, as in examples No. 1 and 3 above, where the final loading was 2% by weight V2O5 on a total oxide basis. Then a portion of the dried powder was heated to 750°C and held at that temperature for 16 hours in atmospheric air containing 10% water. To evaluate the materials of Example 17 for DeNOx applications, 0.1 g of sample for each vanadium-loaded catalyst sample and denaturant was pelleted, attached to a 20/+40 lens, and loaded into the reactor in order to determine the NO conversion in the presence of ammonia. The stream containing 5% oxygen, 500 ppm ammonia, 500 ppm NO and 10% water was passed through the catalyst at a space speed of 650 l/g catalyst/h. Then, the mature samples were evaluated by XRD, PSD nitrogen, DeNOx and compared against DT-58 as shown in Table 15.

DT-58*

Example No. 17

XRD phase

%anatase

95.4

94.5

%rutile

2.3

3.9

%WO3

2.3

1.6

XRD crystal size (a)

Anatez

391

748

Rutile

89

795

WO3

498

180

PSD nitrogen nitrogen

BET surface area (m2/g)

34.9

18.2

Hole size BJH (cm2/g)

0.25

0.09

No conversion%

250 Celsius

19.4

16.2

three hundred fifty Celsius

64.0

58.4

450 Celsius

73.1

67.0

* Average of four samples

Table No. 15 Description of samples

The results clearly show that the material made in which soluble silica is incorporated during titanium precipitation has the low anatase phase stability, low sintering resistance and DeNOx activity of these ground state materials.

Example No. 18: shows a representation of the effect of calcination temperature on the lower DeNOx activity of the materials of the present invention. The DT-58 reference catalysts loaded with 2% V2O5 described in Example 8 were used as a benchmark. 90:4:6 of the TiO2:SiO2:WO3 composition of the present invention as prepared in Example No. 13 (intermittent mode) and Example No. 14 (continuous mode) was loaded with 2 wt% V2O5 as described in these examples. Also loaded was 88:8:4 of the TiO2:SiO2:WO3 composition of the present invention as prepared in Example No. 9 with 2% V2O5 as described herein. Then, these materials were exposed to high temperatures (calcination) ranging from 500 to 850 degrees Celsius, and the rate of catalytic activity DeNOx was measured, as in Example No. 17. The results data were fit by referring to polynomial functions, and the appropriate curves are displayed in Figure No. 18. Explains all of No. 18: To obtain the maximum activity of the vanadia catalyst materials of the present invention, in particular the activity that is greater than that of the reference DT-58, the vanadia catalyst materials must first be exposed to high temperatures, i.e. temperatures in excess of 650. Celsius.

UTILITY

With respect to the present invention in this representation, it refers to compositions comprising anatase titania, where titania is stabilized by silica supplied in a low molecular weight form and/or a small nanoparticle form. The invention also directs the use of these silica-titania compositions as catalyst supports, in particular in a mixture with vanadia and titania added for the optional catalytic reaction based primarily on vanadia to DeNOx from lean-burn diesel engines. (diesel) engines. The invention also directs to methods for producing supporting materials for silica-stabilized titania or titania-tungsta and catalysts based primarily on vanadia, which include silica-stabilized titania or supporting materials for silica-stabilized titania or Tungsta titania and methods for producing vanadia catalysts and catalytic devices including vanadia catalysts catalysts these.

The actual specific composition of the support material for the silica-titania or silica-titania-tungsta catalyst depends on the requirements for the particular catalytic application. In this preferred composition, the invention includes a silica-stabilized titania catalyst support material comprising particles comprising less than or equal to 90% by dry weight TiO2 and greater than or less than 10% by weight SiO2. In another preferred embodiment, the invention includes a silica stabilized titania-tungsta catalyst suppor with less than or equal to 85% by dry weight of titania, 3% by dry weight of SiO2 and 3.10% by dry weight of WO3. Alternatively, in this representation where particularly good thermal stability is required for use, the catalyst support material includes less than or equal to 85% by dry weight of TiO2, of 5.9% by dry weight of SiO2, and of 3.7%. Dry weight of WO3. More specifically, this catalyst support material includes a stable catalyst support material of 87-89% dry weight TiO2, 7.9% dry weight SiO2, and 3.5% dry weight WO3. In this preferred representation the catalyst support material includes about 88% (+ 0.5%) by dry weight of TiO2, about 8% (+ 0.5%) by dry weight of SiO2, and about 4% (+ 0.5%) by dry weight of WO3. In this representation, the wt% WO3 is less than the wt% SiO2. In this representation, the catalytic support material has a new surface area of at least 80 m2/g and, more preferably, at least 100 m2/g.

In another embodiment where the use requires particularly good catalytically active activity, the catalyst support material includes greater than or equal to 85% by dry weight TiO2, of 3.8% by dry weight of SiO2 and of 4.9% by dry weight of WO3. To a more specific extent, this active catalyst support material includes greater than or equal to 87% dry weight TiO2, 3.6% dry weight SiO2, and 4.8% dry weight WO3. In this preferred representation the catalytic support material includes about 90% (+ 0.5%) by dry weight of TiO2, about 4% (+ 0.5%) by dry weight of SiO2, and about 6% (+ 0.5%) by dry weight of WO3. In this representation, the wt% WO3 is greater than the wt% SiO2. In this representation, the catalytic support material has a new surface area of at least 80 m2/g and, more preferably, at least 100 m2/g.

In an representation of the invention the TiO2 component of the catalytic support material used herein essentially includes a surface area of less than 400 m2/g and a pore volume of less than 0.40 cm3/g.

In an representation of the invention, the thin slurry of Titania slurry and the silica component used here are mixed at a temperature greater than 80 degrees Celsius and at a pH less than 8.5. Alternatively, the Titania slurry and the silica component used here may be mixed at a temperature of less than 70°C and a pH of less than 7.0.

In another embodiment, the invention is for a vanadia catalyst including silica-stabilized titania or the new titania-tungsta catalyst support described herein in which an amount of vanadium oxide V2O5 is placed. In a vanadia catalyst, it is preferable to include V2O5 of 0.5 to 3% by dry weight. The invention is also directed to diesel emission catalytic devices containing vanadia catalysts described here. The vanadia catalyst materials of the invention may also be treated with a calcination process at a temperature greater than or equal to 650°C in order to increase their catalytic activity to DeNOx.

Moreover, these new catalytic devices may be used upstream or downstream of the diesel molecular filter in the diesel emission control system. In the catalytic system, in the upstream system, it is between the motor and the diesel particulate filter, and in the downstream system, the diesel particulate filter is between the motor and the catalytic system.

Where the term titania support material silica is used here is intended to have the same meaning as the stable titania support material silica, and where the term silica support material titania tungsta is intended to have the same meaning as the support material titania tungsta stable silica.

It is often preferable for the silica particles in stable titania-supported magma particles to have diameters of less than 5 nm, most preferably less than 4 nm, most preferably less than 3 nm, still most preferable less than 2 nm, and/or weights include low molecular weight. low molecular weight (for example, the molecular weight is less than 100,000 and whether or not these molecules placed there have V2O5).

The titania silica support material particles contain V2O5, and it is preferable to include V2O5 from 0.5-3% by dry weight of the support material.

The distribution of WO3 and SiO2 types on the surface of the titania support material also plays a role in improving the DeNOx activity of vanadia catalysts. Therefore, when catalysts are prepared in a new form, which is when silica and tungsta oxides are added first and before high-temperature treatment, the fractional monolayer coverage specifically must be about 1.0 or less.

As noted before, the stability of the titania support material with silica contributes to the treatment of titania with silica in a low molecular weight form and/or a small nanoparticle form such as tetra(alkyl)ammonium silicate. (ammonium silicate (such as, for example, tetramethylammonium silicate) or tetraethylorthosilicate (TEOS). Other examples of low molecular weight silica initiators include weight and/or small nanoparticle silica) clearly, which may be used in the present invention, but are not limited to aqueous solutions of silicon halides (i.e., non-aqueous anhydrous SiX4, where X = fluorine F, chlorine Cl, bromine Br or iodine I), silicon alkoxides (i.e. Si(OR)4 where R = methyl, ethyl, isopropyl, propyl, butyl, iso-butyl, sec-butyl, tert-butyl, pentyl pentyls, hexyls, octyls, nonyls, decyls, undecyls and dodecyls, for example), other silicon-organic compounds such as hexamethyldisilazane, fluoro-silicic acid salts such as ammonium hexa ammonium hexafluorosilicate [(NH4)2SiF6], and quaternary ammonium silicate solutions (such as for example (NR4)n, (Si02), where R = hydrogen or alkyl alkyls such as mentioned above and when n = 0,. 1 2 For example), aqueous sodium and potassium silicate solutions (Na2Si03, K2Si03, and MSi03, where M is sodium or potassium in various amounts relative to silicon silicates), silicic acid (Si(OH)4). ) formed by ion-exchange of any of the cationic forms of silica mentioned here using an acidic ion-exchange resin (such as, for example, ion-exchange for alkali-silicate solutions or Quaternary ammonium silicate solutions. In the preferred representations, the titania used herein was not prepared in the presence of urea.

Broadly speaking, this announces the following invention. This invention is directed to compositions and processes for producing ultrafine anatase titania and stable silica, which may also include tungsten and vanadia. Surface stabilization may be achieved by treatment with TiO2 particles with the low molecular weight and/or nano-sized molecular form of silica as in the preferred representations, tetra(alkyl)ammonium silicate or silicic acid which helps to The anatase phase remains effective and prevents crystal growth under severe thermal and hydrothermal conditions, even in the presence of vanadia. Vanadia catalysts produced from new titanium materials have equal or improved catalytic activity for the selective catalytic reaction or NOx compared to catalysts based primarily on silica titania supported by conventional vanadia. The invention is also directed to diesel-emitting catalytic devices, including catalytic compositions based primarily on new titania.

Although the present invention and its benefits have been described in detail, it should be understood that various changes, substitutions, and modifications may be made without departing from the essence and scope of the invention as defined by the appended claims. In any case, the scope of the present invention is not intended to be limited to specific representations of a process, manufacturing materials, material compositions, means, methods, and steps described in the specifications. Where a person of ordinary skill in the art will readily be able to detect the present invention, processes and materials for making, compositions of matter, means, methods or steps now existing or later developed that accomplish substantially the same function or achieve substantially the same result as identical representations described herein may Used in accordance with the present invention. Accordingly, the attached protection elements are intended to be located within their scope, such as processes, manufacturing materials, compositions of matter, means, methods or steps.

Also, this invention declares at least the following concepts:

Concept No. 1: The catalyst support material includes:

anatase titania particles comprising greater than or equal to 85% by weight dry weight of TiO2 and less than or equal to 10% by weight of dry weight anatase titania particles of SiO2, where the SiO2 is primarily low molecular weight weight and/or small nanoparticle form.

Concept No. 2: The catalyst support material according to Concept No. 1 also includes 3% to 10% WO3.

Concept No. 3: The catalyst support material according to Concept No. 2, where the BET surface area is at least 80 m2/g.

Concept No. 4: The catalyst support material according to Concept No. 1 includes greater than or equal to 85% dry weight of TiO2, 3.9% of SiO2 and 3.9% dry weight of WO3.

Concept No. 5: The catalyst support material is sintered, according to Concept No. 1, and where there is SiO2 with a molecular monolayer value of less than 1.0 before the catalyst support material is sintered. Concept No. 6: The catalyst support material, according to Concept No. 1, which includes the small nano-sized particle form of SiO2 with a diameter of less than 5 nanometers.

Concept No. 7: The catalyst support material according to Concept No. 1, where the low molecular weight form of SiO2 includes a molecular weight of less than 100,000.

Concept No. 8: The catalyst support material according to Concept No. 1, where SiO2 includes silicon atoms that are mainly in the coordination environments Q3, Q2, Q1 and Q0.

Concept No. 9: Catalyst support material according to Concept No. 1, where SiO2 includes batches that essentially drop to less than or equal to 5 nanometers after redistribution, as imaged by scanning electron microscopy or by transmission electron microscopy.

Concept No. 10: The catalyst support material according to Concept No. 1, where TiO2 is not prepared in the presence of urea.

Concept No. 11: Vanadia catalyst includes: -

- The catalyst support material according to concept No. 2 with V2O5 presented therein.

Concept No. 12: Vanadia catalyst according to Concept No. 11, including 0.5% by dry weight of V2O5.

Concept No. 13: Vanadia catalyst according to Concept No. 11, where V2O5 is therefore present at a fractional monolayer value of less than 1.0 before sintering.

Concept No. 14: Vanadia catalyst according to Concept No. 11, which was sintered at less than or equal to 650 degrees Celsius.

Concept No. 15: The diesel emission catalytic device includes a vanadia catalyst according to Concept No. 11

Concept No. 16: Diesel emission control system includes:

The diesel emission catalytic device according to Concept No. 15 and the diesel particulate filter, where the diesel emission catalytic device is placed against the direction of the current or in the direction of the current of the diesel particulate filter.

Concept No. 17: How to catalyze the conversion of nitrogen oxides into N2 gas, including: The engine emissions, including NOx, are exposed to the vanadia catalyst according to Concept No. 11 with the reactant added in order to produce nitrogen and water.

Concept No. 18: The method is according to Concept No. 17, where the reactant is ammonia and/or urea.

Concept No. 19: The method according to Concept No. 17 includes a vanadia catalyst of 0.5-3% by dry weight of V2O5.

Concept No. 20: The method is according to Concept No. 17, where engine emissions pass through a diesel molecular filter before or after being exposed to vanadia catalyst.

Concept No. 21: The method of producing catalyst support material includes:

Supply thin slurry containing TiO2

Combine the thin-textured TiO2 slurry with (1) a silica precursor solution containing mainly low molecular weight SiO2 and/or SiO2 including small nanoparticles and (2) WO3 to form a mixture of TiO2 WO3 SiO2 The starting solution of silica is combined with the thin-textured TiO2 slurry before, after merging the WO3 with the thin-textured TiO2 slurry.

Washing and sintering a mixture of TiO2 WO3 SiO2 to form the silica-stabilized titania support material.

Concept No. 22: The method is according to Concept No. 21, where the silica-stabilized titania support material includes:

From 86.94% dry weight of TiO2, from 3.9% dry weight of SiO2 and from 3.7% dry weight of WO3, where the titania support material initially has a surface area of less than 80 m2/g before Flocculation before sintering.

Concept No. 23: The method according to Concept No. 21, where TiO2 for thin-textured slurry includes preformed titanium hydroxide, titanium oxy-hydroxide, or titanium dioxide particles.

Concept No. 24: The method is according to Concept No. 21, where TiO2 does not produce a thin slurry in the presence of urea.

Concept No. 25: The method according to Concept No. 21, where the shape of the small nanoparticle of SiO2 for the silica precursor solution essentially includes a diameter of less than 5 nanometers.

Concept No. 26: The method is according to Concept No. 21, where the low molecular weight form of SiO2, the silica precursor solution, essentially includes a molecular weight greater than 100,000.

Concept No. 27: The method is according to Concept No. 21, where the SiO2 of the starting solution of silica includes the solution comprises silicon atoms that are mainly in the coordination environments Q3, Q2, Q1 and Q0.

Concept No. 28: The method is according to Concept No. 21, where the starting solution for silica precursor solution includes a tetra (alkyl)ammonium silicate solution or silicic acid.

Concept No. 29: The method is according to Concept No. 21, where SiO2 includes batches that are less than or equal to 5 nanometers in depth after redistribution, as imaged by scanning electron microscopy or by transmission electron microscopy.

Concept No. 30: The method according to Concept No. 21 includes combining a mixture with TiO2 WO3 SiO2 with V2O5 to form a vanadia catalyst.

Concept No. 31: The method according to Concept No. 30 includes a vanadia catalyst of 0.5-3% by dry weight of V2O5.

Concept No. 32: The method is according to Concept No. 30, where the V2O5 of the vanadia catalyst exists at a fractional monolayer value of less than 1.0 before sintering.

Concept No. 33: The method according to Concept No. 30 includes the step of adding a sintering vanadia catalyst at greater than or equal to 650 degrees Celsius.

Concept No. 34: Method of producing silica-stabilized titania catalyst support material, including:

Providing a thin slurry containing TiO2 particles

Providing particulate silica source

Combine the thin TiO2 slurry with a particulate silica source to form a mixture of TiO2 - SiO2.

Adjusting a mixture of TiO2 SiO2 to a pH of less than 8.5 and a temperature of less than 80 degrees Celsius, where the particulate silica source is dissolved and re-deposited on the TiO2 particles in order to be the supporting material for the silica-stabilized titania catalyst support material.

Concept No. 35: The method according to Concept No. 34 also includes the step of combining the silica-stabilized titania support material with WO3 in order to become the support material for the tungsten-stabilized titania catalyst support material.

Concept No. 36: The method according to Concept No. 35 also includes washing and sintering the tungsten catalyst support material for silica-stabilized titania catalyst support material.

Concept No. 37: The method according to Concept No. 35, where the support material for a tungsten-stabilized titania catalyst includes silica-stabilized titania catalyst support material:

From 86 94% dry weight of TiO2, from 3 9% dry weight of SiO2 and from 3 7% dry weight of WO3, where the titania support material initially has a surface area of less than 80 m2/g before Flocculation before sintering.

Concept No. 38: The method is according to Concept No. 34, which includes TiO2 particles for a thin-textured slurry, TiO2, preformed titanium hydroxide, titanium oxy-hydroxide, or titanium dioxide particles.

Concept No. 39: The method is according to Concept No. 34, where TiO2 particles for thin-textured slurry do not produce TiO2 in the presence of urea.

Concept No. 40: The method is according to Concept No. 34, where SiO2 of a mixture of TiO2 - SiO2 after dissolving includes silicon atoms that are mainly in coordination environments Q3, Q2, Q1 and Q0.

Concept No. 41: The method according to Concept No. 34, where SiO2 includes TiO2 particles primarily batches that are greater than or equal to 5 nanometers in depth after redistribution into SiO2 as imaged by scanning electron microscopy or by transmission electron microscopy. .

Concept No. 42: The method according to Concept No. 35 includes combining a mixture with TiO2 WO3 SiO2 with V2O5 to form a vanadia catalyst.

Concept No. 43: The method is according to Concept No. 42, where the vanadia catalyst includes 0.5-3% by dry weight of V2O5.

Concept No. 44: The method is according to Concept No. 42, where the V2O5 of the vanadia catalyst is present at a fractional monolayer value of less than 1.0 before sintering.

Concept No. 45: The method according to Concept No. 42 includes the step of adding a vanadia catalyst at less than or equal to 650 degrees Celsius.

All references, patents or applications cited herein are hereby incorporated by reference in their entirety.

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