Method for coating amorphous titanium peroxide

[0001] The present invention relates to a method for coating an amorphous titanium peroxide substrate, particularly a viscous amorphous type having excellent adhesiveness even if the surface thereof is a water-repellent substrate. The present invention relates to a method for coating a substrate of titanium peroxide and a substrate having a thin layer of a photocatalytic semiconductor or a dielectric / conductive ceramic using the same as a binder.

[0002] Conventional Techniques Examples of the method of coating a photocatalytic semiconductor or a dielectric / conductive ceramic material on a substrate include a sputtering method, a thin-film deposition method, and a high-temperature sintering method using a transfer printing film, which are conventional techniques. There is technology. As a method for fixing a photocatalytic semiconductor, various organic binders and those that are heat-processed by adding silica gel are well known (Japanese Patent Laid-Open No. 7-171408), and glaze, inorganic glass, thermoplastic resin, solder, etc. are added to the binder. It is also known to be used (Japanese Patent Laid-Open No. 7-232080), SnO₂Is also known as a method of fixing to a substrate to be used as a coagulant (Japanese Patent Laid-Open No. 7-155598).

[0003] However, in the sputtering method and the vapor deposition method, the coating apparatus becomes very expensive, and in the transfer printing method, the thermal stress applied to the substrate or the like due to the thermal processing conditions must be taken into consideration, which limits the selection of materials. was there. Further, in the method of fixing a photocatalytic semiconductor or a dielectric / conductive ceramic material with a binder, if the surface of the substrate is water-repellent, it is necessary to pretreat the surface of the substrate with a solution of a surfactant or caustic soda. was there. Furthermore, it has been difficult for these photocatalytic semiconductors and particles of dielectric / conductive ceramics to be buried in various binders to sufficiently function the redox action and the dielectric / conductive action.

[0004] As titanium peroxide, Japanese Patent Application Laid-Open No. 7-286114 describes a coating liquid for forming a film, which is made of peroxopolytitanic acid, which is a polymer of peroxotitanate. This peroxopolytitanic acid is obtained by adding hydrogen peroxide to a gel, sol or a mixed dispersion of titanium oxide hydrate and heating at room temperature or below 90 ° C (in Example 1, heating at 80 ° C for 1 hour). ) It is stated that it can be obtained. In addition, a viscous liquid or a jelly-like solution obtained by condensing an aqueous solution of titanium hydrogen peroxide is also known (Japanese Patent Laid-Open No. 62-252319). This product is obtained as a yellow film by adding hydrogen peroxide solution to fine powder of titanium hydride to obtain a yellow aqueous solution of titanium peroxide, leaving it at room temperature to gradually evaporate the water and condense the solute. It is stated that it will be done.

[0005] However, the peroxopolytitanic acid described in JP-A-7-286114 is obtained by adding hydrogen peroxide to a gel or sol of titanium oxide hydrate or a mixed dispersion thereof, and at room temperature or at 90 ° C. or lower. On the other hand, the "viscous amorphous titanium peroxide" of the present application obtained by adding hydrogen peroxide to titanium oxide hydrate and reacting at 15 ° C or lower is the same. Not only are the manufacturing methods different, but also the physical properties, especially the viscosity, are significantly different, the function as a binder is inferior, and there is a problem that it is difficult to form a thin layer of a photocatalytic semiconductor or a dielectric / conductive ceramic material. It was.

[0006] Further, the viscous liquid or jelly-like solution obtained by condensing the titanium hydrogen peroxide aqueous solution described in JP-A-62-252319 is yellow by adding hydrogen peroxide solution to the fine powder of titanium hydride. It is obtained as a yellow film by evaporation of water from the aqueous solution of titanium peroxide in the above. On the other hand, hydrogen peroxide is added to titanium oxide hydrate and reacted at 15 ° C or less to form a viscous jelly-like substance. Not only is the production method different from the "viscous amorphous titanium peroxide" of the present application, but also the physical properties are different, and it is also described in JP-A-7-286114 (column 2). As described above, it is stable only at an extremely dilute concentration and cannot exist in a stable state for a long period of time, and the film formed on the base material is prone to cracks and peeling, and is fired when fired at a high temperature. There was a problem that the later film became porous.

[0007] [Problems to be solved by the present invention] Even if the surface of the substrate is water-repellent or thermoplastic, the thermoplasticity of the substrate that does not need to be subjected to hydrophilic treatment with a surfactant or the like is limited. It is an object of the present invention to provide a coating material that does not become a coating material, and to provide a film-forming method in which a thin layer of a photocatalytic semiconductor or a dielectric / conductive ceramic material is easily formed and its thickness is easily controlled, and the photocatalytic semiconductor or the like is not buried by a binder. And.

[Means for Solving the Problems] As a result of diligent research to solve the above problems, the present inventors have fixed a viscous amorphous titanium peroxide or the like to a substrate and used it as a binder layer. By adhering fine particles of photocatalytic semiconductor, dielectric ceramics or conductive ceramics to the amorphous titanium peroxide layer in a uniformly scattered state in gas, and fixing viscous amorphous titanium peroxide or the like to the substrate. The present invention was completed by heating and firing to form a titanium oxide layer having photocatalytic activity.

[0009] That is, the present invention is a method of fixing an amorphous titanium peroxide layer to a substrate, in which an amorphous titanium peroxide sol is coated or a hydrophilic treatment is performed on the surface of the substrate using a surfactant or the like. It is made by a method of fixing an amorphous titanium peroxide layer on a substrate, which is characterized by coating with a viscous amorphous titanium peroxide and then drying and firing at room temperature to less than 250 ° C. The present invention relates to a substrate having an amorphous titanium peroxide layer.

[0010] Further, it is a method of fixing a titanium oxide layer to a substrate, and is viscous without coating an amorphous titanium peroxide sol or performing a hydrophilic treatment on the surface of the substrate using a surfactant or the like. The present invention relates to a method of fixing a titanium oxide layer to a substrate characterized by being coated with an amorphous titanium peroxide and then drying and firing at 250 ° C. or higher, and a substrate having a titanium peroxide layer produced by this method.

[0011] Further, the substrate is coated with an amorphous titanium peroxide sol, or is coated with a viscous amorphous titanium peroxide without performing a hydrophilic treatment on the surface of the substrate using a surfactant or the like, and is amorphous. The amorphous type titanium peroxide layer is formed, and while the amorphous type titanium peroxide layer has adhesiveness, fine particles of photocatalyst semiconductor, dielectric ceramics or conductive ceramics are uniformly scattered in a gas to form the amorphous type. A method for fixing a thin layer of a photocatalyst semiconductor, a dielectric ceramic or a conductive ceramic, which is characterized by adhering to a titanium peroxide layer, a substrate produced by this method, and an amorphous peroxide formed on the substrate. The present invention relates to a substrate composed of a titanium layer and a thin layer of a photocatalyst semiconductor, dielectric ceramics or conductive ceramics formed on the amorphous titanium peroxide layer.

[0012] Furthermore, after reacting the titanium tetrachloride solution and the ammonium hydroxide solution in an acidic region of pH 2 to 6, the precipitated pale bluish white orthotitanium acid is washed, then diluted or concentrated to have a solid content concentration. Add hydrogen peroxide solution to an aqueous solution adjusted to 0.2 to 0.6% by weight, and react at low temperature, preferably at 15 ° C or lower, particularly preferably at about 5 ° C to 8 ° C, and then at room temperature. The present invention relates to a method for producing a viscous amorphous titanium peroxide produced by curing, and a viscous amorphous titanium peroxide produced by this method.

[Embodiment of the Invention] The "amorphous titanium peroxide sol" in the present invention can be produced, for example, as follows. Titanium tetrachloride TiCl₄Ammonia water or alkali hydroxide such as sodium hydroxide is added to the aqueous titanium salt solution as described above, and the mixture is reacted at pH 6 to 7. The resulting pale bluish white, amorphous titanium hydroxide Ti (OH)₄(Orthotitanate H₄TiO₄Also called. ) Is washed and separated, and then treated with hydrogen peroxide solution to obtain an amorphous titanium peroxide sol.

[0014] The "amorphous titanium peroxide sol" in the present invention thus obtained has a pH of 6 to 7 and a particle size of 8 to 20 nm, and has a yellow transparent liquid in appearance, and is stored at room temperature for a long period of time. Is also stable. The sol concentration is usually adjusted to 1.4 to 1.6% by weight, but the concentration can be adjusted as needed, and when used at a low concentration, it is diluted with distilled water or the like before use.

[0015] Further, this amorphous titanium peroxide sol is in an amorphous state at room temperature and has not yet crystallized into anatase type titanium oxide, and has excellent adhesion, high film forming property, and creates a uniform and flat thin film. And the dry film has the property of being insoluble in water. When the amorphous titanium peroxide sol is heated at 100 ° C or higher for several hours, it becomes anatase type titanium oxide sol, and the amorphous titanium peroxide sol coated on the substrate and then dried and fixed is 250 ° C to 940 °. By heating C, it becomes anatase-type titanium oxide.

[0016] The "viscous amorphous titanium peroxide" in the present invention can be produced, for example, as follows. Titanium tetrachloride TiCl₄Ammonia water or an alkali hydroxide such as sodium hydroxide is added to the aqueous titanium salt solution as described above, and the reaction is carried out at pH in an acidic region, preferably pH 2 to 6, particularly preferably pH 2. Precipitated pale bluish white, amorphous titanium hydroxide Ti (OH)₄(Orthotitanate H₄TiO₄Also called. ) Is washed and separated, treated with hydrogen peroxide solution, reacted at low temperature, preferably at 15 ° C or lower, particularly preferably at 5 to 8 ° C with stirring, and then cured at room temperature for 7 to 10 days. Obtained by

The "viscous amorphous titanium peroxide" of the present invention thus obtained has a pH of 2 to 4 and a particle size of about 8 to 20 nm, and its appearance is a yellow transparent, slightly viscous sol to half. It is jelly-like, that is, has various viscosities, has a very strong adhesive force, and is stable even when stored at room temperature for a long period of time. The solid content concentration is usually adjusted to 0.2 to 0.6% by weight, preferably 0.3% by weight, but the concentration can be adjusted as needed.

[0018] The "viscous amorphous titanium peroxide" in the present invention is Titanium tetrachloride TiCl in the manufacturing process thereof.₄By changing the pH at the time of reaction between the aqueous titanium salt solution such as, and aqueous ammonia or alkali hydroxide such as sodium hydroxide within the acidic range, preferably within the range of pH 2 to 6, and by changing the solid content concentration to 0.2. By changing the value within the range of ~ 0.6% by weight, those having various viscosities can be obtained, and various uses can be considered depending on the viscosity. However, for the purpose of forming a thin film having a uniform film thickness, it is homogeneous. It is desirable that the viscosity is about semi-jelly.

When the pH of the above reaction exceeds 6, it becomes an amorphous titanium peroxide sol having low viscosity, and when coating the surface of a substrate such as a metal or plastic having strong water repellency, hydrophilic treatment with a surfactant or the like is performed. It is necessary, and when the pH is less than 2, there is an inconvenience that the precipitation of orthotitanic acid is extremely reduced. Further, if the solid content concentration exceeds 0.6% by weight, there arises a problem that it becomes inhomogeneous semi-jelly and it becomes difficult to form a thin film having a uniform film thickness. On the other hand, if it is less than 0.2% by weight, the surface of the substrate At the time of coating, there is a disadvantage that hydrophilic treatment due to surface activity or the like is required.

[0020] As described above, the viscous amorphous titanium peroxide of the present invention is a novel substance that is transparent and viscous yellow, and has not yet crystallized into anatase-type titanium oxide in an amorphous state at room temperature. Its adhesion and adhesion are extremely excellent in substrates of all grades, including substrates with water repellency. In addition, it has a high film-forming property, a uniform and flat thin film can be easily formed, and the dry film has a property of being insoluble in water.

[0021] Then, when this viscous amorphous titanium peroxide is coated on a substrate and dried and fired at room temperature to 250 ° C., it forms an amorphous titanium peroxide layer having a very strong adhesive force. .. In addition, when dried and fired at 250 ° C to 940 ° C, anatase-type titanium oxide layer is formed, and when heated at 940 ° C or higher, a rutile-type titanium oxide layer is formed, and the function of the photocatalyst is extremely reduced. ..

[0022] In the present invention, as the "base", an inorganic material such as ceramics and glass, an organic material such as plastic, rubber, wood and paper, and a metal material such as aluminum and steel can be used. Among these, application to organic polymer resin materials such as acrylonitrile resin, vinyl chloride resin, polycarbonate resin, methyl methacrylate resin (acrylic resin), polyester resin, and polyurethane resin is particularly effective. Further, the size and shape are not limited, and a film shape, a honeycomb shape, a fiber shape, a filtration sheet shape, a bead shape, a foam shape, or a product obtained by accumulating them may be used. Further, if it is a substrate that allows ultraviolet rays to pass through, it can be applied to the inner surface thereof, and it can also be applied to a painted article.

[0023] For coating the substrate with amorphous titanium peroxide sol or viscous amorphous titanium peroxide, known methods such as dipping and spray spray can be used.

[0024] After coating by coating or spraying as described above, the substrate having the amorphous titanium peroxide layer of the present invention can be produced by drying and firing at less than 250 ° C. and solidifying. It is also possible to produce a substrate in which anatase-type titanium oxide layer is solidified and carried by sintering at around 250 ° C to 400 ° C after coating. Since such a substrate has a photocatalytic function, it is an organic polymer resin that is easily decomposed by a photocatalyst as a substrate, polytetrafluoroethylene (PTFE) which is a high-performance engineering plastic, and polyamide-imide (PAI) which is a super heat-resistant engineering plastic. ), Polyimide (PI), etc., the photocatalytic function of titanium oxide is reduced by sodium ions, and the resin surface is treated with a sodium ion-containing substance such as a sodium hydroxide solution prior to coating. It is advantageous to have a sodium source present, such as by cleaning.

[0025] The coating composition composed of amorphous titanium peroxide sol or viscous amorphous titanium peroxide has a feature that a predetermined thickness can be obtained by one coating. The thickness of the titanium peroxide layer formed by the coating or the thin film of the titanium oxide layer obtained by heating and firing at 250 ° C or higher is the concentration of titanium peroxide in the viscous amorphous titanium peroxide or the like. It can also be adjusted by (% by weight), viscosity and coating thickness before drying. If necessary, the above coating materials can be applied in layers.

[0026] The above-mentioned substrate having an amorphous titanium peroxide layer has excellent weather resistance and can protect a substrate made of a polymer organic material or the like from ultraviolet rays or the like, and when a photocatalytic semiconductor layer is provided on the substrate, It can protect substrates such as organic polymer materials that are easily decomposed by the photocatalytic function.

[0027] In the present invention, the "photocatalytic semiconductor" is TiO.₂, ZnO, SrTiO₃, CdS, Cd0, CaP, InP, In₂O₃, CaAs, BaTiO₃, K₂NbO₃, Fe₂O₃, Ta₂O₅, WO₃, SaO₂, Bi₂O₃, NiO, Cu₂O, SiC, SiO₂, MoS₂, MoS₃, InPb, RuO₂, CeO₂Among these, titanium oxide TiO₂The photocatalytic semiconductor is preferably used in the form of fine particles or fine powder having a diameter of about 0.001 μm to 20 μm.

[0028] Also, Pt, Ag, Rh, RuO for complementing the photocatalytic function.₂, Nb, Cu, Sn, NiO and the like can also be used as additives.

[0029] In the present invention, the "dielectric ceramic" material is SiO.₂, Ta₂O₅, TiO₂, SrTiO₃, BaTiO₃, Pb-based perovskite compounds can be mentioned. In addition, examples of the "conductive ceramics" material include base metal alloys such as copper, nickel, chromium, titanium, and aluminum. These ceramic materials are used in the form of fine particles or fine powder having a diameter of about 0.001 μm to 20 μm. Such fine powder can be suspended in a uniform and dispersed state in a gas.

[0030] In the present invention, "a method of fixing a thin layer of a photocatalytic semiconductor, a dielectric ceramic, or a conductive ceramic" will be described with reference to FIG. 1. The substrate 3 subjected to a hydrophilic treatment with a surfactant or the like is amorphous. The amorphous titanium peroxide layer is formed by coating the substrate with a viscous amorphous titanium peroxide directly without coating the type titanium peroxide sol or performing a hydrophilic treatment to form the amorphous titanium peroxide layer 2. While having adhesiveness (usually within 1 to 10 minutes at room temperature after coating), the fine particles 1 of the photocatalytic semiconductor, dielectric ceramics or conductive ceramics are placed in a gas using a closed / atmospheric pressure container. There is a method in which the ceramic is uniformly scattered and adhered to the amorphous titanium peroxide layer by natural adhesion or air pressure adhesion to remove excess fine particles. Further, by fixing a thin layer of a photocatalytic semiconductor, a dielectric ceramic or a conductive ceramic to an amorphous titanium peroxide layer and then applying pressure, the adhesiveness between the layers is remarkably improved. In this way, a homogeneous thin film can be made.

[0031] By forming a thin layer of such a photocatalytic semiconductor, a dielectric ceramic, or a conductive ceramic, it is possible to reduce the size and weight of electronic devices and the like, and to reduce the capacity. Further, as the photocatalyst functional substrate, the laminated thin film of the photocatalyst semiconductor has an effect of eliminating the functional deterioration due to mutual interference of the particle surfaces due to electron transfer and the economic loss due to the film thickness during the redox of the photocatalyst semiconductor.

[Examples] Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited to these examples.

Reference Example 1 (Manufacturing of amorphous titanium peroxide sol) Titanium tetrachloride TiCl₄100 ml of 50% solution (Sumitomo Citics Co., Ltd.) diluted 70 times with distilled water and ammonium hydroxide NH₄A 25% solution of OH (Takasugi Pharmaceutical Co., Ltd.) diluted 10-fold with distilled water is adjusted to pH 6.5 to 6.8 and the reaction is carried out. After the reaction, leave it for a while and then discard the supernatant. Remaining Ti (OH)₄Add about 4 times the amount of distilled water in the gel, stir well and leave. Repeat washing with a conductivity meter until the conductivity reaches 2 to 10 μS, and finally discard the supernatant to leave only the precipitate. In some cases, the concentration process can be performed by a concentrator. This pale bluish white Ti (OH)₄To 3600 ml, 210 ml of 35% hydrogen peroxide solution is added in two portions every 30 minutes, and the mixture is stirred at about 5 ° C overnight to obtain about 3800 ml of a yellow transparent amorphous titanium peroxide sol. In the above steps, if heat generation is not suppressed, water-insoluble substances such as metatitanic acid may precipitate, so it is desirable to suppress heat generation in all steps.

Example 1 (Production of Viscous Amorphous Titanium Peroxide) Titanium tetrachloride TiCl₄100 ml of 50% solution (Sumitomo Citics Co., Ltd.) diluted 70 times with distilled water and ammonium hydroxide NH₄A 25% solution of OH (Takasugi Pharmaceutical Co., Ltd.) diluted 10-fold with distilled water was mixed and adjusted so that the pH became 2.0, and the reaction was carried out. After the reaction, leave it for a while and then discard the supernatant. Remaining Ti (OH) orthotitanate₄Add about 4 times the amount of distilled water in the gel, stir well and leave. Repeat washing with a conductivity meter until the conductivity reaches 2 to 10 μS, and finally discard the supernatant to leave only the precipitate. In some cases, the concentration process can be performed by a concentrator. This pale bluish white orthotitanate Ti (OH)₄Add 200 ml of 35% hydrogen peroxide solution to 2550 ml of aqueous solution in 2 portions every 30 minutes, stir overnight at about 5 ° C, and cure at room temperature for 7 to 10 days. Approximately 2800 ml of thick amorphous titanium peroxide was obtained.

Example 2 (Method for producing various viscous viscous amorphous titanium peroxides) In Example 1, the same procedure as in Example 1 was carried out except that the pH at the time of reaction was set to 3, 4 and 5. As the pH increased, a harder jelly-like substance was obtained than the viscous amorphous titanium peroxide obtained in Example 1, and the solid content concentration gradually increased.

[0036] Example 3 An acrylic resin plate, a methacrylic resin plate, and a methyl methacrylate resin plate were used as the substrates. The surfaces of these resin plates were washed with water and dried, and the resin plates were coated once with 0.3% by weight of the viscous titanium peroxide prepared in Example 1 by depping. When the coating surface is wet, anatase-type titanium oxide powder ST-01 (manufactured by Ishihara Sangyo Co., Ltd.) is adhered in a container in a uniform gas suspension state, dried at 50 ° C, and then heated at 200 ° C under pressure. Then, it was washed to prepare a photocatalytic semiconductor substrate. These substrates are remarkably excellent in that the photocatalyst layer is a thin film, there is no risk of peeling as compared with the conventional thick film, and the organic compound decomposition performance is not changed at all.

Example 4 As a substrate, a semi-porcelain glazed tile (made by INAX Co., Ltd .: 100 × 100 × 5 mm), a ceramic coated steel plate (210 × 296 × 0.8 mm), and a keramitt plate (glazed type: 157 × 223 × 4 mm). Was used. After cleaning these surfaces and drying them at room temperature, 0.3% by weight of the viscous titanium peroxide prepared in Example 1 was squeeze plate, 0.1 to 0.2 g / sheet for semi-porcelain glazed tiles, and ceramic coated steel. The board was coated with 2.0 to 2.3 g / sheet, and the porcelain board was coated with 1.5 to 1.8 g / sheet. When the coating surface was wet, anatase-type titanium oxide powder ST-01 (manufactured by Ishihara Sangyo Co., Ltd.) was adhered in a container in a uniform gas suspension state for 1 minute. / Sheet, 0.1 ~ 0.2g / sheet on ceramic coated steel plate, 0.1g / sheet on anatase plate, each with anatase type titanium oxide powder attached, dried at 50 ° C and at 500 ° C A photocatalytic semiconductor substrate was prepared by firing for 30 minutes. The photocatalytic function of these substrates was remarkably excellent in terms of cosmetic properties and adhesiveness.

[0038] Example 5 A polyester / rayon-based non-woven fabric (300 × 300 mm) was used as the substrate. After washing this non-woven fabric with water, it is dried, and 0.3% by weight of the viscous titanium peroxide prepared in Example 1 is attached by depping, and then anatase-type titanium oxide powder ST-01 (manufactured by Ishihara Sangyo Co., Ltd.) is gas-uniformized. It adhered in a floating state and dried and fixed at 50 ° C. Then, this dried product was pressed with an iron at 120 to 150 ° C. to further improve the adhesiveness between the layers. This substrate was particularly excellent in decomposition performance as well as cosmetic property and adhesiveness.

[0039] Example 6 A decomposition test of an organic substance was carried out as follows. As the substrate, paragrass (methacrylic resin manufactured by Kuraray Co., Ltd.) having a length and width of 210 x 296 mm was used. 0.3% by weight of the viscous titanium peroxide prepared in Example 1 was attached to this substrate by depping, and then anatase-type titanium oxide powder ST-01 (manufactured by Ishihara Sangyo Co., Ltd.) was attached in a uniform gas suspension state 50. Dryed and fixed at ° C. Then, this dried product was pressed with an iron at 120 to 150 ° C. to further improve the adhesiveness between the layers. A photocatalyst carrying a photocatalyst was obtained. These test photocatalysts were placed in a test container, and then a colored solution of an organic substance to be decomposed was poured into the container to a depth of 1 cm. This coloring solution is a 30-fold dilution of Pollux Red PM-R (manufactured by Sumika Color Co., Ltd.), which is an aqueous dispersion (red liquid) of monoazored. Next, in order to prevent evaporation of the coloring solution in the container, the container was covered with a float glass (wavelength of 300 nm or less was cut). Two ultraviolet radiators (20w blue color fluorescent tubes) were installed 5 cm above the test container and 9.5 cm from the substrate at a distance of 13 cm, and when the photocatalyst was irradiated and the color of the coloring solution disappeared. It is assumed that the decomposition of organic matter has been completed. As a result, it was found that the color disappeared completely 2 days after the start of the test and that the test had an excellent photocatalytic function.

[Effect of the Invention] When the viscous amorphous titanium peroxide according to the present invention is used, an amorphous titanium peroxide layer can be formed without subjecting any substrate to a hydrophilic treatment with a surfactant or the like. It is possible to fix a thin layer of a photocatalytic semiconductor, a dielectric ceramic, or a conductive ceramic due to its excellent adhesive force, and it is possible to achieve miniaturization, weight reduction, and capacity reduction of an electronic device or the like using the thin layer. Further, as the photocatalyst functional substrate, the laminated thin film of the photocatalytic semiconductor has an effect of eliminating the functional deterioration due to mutual interference of the particle surfaces due to electron transfer and the economic loss due to the film thickness during the redox of the photocatalyst semiconductor.

BRIEF DESCRIPTION OF THE DRAWINGS [FIG. 1] FIG. 1 is an explanatory diagram showing a method of fixing a thin layer of a photocatalytic semiconductor, a dielectric ceramic, or a conductive ceramic.

[Description of Code] 1 Fine particles of photocatalytic semiconductor, dielectric ceramics or conductive ceramics 2 Amorphous titanium peroxide layer 3 Substrate