Process for producing photocatalytically active TiO2 particles and substrates with photocatalytic TiO2 layer

The present invention is a photocatalytic TiO with improved photocatalytic activity.₂It relates to a support having a containing layer and a method for preparing them.

TiO₂The photocatalytic properties of particles have long been known in the literature and have been thoroughly investigated. The photocatalytic effect is that photons form hole electron pairs with relatively long recombination times.₂Based on the semiconductor characteristics of. Diffusion of holes and electrons onto the surface begins in a dynamic process that produces a strong oxidizing action, either directly or indirectly, through water with subsequent hydrogen peroxide formation. Oxidation potentials above 3 eV are so high that in practice such TiO₂All organic substances that come into contact with the particles are oxidized. However, this process only proceeds when significant UV light fractions are present in the incident light. The fraction of UV light in visible light is relatively small and the photocatalytic action resulting from incident photons is limited. The recombination of electrons and holes further reduces efficiency.

On supports or surface layers that themselves oxidize (eg, in the case of organic polymer supports or layers), prevent oxidation by the photocatalytic layer applied to them and therefore damage to the supports or layers. Was found to be difficult. Even in the case of glass supports or surface layers, direct application of the photocatalytic layer can diffuse sodium ions in the glass into the photocatalytic layer (which damages the glass and / or interferes with the photocatalytic process). It has the disadvantage of.

<p> Therefore, it is an object of the present invention to achieve increased photocatalytic activity and / or to provide protection against a support or surface layer that is sensitive to the photocatalytic layer.</p>

<p> One embodiment of the present invention provides a method for producing a support having a photocatalytic layer, which comprises the following steps: a) Preparing at least one hydrolyzable titanium compound, a mixture containing water and an organic solvent in substoikiometric amounts, based on the hydrolyzable group of the titanium compound. b) The resulting mixture is treated at a temperature of at least 60 ° C and TiO₂The process of forming a dispersion or precipitate of particles, c) If necessary, remove the solvent and TiO₂The solvent was exchanged by forming a powder of particles and adding another solvent, TiO₂The process of forming a dispersion of particles, d) The process of applying the dispersion to the support, as well as e) A step of heat-treating the applied dispersion to form a photocatalyst layer.</p><p> In a preferred embodiment, TiO₂In a method for producing particles or for preparing a support having a photocatalytic layer, at least one dopant is further added in step a) and / or hot water treatment or reflux in step b). Heating underneath is carried out.</p><p> The support with the photocatalytic layer can be made of any material suitable for this purpose. Examples of suitable materials are metals or metal alloys, glass, ceramics (including oxide ceramics), glass ceramics, or plastics. Of course, a support having a surface layer made of the above-mentioned material can also be used. For example, the surface layer is a metallization, enamel, glass or ceramic layer or lacquer.</p><p> Examples of metals or metal alloys are steel (including stainless steel), chronium, copper, titanium, tin, zinc, brass and aluminum. Examples of glass are soda lime glass, borosilicate glass, lead crystal and silica glass. The glass can be, for example, flat glass, hollow glass such as vessel glass, or laboratory glass. Ceramic is, for example, oxide SiO₂, Al₂O₃, ZrO₂Alternatively, it is a ceramic based on MgO, or the corresponding mixed oxide. Examples of plastics (which can exist as films as well as metals) are polyethylene (eg HDPE or LDPE), polypropylene, polyisobutylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinylbutyral, polytetrafluoroethylene. , Polychlorotrifluoroethylene, polyacrylate, polymethacrylate (such as polymethylmethacrylate), polyamide, polyethylene terephthalate, polycarbonate, regenerated cellulose, cellulose nitrate, cellulose acetate, cellulose triacetate (TAC), cellulose acetate butyrate or hydrochloric acid It is rubber. The lacquered surface can be formed from conventional primer paints or lacquers.</p><p> In order to form a photocatalytic layer on the support, in the first embodiment of the present invention, TiO₂The dispersion containing the particles is prepared according to the sol-gel process described later. TiO₂The particles can also precipitate to form a precipitate. Removal of solvent gives powder.</p><p> In the method of the first embodiment of the present invention, a mixture containing water and an organic solvent in a substoikiometric amount based on at least one hydrolyzable titanium compound and a hydrolyzable group of the titanium compound is obtained in step a). First prepared in, and the mixture thereof also contains at least one metal compound, such as a dopant, if desired.</p><p> Hydrolyzable titanium compounds, in particular, formula TiX₄(Here, different, but preferably the same, hydrolyzable X groups are, for example, hydrogen, halogen (F, Cl, Br or I, especially Cl and Br), alkoxy (preferably Cl and Br). , C_1-6-Alkoxy, especially C_1-4-Alkoxy (eg, methoxy, ethoxy, n-propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, and tert-butoxy), aryloxy (preferably C)_6-10-Aryloxy (eg, phenoxy)), acyloxy (preferably C)_1-6-Acyloxy (eg, acetoxy or propionyloxy)) or alkylcarbonyl (preferably C)_2-7-Alkylcarbonyl (eg, acetyl)). An example of a halide is TiCl₄Is. Preferred hydrolyzable X groups are alkoxy groups, especially C_1-4-Alkoxy. A specific titanate preferably used is Ti (OCH).₃)₄, Ti (OC₂H₅)₄, And Ti (n- or iso-OC)₃H₇)₄Is.</p><p> The mixture contains water in substoikiometric amounts based on the hydrolyzable groups of the titanium compound, i.e. less than 1 mol of water is present based on 1 mol of hydrolyzable groups in the titanium compound. In other words, less than 4 mol of water is added based on 1 mol of the hydrolyzable titanium compound having 4 hydrolyzable groups. Based on 1 mol of hydrolyzable group in the titanium compound, preferably 0.7 mol or less, more preferably 0.6 mol or less, and especially 0.5 mol or 0.4 mol or less, and 0.35 mol or more, preferably 0.30 mol or more of water is used. Will be done.</p><p> In a preferred embodiment for the preparation of doped particles, the metal compound used for doping may be a suitable metal compound (eg, oxide, salt or complex (eg, halide, nitrate, sulfate, carboxylate). (For example, acetate) or acetylacetonate)). The compound is preferably soluble in the solvent used in the mixture. Suitable metals are any metal, in particular metals selected from groups 5-14 of the Periodic Table of the Elements, as well as lanthanoids and actinides. The tribe is here, Rompp Chemie Lexikon, 9^th Described according to the new IUPAC system recreated in the edition. The metal is present in any suitable oxidation precursor in the compound.</p><p> According to the new IUPAC system, groups 1, 2 and 13-18 correspond to 8 main group groups (IA to VIIIA according to CAS), groups 3 to 7 correspond to 3 to 7 transition groups (IIIB to VIIB according to CAS), and Groups 8-10 correspond to 8 transitions (VIII according to CAS), and groups 11-12 correspond to 1 and 2 transitions (Cu and Zn, IB and IIB according to CAS).</p><p> Examples of suitable metals for metal compounds are W, Mo, Cr, Zn, Cu, Ag, Au, Sn, In, Fe, Co, Ni, Mn, Ru, V, Nb, Ir, Rh, Os, Pd and Pt. Preferably, W (VI), Mo (VI), Cr (III), Zn (II), Cu (II), Au (III), Sn (IV), In (III), Fe (III), Co ( II), V (V) and Pt (IV) metal compounds are used. In particular, very good results are obtained when W (VI), Mo (VI), Zn (II), Cu (II), Sn (IV), In (III) and Fe (III) are used. Specific examples of preferred metal compounds are WO₃, MoO₃, FeCl₃, Silver acetate, zinc chloride, copper (II) chloride, indium (III) oxide and tin (IV) acetate.</p><p> The ratio of metal compounds to titanium compounds also depends on the metal used and its oxidation. In general, for example, the resulting molar ratio of the metal of the metal compound to titanium of the titanium compound is 0.0005: 1 to 0.2: 1, preferably 0.001: 1 to 0.1: 1, more preferably 0.005: 1 to 0.1: 1. A ratio such that (Me / Ti) is used.</p><p> Doping instead of metal doping and with metalloid or non-metallic elements (eg with carbon, nitrogen, phosphorus, sulfur, boron, arsenic, antimony, selenium, tellurium, chlorine, bromine and / or iodine) Can be done. For this purpose, the dopant used is either the element itself or a suitable elemental compound.</p><p> Doped TiO, given the proper selection of doping elements and methods₂Particles It has the special property of having photocatalytic activity even in the generation of excitations with visible light (visible or daylight catalysts) with a wavelength of&gt; 380 nm. </p><p> The solvent used is an organic solvent in which the hydrolyzable titanium compound is preferably soluble. The solvent can also be preferably miscible with water. Examples of suitable organic solvents include alcohols, ketones, ethers, amides, and mixtures thereof. Alcohol, preferably lower fatty alcohol (C)₁-C₆-Alcohol), such as ethanol, 1-propanol, isopropanol, sec-butanol, tert-butanol, isobutyl alcohol, n-butanol and pentanol isomers (particularly 1-pentanol) are preferably used, among others. Particularly preferred are 1-propanol and 1-pentanol.</p><p> The mixture preferably contains a catalyst for hydrolysis and condensation under sol-gel conditions, in particular an acidic condensation catalyst (eg, hydrochloric acid, phosphoric acid or formic acid).</p><p> The resulting mixture was then treated at a temperature of at least 60 ° C and doped or undoped TiO.₂Form a dispersion or precipitate of particles. This heat treatment is preferably carried out by heating with hot water or under reflux. Appropriately, a relatively high dilution is used in the heat treatment (especially when heating under reflux).</p><p> The heat treatment is preferably carried out over 0.5-30 h, preferably 4-24 h, the time of which depends on the temperature applied and any pressure. For example, anatase is obtained by hot water treatment at 200 ° C. and intrinsic pressure in nanoparticle form with a yield of about 35% of theory after a reaction time of 1 h.</p><p> Heating under reflux is typically carried out for at least 3 hours. The solvent used is preferably an alcohol having at least four, preferably at least five carbon atoms, such as n-pentanol, hexanol, heptanol or octanol. However, other polar solvents such as thiols (eg n-butyl, amyl, hexyl or heptyl mercaptan) can also be used.</p><p> Hot water treatment generally refers to the heat treatment of an aqueous solution or suspension under high pressure (eg, at a temperature above the boiling point of the solvent and at a pressure above 1 bar). In the present invention, hot water treatment refers to heat treatment under high pressure mainly in an organic solvent (containing a small amount of water, if any).</p><p> In hot water treatment, the mixture is heat treated in a closed container or a closed autoclave. This treatment is preferably carried out at a temperature in the range of 75 ° C to 300 ° C, preferably higher than 200 ° C, more preferably 225 to 275 ° C (eg, about 250 ° C). Heating (especially above the boiling point of the solvent) increases the pressure (intrinsic pressure) in the closed container or autoclave. The pressure generated can be, for example, higher than 1 bar, in particular 50-500 bar or higher, preferably 100-300 bar (eg 200 bar). Generally, hot water treatment is carried out for at least 0.5h and preferably up to 7 or 8h.</p><p> The heat treatment in step b) is the desired doped or undoped TiO.₂This is done until the particles are formed. The dispersion or precipitate can be used to coat the support immediately or after solvent exchange. Powdered TiO₂To obtain the particles, the solvent is removed.</p><p> Obtained doped or undoped TiO of dispersions, precipitates or powders₂The particles are predominantly crystalline or anatase type. The obtained doped TiO₂The crystalline fraction of the particles preferably reaches an amount of more than 90%, preferably more than 95%, particularly preferably more than 97% (ie, the amorphous fraction is particularly less than 3% (eg, 2%)). Amount). The average particle size is preferably 20 nm or less, more preferably 10 nm or less. In a particularly preferred embodiment, particles having an average particle size of about 2-10 nm are obtained. Existing TiO₂TiO prepared according to the present invention as compared to the material₂Particles are characterized by agglomerate-free dispersibility. TiO₂When the particles are doped, a particularly uniform distribution of the doping metal is obtained.</p><p> The resulting dispersion can be used as a coating for the support. Appropriately, the solvent exchange is performed first. In this case, it is preferable to remove the particles from the solvent in the dispersion obtained in step b). All methods known to those of skill in the art can be used for this purpose. Centrifugation is particularly suitable. Removed TiO₂The particles are then dried (eg at 40 ° C and 10 mbar). The particles can be stored ready for use in this form.</p><p> TiO for application to supports₂The particles are redispersed in the solvent. For this purpose, the solvents or waters listed above are preferred. The solvent used is preferably a water / alcohol mixture, more preferably water alone.</p><p> In a preferred embodiment, the inorganic or organically modified inorganic matrix-forming material is added to the resulting dispersion after steps b) or c). This can be, in particular, an inorganic sol or an organically modified inorganic hybrid material or nanocomposite. Examples of them are at least one glass-or ceramic-forming element M, especially groups 3-5 and / or 12-15 of the periodic table of the elements, preferably Si, Al, B, Ge, Pb, Sn, Ti. , Zr, V and Zn, especially Si and Al, most preferably Si, or mixtures thereof, optionally organically modified oxides, hydrolysates, and (heavy) condensates. Fractions of Group 1 and Group 2 elements of the Periodic Table (eg Na, K, Ca and Mg) and Groups 5-10 of the Periodic Table (eg Mn, Cr, Fe and Ni) or lanthanoids are also oxides. Present in hydrolysates or (heavy) condensates. Polyorganosiloxane is a preferred organically modified inorganic hybrid material. For this purpose, it is particularly preferred to use a hydrolyzate of glass-or ceramic-forming elements (particularly silicon).</p><p> Inorganic or organically modified inorganic matrix-forming materials preferably have a titanium molar ratio of titanium compound to glass-or ceramic-forming element M of 100: 0.01 to 0.01: 100, preferably 300: 1 to 1. It is added in an amount such that: 300. Very good results are obtained with a Ti / M molar ratio of about 10: 3 to 1:30. This addition results in an improvement in adhesion. When an organically modified inorganic matrix-forming material is used, only all or part of the glass-or ceramic-forming element M present may have one or more organic groups as non-hydrolyzable groups.</p><p> Inorganic or organically modified inorganic matrix-forming materials are known methods such as flame pyrolysis, plasma, gas phase condensation processes, colloidal techniques, precipitation methods, sol. -Can be prepared by gel method, controlled nucleation and growth method, MOCVD method and (micro) emulsion method. When solvent-free particles are obtained from this method, they are preferably dispersed in the solvent.</p><p> Inorganic sol and especially organically modified hybrid materials are preferably obtained by the sol-gel method. In the sol-gel process, which can be used for the separation and preparation of particles, the hydrolyzable compounds are conventionally hydrolyzed with water, optionally under acidic or basic catalysts, and at least partially, if desired. Is condensed into. Hydrolysis and / or condensation reactions result in the formation of compounds or condensates with hydroxyl, oxo groups and / or oxo crosslinks that act as precursors. A substoicometric amount (less or more) of water can be used. The sol formed can be adjusted to the desired viscosity for the coating composition by appropriate parameters (eg, degree of condensation, solvent or pH). Further details of the sol-gel method can be found, for example, in CJ Brinker, GW. Scherer: "Sol-Gel Science-The Physics and Chemistry of Sol-Gel Processing", Academic Press, Boston, San Diego, New York, Sydney (1990).</p><p> In a preferred sol-gel process, the oxide, hydrolyzate or (heavy) condensate is hydrolyzed from the hydrolyzable compound of the glass-or ceramic-forming element, which further has a non-hydrolyzable organic substituent, if desired. An organic-modified inorganic hybrid material obtained by hydrolysis and / or condensation is prepared.</p><p> Inorganic salts are used in the sol-gel process, especially in the general formula MX._n(Here, M is the glass-or ceramic-forming element, and X is as defined by the following formula (I) (where the two X groups are replaced by one oxo group). May be), n corresponds to the valence of the element and is usually formed from 3 or 4) hydrolyzable compounds. They are preferably hydrolyzable Si compounds, especially of the formula (I) below.</p><p> An example of a hydrolyzable compound in which element M other than Si can be used is Al (OCH).₃)₃, Al (OC₂H₅)₃, Al (OnC₃H₇)₃, Al (OiC₃H₇)₃, Al (OnC₄H₉)₃, Al (O-sec-C₄H₉)₃, AlCl₃, AlCl (OH)₂, Al (OC₂H₄OC₄H₉)₃, TiCl₄, Ti (OC₂H₅)₄, Ti (OnC₃H₇)₄, Ti (OiC₃H₇)₄, Ti (OC₄H₉)₄, Ti (2-ethylhexoxy)₄, ZrCl₄, Zr (OC₂H₅)₄, Zr (OnC₃H₇)₄, Zr (OiC₃H₇)₄, Zr (OC₄H₉)₄, ZrOCl₂, Zr (2-ethylhexoxy)₄, And Zr compounds with complex-forming groups (eg, β-diketone and (meth) acryloyl groups), sodium methoxide, potassium acetate, boric acid, BCl.₃, B (OCH₃)₃, B (OC₂H₅)₃, SnCl₄, Sn (OCH₃)₄, Sn (OC₂H₅)₄, VOCl₃ And VO (OCH₃)₃Is.</p><p> The above description regarding preferable silicon is also applied to the other element M with appropriate modifications. It is particularly preferred to obtain sol or organic-modified inorganic hybrid materials from one or more hydrolyzable and condensable silanes, and at least one silane will optionally contain non-hydrolyzable organic groups. Have. It is particularly preferred to use one or more silanes with the following general formulas (I) and / or (II): SiX₄ (I) (Here, the X group is the same or different, a hydrolyzing group or a hydroxyl group) R_aSiX_(4-a) (II) (Here, R is a non-hydrolyzable group that is the same or different and has functional groups as needed, X is defined as above, and a is 1, 2 or 3, preferably 1 or 2. Is).</p><p> In the above formula, the hydrolyzable X group is, for example, hydrogen or halogen (F, Cl, Br or I), alkoxy (preferably C)._1-6-Alkoxy, such as methoxy, ethoxy, n-propoxy, isopropoxy and butoxy), aryloxy (preferably C)_6-10-Aryloxy, eg phenoxy), acyloxy (preferably C)_1-6-Acyloxy, eg acetoxy or propionyloxy), alkylcarbonyl (preferably C)_2-7-Alkylcarbonyl, eg acetyl), amino, monoalkylamino or dialkylamino having 1-12 carbon atoms, especially 1-6 carbon atoms in the alkyl group.</p><p> Non-hydrolyzable R groups are, for example, alkyl (preferably C)._1-6-Alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl and t-butyl, pentyl, hexyl or cyclohexyl), alkenyl (preferably C)_2-6-Alkenyl, eg vinyl, 1-propenyl, 2-propenyl and butenyl), alkynyl (preferably C)_2-6-Alkynes, such as acetylenyl and propargyl), aryls (preferably C)_6-10-Aryl, eg phenyl and naphthyl).</p><p> The above-mentioned R and X groups may be functional groups such as one or more conventional substituents such as halogen, ether, phosphoric acid, sulfonic acid, cyano, amino, mercapto, thioether or alkoxy group as required. Can have.</p><p> The group R may have a functional group on which cross-linking can occur. Specific examples of the functional group of the R group are epoxy, hydroxyl, amino, monoalkylamino, dialkylamino, carboxyl, allyl, vinyl, acryloyl, acryloyloxy, methacryloyl, methacryloyloxy, cyano, aldehyde and alkylcarbonyl groups. These groups are preferably attached to silicon atoms via alkylene, alkenylene or arylene cross-linking groups that can be separated by oxygen or sulfur atoms, or -NH groups. The crosslinked groups mentioned are derived, for example, from the alkyl, alkenyl or aryl groups mentioned above. The cross-linking group of the R group preferably contains 1 to 18, especially 1 to 8 carbon atoms.</p><p> Particularly preferred hydrolyzable silanes of the general formula (I) are tetraalkoxysilanes (eg, tetramethoxysilanes, and especially tetraethoxysilanes (TEOS)). Particularly preferred is an inorganic sol (eg, TEOS hydrolyzate) obtained by an acidic catalyst. Particularly preferred organosilanes of formula (II) are methyltriethoxysilane (MTEOS) and MTEOS hydrolysates, epoxysilanes (eg, 3-glycidyloxypropyltrimethoxysilane (GPTS), methacryloyloxypropyltrimethoxysilane, and , Acryloyloxypropyltrimethoxysilane), among which GPTS hydrolysates are conveniently used.</p><p> When an organic-modified inorganic hybrid material is prepared, it is possible to use exclusively silanes of formula (II) or mixtures of silanes of formulas (I) and (II). For inorganic silicon-based sol, the silane of formula (I) is used exclusively, and the above formula MX_nA fraction of the hydrolyzable compound of is added as needed.</p><p> If the inorganic sol consists of oxide particles dispersed and discrete in a solvent, they can improve the hardness of the layer. These particles are especially nanoscale inorganic particles. The particle size (volume average measured by X-ray) is, for example, in the range of 200 nm, particularly 100 nm, preferably 50 nm, for example 1 nm to 20 nm.</p><p> According to the present invention, the nanoscale particles used are, for example, SiO.₂, ZrO₂, GeO₂, CeO₂, ZnO, Ta₂O₅, SnO₂And Al₂O₃Inorganic sol (especially like boehmite AlO (OH)) in all transformations, preferably SiO₂, Al₂O₃, ZrO₂, GeO₂And can be a sol of their mixture. Some such sol are also commercially available (eg, silica sol such as Levasils® commercially available from Bayer AG).</p><p> The inorganic or organically modified inorganic matrix-forming material used is also such nanoparticles having a sol or organic-modified hybrid material present in the form of a hydrolyzate or (hyper) condensate. These may be combinations of, and these are referred to herein as nanocomposites.</p><p> Where appropriate, any type of organic monomer, oligomer or polymer can also be present as an organic matrix-forming material that acts as a softener, which is a conventional organic binder. They are also used to improve coatability. Generally, they are photocatalytically decomposed after the layer is completed. Oligomers and polymers may have functional groups that can be crosslinked. This cross-linking means is also possible in some cases of the organically modified inorganic matrix-forming materials described above. Mixtures of inorganic, organic-modified inorganic and / or organic matrix-forming materials are also possible.</p><p> Examples of organic matrix-forming materials that can be used are polymers and / or oligomers with polar groups (eg, hydroxyl, primary, secondary or tertiary amino, carboxyl or carboxylate groups). Typical examples are polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyvinylpyridine, polyallylamine, polyacrylic acid, polyvinylacetate, polymethylmethacrylic acid, starch, gum arabic, and other polymerizable alcohols (eg, polyethylene-polyvinyl alcohol copolymers, etc.). Polyethylene glycol, polypropylene glycol, and poly (4-vinylphenol)) or monomers or oligomers derived from it. The polyvinyl alcohol used can be, for example, Mowiol® 18-88 commercially available from Hoechst.</p><p> The degree of dilution of the dispersion applied in step d) depends on factors including the desired coating thickness. In general, the dispersion has a solid content of less than 50% by weight, particularly less than 20% by weight, and preferably less than 10% by weight, for example 2.5% by weight.</p><p> For application, conventional methods are used, such as dipping method, roll coating, knife coating, flow coating, drawing, spraying, spinning or spreading. The applied dispersion is dried and heat treated, if necessary, for example for curing or compaction. The heat treatment used for this purpose depends on the course on the support. In the case of plastic supports or plastic surfaces, which generally have a barrier layer (see below), their properties make it impossible to use very high temperatures. For example, a polycarbonate (PC) support is heat treated, for example, at about 130 ° C. for 1 h. Generally, the heat treatment is carried out, for example, at a temperature of 100-200 ° C and up to 500 ° C or higher, in the absence of plastic. The heat treatment is performed, for example, between 15 min and 2 h. Generally, a layer thickness of 50 nm to 30 μm can be obtained. Preferably, it is 100 nm to 1 μm, for example 50 to 700 nm.</p><p> The inorganic sol or organic-modified inorganic hybrid material serves not only as a matrix-forming material for the photocatalytic layer, but also for improved layer adhesion. TiO₂Can also be present in the layer as matrix-forming components and / or particles.</p><p> The photocatalytic layer is activated as needed and preferably by irradiation with visible and / or UV light (eg, using a 700 W high pressure mercury lamp for 1-5 min, or 750 W xenon lamp for 1-10 min). Be transformed. High-pressure mercury lamps have a relatively high proportion of UV light; the spectrum of xenon lamps corresponds almost to that of sunlight. Irradiation with UV light or a high proportion of UV light is preferred. A highly active photocatalytic layer is obtained, and its efficiency can be increased up to 10-fold compared to the prior art.</p><p> As already mentioned above, in the case of a support consisting of a sensitive material or having a surface layer of such a sensitive material (eg, lacquer or enamel), direct application, if possible, is only difficult. It is possible with it. The barrier layer can be placed between the support (with a surface coating if desired) and the photocatalytic layer. For this purpose, an inorganic layer of inorganic matrix-forming material can be used, for which the aforementioned inorganic sol can be used.</p><p> According to the present invention, TiO in the photocatalytic layer₂It has been further found that by forming a concentration gradient of, a photocatalytic layer with an "incorporated" barrier layer can be obtained. This barrier layer can be advantageously used not only for photocatalytic layers prepared according to the present invention, but also in conventional photocatalytic layers.</p><p> Therefore, the second embodiment of the present invention is a photocatalytically active TiO.₂And contains matrix material, TiO₂TiO with a concentration gradient such that the concentration of is enriched on the surface of the photocatalytic layer₂Is present and the purely inorganic barrier layer is photocatalytically active TiO₂Provided is a support having a photocatalytic layer formed between the and the support.</p><p> TiO₂TiO that maximizes the concentration of TiO on the surface of the photocatalyst layer₂These photocatalytic layers, which have a concentration gradient of, are particularly surface-modified TiO.₂The particles can be prepared by the method by which the particles naturally form a concentration gradient in the matrix-forming material.</p><p> Conventional prior art TiO for surface modification₂Particles can be used and they are available, for example, commercially. TiO₂The particles are, for example, from Degussa, P25 (d₅₀= 30-40nm) is available.</p><p> In the second embodiment of the present invention, doped or undoped TiO₂Particles can be used. Doping can be performed by prior art methods in which prior art metal or non-metal dopants (eg, the metals and non-metals described above for the first embodiment of the invention) can be used. Doping surprisingly achieves increased activity and often photocatalytic activity in the visible light region (visible light photocatalyst).</p><p> TiO obtained by the sol-gel method₂It is preferable to use particles. For this purpose, the hydrolyzable titanium compounds described above can be used. In a preferred embodiment, the particles prepared in steps a) and b) are used and doped or undoped TiO in accordance with the first embodiment of the present invention.₂Particles can be used.</p><p> TiO in solvent₂Particle dispersions are generally prepared. Toluene is suitable for this purpose, for example. TiO in solvent₂Particle slurry or solvent-free TiO₂Particle powder can also be used. For this purpose, a surface modifier having at least one hydrophobic or hydrophilic group (where hydrophobic groups are preferred) is added.</p><p> Suitable surface modifiers are primarily TiO₂It has one or more groups capable of reacting or at least interacting with reactive groups (eg, OH groups) present on the surface of the particles, and secondly has at least one hydrophobic or hydrophilic group (preferably). A compound (which is a low molecular weight or oligomer and in some cases a polymer).</p><p> TiO₂Surface modification of the particles can be performed, for example, by mixing the particles with the appropriate compounds shown below, optionally in a solvent and in the presence of a catalyst. It is often appropriate to stir the surface modifier and the particles at room temperature for a predetermined time (eg 1-3 h). Treatment in an ultrasonic bath can often have a beneficial effect.</p><p> The surface modifier is, for example, TiO₂Either covalent bonds (including coordination bonds in the form of complexes) or ionic (salt-type) bonds can be formed on the surface of the particles, while dipole-dipole interactions, hydrogen bonds and van der Waals. Waals interactions can be mentioned as an example of pure interactions. The formation of covalent bonds is preferred.</p><p> It is also preferred that the surface modifier has a relatively low molecular weight according to the present invention. For example, its molecular weight may be less than 1500, especially less than 1000, and preferably less than 700. This, of course, does not exclude compounds with significantly higher molecular weights (eg, 2000 and above).</p><p> TiO₂Suitable surface modifiers having groups capable of reacting or interacting with the surface groups of the particles include, for example, hydrolyzable silanes, carboxylic acids, carbonyl halides, carboxylic acid esters, carboxylic acid anhydrides, oximes, β-dicarbonyl compounds. (For example, β-diketone), alcohols, polyethers and functionalized polyethers (eg, trioxadecanoic acid), amines, alkylhalides, and derivatives thereof.</p><p> As a basic concept of chemistry, the concept of hydrophilicity / hydrophobicity is very well known to those skilled in the art. Hydrophobic substances or groups repel water, while hydrophilic substances or groups attract water. Hydrophilic properties can be formed, for example, by hydroxyl, oxy, carboxylate, sulfate, sulfonate functional groups or polyether chains in the material. Suitable hydrophobic groups are, for example, long-chain aliphatic hydrocarbon groups (eg, having 3 to 30 or more carbon atoms), particularly alkyl groups, aromatic groups, or groups having at least one fluorine atom (preferably). Is a hydrocarbon group (particularly an alkyl group) having 3 to 20 or more carbon atoms and 1 to 30 fluorine atoms.</p><p> The surface modifier used is preferably a hydrolyzable silane having at least one hydrolyzable hydrophobic group or a hydrophilic group, and among them, one having a hydrophobic group is preferable. They are more preferably at least one hydrate containing at least one fluorine atom (fluorosilane) or a long-chain aliphatic hydrocarbon group having, for example, 3-30 carbon atoms, preferably an alkyl group or an aromatic group. It is a hydrolyzable silane having a degradable group.</p><p> Surface modifiers that have a hydrophobic group and can be used in addition to hydrolyzable silanes include, for example, formula R.^{o o}-Y (where Y is -COOH, -OH, -COZ, -Z (where Z = F, Cl, Br or I-like halides), -C (O) O (O) CB (here And B is any group of carboxylic acids, or R^{o o}Or other functional groups of the aforementioned compounds (including additional functional groups such as B, if desired), as well as R.^{o o}Is a long-chain aliphatic hydrocarbon group, preferably an alkyl group, or an aromatic group (eg, optionally substituted phenyl or naphthyl), or a hydrocarbon group, for example having 3 to 30 carbon atoms. Is an alkyl group having at least one fluorine atom). In carboxylic acid esters, for example, carboxylic acid groups and / or alcohol groups can form hydrophobic groups.</p><p> Preferred hydrolyzable silanes having a long-chain aliphatic hydrocarbon group as the hydrophobic group are particularly preferred formulas (II) (R) shown above._aSiX_(4-a)) (Here, a and X are as described above, a is preferably 1, and R is a long-chain aliphatic hydrocarbon group having, for example, 3 to 30 carbon atoms). is there. The long-chain aliphatic hydrocarbon group is preferably an alkyl group. If desired, a silane of formula (II) can also be used (where R is an optionally substituted aromatic group).</p><p> According to the present invention, particularly preferably, a hydrolyzable silane compound having at least one non-hydrolyzable group as a hydrophobic group and having the following general formula is used: Rf (R)_bSiX_(3-b) (III) (Here, X and R are as defined in formula (I) or (II), respectively, and Rf is preferably 1 ~ ~ bonded to a carbon atom separated from Si by at least 2 atoms. A non-hydrolyzable group having 30 fluorine atoms, preferably an ethylene, propylene, ethyleneoxy or propyleneoxy group, where b is 0, 1 or 2 and preferably 0 or 1). R is a group having no functional group, preferably an alkyl group, particularly C._1-4-Alkyl (eg, such as methyl or ethyl). The Rf group preferably contains 3 to 25, particularly 3 to 21, fluorine atoms bonded to aliphatic (including alicyclic) carbon atoms. Rf is preferably a fluorinated alkyl group having 3 to 20 carbon atoms separated by one or more oxygen atoms as needed.</p><p> An example of Rf is CF₃CH₂CH₂, C₂F₅CH₂CH₂, NC₆F₁₃CH₂CH₂,I c₃F₇OCH₂CH₂CH₂, NC₈F₁₇CH₂CH₂And nC₁₀F₂₁-CH₂CH₂Is.</p><p> Any fluorine atom bonded to an aromatic carbon atom (eg C)₆F₄) Is also not considered. The fluorine-containing Rf group can also be a chelating ligand. One or more fluorine atoms may be present on the carbon atom at which the double or triple bond begins. An example of a fluorosilane that can be used is CF.₃CH₂CH₂SiCl₂(CH₃), CF₃CH₂CH₂SiCl (CH₃)₂, CF₃CH₂CH₂Si (CH₃) (OCH₃)₂, C₂F₅-CH₂CH₂-SiZ₃, NC₆F₁₃-CH₂CH₂SiZ₃, NC₈F₁₇-CH₂CH₂SiZ₃, NC₁₀F₂₁-CH₂CH₂SiZ₃(Here, Z = OCH₃, OC₂H₅Or Cl); iC₃F₇O-CH₂CH₂CH₂-SiCl₂(CH₃), NC₆F₁₃-CH₂CH₂-Si (OCH₂CH₃)₂, NC₆F₁₃-CH₂CH₂-SiCl₂(CH₃) And nC₆F₁₃-CH₂CH₂-SiCl (CH₃)₂Is. Preferably, (3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl) triethoxysilane (FTS) is used.</p><p> Examples of hydrolyzable silanes with long-chain aliphatic hydrocarbon groups are hexadecyltrimethoxysilane (HDTMS), dodecyltriethoxysilane and propyltrimethoxysilane. Further examples of surface modifiers with hydrophobic groups are heptadecafluorononanoic acid, stearic acid, heptafluorobutyryl chloride, hexanoyl chloride, methylhexanoate, methylperfluoroheptanoate, perfluorooctanoic anhydride. , Hexane anhydride, 2-heptanone oxime, 1,1,1-trifluoro-5,5-dimethylhexane-2,4-dione 2-oxime, 1,1,1,2,2,3,3 -Hepta-fluoro-7,7-dimethyl-4,6-octandione, 1H, 1H-pentadecafluorooctanol, octanol, hexyl chloride, and nonafluorobutyl chloride.</p><p> In addition to the above compound classes, suitable surface modifiers with hydrophilic groups are also unsaturated carboxylic acids, β-carbonylcarboxylic acids with polymerizable double bonds, ethylenically unsaturated alcohols and amines, amino acids, epoxides. And diepoxide.</p><p> Specific examples of organic compounds for surface modification with hydrophilic groups include diepoxide (eg, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, bis (3,4-epoxycyclohexyl) adipate, bis (3,4-epoxycyclohexyl) adipate, Cyclohexanedimethanol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, propylene glycol diglycidyl ether, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, unsaturated carboxylic acid (eg acrylic) Acids and methacrylic acids), and β-diketones (eg, acetylacetonates).</p><p> Further particularly preferred compounds for surface modification with hydrophilic groups are hydrolyzable silanes with at least one (and preferably) hydrolyzable group with hydroxyl, carboxylate or epoxy or glycidyloxy groups. These are, in particular, the silanes of formula (II). Examples are glycidyloxyalkyltrialkoxysilanes (eg, 3-glycidyloxypropyltrimethoxysilane and 3-glycidyloxypropyltriethoxysilane).</p><p> Further examples of surface modifiers are diphosphate, polyphosphate, polyvinyl alcohol, polyvinylpyrrolidone and methyl vinyl ether maleic anhydride copolymers.</p><p> In surface modification, for example, 1 g of TiO₂For the powder, 10 ml of solvent is used. The resulting dispersion containing the surface modifier is simply stirred for, for example, 2 hours to achieve surface modification of the particles. TiO added₂The ratio of the surface modifier to the surface modifier is preferably 1: 0.005 to 1: 0.1, particularly 1: 0.01 to 1: 0.02, based on the mole, which is particularly a surface modifier having at least one fluorine atom. Applies to.</p><p> After this, the solvent is preferably exchanged with another organic solvent (eg, methyl ethyl ketone, acetone, chloroform or petroleum ether).</p><p> Subsequently, an inorganic or organically modified matrix-forming material is added. For this purpose, for example, an inorganic sol or an organic-modified inorganic hybrid material as shown above with respect to the first embodiment of the present invention may be added. The nanoscale particles mentioned above can also be present.</p><p> The surface modifier works to create a concentration gradient in the matrix of the matrix-forming material. In the hydrophilic matrix, a surface modifier having a hydrophobic group is used, and in the case of a hydrophobic matrix, a surface modifier having a hydrophilic group is used. This is a surface-modified TiO₂Achieve potential differences that result in demixing so that the particles are enriched on the surface. Since the matrix-forming materials and solvents used are generally hydrophilic, surface modification with hydrophobic groups is preferred.</p><p> The application of the obtained dispersion to the support and the heat treatment are carried out by a conventional method, for example, as described above. TiO₂The hydrophobic properties of the hydrophobic groups on the surface of the particles result in segregation in the resulting dispersion, thereby surface-modified TiO.₂The particles are enriched on the surface of the photocatalytic layer after application to the support. Thus, in the process of curing the coating layer, surface-modified TiO in other inorganic or organically modified matrix-forming materials or in matrices obtained from them.₂A particle concentration gradient is formed. Inorganic or organically modified inorganic matrices-Forming materials or matrices formed from them are primarily located in the lower regions of the layer.</p><p> In the process of illumination, the photocatalytic activity of the layer destroys at least hydrophobic organic groups, which is manifested in a significant reduction in the contact angle after irradiation. As a result of the concentration gradient, the matrix of inorganic or organically modified matrix-forming material resides primarily at the interface of the support, where it is substantially TiO.₂Does not include. When organically modified inorganic matrix-forming materials are used, photocatalytic oxidation of organic components (discussed above for "insulated" barrier layers) is TiO.₂-Enriched areas and virtually TiO₂-A free region occurs in the region of the adjacent photocatalytic layer, thereby forming an inorganic barrier layer there. An "integrated" barrier layer of inorganic material that can protect the support placed beneath it is thus formed according to the present invention.</p><p> Again, in principle, all of the aforementioned supports can be used. Particularly advantageously, the photocatalytic layer with an integrated barrier layer is applied to a glass or plastic support or, in this regard, to the surface layer of the support.</p><p> Furthermore, it has been found that certain hybrid layers of organically modified inorganic materials provide excellent barrier layers. This barrier layer can be used not only in the photocatalyst layer produced according to the present invention, but also in the conventional photocatalyst layer.</p><p> Therefore, a third embodiment of the present invention is a photocatalytic TiO, characterized in that a hybrid layer of organically modified inorganic material is provided between the support and the photocatalytic layer.₂A support having an containing layer is provided. In this material, the first activation by illumination results in a gradient of carbon content on the surface of the barrier layer due to the oxidation of organic components. The gradient material thus obtained has a photocatalytically active TiO on its surface.₂It has an inorganic layer containing the above, followed by an inorganic barrier layer that coalesces into an inorganic-organic hybrid material as the depth of the layer increases. TiO on the surface of the barrier layer in layer manufacturing₂Particle diffusion is similarly TiO₂Form a gradient in concentration.</p><p> This barrier layer first provides the advantage of ensuring reliable protection of sensitive materials from the photocatalytic layer, and secondly, the barrier layer is a simple wet-chemical method (wet-). It can be applied in chemical manner) and at the desired layer thickness directly and without causing crushing. The organic component achieves a certain degree of flexibility in the coating and, surprisingly, a reliable barrier action is achieved despite the organic component used.</p><p> In principle, the support used may be any of the above-mentioned supports. Particularly advantageous, the barrier layer is applied to the surface layer of a glass or plastic support or a support made from this material.</p><p> The barrier layer has at least a photocatalyst TiO with an organic component.₂A hybrid layer made from an organically modified inorganic material that is photocatalytically decomposed at the interface to the layer to form a purely inorganic protective layer.</p><p> To produce this hybrid layer, the organic-modified inorganic hybrid material described above is used as the coating composition. Hybrid material is TiO₂Although not added to the containing dispersion, but rather applied to the support itself, all the statements made with respect to this material apply unless otherwise stated.</p><p> 10 mol% or less, preferably 5 mol% or less, particularly 3 mol% or less, and preferably at least 0.1 mol%, more preferably at least 0.5 mol%, especially at least 1 mol% of the glass-or ceramic-forming element M present, eg, It is preferable to use an organic-modified inorganic hybrid material containing 1 or more organic groups in an amount of 0.1 to 10 mol%, preferably 1 to 3 mol%. In other words, preferably 10 mol% or less, particularly 3 mol% or less, for example 0.1 to 10 mol%, preferably 1 to 3 mol% of the glass-or ceramic-forming element M present has one or more organic groups. At least some or all of the organic groups preferably have functional groups that can be crosslinked. The hybrid material is preferably prepared by the sol-gel method. Useful solvents are as described above. More preferably, it is a hydrolyzate or condensate of the silane of the formulas (I) and (II). At least a portion of the silane of formula (I) can be optionally replaced by other hydrolyzed compounds of glass-or ceramic-forming element M.</p><p> To prepare the hybrid material, it is preferable to add a stoichiometric amount of water to the hydrolyzable compound. The resulting coating composition is used, for example, in the form of 1-70 wt% sol / gel (based on solid content) in alcohol. Particularly preferred combinations of hydrolyzable compounds are TEOS or MTEOS and GPTS.</p><p> The organically modified inorganic hybrid material preferably contains the aforementioned nanoscale particles and can form nanocomposites. It is preferred that no organic polymer is added to the organic-modified inorganic hybrid material (ie, the coating composition preferably has no organic polymer).</p><p> The hybrid material is applied in a conventional manner (eg, by the method described above). The applied layer is dried and cured as needed, and the curing can be done by heat or irradiation. If desired, the heat treatment can be performed with the photocatalytic layer. With respect to temperature and time, the conditions detailed above for the photocatalytic layer may apply. The thickness of the obtained layer is, for example, 50 nm to 1 μm, preferably 100 nm to 1 μm, for example, 100 to 700 nm.</p><p> TiO₂-The containing composition is applied to the hybrid layer and surface-modified TiO₂Contains particles. Surface-modified TiO₂The particles are used as described above for the second embodiment of the invention. It is possible to use a surface modifier having a hydrophobic or hydrophilic group.</p><p> Generally, photocatalytically active TiO₂Particles are distributed in the matrix, TiO₂Can also be part of the matrix. The layer is TiO₂May consist only of. The matrix can generally be formed from an inorganic or organic-modified inorganic matrix-forming material. Thus, the composition also contains an inorganic or organic-modified inorganic matrix-forming material, as described above. The nanoscale particles mentioned above may also be present. However, the composition is also TiO₂TiO so that a photocatalytic layer consisting of chisel is formed₂It may contain only particles.</p><p> As a result of the photocatalytic oxidation of the organic fraction, it was found that the layers of the hybrid material coalesce into a purely inorganic system, at least at the interface to the photocatalytic layer. In this system, photocatalytic oxidation of the organic components of the underlying hybrid layer is carried out through the overlapping photocatalytic active layers. This process is often limited to the top few nanometers of this layer, as the diffusion of holes and electrons has a very short range. The conversion of the hybrid layer to the topmost inorganic layer ends the decomposition process and prevents the diffusion of sodium ions from the glass support into the active barrier layer, which prevents the diffusion of sodium ions from the glass support into the photocatalytic layer, making the sensitive plastic support. Protects against damage from the photocatalytic layer). In addition, surface-modified TiO₂The organic group of is photocatalytically decomposed.</p><p> In all three embodiments described, if a conductive sublayer is used below the photocatalytic layer and / or certain conductive particles are added to the photocatalytic layer, further photocatalytic activity The increase is achieved.</p><p> Doped metal oxides used as conductive particles include, for example, tin oxides (eg, ITO (indium tin oxide), ATO (antimony-doped tin oxide) and FTO (fluorine). Doped tin oxides) and / or aluminum-doped zinc oxides can also be used. Conductive polymers such as BAYTRON commercially available from Bayer AG can also be used. Useful semiconductors are, for example, if desired. Doped with germanium or silicon. Conductive particles can be added to the dispersion for the photocatalyst layer, for example in the form of a dispersion in powder or solvent.</p><p> It is preferable to use conductive particles having high transparency. This prevents high light absorption, for example caused by conductive metal particles, and provides a more effective photocatalytic layer.</p><p> Alternatively or simultaneously, a conductive sublayer may be provided as a layer underneath the photocatalytically active layer. The conductive sublayer can be a metal, semiconductor, conductive polymer, or doped metal oxide. Examples of doped metal oxides, semiconductors or conductive polymers are the same as described above as examples of conductive particles. Examples of metals (which may be metal alloys) are steel (including stainless steel), chromium, copper, titanium, tin, zinc, brass and aluminum.</p><p> The sublayer may exist as a layer on the support or may itself be a support. For the application of the conductive layer as a sublayer to the support, methods well known to those skilled in the art (eg, wet chemistry, vapor deposition (sputtering) or metallization) may be used. In general, a thin layer is sufficient.</p><p> In all the embodiments described, the support can be fired with a photocatalytic layer to give a purely inorganic layer. In addition, particles with large diameters (eg, in the μm range) can also be mixed into all layers.</p>

<p> The support of the present invention having a photocatalytic layer can be used, for example, as a self-cleaning surface (optionally assisted by irradiation with light) or for air cleaning.</p><p> Supports with a photocatalyst layer prepared in accordance with the present invention include and / or self-cleaning for antibacterial purposes (eg, machinery, paints, lacquer, furniture, façade, roofs, textiles, vehicles, signal systems, films, etc. Protective walls and bulkheads, transportation technology, automobiles, aviation and railroad vehicles, windows, doors, greenhouses, walls, tiles, floors, tents, tarpaulins, outdoor structures, fences, natural stones, concrete, renders, plasters, Bottom plates, monuments, wood, slabs, cladding, window frames, textiles, covers, concrete, all types of plastic surfaces, plastic glazing, helmets, visors, casings, outdoor structures, all Suitable for a wide variety of applications for type of equipment (eg medical equipment, household equipment, traffic signs, steel structures and steel façade). Layers are also glass, mirrors, cladding or It is suitable as an antifogging layer for partitions. In addition, magnetic (eg, supernormal magnetic) particles can also be used.</p><p> Special areas of application are in all types of equipment, especially in medical (including veterinary and dental) equipment, and in the sanitary field against contamination by, for example, infectious agents (eg, prions) (eg, for BSE control). Sterilization or protection of equipment. Further important areas of application are food technology and dairy industry.</p>

The following abbreviations are used: TEOS: Tetraethoxysilane FTS: (3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl) triethoxysilane GPTS: (3-glycidyloxypropyl) trimethoxysilane HDTMS: Hexadecyltrimethoxysilane Example 1 <u style="single">TiO</u>_{<u style="single">2</u>}<u style="single">Hot water preparation of (anatase)</u> 9.6 g (0.034 mol) of titanium isopropoxide (Ti (O)ⁱPr)₄) Is added to 14.5 g of n-propanol, stirred at room temperature for 5 min, and then mixed with 0.67 g (0.0068 mol) of 37% HCl. After 20 min, add 0.712 g (0.063 mol) of water with vigorous stirring.

The mixture is then diluted with 41.9 g of n-propanol and then treated for 7 hours at 250 ° C. and 200 bar pressure. The resulting anatase is centrifuged off and dried at 50 ° C and 10 mbar.

Example 2<u style="single">Dope TiO</u>_{<u style="single">2</u>}<u style="single">(Anatase, Sn (CH)</u>_{<u style="single">3</u>}<u style="single">CO</u>_{<u style="single">2</u>}<u style="single">)</u>_{<u style="single">4</u>}<u style="single">Dopant) hot water preparation</u> 9.6g (0.034mol) of titanium isopropoxide (Ti (O)ⁱPr)₄) Is added to 14.5 g of n-propanol, stirred at room temperature for 5 min, and then mixed with 0.67 g (0.0068 mol) of 37% HCl. After 20 min, add 0.712 g (0.063 mol) of water with vigorous stirring.

The mixture was then diluted with 41.9 g of n-propanol and then the mixture was combined with 0.635 g (0.0018 mol) of Sn (CH).₃CO₂)₄Mix with and treat at 250 ° C and 200 bar for 7 hours. The resulting anatase is centrifuged and removed and dried at 50 ° C and 10 mbar.

Example 3<u style="single">Dope TiO</u>_{<u style="single">2</u>}<u style="single">(Anatase, WO</u>_{<u style="single">3</u>}<u style="single">Dopant) hot water preparation</u> 9.6 g (0.034 mol) of titanium isopropoxide (Ti (O)ⁱPr)₄) Is added to 14.5 g of n-propanol, stirred at room temperature for 5 min, and then mixed with 0.67 g (0.0068 mol) of 37% HCl. After 20 min, add 0.712 g (0.063 mol) of water with vigorous stirring.

The mixture was then diluted with 41.9 g n-propanol and then the mixture was 0.039 g (0.00017 mol) of WO.₃And treat at 250 ° C and 200 bar for 7 hours. The resulting anatase is centrifuged and removed and dried at 50 ° C and 10 mbar.

Example 4<u style="single">TiO using FTS</u>_{<u style="single">2</u>}<u style="single">(Anatase) Powder surface modification</u> TiO prepared according to Examples 1 to 3₂1.0 g of powder is stirred with 8.67 g of toluene in each case and then mixed with 0.077 g of FTS. After stirring for 2 hours, the toluene is removed on the rotary evaporator.

Example 5<u style="single">TiO using HDTMS</u>_{<u style="single">2</u>}<u style="single">(Anatase) Powder surface modification</u> TiO prepared according to Examples 1 to 3₂1.0 g of powder is stirred with 8.67 g of toluene in each case and then mixed with 0.312 g of HDTMS. After stirring for 2 hours, the toluene is removed on the rotary evaporator.

Example 6<u style="single">Undoped TiO</u>_{<u style="single">2</u>}<u style="single">Manufacture of photocatalyst layer using</u> To prepare the GPTS hydrolyzate, mix 23.6 g (0.1 mol) of GPTS with 5.4 g (0.3 mol) of water. The mixture is then stirred at room temperature overnight.

0.05 g of FTS-modified undoped TiO prepared according to Example 4₂The powder is dispersed in 1.56 g MEK (methyl ethyl ketone) and then mixed with 0.44 g formamide. The resulting dispersion is mixed with 4.14 g of the prepared GPTS hydrolyzate with stirring.

The obtained coating composition is applied to a 10 cm × 10 cm polycarbonate plate (PC plate) at 1000 rpm by a spin coating device (spin coater). Subsequently, the plate is cured at 128 ° C for 1 h. The thickness of the coating is 2-3 μm. The contact angle of the obtained layer with water is 101 °.

Irradiate the coated PC plate with a xenon lamp (750W) for 4 minutes. After irradiation, the contact angle of the PC plate with water is only 10 °.

In order to measure the photocatalytic activity of the obtained PC plate, the time course of the light absorption of the rhodamine B solution at 553 nm is measured. For this purpose, 20 ml of aqueous Rhodamine B solution (concentration 6 ppm) is brought into contact with a PC plate irradiated with a xenon lamp (750 W). The absorption of rhodamine B solution at 553 nm is measured at intervals and the degradation of rhodamine B is monitored. After about 1 hour, all rhodamine B is degraded.

Example 7<u style="single">Sn-doped TiO</u>_{<u style="single">2</u>}<u style="single">Manufacture of photocatalyst layer using</u> 0.05 g of HDTMS-modified Sn-doped TiO prepared in Example 5₂The powder is dispersed in 1.56 g petroleum ether and then mixed with 0.44 g formamide. The resulting dispersion is mixed with 4.14 g of the GPTS hydrolyzate prepared in Example 6 with stirring.

The obtained coating composition is applied to a 10 cm × 10 cm polycarbonate plate (PC plate) at 1000 rpm by a spin coating device (spin coater). Subsequently, the plate is cured at 128 ° C for 1 h. The layer thickness is 2-3 μm. The contact angle of the obtained layer with water is 92 °.

Irradiate the coated PC plate with a xenon lamp (750W) for 4 minutes. After irradiation, the contact angle of the PC plate with water is less than 10 °.

By measuring the light absorption of the Rhodamine B solution at 553 nm, the photocatalytic activity of the obtained PC plate is measured with the same experimental settings as in Example 6. After about 35 minutes, all rhodamine B decomposes.

Example 8<u style="single">Preparation of photocatalytic layer using TEOS hydrolyzate</u> To prepare the TEOS hydrolyzate, mix 12.36 g (0.0594 mol) of TEOS in 15.96 g of ethanol with 9.06 g of water. To this, add 0.2 g of concentrated (37%) HCl with stirring. After 1 h of stirring, 0.28 g of GPTS is added and the mixture is stirred at room temperature overnight. A TEOS hydrolyzate containing 2 mol% GPTS is obtained.

In each case, the FTS-modified TiO prepared in Example 4₂Prepare a 2.5 wt% methyl ethyl ketone solution of powder (undoped, Sn-doped, W-doped) and mix with 0.2 g of prepared TEOS hydrolyzate containing 2 mol% GPTS (mol Ti: Si). Ratio = 10: 5).

The obtained coating composition is applied to a 10 cm × 10 cm polycarbonate plate (PC plate) by a spin coating device. Subsequently, the plate is cured at 128 ° C for 1 h.

Example 9<u style="single">Dope TiO</u>_{<u style="single">2</u>}<u style="single">Measurement of photocatalytic activity of layers with</u> Doped TiO to measure photocatalytic activity₂The layer with was examined. Sn-doped TiO for this purpose₂Powder (Sn (IV)), W-doped TiO₂Powder (W (VI)), Fe-doped TiO₂Powder (Fe (III)) and In-doped TiO₂The powder (In (III)) is used at different ratios of Ti to the doping metal.

Sn- and W-dope TiO₂Powder, Sn (CH₃CO₂)₄And WO₃Is prepared according to Examples 2 and 3 and the amount used is varied according to the desired ratio of Ti to dopant (0.5-10 mol% dopant). In a similar way, dope TiO₂FeCl powder₃And In₂O₃Prepared using. For comparison, unmodified anatase can also be prepared under the same conditions for each case.

In each case, the prepared dope TiO₂A 2.5 wt% methyl ethyl ketone solution of powder is prepared and mixed with 0.2 g of TEOS hydrolyzate prepared as in Example 8 containing 2 mol% GPTS.

The obtained coating composition is applied to a polycarbonate plate (PC plate) by a spin coating device. Subsequently, the plate is cured at 128 ° C for 1 h.

Rhodamine B solution (H₂Photocatalytic activity is measured again using 6 ppm) in O. Each coated plate is contacted with 20 ml of Rhodamine B solution and then irradiated with UV light for 10 min. Then, the absorption of the rhodamine B solution is measured at 553 nm. For comparison, measurements on rhodamine B are made in a similar manner, without contact with the photocatalytic layer and with undoped anatase. The results are listed in the table below. It can be seen that doping achieves a clearly faster degradation rate in some cases.

<tables num="1"><img file="JP4974459B2_D0001.tif" /></tables>

Example 10<u style="single">TiO under reflux</u>_{<u style="single">2</u>}<u style="single">(Anatase) preparation</u> 19.2g (0.068mol) titanium isopropoxide (Ti (O)ⁱPr)₄) Is added to 29.02 g of 1-pentanol, stirred at room temperature for 5 min, and then mixed with 1.33 g (0.0136 mol) of 37% HCl. After 20 min, add 1.42 g (0.079 mol) of water immediately with vigorous stirring, and further stir for 20 min at room temperature. Subsequently, the mixture is boiled at 132 ° C. for 16 hours under reflux. The resulting anatase is centrifuged and removed and dried at 50 ° C and 10 mbar.

<u style="single">Refluxed TiO using TODA</u>_{<u style="single">2</u>}<u style="single">(Anatase) Powder surface modification</u> 1g of TiO obtained above₂The powder is stirred with 4 g of water in each case and then mixed with 0.2 g of TODA (trioxadecanoic acid). After 10 min sonication, a clear solution is obtained.

<u style="single">Refluxed TiO with toluene</u>_{<u style="single">2</u>}<u style="single">(Anatase) Powder dispersion</u> 1g of TiO obtained above₂The powder is stirred with 1.5 g of toluene in each case. After 1 min of sonication, a clear solution is obtained.