Photocatalyst body and method of production thereof

TECHNICAL AREA

0001These Invention relates to a method for making a photocatalytic body with a good photocatalytic property and a photocatalytic Body.

BACKGROUND TECHNOLOGY

0002If Semiconductors are irradiated with light whose wavelength is a Energy, which is greater as the band gap, an oxidation-reduction reaction is brought about. On Such a semiconductor is a photocatalytic semiconductor or just called a photocatalyst.

0003photocatalysts are in the form of powder in front and can be suspended in a solution or can be be used supported on a substrate. From the standpoint of photocatalytic activity her former is more active because of the larger surface, from the standpoint of practical applications ago has often been experienced, that because the easier handling unavoidable the latter instead of the former must be used.

0004Around to hold a photocatalyst on a substrate, a method been used in which the particles of a photocatalyst sintered at high temperatures and deposited on the substrate will. Another method has been proposed in which uses a certain type of a fluoropolymer as a binder is applied a photocatalyst onto a substrate with the becomes. For example specifies the Japanese Patent Application Laid JP-A-42 84851 represents a process in which a mixture of the particles constructed of a photocatalyst and a fluoropolymer layers is bound and under compression. Japanese Laid-Open Patent application JP-A-43 34552 sets forth a method wherein the thermally bonded particles of a photocatalyst to a fluoropolymer mer will. About that also specifies the Japanese Laid-Open Patent Application JP-A-7 171408 a method represents, in which the particles of a photocatalyst on a substrate be bound by a hard to decomposing binder which an inorganic binder, such as water glass, or an organic binder, such as a silicone copolymer, and also a method for making a photocatalytic body which on a substrate a first layer, which is difficult to a decomposing binder consists, and a second layer, which on the first layer is formed and a difficult to be decomposed Binder and the particles of the photocatalyst is prepared, includes. In addition, describes Japanese Laid-Open Patent Application JP-A-5 309267 a method, wherein the metal oxide obtained from a metal oxide sol has been is used to adhere the powder of a photocatalyst to maintain order and to fix. It is noted that the metal oxide sols from organometallic compounds such as alkoxides, acetylacetonate, Carboxylates of metals as used in a sol-gel process, be obtained by hydrolysis or an alcoholic solution of Chlorides, such as titanium tetrachloride, in the presence of an acid or alkaline catalyst can be obtained.

0005The JP-A-62 283817 discloses a process for depositing a titanium oxide sol on a substrate, wherein titania sol obtained by an acid-Entflockulationsverfahren has been obtained when the titanium oxide can be used, and the diluted Titanium oxide sol obtained by diluting a titanium oxide solution has been obtained, prepared by dissolving a gel with hydrogen peroxide, followed by heating and hydrolysis of the solution, can be used.

EPIPHANY THE INVENTION

0006In recent years, attempts have been made, harmful substances, aggressive odorous components and oily components around daily Life can be attributed to the use of photocatalysts to decompose to clean and sterilize, thus leading to a rapid extension of the scope of photocatalysts out has. This, in turn, requires a method that causes the particles a photocatalyst fixed on all types of substrates over a be kept for a long time without their photocatalytic function is sacrificed. In particular, when a titanium oxide sol, which comprises good photocatalytic function displays, but poorly in the function binding to a substrate, is used as a photocatalyst, it is necessary to improve the bonding property.

0007however with these processes of the prior art, the bonding strength not satisfactory, so that a few A method holding for a long time to make sure. If it is thought, a photocatalytic body produce, having an improved bonding strength and holding a ensures long time, the problem has arisen that the photocatalytic function decreases. In the case that the substrate, which has been prepared from an organic polymer resin used is and rutile titanium oxide, which in the photocatalytic function weaker is is used as anatase titanium oxide, the photocatalytic reaction proceeds continued. Not only is subject to the organic Polymerharz as such a photochemical reaction, but also the use over a long lead to degradation and decomposition.

0008Furthermore is, when organic polymer resins are used as a substrate, tried the preliminary coating for example, a silica sol been, with the attendant problem that during the course of the Koagulationstrocknens Sols of silica- Cracks or voids are formed, thus presenting a problem for their binding quality.

0009Around To solve the above problems, are studies about accomplished been, as the particles of a photocatalyst on all types substrates over a long time are to hold, without its photocatalytic hindering effect. As a result, unexpectedly found been that when an amorphous titanium peroxide sol is used as a binder, the particles of a photocatalyst fixed on all types of substrates over a a long time can be maintained, without the photocatalytic function to obstruct. The invention has come based on the finding about.

0010The Invention is defined by the process of Claim 1.

0011More accurate the invention relates to a method for making a photocatalytic body by Use of a photocatalyst such as of titanium oxide, and a amorphous titanium peroxide sol so that the photocatalyst fixed held on a substrate, and also a method for producing a photocatalytic body, which comprises forming, on a substrate, a first layer of amorphous Titanium peroxide sol without photocatalytic function and continue the Forming a second layer on the first layer, wherein the second Layer made of a photocatalyst and an amorphous titanium peroxide sol is prepared, having. Further, the invention relates to a photocatalytic Body, which has been obtained by these methods.

0012the amorphous titanium peroxide sol used in carrying out the invention is may be prepared, for example, in the following manner. An alkali metal hydroxide, such as aqueous ammonia or Sodium hydroxide is added to an aqueous solution of a Titanium salt such as titanium tetrachloride, TiCl₄. added. The resultant light bluish-white amorphous titanium hydroxide Ti (OH)₄May ortho titanic acid, H₄TiO₄, to be named. This titanium hydroxide washed and separated, after which it is treated with a aqueous hydrogen peroxide solution is to provide a solution to obtain amorphous titanium peroxide, the present at the is usable invention. The amorphous titanium peroxide sol has a pH of 6.0 ~ 7.0 and a particle size of 8 ~ 20 nm, with an appearance in the form of a yellow transparent liquid. The sol is a long time stable when stored at normal temperatures. The sol concentration is usually ~ 1.60% to a value of 1.40. If necessary, the concentration can be optimally controlled. When the sol at low concentrations is used, it is prepared by diluting, such as with distilled Water used.

0013the amorphous titanium peroxide remains amorphous and is at normal temperatures will not crystallize in the form of anatase titanium oxide. The sol has good Adhesiveness a good film-forming property and is capable of a uniform flat thin to form film, and a dried film has such a property, that he insoluble in water is.

0014It will be noted that, when the amorphous titanium peroxide sol at 100 ° C or above is heated, it in anatase titanium oxide sol is converted. The amorphous titanium peroxide sol, the deposition according to the has been dried and fixed on a substrate, is in the anatase titanium oxide converted if it at 250 ° C or above is heated.

0015Of the Photocatalyst usable in the present invention is, TiO₂, Titanium oxide may be in the form use of particles or powder or in the form of a sol.

0016titanium oxide in the form of a sol, that is, a titanium oxide sol, can be prepared be by an amorphous titanium oxide sol to a temperature of 100 ° C or about that is heated. The properties of the titanium oxide sol change more or less depending on the heating temperature and heating time. For instance, an anatase titanium oxide sol, which by treatment at 100 ° C over 6 hours is formed, a pH of 7.5 ~ 9.5 and a particle size of 8 ~ 20 nm, with its appearance being in the form of a yellow suspension.

0017the Titanium oxide sol is stable when on a long time at normal Temperatures is stored and can be a precipitate upon mixing with an acid form or a metallic aqueous solution. About that addition, the Sol in its photocatalytic activity or in an acid resistance limited be when Na ions are present simultaneously. The sol concentration is usually 2.90% adjusted to a value of 2.70 ~ and can after setting the concentration, if necessary be is used.

0018On Titanium oxide sol is preferably used as a photocatalyst. Commercially available "ST-01" (ISHIHARA Sangyou KAISHA Ltd.) or "ST-31" (ISHIHARA Sangyou KAISHA Ltd.) can also be usable.

0019At the exercise of the invention, the substrate used is made of inorganic materials be as ceramics, glass and the like, organic Materials, such as plastics, rubber, wood, paper and the like, and metals such as aluminum, steels and the like. Of these show applications with organic polymeric resin materials, such as Acrylonitrile resin, vinyl chloride resin, polycarbonate resins, Methylmethacrylharz (Acrylic resins), polyester resins, polyurethane resins and the like good Effect. The substrate is not critical with respect to the size or Shape and may be in the form of a honeycomb, fibers, a filter layer, a bead, a foamed body or Combination of these present. If a substrate which the Passage of UV light allowed, is used, a photocatalytic body the inner surface applied the substrate. The body may also be coated on objects be be applied.

0020at the present invention means a binder that is not a Photocatalyst can be decomposed, those binders which can not be decomposed photocatalysts and composed of inorganic composed binders such as water glass, kol loides Silica, cement and the like, and organic binders, as fluoropolymers, silicone polymers and the like, as in the aforementioned JP-A-7 171408 discloses.

0021The Composition which is used to make a photocatalytic body produce, can be prepared by several methods.

0022One includes such methods the use of a uniform Suspension of titanium oxide powder in an amorphous titanium peroxide sol. For the uniform suspension it is advantageous to employ ultrasonic wave after mechanical agitation.

0023As next the titanium oxide sol and the amorphous titanium oxide sol are mixed, to obtain a mixed sol. The mixing ratio is dependent on the proportion of a product is determined in which a photocatalytic body is to be applied, and the conditions of use of an instrument, which the body used. When mixing considerations should be made through the Adhesion to a substrate, film-forming properties, corrosion resistance and decorative effects of the photocatalytic body, by Using the mixed sol is produced. The mixing ratio can be accurately determined, depending on the types of objects, wherein which it is applied generally in the following three groups are classified. <ul><li>(1) Those items that touching or most likely touched and the need of visual standpoint decorative effect, z. B. Tiles the interior, sanitary ware, different types of unit articles, Dinnerware, exterior materials for buildings, interiors in vehicles and the like.</li><li>(2) Those products are not affected, but the visible decorative require action, for example, outer plates for light fittings, Underpasses, Tunnel, materials for Construction and electrical equipment.</li><li>(3) Those items that can not be touched or usually looks and in which the function of decomposing organic matter based on a photocatalytic property or properties, the semiconducting metals are inherent, be used for. B. built elements within water purification tanks, various types of sewage water treatment equipment, water heaters, bathtubs, Air conditioners, the hoods of microwave ovens and other equipment.</li></ul>

0024For group (1) a photocatalytic body, is obtained in the form of a film from a mixed sol, wherein the titanium oxide sol in an amount of 30th% or less is blended, based on the total amount of the titanium oxide sol, and an amorphous titanium peroxide sol is preferred. It is found been that items that the body use for sterilization or disinfection in daily life and also for the decomposition of residual odors are sufficient. About that addition, the film surface so hard that they wear is, for example, by wiping or dusting and free from any deposit of foreign matter, along with the fact that it is not likely is that when Touch fingerprints will leave.

0025at Water purification tanks, belonging to the group (3), for example, the high photocatalytic activity the most important feature that required for the photocatalytic body is a biological oxygen demand (BOD - biological oxygen demand) in the final reduce sewage treated water. It has been found that a photocatalytic body in the form of a film, which is formed of a mixed sol, wherein the titanium oxide sol in an amount of 70th% or mixed about has been based on the total amount of the titanium oxide sol and the amorphous titanium peroxide sol, suitable for this purpose at is. This photocatalytic body is poor in its decorative effect. Since the products of the Group are some who neither in contact with People come yet catch the eye. Furthermore has also been found that a Such a problem of depositing a residue in a slight extent by periodic removal and cleaning may be solved.

0026For Articles the group (2) has been found that a photocatalytic body in the form of a film by using a mixed sol is formed, wherein the titanium oxide sol in an amount of 20 ~ 80 % Is mixed wt., Based on the total amount of the titanium oxide sol, and is an amorphous titanium peroxide sol, are suitable. This photocatalytic body exhibits properties intermediate between the former two bodies, with respect to the hardness, the adhesion of foreign substances and the photocatalytic activity.

0027For depositing or spraying a titanium oxide sol, an amorphous titanium peroxide sol or a mixed sol onto a substrate, any known procedure be used, including for example, dipping, spraying, depositing and the same. Good results in the deposition are often obtained, when the deposition step is repeated several times.

0028After depositing or spraying as mentioned above the sol is dried and solidified to form a photocatalytic body the invention to obtain. The sol can at about 200 ~ 400 ° C baked and are deducted fixed on a substrate. The photocatalytic Function of titanium oxide is reduced by the action of sodium ions. Accordingly, when an organic polymer resin which is probably due to a photocatalyst the decomposition is subject, as a substrate is used, it is preferably, the resin surface containing sodium ions with a material, such as a sodium hydroxide solution to clean, to allow that a sodium source present.

0029It is noted that, when an amorphous titanium peroxide sol is used as a first layer, the peroxide while heating to 250 ° C or above in the crystals of anatase titanium oxide is converted, which thus causes a photocatalytic Function developed. Accordingly, lower Temperatures, for example 80 ° C or below, used for drying and solidification. In this case, Sodium ions are added for the reasons explained above to the titanium peroxide sol.

0030In front the forms may the particles of a material that emits UV spontaneously or a material of the light storage-type, which emits UV, or Particles containing such radiating materials, with a Photocatalyst are mixed.

0031the Material that emits UV spontaneously (ie a spontaneous light emitting Ceramic) is able to light by consumption of its internal energy to emit and uses the radioactive decay of radium or Promethium. The emitted light is in the UV range. In practice is a purified rock powder, such a component contains, as it is mentioned above, is fixed as a solid body, and the particles, obtained by pulverizing the massive body into pieces, be used.

0032the UV radiating material light storage type (a light Ceramic light storage type) is one which receives external power emitting and light while once absorbed energy is released. The emitted light is within a UV range. Such a material is commercially available available under the names "Lumi-Nova" (trade name of NEMOTO &amp; CO., LTD) and "KEPRUS" (trade name of Next · I CO., LTD). These consist mainly of strontium aluminate (SrAl₂O₄) containing high purity components, such as aluminum oxide, strontium carbonate, Europium, dysprosium and the like. The maximum point of the absorption spectra is 360 nm, and the particle size is ~ 20 microns 50 microns. Powdered particles before pulverizing can be used as they are.

0033It will be noted that, when some commercially available Materials are derived from their performance in absorbing moisture considerably are lower, they can be used after or in glass a transparent organic polymer resin, such as polycarbonate, encapsulated, or by incorporation into a substrate or by Mounting on the surface a substrate can be used.

0034If a photocatalytic body of a mixture of particles of a spontaneous light emitting Ceramic or a light-emitting ceramic light storage type or molded particles obtained by mixing the fine particles of these ceramics have been obtained with a photocatalyst is (hereinafter referred to as mixed particles), prepared, is the photocatalytic semiconductor of the photocatalytic body by means of UV light, the radiated from the spontaneous light-emitting ceramic particles is or generated by consumption of energy of the particles in light emitting ceramics collected by the light storage-type is excited. Thus, the photocatalytic function acts on, when UV irradiation is interrupted against the photocatalytic body is. About that , the particles of the spontaneous light-emitting ceramic radiation or the light-emitting ceramic light storage type usually green, blue or orange color visible Light of what for decoration can be used or as a direction sign in the dark.

0035If the photocatalytic semiconductor controlled in its composition is (by the addition of inorganic pigments or metals) or the thermal treatment during course of the manufacturing is controlled, it may be possible to a wavelength (Absorption band) of UV light to change, which is necessary to to show the catalytic function, that is an excitation wavelength. If the example CrO₃ in small amounts to the TiO₂ is added to the absorption band will shifted toward a side of a longer wavelength. This allows that the photocatalytic body in accordance radiating with the spectral characteristics of the emission of a spontaneous UV Material or a UV radiation material light storage type is. Proper selection of a photocatalytic semiconductor in accordance having a wavelength of UV light which is to be placed on it, is possible.

0036in the can contrast radiating the spectral characteristics of the emission of a spontaneous UV Material or a UV radiation material light storage type in accordance with the excitation wavelength brought a photocatalytic semiconductor. For example is the excitation wavelength of titanium oxide in the range of 180 nm ~ 400 nm. UV radiating Materials light storage type, the responsible for the wavelength are, have never been available commercially.

0037Light memory ceramics, the commercially available are and the afterglow over allow a long time, include the "LumiNova" series of NEMOTO &amp; CO., LTD, with some of the series a have persistence which exceeds 1000 minutes. The light storing ceramics with the long-lasting afterglow are prepared by Alumina a starting main material such as strontium or calcium carbonate added, is by further europium or dysprosium as an activator added is then an element, such as lanthanum, cerium, praseodymium, samarium, Cadmium, terbium, holmium, erbium, thulium, ytterbium, ruthenium, Manganese, tin and bismuth, and boric acid as a flux added is followed by thermal treatment at 1300 ° C. The product, which is obtained with this mixing procedure, is a Emittierer for blue Light with a peak of the shortest wavelength of 440 nm.

0038Around the emission wavelength 400 nm or to move among them, which the excitation wavelength of Titanium oxide equivalent, can added additive metal elements are to the absorption wavelength of "LumiNova" having a peak at 360 nm and the emission wavelength with a peak at 400 nm in more detail to bring together. Alternatively, if an emission wavelength of 440 nm or less not in the emission of blue light at about generates 450 nm, which is a phosphorescent wavelength characteristic is that, as strontium, potassium and borax minerals inherent , a mineral element that no phosphorescent Emitting color, the shorter in the wavelength is as strontium and an emission wavelength of 400 nm or below without Development of any color has to be purified and formulated, a UV light to develop radiation material from the storage type.

0039Of the photocatalytic semiconductor may in advance of only the surfaces Unit particles are worn or can on the entire surface of a Form after mixing of unit particles with the particles of a spontaneous light-emitting ceramic or a light storage ceramic or the mixed particles and forms are borne of the mixture. In the former case, little photocatalytic semiconductor on the surfaces the particles of a spontaneous light-emitting ceramic or a light storage ceramic deposited or the mixed particles, so that the amount of UV light emitted from these particles is irradiated, becomes larger. With the particles the ceramic particles from the light storage-type UV light can by outside be absorbed effectively.

0040The photocatalytic body can support with the photocatalytic function additive metals (Pt, Ag, Rh, RuO, Nb, Cu, Sn, NiO and the like) during the course of its Production are mixed. For these additives is well known to the photocatalytic facilitate reaction.

BEST MODE FOR THE INVENTION CARRY

0041The Invention will be described in more detail by references and examples, which should not be considered to the scope of the invention limiting it.

Reference 1 (Preparation an amorphous titanium oxide sol)

0042A 1: 70-dilution a 50% solution of titanium tetrachloride, TiCl₄(SUMITOMO SITX CO) with distilled water and a 1:. 10 dilution of a 25% solution of ammonium hydroxide, NH₄OH, (Takasugi PURE CHEMICAL INDUSTRY Ltd.) are mixed with distilled water in a volume ratio of 7: 1 for the neutralization reaction mixed. After completion of the neutralization reaction the pH is adjusted to 6.5 ~ 6.8 and the mixture was allowed for a while, gefollowed by discarding the supernatant liquid. Distilled Water was added to the resultant Ti (OH)₄ in an amount of about 4 times of the gel added, followed by sufficient stirring and standing. While was tested with silver nitrate, The washing was repeated until no more chlorine in the supernatant liquid was detected. After all the supernatant was liquid disposed to leave a gel alone. In some cases the gel of the dehydrogenation to by centrifuge. 210 ml of an aqueous 35 % Hydrogen peroxide solution is in two halves shared and 3600 ml light yellowish white Ti (OH)₄ all Added 30 minutes followed by stirring at about 5 ° C overnight, to about 2500 to obtain ml of a yellow transparent amorphous titanium peroxide sol.

0043If the generation of heat is not suppressed in the above steps, there is the possibility, that water-insoluble Substances like metatitanic, deposit. Thus, it is preferred to carry out all of the steps, while the Generation of heat repressed becomes.

Reference 2 (Manufacture of titanium oxide sol from amorphous titanium peroxide sol)

0044If the amorphous titanium peroxide sol is heated to 100 ° C, it is to the lapse of about 3 converted hours in anatase titania and after heating for 6 hours converted to an anatase titanium oxide sol. In addition, when the sol 8 Hours at 100 ° C is heated, it takes a slightly yellow, slightly suspended fluorescence at. When concentration is a yellow opaque material receive. Next, when the sol is heated at 100 ° C for 16 hours, This gives a very light yellow material. These materials reduce the Dry adhesion more or less in comparison with that over by heating at 100 ° C for six obtained hours.

0045the Titania sol is less than amorphous titanium oxide in the viscosity and after concentration to 2.5 wt.% because of easier Immersing used.

example 1

0046Of the Decomposition test for organic substances, with different mixing ratios used between the amorphous titanium peroxide sol and the titanium oxide sol be carried out in the following manner. A 150 mm long × 220 wide × 3 mm thick dekora tive film KERAMIT (Clay Burn Ceramics Co., Ltd.) was used as a substrate used. Mixed Sole with different mixing ratios were each applied to the substrate in a thickness of about 2 microns by spraying and dried from normal temperatures to 70 ° C, followed by baking at about 400 ° C for 30 minutes, at five o'clock Types photocatalytic body to receive, in which different types of photocatalysts were each held on the substrate. This photocatalytic specimens were each placed in a test container, in a colored solution an organic substance, which should be decomposed in a Depth of 1 cm was placed. This colored solution was a 1: 30 dilution of POLLUX Red OM-R (SUMIKA COLOR CO., LTD.), Which is an aqueous dispersion (Red liquid) was of monoazo red. Next, the evaporation of the colored solution in the container to prevent the vessel was charged with a float glass (which is capable of a wavelength of 300 nm cut off or underneath) covered. Two UV lamps (Each a fluorescent tube with 20 W for blue color) were 5 cm above the test container and furnished 9.5 cm from the substrate, wherein they distance under a were kept away from each other by 13 cm. The individual photocatalytic body were irradiated, at which time, if the colored solution bleached was rated the decomposition of organic matter as closed has been. The results are described hereinafter.

0047Of the Body, wherein 100% titanium oxide sol was applied to the substrate was capable of the color within 72 hours from the start of the test bleach. Thus was what the ability of decomposing organic substance is concerned, the photocatalytic function well, However, a rest was after decomposition large in quantity. on the other hand was the body, in which 100% of the amorphous titanium peroxide sol was used, the Color bleached in 150 hours, so that the capability of decomposing the organic Substance, that the photocatalytic function was worse than the use of 100% titanium oxide sol. Nevertheless the adherence were, Film-forming properties, corrosion resistance and decorative effect better. The color was in 78 hours at a mixing ratio between the amorphous titanium peroxide sol and the titanium oxide sol at a mixing ratio of 1: 3 bleached in 78 hours in 102 hours at a mixing ratio of 1: 1 and in 120 hours at a mixing ratio of 3: 1. From the above, Test, it was confirmed that the photocatalytic function opposite to the adhesion, for Film-forming property, the corrosion resistance and the decorative Properties behaved. Thus, it was found that according to the invention, when the mixing ratio was changed, a diversity of applications (portions of articles, applied in which will, and working conditions) were ensured.

example 2

0048A Acrylic resin plate and a methacrylic resin plate were respectively as a substrate available posed. These resin plates were dipped in each case for 30 minutes in a 2% sodium hydroxide solution at 80 ° C immersed, washed with water and dried. The titanium peroxide sol, which in Reference 1 was prepared, to which 0.5% of a surfactant added agent was deposited by 3 ~ 4 times dipping was repeated to form a first layer. The drying was performed for 10 minutes at 70 ° C causes.

0049On second layer was formed by five blends of amorphous Titanium peroxide sol and the titanium oxide sol with such mixing ratios deposited as in Example 1 by repeatedly dipping 3 ~ 4 times were. The solidification-drying was conducted under the conditions 120 ° C and 3 minutes for the acrylic resin plate causes and was terminated for Metacrylharzplatte, as the temperature of a dryer reached 119 ° C. The results of the photocatalytic function were similar to those in Example. 1 With regard to the adhesive force on the resin plates and the unlikelihood of decomposing the resin plates with the catalyst, the bodies had with the first layer much excellent.

example 3

0050A highly water commercially available tile was used as a Substrate. The tile was using a neutral detergent washed, dried and provided with a surface active agent. A photocatalyst composition used was one which receive was by using a portion, on a weight basis, of titanium oxide powder "ST-01" (ISHIHARA SANGYO KAISHA Ltd.) to 50 parts of titanium peroxide sol (pH 6.5), the prepared in Reference 1, was added mechanically for approximately 15 minutes touched and was further stirred by ultrasonic waves to no flakes to leave. The immersion at a rate causes of 0.3 ~ 0.5 cm / second, followed by drying overnight at 30 ° C. This was at 400 ° C Baked for 30 minutes to prepare a photocatalytic body.

0051The Photocatalyst layer was laid on the tile surface with a long time bound.

0052On the other hand, if the tile with a dispersion of titanium oxide powder in distilled Water was coated, not a good bond was achieved.

example 4

0053On Float glass, the degreased and treated with a surface active agent was, was applied to its surface coated with a glass sphere suspension by means of a spray gun several times. After drying at 40 ° C the coating was baked for 30 minutes at 700 ° C. The float glass, on which the glass balls were fixed was further coated with a photocatalyst composition coated, which was used in Example 3, dried and 30 Minutes at 400 ° C baked to obtain a photocatalytic body. This photocatalytic body was strong on a long time bonded to the glass balls, which is mounted on the float glass were.

example 5

0054On UV radiation material light storage type "KEPRUS" (trade name of Next · I CO., LTD) was mixed with an amorphous titanium peroxide sol in an amount of 25 wt.% Mixed based on the titanium peroxide in the sol, agitated, via a decorative layer KERAMIT sprayed, which was used as a substrate, dried at normal temperature, 30 minutes at 400 ° C baked and cooled. Thereafter, a titanium oxide sol whose excitation wavelength on an emission wavelength the radiative material was set, sprayed in a thickness of 1 .mu.m, dried and 30 minutes at 40 ° C baked. The resultant photocatalytic body had the photocatalytic action by means of UV light, the radiated from the UV radiating material was, further, when the irradiation of the UV light against the body interrupted has been.

INDUSTRIAL APPLICABILITY

0055According to the invention , a photocatalyst held and fixed on a substrate be without the photocatalytic function of the photocatalyst to decrease, so that the photocatalytic body to disposal is provided, via a has long used. The photocatalytic body of the invention can be used as Indoor and outdoor element for building and tiles inside and outside, Sanitary ware, Air conditioning, baths and the like, outer panels of various Types of electrical equipment, as light fittings, interior elements for vehicles, inner walls of subways and tunnels, water purification tanks and the like.