JP2004290974A - Optical catalyst compound, optical catalyst containing substance, optical catalyst function exerting material and method for manufacturing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a more efficient catalyst reaction related to an optical catalyst. <P>SOLUTION: When nitrogen oxide (nitric oxide) contacts or approaches titanium dioxide in a state in which titanium dioxide as an optical catalyst and amphoteric metal oxide (aluminum etc.) or basic metal oxide (barium oxide, strontium oxide, etc.) are compounded, the nitric oxide is oxidized to nitrogen dioxide (gas) by -OH, an active oxygen species generated by titanium dioxide in response to irradiation with light. The nitrogen dioxide is an acidic gas, judging from its molecular structure. The aluminum is the amphoteric metal oxide. The barium oxide and the strontium oxide are the basic metal oxide. Ascribing an oxygen atom having the basic metal oxide to a base point against acidic gas, the nitrogen dioxide is attracted by and combined with the oxygen atom chemically and held by the metal oxide and finally retained by approaching the nitrogen dioxide, the optical catalyst, wherein the nitrogen dioxide. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

Technical field to which the invention belongs

  The present invention relates to a photocatalyst compound containing a photocatalyst that functions as a catalyst when irradiated with light, a photocatalytic function-executing material using the photocatalyst compound, and a method for producing a photocatalyst compound.

Conventional technology

Heretofore, this kind of photocatalyst has been expanding its use since the energy used for the catalytic reaction is inexhaustible with light energy such as sunlight. For example, titanium dioxide (TiO ₂ ), which is a kind of photocatalyst, particularly titanium dioxide having an anatase crystal form, generates excited electrons and holes by the energy of irradiated light (ultraviolet light), and generates the excited electrons and holes. The holes generate active oxygen species such as O ₂ —, O—, and OH (where • represents an unpaired electron and is a radical species) in the presence of oxygen and moisture on the catalyst surface. Utilizing the radical nature of the active oxygen species, it is used for air purification, in which nitrogen oxides (NOx) in the atmosphere are subjected to an oxidation reaction by the active oxygen species to produce harmless reactants (nitric acid). In addition, bacterial decomposition through oxidation of organic components, so-called antibacterial uses, and the like have been proposed.

By the way, in the process in which the nitrogen oxide undergoes the oxidation reaction by the active oxygen species, nitrogen dioxide (NO ₂ ) is generated as an intermediate product, and this dinitrogen oxide is further oxidized to finally nitric acid. Then, by the generation of nitric acid, nitrogen oxides in the atmosphere are reduced and the atmosphere is purified. Therefore, in order to increase the efficiency of reducing nitrogen oxides, it is essential that active oxygen species coexist with nitrogen oxides or nitrogen dioxide. However, since nitrogen dioxide is a chemically stable compound (gas), the generated nitrogen dioxide escapes out of the reaction system, reducing the efficiency of the oxidation reaction by the active oxygen species, resulting in a reduction. Efficiency is also reduced. It is conceivable to suppress the release of nitrogen dioxide by using a porous adsorbent such as activated carbon, but it is not necessarily effective as described below.

  In such an adsorbent, once the released nitrogen dioxide is adsorbed, the nitrogen dioxide may not be released while being adsorbed in the pores of the adsorbent. For this reason, the adsorbed nitrogen dioxide may not be subjected to this oxidation reaction outside the oxidation reaction system by the active oxygen species, and may not be converted into nitric acid as a final product. Therefore, the nitrogen oxides do not finally change to nitric acid, and the reduction efficiency is hindered. However, nitrogen dioxide adsorbed by the adsorbent is oxidized to nitric acid in the region where it can coexist with active oxygen species and is in the reaction system, that is, in the region close to the photocatalyst, while the region close to the photocatalyst is adsorbed. Since the entire adsorption area (including pores) of the substance in the agent is very limited, the ratio of nitrogen dioxide that is not oxidized to nitric acid can be said to be high. In other words, even if an adsorbent is used, it can only be said that dinitrogen oxide is adsorbed and held, and the reduction of nitrogen oxide through the transition to nitric acid is not considered to be sufficient.

The present invention has been made to solve the above problems, and aims to further improve the efficiency of a catalytic reaction involving a photocatalyst, or to evolve a reactant subjected to the catalytic reaction into a final product. The purpose is to improve the reduction efficiency. Another object is to supplement the function performed by the photocatalyst.
The present invention relates to a photocatalyst compound containing a photocatalyst that functions as a catalyst when irradiated with light, a photocatalytic function-executing material using the photocatalyst compound, and a method for producing a photocatalyst compound.

Means for solving the problems and their functions and effects

In order to solve such a problem, the first photocatalyst formulation of the present invention comprises:
A photocatalyst compound comprising a photocatalyst functioning as a catalyst when irradiated with light and another compound,
The other compound is
When the reactant subjected to the catalytic reaction involving the photocatalyst undergoes the catalytic reaction and undergoes a chemical change and changes to a final product defined by the structure of the reactant and the catalytic reaction, the photocatalyst and A compound that functions to increase the degree of transition from the reactant to the final product in the presence of

  According to the first photocatalyst composition of the present invention having the above-described configuration, the degree of change from the reactant to the final product increases, so that the efficiency of reducing the reactant can be increased.

In the first photocatalyst composition of the present invention having the above configuration, the following aspects can be adopted. The first aspect is
The other compound is
The reactant or the compound chemically bonded to an intermediate product generated before the reactant undergoes the catalytic reaction and changes to the final product.

  In the first embodiment, the reactant or the intermediate product is retained by being chemically bonded to another compound compounded with the photocatalyst. Since the reactant or the other compound holding the intermediate product does not have a porous structure, the reactant is located outside the catalytic reaction involving the photocatalyst, that is, in a region away from the photocatalyst. These reactants or intermediate products are placed in the catalytic reaction system through the adjacency with the photocatalyst blended with the photocatalyst, which is not put together. In addition, since the bond with the reactant or the intermediate product is a chemical bond, the reactant or the intermediate product can be reliably placed in the catalytic reaction system. As a result, according to the photocatalyst composition of the first embodiment, the opportunity for the reactant to be subjected to the catalytic reaction and the opportunity for the intermediate product to be further subjected to the catalytic reaction can be ensured. It can proceed more efficiently. Since the degree of transition from the reactant to the final product increases through the improvement of the efficiency of the catalytic reaction, the efficiency of reducing the reactant can be increased.

The second aspect is
The photocatalyst is a photocatalyst that generates excited electrons and holes by the energy of irradiated light, and generates active oxygen species by the excited electrons and holes in the presence of oxygen and moisture on the surface of the catalyst.

  According to the second aspect, the reactant or the intermediate product is placed in the catalytic reaction system based on the active oxygen species generated by the photocatalyst, and the reactant or intermediate product is used for the catalytic reaction. The opportunity for the product to be further subjected to this catalytic reaction can be reliably secured, and the catalytic reaction can proceed more efficiently. Therefore, the efficiency of reducing the reactants can be increased.

In this case, examples of the photocatalyst include titanium dioxide (ThO ₂ ), zinc oxide (ZnO), vanadium oxide (V ₂ O ₅ ), and tungsten oxide (WO ₃ ). These photocatalysts are not caught by the crystal forms of the photocatalysts. For example, any of titanium oxide having anatase, rutile or brookite crystal forms may be used. Most preferred is anatase-type titanium dioxide from the viewpoint of availability and the like. The reactants and intermediates and final products subjected to the catalytic reaction based on the active oxygen species include nitrogen oxides, nitrogen dioxide and nitric acid, sulfur oxides and sulfur dioxide and sulfuric acid or sulfurous acid, and the like. Examples thereof include carbon oxide, carbon dioxide, and carbonic acid. Ammonia can also be exemplified as a reactant, and in this case, an intermediate product and a final product are nitric oxide, nitrogen dioxide, and nitric acid generated from ammonia.

A third aspect is:
The other compound is an amphoteric metal oxide, a basic metal oxide or an acidic metal oxide chemically bonded to the reactant or the intermediate product subjected to the catalytic reaction based on the active oxygen species. At least one metal oxide.

  According to the third aspect, when the reactant or the intermediate product is placed in the catalytic reaction system based on the active oxygen species generated by the photocatalyst, the reactant or the intermediate product is acidic. The so-called base point can be formed by a specific atom derived from the atomic arrangement of the basic metal oxide, and the basic metal oxide can be reliably chemically bonded to the reactant or the intermediate product at this base point. it can. When the reactant or the intermediate product is basic, a so-called acid site can be formed by a specific atom derived from the atomic arrangement of the acidic metal oxide, and the acid site reacts with the acidic metal oxide at this acid site. Products or intermediates can be chemically bonded reliably. Furthermore, if the other compound is an amphoteric metal oxide, a specific atom resulting from the atomic arrangement of the amphoteric metal oxide should be a base point or an acid point suitable for the properties of the reactant or the intermediate product. Therefore, regardless of whether the reactant or the intermediate product is basic or acidic, the amphoteric metal oxide can be reliably chemically bonded to the reactant or the intermediate product.

In this case, examples of the amphoteric metal oxide include alumina (Al ₂ O ₃ ), zinc oxide (ZnO), and tin oxide (SnO, SnO ₂ ). Examples of the basic metal oxide include strontium oxide (SrO), barium oxide (BaO), magnesium oxide (MgO), calcium oxide (CaO), rubidium oxide (Rb ₂ O), sodium oxide (Na ₂ O), Potassium oxide (K ₂ O) and the like can be exemplified. Further, examples of the acidic metal oxide include phosphorus oxide (P ₂ O ₅ ). The formation of base points or acid sites in these metal oxides is due to the difference in electronegativity between the metal atoms and oxygen atoms that make up the metal oxide and the atomic arrangement of the metal and oxygen atoms on the metal oxide surface. I do. Then, the above-mentioned basic metal oxide, acidic metal oxide, and amphoteric metal oxide are appropriately selected in accordance with the above-mentioned reactant and the intermediate product subjected to the catalytic reaction based on the active oxygen species. Just fine. Since zinc oxide is both a photocatalyst and an amphoteric metal oxide, when zinc oxide is selected as the photocatalyst, it is needless to say that zinc oxide is not selected as the amphoteric metal oxide.

  Here, taking the case where the photocatalyst is titanium dioxide, the compound is alumina which is an amphoteric metal oxide, and the reactant is nitrogen oxide (nitrogen monoxide), the progress of the catalytic reaction and the bonding by alumina Will be described. In this case, nitrogen monoxide is oxidized by the active oxygen species generated by titanium dioxide, and becomes nitrogen dioxide as an intermediate product. As shown schematically in FIG. 1, when nitric oxide comes into contact with or comes close to titanium dioxide as a photocatalyst, this nitric oxide is an active oxygen species that is generated by the irradiation of light to produce titanium dioxide. It is oxidized to nitrogen dioxide (gas) by the acid radical) (FIG. 1A). Nitrogen dioxide is acidic due to its molecular structure.Alumina is an amphoteric metal oxide and its oxygen atom is used as a base point for acid gas. And held by alumina (FIG. 1 (b)). The force that draws nitrogen dioxide to oxygen atoms is Coulomb force, and the bond is chemical.

  Since nitrogen dioxide bonded to oxygen atoms of alumina is kept close to titanium dioxide as a photocatalyst, it is present in an oxidation reaction (catalytic reaction) caused by hydroxyl radicals / OH (FIG. 1 (b)). ). Therefore, an opportunity to oxidize nitrogen dioxide by the hydroxyl radicals / OH is reliably secured, and oxidation of nitrogen dioxide proceeds efficiently. In addition, the oxidized nitrogen dioxide becomes nitrate ions, and is bound and held in the form of nitric acid (final product) to the oxygen atoms of the above-mentioned base point alumina together with the hydrogen atoms in the hydroxyl radical OH. It is possible (FIG. 1 (c)).

  In this case, if nitrogen dioxide is present from the beginning, that is, if the nitrogen dioxide is a reactant, the nitrogen dioxide is directly oxidized by the reactive oxygen species generated by the titanium dioxide, and chemically converted to the alumina as described above. The chemically bound nitrogen dioxide will also be oxidized by the reactive oxygen species. In other words, in such a case, the alumina chemically binds nitrogen dioxide as a reactant.

  Next, the state of bonding by alumina when sulfur monoxide (SO) and carbon monoxide (CO) are oxidized by the active oxygen species generated by titanium dioxide will be described. When these oxides are oxidized, they become sulfur dioxide and carbon dioxide, which also become acidic gases. For this reason, as schematically shown in FIG. 2, sulfur dioxide is chemically bonded to an adjacent oxygen atom, which is a base point of alumina, which is an amphoteric metal oxide, and is retained by alumina. Also, as schematically shown in FIG. 3, since carbon dioxide can bond with a bond order different from that of a carbon atom and an oxygen atom, carbon dioxide and a single oxygen atom serving as a base point as described above (FIG. 3 (a) ) Or a chemical bond with an adjacent oxygen atom which becomes a base point (FIG. 3B) and is retained by alumina. The sulfur dioxide thus bound and retained further reacts with the reactive oxygen species (hydroxyl radical, OH) generated by the titanium dioxide to form sulfuric acid or sulfurous acid (final product), and carbon dioxide is converted into carbonic acid (final product). Product). In addition, in the case of carbon dioxide, it is considered that a reaction based on a radical hydrogen atom generated at the time of generation of a hydroxyl radical, OH, which is an active oxygen species, and an active oxygen species causes a transition to methane or methanol, In this case, the methane and methanol can be said to be final products.

A fourth aspect is:
The other compound is blended so that a / (a + b) is about 0.0001 to 0.8 when the weight is a and the weight of the photocatalyst is b.

  As in the fourth embodiment, when a / (a + b) is about 0.0001 or more, the compound represented by a may be used as another compound (amphoteric metal oxide, basic metal oxide, or acidic metal oxide). It is preferable because the chemical bond of the reactant or the intermediate product is secured and the efficiency of the catalytic reaction is not reduced. When a / (a + b) is about 0.8 or less, the amount of the photocatalyst represented by b is not too small with respect to the above other compounds, and the efficiency of the catalytic reaction is not reduced. .

  In this case, the amount of the photocatalyst is about 20 to 95% by weight based on the total amount of the photocatalyst and the above-mentioned compound, which is another compound, and the other compound, if any. I just need.

In a fifth aspect,
The photocatalyst and the other compound are adjusted and blended in a particle size range of about 0.005 to 0.5 μm.

  As in the fifth embodiment, when the particle diameter of the photocatalyst and other compounds (amphoteric metal oxide, basic metal oxide, acidic metal oxide) is in the range of about 0.005 to 0.5 μm, the ball mill is used. It is preferable because the particle size can be easily adjusted by an existing pulverizer such as the above or a sol-gel method. Further, according to the fifth aspect, since there is no remarkable difference in the particle diameter between the photocatalyst and the other compound, the photocatalyst and the other compound come close to each other with particles of substantially the same size. Therefore, a reaction product or an intermediate product chemically bonded to the other compound can be brought close to the photocatalyst, and high efficiency can be achieved through securing a sufficient opportunity for the progress of the catalytic reaction, which is preferable.

In a sixth aspect,
In addition to the photocatalyst and the other compound, a compound having a property of chemically adsorbing a hydroxyl group is provided as a third component,
The hydroxyl group is chemically adsorbed and held on the surface of the photocatalyst and the compound as the third component, and exhibits hydrophilicity by the held hydroxyl group.

  In the sixth embodiment, the hydroxyl group generated through the catalytic reaction of the photocatalyst is chemically adsorbed on the surface of the compound of the third component as well as the photocatalyst and retained. Then, since no water (water vapor in the air, rainwater, etc.) on the catalyst surface becomes zero, it can be said that the hydroxyl groups are constantly generated during the irradiation with light. For this reason, the hydroxyl groups are held at an extremely high density, and the holding is performed by a bond called chemisorption, so it can be said that the hydroxyl groups are firmly held. On the other hand, while light is not irradiated, hydroxyl groups are not generated by the photocatalyst, but the hydroxyl groups that have been generated up to that point are firmly held on the surface of the photocatalyst and the compound of the third component. Is not removed. In addition, when light is irradiated again, even if the density of the hydroxyl group has been reduced by that time, the state quickly returns to the high-density holding state. Therefore, if the photocatalyst composition of the sixth aspect is fixed to the surface of any substrate, the surface of the substrate can be reliably made highly hydrophilic, and this high hydrophilicity can be reliably maintained for a long period of time. That is, the photocatalyst composition of the sixth embodiment is a hydrophilicity-imparting material that imparts high hydrophilicity to the substrate surface.

  Here, the effect of providing hydrophilicity will be described. The hydrophilicity strongly affects the contact angle with water, and the higher the hydrophilicity, the smaller the contact angle. On the other hand, if the contact angle is small, it is difficult for water to stay on the surface, so that dirt attached to the surface flows down with the water and is removed from the surface. Therefore, if hydrophilicity capable of exhibiting a contact angle smaller than the contact angle of inorganic dust such as urban dust or clay mineral containing a large amount of lipophilic components is obtained, these dusts are removed without exhibiting affinity. it can. In addition, as the contact angle approaches zero degree, the hydrophilicity increases, and the water diffuses in a film form on the surface of the base material and flows easily. Therefore, not only the above-mentioned urban dust but also the inorganic dust easily flows down with water from the base material surface. In this case, in order to enhance the stain prevention effect, it is more preferable that the contact angle is approximately 20 ° or less and a value close to zero.

  Therefore, if the photocatalyst composition of the sixth aspect is fixed to the inner or outer wall surface of a building or the surface of a vehicle body such as an automobile or a train, it is possible to obtain a high stain prevention effect with the high hydrophilicity imparted as described above. Can be. In this case, if these surfaces are occasionally rained, the surfaces are self-purified because the dust and contaminants on the surfaces are washed away from the surfaces together with the rainwater each time the rains are imparted because of the high hydrophilicity. . That is, a so-called rain streak stain in which dust or the like remains in a streak shape along the flow of water is effectively suppressed. Further, when the photocatalyst composition of the sixth aspect is fixed to the surface of glass, a lens, a mirror, or the like, it can have high hydrophilicity and a high antifogging effect.

In a seventh aspect,
The compound as the third component is a compound having a heat of wetting equal to or higher than that of the photocatalyst.

The heat of wetting can be regarded as an index indicating the retention property of the hydroxyl group on the surface of a substance having a hydroxyl group on the surface. The higher the heat of wetting, the higher the degree of retention of the hydroxyl group and the higher the hydroxyl group density. Therefore, according to the seventh aspect, the hydroxyl groups generated by the photocatalyst can be more effectively and densely adsorbed and retained on the compound of the third component, and the high hydrophilicity can be more reliably provided on the substrate surface. And it can be applied for a long time. In this case, particularly preferred wetting heat of titania in anatase 320~512x10 ^-3 Jm ^-2, since rutile is ^{293~645x10 -3 Jm -2, 500x10 -3 Jm} -2 or more wetting as a photocatalyst More preferably, the compound has heat.

In an eighth aspect,
The compound as the third component is at least one metal oxide selected from SiO ₂ , Al ₂ O ₃ , ZrO ₂ , GeO ₂ , ThO ₂ , and ZnO.

These metal oxides have a heat of wetting equal to or higher than that of titania, which is particularly preferable as a photocatalyst. In particular, silica (SiO ₂ ), alumina (Al ₂ O ₃ ), GeO ₂ , and ThO ₂ are more preferable because the upper limit of the heat of wetting thereof exceeds 1000 × 10 ⁻³ Jm ⁻² .

In this case, each compound (SiO ₂ , Al ₂ O ₃ , ZrO ₂ , GeO ₂ , ThO ₂ , ZnO) as the third component is blended together with a reactant or a photocatalyst for the purpose of reduction according to the present invention. In combination with other compounds (Al ₂ O ₃ , ZnO, SnO, SnO ₂ , SrO, BaO, MgO, CaO, Rb ₂ O, Na ₂ O, K ₂ O, P ₂ O ₅ ) Can be Explaining with a specific example, when Al ₂ O ₃ is selected as another compound to be blended with the photocatalyst, the compound as the third component is SiO ₂ other than Al ₂ O _{3 in} order to avoid component duplication. ₂ , ZrO ₂ , GeO ₂ , ThO ₂ , and ZnO are selected as the third components. When that can not be chemically bonded to Al ₂ the reaction product of O ₃ is reduced object or an intermediate product as other compounds, ZnO other than Al ₂ O ₃ as the other compound, SnO, SnO _{2, SrO, BaO, MgO,} CaO, Rb 2 O, Na 2 O, K 2 O, is P ₂ O ₅ is selected, as the third component, Al ₂ O ₃ of the above respective compounds, including (SiO ₂ , one of _{Al 2 O 3, ZrO 2,} GeO 2, ThO 2, ZnO) is selected. The same applies to ZnO.

The ninth aspect is
In addition to the photocatalyst, the other compound and the compound as the third component, a metal exhibiting antibacterial properties is compounded as a fourth component, and
The metal as the fourth component is supported on the photocatalyst.

  In the ninth aspect, it is possible that the photocatalyst itself can perform an antibacterial function during irradiation with light, and that the antibacterial function can be performed by a metal supported on the photocatalyst during non-irradiation. it can. For this reason, the antibacterial function performed by the photocatalyst can be complemented, and a synergistic antibacterial property can be exhibited by the metal and the photocatalyst exhibiting the antibacterial property.

In a tenth aspect,
The metal as the fourth component is a metal having a reduction potential equal to or higher than the potential of free electrons emitted by the photocatalyst.

  In the tenth aspect, the loading of the metal on the photocatalyst can be easily performed by the reduction potential of the metal. In this case, the reduction potential is at least one metal selected from Ag, Cu, Pd, Fe, Ni, Cr, Co, Pt, Au, Li, Ca, Mg, Al, Zn, Rh, and Ru. And Ag, Cu, Pd, Pt, and Au are particularly preferable since the reduction potential has a positive value, so that reduction carrying easily occurs. The metal selected as the fourth component may be blended so that c / d is about 0.00001 to 0.05 when the weight of the metal is represented by c and the weight of the photocatalyst is represented by d. preferable. In other words, if the metal of the fourth component is 0.00001 (= c / d) or more, the situation that the metal is too small to exhibit synergistic antibacterial properties at all does not occur, and 0.05 (= If c / d) or less, it is preferable because the metal does not become excessive and adversely affect the catalytic reaction of the photocatalyst.

The second photocatalyst-containing material of the present invention comprises:
A photocatalyst-containing material having a photocatalyst that functions as a catalyst when irradiated with light, wherein the photocatalyst composition of the first aspect of the present invention or the photocatalyst composition of each embodiment is mixed and dispersed in a paint or glaze. It is.

  In the paint and glaze as the second photocatalyst-containing material of the present invention having the above-mentioned structure, the efficiency of reducing the reactants can be increased or the reactants can be included in the catalytic reaction system, similarly to the first photocatalyst composition of the present invention. Products or intermediate products can be reliably maintained. Therefore, the reactants can be efficiently reduced on the surface of the surface to which the paint is applied or on the surface of the surface to which the glaze is applied. In addition, on these surfaces, the opportunity for the reactant to be subjected to the catalytic reaction and the opportunity for the intermediate product to be further subjected to the catalytic reaction can be reliably ensured, and the catalytic reaction can proceed more efficiently. .

  In this case, the paint or glaze to be mixed and dispersed between the photocatalyst and the compound may be an existing one, and in the case of a glaze, the photocatalyst and the compound together with the glaze material, for example, a frit of feldspar or potassium carbonate, etc., are in solution. Distributed. When the photocatalyst and the compound are dispersed and mixed, they may be blended together with the above glaze raw materials in the glaze production process, or may be blended into the finished glaze prior to the glaze application.

In the above-mentioned second photocatalyst-containing material of the present invention,
The photocatalyst is a photocatalyst that generates excited electrons and holes by the energy of irradiated light, and generates active oxygen species by the excited electrons and holes in the presence of oxygen and moisture on the catalyst surface,
The other compound is an amphoteric metal oxide, a basic metal oxide or an acidic metal oxide chemically bonded to the reactant or the intermediate product subjected to the catalytic reaction based on the active oxygen species. The photocatalyst-containing material (paint or glaze) that is at least one metal oxide has the following advantages.

  According to this photocatalyst-containing material, similarly to the above-described embodiment of the first photocatalyst composition of the present invention, the reactant or the intermediate product is securely bound and held at the base point or the acid point, and the active oxygen species is These reactants or intermediate products can be placed in a catalytic reaction system based on the above. Therefore, on the surface of the material coated with the photocatalyst-containing material or on the surface of the material coated with the glaze, the catalytic reaction can proceed more efficiently, thereby increasing the efficiency of reducing the reactants. be able to. In the case where a photocatalyst composition having a compound of the third component is used as in the sixth to eighth aspects of the first photocatalyst composition of the present invention, the surface becomes highly hydrophilic. It is preferable because a high stain prevention effect based on the above can be obtained. Furthermore, when the photocatalyst composition having the metal of the fourth component is used as in the ninth to tenth aspects of the first photocatalyst composition of the present invention, antibacterial properties are exhibited on these surfaces. The preferred metal and the photocatalyst can exhibit synergistic antibacterial properties.

  In addition, the second photocatalyst-containing material of the present invention, particularly the paint, is applied to the existing structures such as the inner and outer walls of buildings, houses, bridges and other architectural structures, road guardrails and sound insulation walls. Thus, a coating film of the photocatalyst-containing material can be formed. Therefore, the existing structure can be easily changed to a structure having a high efficiency of reducing the reactants and also having a high contamination prevention effect.

The third photocatalytic function-exhibiting material of the present invention is:
A material having a base layer and a surface layer formed on the surface thereof, and exhibiting a photocatalytic function when irradiated with light,
As the surface layer,
A photocatalytic function-executing material having a surface layer comprising the above-described first photocatalyst composition of the present invention or the photocatalyst composition of each aspect thereof, or a surface layer comprising the above-mentioned second photocatalyst-containing material of the present invention.

The third photocatalytic function-presenting material of the present invention comprises a compound as a third component, or a photocatalyst compound or a photocatalyst-containing material having a metal as a fourth component in addition to the third component. If you have
The surface layer may have a surface property that satisfies one of the following conditions (1) and (2).
(1) Surface layer thickness: about 0.01 to about 3.0 μm
(2) In the state where a 1% silver nitrate solution is adhered to the surface layer, the ultraviolet ray intensity on the surface layer is 1.2 mW / cm ² , and the ultraviolet ray is irradiated on the surface layer for 5 minutes before and after ultraviolet irradiation. Color difference of surface layer after irradiation ΔE: 1 to 50

  In the photocatalytic function-exhibiting material of this embodiment, the surface layer contains a compound as the third component. Therefore, the sixth component of the first photocatalyst formulation of the present invention is produced by the compound of the third component. As in the eighth embodiment, in this surface layer, the contact angle is reduced, the hydrophilicity is improved, and a high antifouling effect can be achieved. If the thickness of the surface layer is about 0.01 μm or more, the film (surface layer) is not too thin, so that the contact angle of the surface layer itself can be surely exhibited as this material, which is preferable. That is, even if the substrate has a large contact angle, the contact angle is reduced by the surface layer formed on the substrate, and a high stain prevention effect can be achieved. On the other hand, when the thickness of the surface layer is about 3.0 μm or less, the adhesion of the surface layer to the substrate can be maintained, so that peeling of the surface layer (film peeling) can be suppressed, which is preferable. The same applies to those having a metal as the fourth component in addition to the compound as the third component.

  Further, silver ions in the silver nitrate solution attached to the surface layer are reduced and precipitated by receiving excited electrons from a photocatalyst which has been irradiated with ultraviolet rays and turned into an excited state, thereby forming a color. Therefore, a color difference ΔE is observed before and after the ultraviolet irradiation. Accordingly, the color difference ΔE increases as the number of excited electrons increases. Since the amount of excited electrons generated is a factor that determines the magnitude of the photoactivity of the photocatalyst, the magnitude of the photocatalytic activity can be evaluated using the color difference ΔE. The excited electrons of the photocatalyst generate active oxygen species such as hydroxyl radicals and OH in the air. Therefore, the larger the photocatalytic activity, that is, the larger the color difference ΔE, the more active oxygen species such as hydroxyl radical and OH are generated. .

  By the way, the compound of the third component contained in the surface layer has a role of retaining hydroxyl radicals / OH generated by excited electrons of the photocatalyst, and the larger the amount of the generated hydroxyl radicals / OH, the more the third component. The hydroxyl group density on the compound surface of the component is also increased, the contact angle of water is reduced, and the hydrophilicity is increased. Further, the larger the amount of hydroxyl radical / OH, the greater the amount of decomposition of the organic compound in the surface layer, which is advantageous for hydrophilicity. Therefore, if the surface layer has a color difference ΔE of 1 or more, it has sufficient photocatalytic activity to form a high hydroxyl group density, and the contact angle of the surface layer is reduced to such an extent that the stain prevention effect can be exhibited. It is believed that the size can be surely reduced, which is preferable. On the other hand, when the amount of the photocatalyst with respect to the binder per unit area of the surface area increases, the color difference ΔE increases. However, in this case, it is considered that the adhesion to the base material is reduced and the surface layer is easily peeled. Therefore, a surface layer having a color difference ΔE of 50 or less is preferable from the viewpoint of suppressing peeling of the surface layer.

The fourth photocatalytic function-exhibiting material of the present invention comprises:
A material having a base layer and a surface layer formed on the surface thereof, and exhibiting a photocatalytic function when irradiated with light,
The surface layer,
The first photocatalyst composition of the present invention or the photocatalyst composition of each aspect thereof is a photocatalytic function-executing material which is a surface layer formed on the surface of the base material layer with a binder interposed therebetween.

In the fourth photocatalytic function-exhibiting material of the present invention,
The binder is preferably a binder that polymerizes or melts to adhere the photocatalyst compound to the surface of the substrate layer at a temperature not higher than the deterioration temperature of the substrate of the substrate layer, or is a glaze or a paint. .

The fifth photocatalytic function-exhibiting material of the present invention comprises:
A material having a base layer and a surface layer formed on the surface thereof, and exhibiting a photocatalytic function when irradiated with light,
The surface layer, in addition to TiO ₂ as a photocatalyst, Al ₂ O _3, and SiO _2, a photocatalytic exert material containing metal exhibits antimicrobial properties.

  In the third to fifth photocatalytic function-exhibiting materials of the present invention having the above-described structure, the reduction efficiency of the reactant is reduced on the surface of the surface layer formed on the base material layer, similarly to the first photocatalyst compound of the present invention. And the amount of reactants or intermediate products can be reliably maintained in the catalytic reaction system. Therefore, on the surface layer surface of the photocatalytic function exhibiting material, the reactants can be efficiently reduced, and the opportunity for the reactants to be subjected to the catalytic reaction and the opportunity for the intermediate products to be further subjected to the catalytic reaction can be ensured. , And the catalytic reaction can proceed more efficiently. Further, since the surface layer contains a metal exhibiting antibacterial properties, the metal exhibiting antibacterial properties and the photocatalyst can exhibit synergistic antibacterial properties in this surface layer, which is preferable.

In the third and fourth photocatalytic function-exhibiting materials of the present invention,
The photocatalyst is a photocatalyst that generates excited electrons and holes by the energy of irradiated light, and generates active oxygen species by the excited electrons and holes in the presence of oxygen and moisture on the catalyst surface,
The other compound is an amphoteric metal oxide, a basic metal oxide or an acidic metal oxide chemically bonded to the reactant or the intermediate product subjected to the catalytic reaction based on the active oxygen species. The photocatalytic function exhibiting material, which is at least one metal oxide, has the following advantages.

  According to this photocatalyst function exhibiting material, similarly to the above-described embodiment of the first photocatalyst formulation of the present invention, the reactant or the intermediate product is securely bound and held at the base point or the acid point, and the active oxygen These reactants or intermediates can be placed in a species-based catalytic reaction system. Therefore, the catalytic reaction can proceed more efficiently on the surface layer surface of the photocatalytic function-exhibiting material, and the efficiency of reducing the reactants can be increased. In the case where a photocatalyst composition or a photocatalyst-containing material having a compound of the third component is used as in the sixth to eighth aspects of the first photocatalyst composition of the present invention, on these surfaces, It is preferable because a high stain prevention effect based on high hydrophilicity can be obtained. Furthermore, when a photocatalyst formulation or a photocatalyst-containing material having a metal of the fourth component is used as in the ninth to tenth aspects of the first photocatalyst formulation of the present invention, on these surfaces, It is preferable that a metal exhibiting antibacterial properties and a photocatalyst can exhibit synergistic antibacterial properties.

  In the third to fifth photocatalytic function exhibiting materials of the present invention described above, the following aspects can be adopted. In the first aspect, the base material layer may be any one of ceramic, resin, metal, glass, pottery, wood, siliceous board, concrete board, cement board, cement extruded shaping board, gypsum board or autoclave cured lightweight concrete board. It consists of such a base material. According to this aspect, at the place where these base materials are used, for example, at the inner and outer walls and roads of building structures such as buildings, houses, and bridges, nitrogen oxides, sulfur oxides, and carbon dioxide gas are exhibited by exhibiting a photocatalytic function. It can decompose environmental pollutants and purify the atmosphere. Furthermore, when a photocatalyst compound having the compound of the third component is used, a high stain prevention effect based on high hydrophilicity can be exerted on the inner and outer walls and roads of these building structures.

  In a second aspect, the surface layer is formed by heat treatment, for example, baking. According to this aspect, the surface layer can be firmly formed on the base material layer.

  In a third aspect, a metal or a metal compound exhibiting antibacterial properties is fixed to the surface of the surface layer. According to this aspect, the antibacterial function that can be performed by the photocatalyst in the surface layer during the light irradiation, and the antibacterial function during the time when the light is not irradiated, the metal or metal oxide on the surface layer surface. Can be fulfilled by things. Therefore, the antibacterial function performed by the photocatalyst can be complemented. In addition, since the surface layer contains the above-mentioned other compounds in addition to the photocatalyst, in addition to the antibacterial function, the decomposition of environmental pollutants and the purification of the atmosphere are pursued through the improvement of the efficiency of the above-mentioned catalytic reaction involving the photocatalyst. be able to. In the case where a photocatalyst composition having a compound of the third component or a photocatalyst-containing material is used as in the sixth to eighth aspects of the first photocatalyst composition of the present invention, in these surface layers, It is preferable because a high stain prevention effect based on high hydrophilicity can be obtained. In the case of using a photocatalyst composition or a photocatalyst-containing material having a metal of the fourth component as in the ninth to tenth aspects of the first photocatalyst composition of the present invention, Since the synergistic antibacterial property can be exerted even by the metal of the fourth component, the amount of the metal or metal compound to be fixed to the surface of the surface layer can be extremely small. If the synergistic antibacterial property of the metal of the fourth component is high, the adhesion of the metal or the metal compound to the surface layer surface can be omitted.

The method for producing a sixth photocatalytic function-exhibiting material of the present invention comprises:
A method for producing a material having a substrate layer and a surface layer formed on the surface thereof, and exhibiting a photocatalytic function when irradiated with light,
Preparing the first photocatalyst formulation of the present invention or the photocatalyst formulation of each aspect thereof or a photocatalyst formulation dispersion sol in which the photocatalyst formulation is dispersed,
An arrangement step of arranging the photocatalyst composition or the photocatalyst composition dispersion sol in a layer on the surface of the base material layer,
Forming the surface layer.

  In this case, the photocatalyst formulation dispersion sol can be obtained by dispersing the photocatalyst formulation in a solution such as water or alcohol.

  According to the sixth production method of the present invention, since no special process is required, as described in the first photocatalyst formulation of the present invention, the reactant or the intermediate product is contained in the catalytic reaction system. As a result, a novel photocatalytic function-exhibiting material that causes a catalytic reaction with high efficiency in the surface layer can be easily produced. At this time, in forming the surface layer, an appropriate method, for example, a heat treatment or a drying treatment can be adopted according to the photocatalyst compound or the photocatalyst compound dispersion sol provided.

In the sixth manufacturing method of the present invention,
The disposing step includes:
When disposing the photocatalyst composition or the photocatalyst composition dispersion sol in a layer on the surface of the substrate layer, the photocatalyst composition or the photocatalyst composition dispersion sol is placed in a layer on the surface of the substrate layer, A method for producing a photocatalytic function exhibiting material having a step of coating or printing has the following advantages.

  According to the sixth production method of the present invention, it is possible to easily produce a novel photocatalytic function-exhibiting material which is made of a photocatalyst compound and has a highly efficient catalytic reaction on a surface layer having a substantially uniform thickness. The layered application of the photocatalyst compound on the surface of the base material layer can be performed by an appropriate application method such as spray coating, and the layered printing can be performed by an appropriate printing method such as roll printing.

The method for producing a seventh photocatalytic function-exhibiting material of the present invention comprises:
A method for producing a material having a substrate layer and a surface layer formed on the surface thereof, and exhibiting a photocatalytic function when irradiated with light,
Preparing the first photocatalyst formulation of the present invention or the photocatalyst formulation of each aspect thereof or a photocatalyst formulation dispersion sol in which the photocatalyst formulation is dispersed,
A step of disposing a binder in a layer on the surface of the base material layer to form a binder layer,
An arrangement step of disposing the photocatalyst composition or the photocatalyst composition dispersion sol in a layer on the surface of the binder layer,
Heat-treating the surface layer according to the properties of the binder to form the surface layer.

  According to the seventh manufacturing method of the present invention, at the boundary between the binder layer and the surface layer, the photocatalyst compound in the surface layer can be held in a state of being buried in the binder layer, and the surface layer can be formed on the surface of the binder layer. . Therefore, the surface layer can be firmly fixed to the binder layer, and the photocatalyst composition can be effectively brought into contact with the outside air. And, as described in the first photocatalyst composition of the present invention, a novel photocatalyst function exhibiting a highly efficient catalytic reaction in the surface layer by ensuring that the reactant or the intermediate product is placed in the catalytic reaction system. Materials can be manufactured.

  In this case, the binder is used as a glaze, and in forming the surface layer, the softening temperature of the glaze is higher in the range of 30 ° C. or more and 300 ° C. or less, and is lower than the deterioration temperature of the base material of the base layer. The heat treatment can be performed in a low temperature environment. Since the heating temperature is higher than the softening temperature of the binder (glaze) by 30 ° C. or more, it is preferable that the softening of the glaze by heating does not require a carelessly long time. In addition, since the heating temperature is not higher than the softening temperature of the glaze by more than 300 ° C., it is possible to avoid the rapid melting of the glaze, and to prevent problems such as excessive filling of the photocatalyst compound, generation of uneven surfaces, and generation of pinholes. Can be suppressed. Further, in forming the surface layer, it is preferable to perform a heat treatment in a temperature environment of about 150 to about 1300 ° C. In this way, a novel photocatalytic material exhibiting a catalytic reaction with high efficiency can be manufactured using an existing heating device. If the heat treatment temperature is set to about 150 ° C. or higher, the heat treatment temperature of the existing glaze is matched, and the heat treatment conditions do not need to be changed from those of the conventional glaze. When the heat treatment temperature is set to about 1300 ° C. or lower, the heat treatment temperature at the time of producing a substrate requiring heat treatment, for example, a tile or a porcelain, is matched.

  Further, in forming the surface layer by using the binder as a coating material, heat treatment may be performed in a temperature environment equal to or lower than an alteration temperature of the base material of the base material layer. This is preferable because the surface layer can be formed without deteriorating the base material.

  Further, in the sixth and seventh manufacturing methods of the present invention described above, following the step of forming the surface layer, a metal or a metal compound exhibiting antibacterial properties is dispersed on the surface of the formed surface layer. The method may include a step of applying a solution and a step of fixing the metal or metal oxide on the surface of the surface layer.

  According to the method for producing a photocatalytic function-exhibiting material of this embodiment, a novel photocatalytic function-executing material capable of exhibiting antibacterial properties in a surface layer regardless of a light place or a dark place and causing a catalytic reaction in the surface layer with high efficiency Can be easily manufactured. In addition, such a property that the antibacterial property can be exhibited regardless of whether it is in a light place or a dark place can be later provided to the photocatalytic function-exhibiting material having the surface layer formed thereon.

Further, in the sixth and seventh manufacturing methods of the present invention,
The disposing step includes:
After arranging the photocatalyst composition or the photocatalyst composition dispersion sol in a layer, a step of applying a solution in which a metal or a metal compound exhibiting antibacterial properties is dispersed,
The step of forming the surface layer,
The method may include a step of fixing the metal or metal oxide to the surface of the surface layer at the same time as the formation of the surface layer.

  According to the method for producing a photocatalytic function-executing material of this aspect, a novel photocatalytic function exhibiting both the property of exhibiting antibacterial property and the property of causing a catalytic reaction with high efficiency from the beginning regardless of whether it is under a light place or a dark place The material can be easily manufactured.

Further, in the sixth and seventh manufacturing methods of the present invention,
Following the step of forming the surface layer, a step of applying a metal salt aqueous solution containing ions of a metal exhibiting antibacterial properties to the surface of the formed surface layer, and irradiating the surface layer with ultraviolet light to form the metal. The method may include a step of supporting and fixing the metal on the photocatalyst in the surface layer using photoreduction of ions to a photocatalyst.

  According to the method for producing a photocatalytic function-exhibiting material of this embodiment, a novel photocatalytic function-executing material capable of exhibiting antibacterial properties in a surface layer regardless of a light place or a dark place and causing a catalytic reaction in the surface layer with high efficiency Can be easily manufactured. Moreover, since the metal contributing to the complementation of antibacterial properties is supported and fixed on the photocatalyst in the surface layer using photoreduction, the metal is less likely to fall off. Therefore, the antibacterial complementing performance can be maintained for a long time. In addition, such a property that the antibacterial property can be exhibited regardless of whether it is in a light place or a dark place can be provided later to the photocatalytic function exhibiting material having the surface layer formed thereon. In the case where the photocatalyst composition having the metal of the fourth component supported thereon is used as in the ninth and tenth aspects of the first photocatalyst formulation of the present invention, the fourth component is used. Since the synergistic antibacterial property can be exhibited by the metal of the above, the amount of the metal supported on the surface layer surface through the application of the aqueous metal salt solution and the subsequent irradiation with ultraviolet light can be reduced. If the synergistic antibacterial property of the metal of the fourth component is high, the supporting of the metal on the surface layer surface can be omitted.

The method for producing the eighth photocatalyst composition of the present invention comprises:
A method for producing a photocatalyst compound in which a photocatalyst that functions as a catalyst when irradiated with light, the other compound, a compound as the third component, and a metal as the fourth component are mixed,
Preparing a photocatalyst-dispersed sol in which at least the photocatalyst is dispersed among the photocatalyst, the other compound, and the compound as the third component;
A method for producing a photocatalyst compound containing a photocatalyst that functions as a catalyst when irradiated with light,
Preparing a photocatalyst formulation dispersed sol in which the photocatalyst formulations of the sixth to eighth aspects of the first photocatalyst formulation of the present invention are dispersed;
Mixing a metal salt aqueous solution containing ions of a metal exhibiting antibacterial properties with the photocatalyst composition dispersion sol, and supporting the metal as a fourth component on the photocatalyst.

The method for producing a ninth photocatalyst composition of the present invention comprises:
A method for producing a photocatalyst compound in which a photocatalyst that functions as a catalyst when irradiated with light, the other compound, a compound as the third component, and a metal as the fourth component are mixed,
Preparing a photocatalyst-dispersed sol in which at least the photocatalyst is dispersed among the photocatalyst, the other compound, and the compound as the third component;
After mixing a metal salt aqueous solution containing a metal ion exhibiting antibacterial properties with the photocatalyst dispersion sol, co-precipitate the metal salt and the photocatalyst compound, and carry the metal as a fourth component on the photocatalyst. And a process.

According to a tenth method for producing a photocatalyst compound of the present invention, the photocatalyst that functions as a catalyst when irradiated with light, the other compound, the compound as the third component, and the metal as the fourth component are formed. A method for producing a compounded photocatalyst composition,
Preparing a photocatalyst-dispersed sol in which at least the photocatalyst is dispersed among the photocatalyst, the other compound, and the compound as the third component;
A metal salt aqueous solution containing a metal ion exhibiting antibacterial properties is mixed with the photocatalyst-dispersed sol, and then irradiated with ultraviolet light, and the metal is loaded on the photocatalyst as a fourth component by using photoreduction of the metal ions. And a process.

  According to the eighth to tenth methods for producing a photocatalyst compound, the surface layer formed using the photocatalyst compound exhibits antibacterial properties regardless of whether it is under a light place or a dark place. In the present invention, a novel photocatalyst compound that causes a catalytic reaction with high efficiency can be easily produced. In addition, in the eighth manufacturing method of the present invention, when the metal contributing to the complementation of antibacterial properties is preliminarily supported and fixed on the photocatalyst, only the photocatalyst-dispersed sol and the metal salt aqueous solution are mixed. Can be planned. Further, in the ninth and tenth production methods of the present invention, coprecipitation or photoreduction is used to preliminarily support and fix a metal contributing to the complementation of antibacterial properties on the photocatalyst. It is possible to maintain the antibacterial complement performance for a long period of time. Furthermore, the tenth manufacturing method of the present invention merely irradiates ultraviolet rays when carrying and fixing the metal, and does not require any chemicals or the like, so that the process can be simplified.

  In the eighth to tenth methods for producing a photocatalyst compound, the photocatalyst-dispersed sol is a sol in which the photocatalyst, the other compound and the compound as the third component are all dispersed, that is, the first photocatalyst compound of the present invention. The photocatalyst composition of the sixth to eighth aspects of the present invention may be a sol in which the photocatalyst composition is dispersed. Further, another compound and a compound as the third component can be dispersed in the photocatalyst dispersion sol after supporting the metal. Furthermore, in order to keep a powdery photocatalyst composition for convenience of storage and the like, a photocatalyst carrying a metal as a fourth component, another compound and a sol in which a compound as a third component is dispersed are dried. Just do it.

Other aspects of the invention

The present invention can also adopt the following other aspects, and a first other aspect is a method for producing a blend containing a photocatalyst that functions as a catalyst when irradiated with light. ,
A step (A) of preparing a first sol in which the particles of the photocatalyst are dispersed;
A second sol in which particles of the other compound that are chemically bonded to an intermediate product generated before the reactant or the reactant undergoes the catalytic reaction and changes to the final product are dispersed. (B) preparing
A step (C) of mixing the first sol and the second sol.

  According to the manufacturing method of the first other embodiment, the photocatalyst and the other compound can be easily dispersed in the solvent by mixing the first and second sols. In the mixed sol that has passed through the step (C), the photocatalyst alone and the other compounds are not agglomerated, and the other compounds alone are not agglomerated. It becomes a mixed and dispersed sol. Therefore, this mixed sol is suitable for use as a photocatalyst compound dispersion sol, and facilitates the incorporation of a photocatalyst and other compounds into a material used in a liquid state, for example, a paint or glaze. Further, since the first and second sols are easily weighed because they are in a sol form, the mixing ratio of the photocatalyst and the other compound can be easily adjusted through the weighing of each sol. In addition, if the solvent in the mixed sol is removed by a method such as drying, a solid and granular compound in which the photocatalyst and other compounds are almost uniformly mixed is obtained.

  In this case, it is preferable to use the same solvent for the first sol and the second sol, or to use a so-called familiar solvent.

In the manufacturing method according to the first other aspect,
In the step (A), the photocatalyst generates excited electrons and holes by the energy of the irradiated light, and generates active oxygen species by the excited electrons and holes in the presence of oxygen and moisture on the catalyst surface. Having a step of adjusting the particles,
In the step (B), an amphoteric metal oxide, a basic metal oxide, or an acidic metal oxide chemically bonded to the reactant or the intermediate product subjected to the catalytic reaction based on the active oxygen species Preparing the at least one metal oxide as the other compound, and adjusting particles of the metal oxide.

  According to the second other aspect, the photocatalyst that causes a catalytic reaction based on the active oxygen species and the other compound that reliably binds and holds the reactant or the intermediate product at the base point or the acid point are almost uniformly formed. A mixed photocatalyst formulation can be easily obtained.

Further, in the manufacturing method of the first other aspect,
In the step (C), when the weight of the metal oxide is expressed as a and the weight of the photocatalyst is expressed as b, the first sol is adjusted so that a / (a + b) becomes about 0.0001 to 0.8. And a step of preparing a second sol.

  According to the third other aspect, the amount of the metal oxide (amphoteric metal oxide, basic metal oxide, acidic metal oxide) is not too small, and the amount of the photocatalyst is the above-mentioned metal oxide. It is possible to easily obtain a photocatalyst formulation that is not too small for the product and does not reduce the efficiency of the catalytic reaction.

Further, in the manufacturing method of the first other aspect,
The step (A) includes a step of adjusting the photocatalyst to particles in a particle size range of about 0.005 to 0.5 μm,
The step (B) may include a step of adjusting the metal oxide to particles having a particle size range of about 0.005 to 0.5 μm.

  According to the fourth other aspect, the photocatalyst and the metal oxide (amphoteric metal oxide, basic metal oxide, acidic metal oxide) can be easily formed by an existing pulverizer such as a ball mill or a sol-gel method. The particle size can be adjusted, which is preferable. In addition, a photocatalyst compound that does not cause the reactant or the intermediate product to separate from the photocatalyst and does not cause a reduction in the efficiency of the catalytic reaction can be easily obtained. Furthermore, according to this aspect, the photocatalyst and the metal compound can be brought close to each other with particles of substantially the same size to bring the reactant or the intermediate product close to the photocatalyst, so that the photocatalyst compounding with high catalytic reaction efficiency can be achieved. Things can be easily obtained.

Embodiment of the Invention

  Next, embodiments of the present invention will be described based on examples.

  First, the preparation of the photocatalyst composition used in the examples will be described. Anatase-type titanium dioxide was used as a photocatalyst, and as a metal oxide to be mixed with the photocatalyst, alumina as an amphoteric metal oxide and strontium oxide and barium oxide as basic metal oxides were used. The following steps were taken when preparing the photocatalyst composition.

1) Procurement of particles of photocatalyst and metal oxide The above-mentioned raw materials of titanium dioxide, alumina, strontium oxide and barium oxide are procured, and each is pulverized by a pulverizer such as a ball mill, or titanium dioxide, Obtain fine particles of alumina, strontium oxide and barium oxide. At this time, the particle size is adjusted so that the particle size of each particle is in the range of approximately 0.005 to 0.5 μm.

2) Preparation of sol Next, each compounded material prepared as described above is dispersed in a solvent such as water or alcohol, and a sol for each compounded material is prepared. In this case, the amount of dispersion of the dispersant in each sol (for example, the weight of the blended material / solvent volume) is defined.

3) Adjustment of photocatalyst composition After that, a metal oxide sol of alumina sol, strontium oxide sol, and barium oxide sol is mixed with the prepared titanium dioxide sol (photocatalytic sol), and a titanium dioxide / alumina mixed sol (Ti / Al sol), A titanium dioxide / strontium oxide mixed sol (Ti / Sr sol) and a titanium dioxide / barium oxide mixed sol (Ti / Ba sol) are obtained. In this case, in adjusting each of the above mixed sols, the mixed amount of the photocatalyst sol and the mixed amount of the metal oxide sol are weighed, and by changing the weighed amounts, the mixing ratio of the photocatalyst and the metal oxide is varied. Is adjusted. That is, when the weight of the metal oxide in each mixed sol is represented by a and the weight of the photocatalyst is represented by b, the blending ratio represented by a / (a + b) (hereinafter, a / (a + b) is determined by the blending ratio determining ratio ) Are adjusted variously.

  In addition to the steps 1) to 3) described above, a Ti / Al sol or the like can be obtained by adding particles such as alumina whose particle size has been adjusted to the prepared photocatalytic sol and dispersing them. Alternatively, the photocatalyst particles and the particles of alumina or the like whose particle size has been adjusted may be alternately or simultaneously dispersed in the above-mentioned solvent to obtain a Ti / Al sol or the like in which the photocatalyst particles and the particles of alumina or the like are dispersed from the beginning.

  Next, a photocatalyst function exhibiting material that exhibits a photocatalytic function by using the photocatalyst composition (each mixed sol of Ti / Al sol, Ti / Sr sol, and Ti / Ba sol) adjusted as described above will be described. In the present example (first example), this photocatalytic function-exhibiting material was used as a tile and manufactured as follows.

  An unglazed tile is prepared as a base material, and the above-mentioned mixed sol at a specified concentration is spray-coated on the tile surface. In this spray coating, the coating amount, that is, the spray time, is adjusted so that the thickness of the photocatalyst mixture on the tile surface after firing becomes about 0.85 μm. Next, at a temperature (about 800 ° C. in the present embodiment) at which the melting temperature of silica or the like blended for fixing the photocatalyst and the melting temperature of titanium dioxide and each of the above metal oxides are considered, the mixed sol is heated. By firing the tile after spray application for about 60 minutes, the final photocatalytic function having a surface layer containing the sol neutral component (photocatalyst, alumina, etc.) on the surface of the base material (tile) is exhibited. (Photocatalytic function display tile). Here, the evaluation will be described. The evaluation was made based on the effect of reducing nitrogen oxides, ammonia and sulfur dioxide, which are desired to be reduced as harmful substances in the air or indoors. The outline of the test is as follows. First, the reduction of nitrogen oxides will be described. In addition, it is a matter of course that a technique such as spin coating and dip coating can be adopted instead of the spray coating of the mixed sol.

(1-1) Evaluation Test 1: Influence of Alumina, etc. on Reduction of Nitrogen Oxide First, in order to compare with the product of the embodiment of the present invention, only titanium dioxide containing no alumina, strontium oxide and barium oxide was used. A photocatalytic function exhibiting tile (comparative tile) and a photocatalytic function exhibiting tile (example tile) of the example using the compounded photocatalyst composition were prepared as follows. The tile of the comparative example is a tile obtained by spray-coating a photocatalytic sol in which titanium dioxide accounts for 7.5% by weight on the tile surface, and firing under the above firing conditions (about 800 ° C. for 60 minutes). At the time of this spray coating, the application time and the like are adjusted so that the weight of titanium dioxide on the tile surface after firing is about 3.3 × 10 ⁻⁴ g / cm ² (the thickness of titanium dioxide in this case is about 0.85 μm). Was determined. Example tiles are the following Ti / Al tile, Ti / Sr tile, and Ti / Ba tile.

  The Ti / Al tile has a mixing ratio of alumina such that the mixing ratio determination ratio a / (a + b) is 1/11, with respect to the photocatalytic sol in which titanium dioxide occupies 7.5 wt% in the same manner as the comparative tile. This is a tile obtained by spray-coating and baking Ti / Al sol (Ti / Al sol in which the weight ratio of alumina to titanium dioxide is 0.1) adjusted to the same condition as the above comparative example tile. The Ti / Sr tile is a tile in which a Ti / Sr sol in which titanium dioxide and strontium oxide are blended in the same blending ratio as the Ti / Al tile is spray-coated and fired under the same conditions as the above-described comparative tile. The same applies to Ti / Ba tiles. That is, since the comparative example tile has only the titanium dioxide on the tile surface and exhibits the catalytic function as a reference on the comparative control, by comparing this comparative example tile with each of the above example tiles, The presence or absence of the improvement of the catalytic function obtained by blending the metal oxide and the degree of the improvement are clarified. The tile of the comparative example has a surface layer composed of only titanium dioxide on the tile surface, and the tile of the example has a surface layer composed of a mixture of titanium dioxide and alumina or strontium oxide or barium oxide. become.

This comparative example tile and each example tile were tested as follows. In the test, a 10 cm square sample piece of each of the comparative example tile and each of the example tiles was used, and the nitrogen oxide reduction effect was measured by a test device shown in FIG. This test apparatus is provided with a cylinder 12 filled with a fixed concentration of nitric oxide gas upstream of a sealed glass cell 10 on which a sample piece is placed, and the NO gas from the cylinder is suctioned by an air pump 14. The air whose humidity has been adjusted by the humidity controller 15 is mixed by a flow rate control valve 16, and a predetermined concentration (about 0.95 ppm) of NO gas at a predetermined concentration (about 0.95 ppm) is supplied from the flow rate control valve 16 to the glass cell 10. (Test gas). Further, downstream of the glass cell 10, there is provided a concentration-side measurer (NOx sensor) 18 for measuring the concentration of nitrogen oxide in the gas passing through the cell. The NOx sensor 18 measures the NO concentration and the nitrogen dioxide concentration (NO ₂ concentration) in the gas as needed, adds the measured NO concentration and NO ₂ concentration, and calculates the sum of the two concentrations as the nitrogen oxide concentration (NOx concentration). Is output. Further, the test apparatus has a lamp 20 for irradiating the inside of the glass cell 10 with ultraviolet rays (wavelength: 300 to 400 nm). In this case, the lighting of the lamp 20 is controlled so that the ultraviolet intensity on the sample piece becomes 1.2 mW / cm ² . Then, the sample piece was placed on the glass cell 10 of this test apparatus and placed in an environment irradiated with ultraviolet rays. With respect to the comparative example tile and each example tile, each time elapsed from the start of the test gas flow, The NO ₂ concentration and the NOx concentration were plotted. The result is shown in FIG. The lamp 20 was turned on after the NOx concentration (NO concentration) on the outlet side became stable after the start of the flow of the test gas.

In the evaluation test 1, if the reaction for oxidizing nitric oxide does not occur, for example, if the glass cell 10 is raised in a dark room and no active oxygen species is generated by titanium dioxide on the surface layer and no catalytic reaction occurs, the test gas is: It flows to the NOx sensor 18 without any reaction. Therefore, the output of the NOx sensor 18 in this case, for the NO concentration (CNO / out) is the same as the test gas concentration (CNO / in), NO ₂ concentration (CNO ₂ / out) is zero, NOx concentration (CNOx / Out) is the same as CNO / out or CNO / in. However, if NO is oxidized by a catalytic reaction based on the active oxygen species generated by titanium dioxide in the surface layer, the NO concentration decreases from CNO / in by the amount of the oxidation. If NO ₂ generated by NO oxidation is separated from the tile surface, the NO ₂ concentration increases by the amount of the separated NO ₂ . Then, the NO concentration decreased by NO oxidation, the relationship between the withdrawal NO ₂ concentration increased by from the generated NO ₂ in the tile surface, about the reduction of NOx is determined.

As shown in FIG. 5, in the comparative example tile, the NOx concentration rapidly decreases with the start of the test, and after about 5 minutes from the start of the test, the NOx concentration starts increasing and approaches the test gas concentration. . In this comparative example tile, the NO ₂ concentration gradually increased after the start of the test, and reached about 0.18 ppm after 30 minutes. The tendency of the increase in the NOx concentration and the tendency of the increase in the NO ₂ concentration are almost the same. For these reasons, in the comparative example tiles, but NO proceeds photocatalytic reaction by titanium dioxide in the surface layer is by concentration of NO oxidation decreases, with increasing NO ₂ concentration, the reduction of overall NOx proceed Will not be. Therefore, it can be said that in the comparative example tile, since NO ₂ is separated from the tile surface, further oxidation of NO _{2 on} the tile surface is not so much occurred. Since the NOx concentration after 30 minutes was about 0.66 ppm, the NOx reduction efficiency of this comparative example tile was about 30.5% ((0.95-0.66) /0.95). Was.

On the other hand, in each of the Ti / Al tiles, Ti / Sr tiles, and Ti / Ba tiles, similarly to the comparative example tile, the NOx concentration sharply decreased with the start of the test, and the lowest It changed at a concentration slightly increased from the concentration. In each of the example tiles, the NO ₂ concentration from the start of the test showed a small increase and reached only about 0.05 ppm after 30 minutes. From these facts, it can be said that, in each of the example tiles, first, the photocatalytic reaction by the titanium dioxide on the surface layer proceeds, NO is oxidized, and the NO concentration decreases. Also, it can be said that NO ₂ is bound to alumina, strontium oxide, and barium oxide and does not relatively escape from the tile surface, and further oxidation of NO ₂ by titanium dioxide actively proceeds, so that the NO ₂ concentration does not increase. . For this reason, according to each example tile, it can be said that NOx can be reduced with extremely high efficiency. Since the NOx concentration after 30 minutes has passed is about 0.45 ppm, the NOx reduction efficiency in each example tile is about 52.6% ((0.95−0.45) /0.95). Which was almost twice as large as that of the comparative example tile. When the above test was continued for these example tiles, it was found that the NOx reduction efficiency was maintained at a high value. After the elapse of 12 hours, the test was finished, the tile surface of the example was washed with water, and the substance contained in the washing water was analyzed. As a result, the presence of nitric acid was confirmed.

  In each of the example tiles, the surface condition was excellent without any abnormality observed in the degree of unevenness or the like. In addition, when a sliding wear test using a plastic eraser was attempted in accordance with JIS-A6808, no deterioration or peeling was observed on the surface layer of each of the example tiles even after the reciprocal sliding of about 40 times. It was also found to be excellent in wear properties. This means that the photocatalyst formulation produced by the above-mentioned method of mixing sols can be applied to firing, printing, binders, etc. as well as firing paints and glazes. In addition, it can be said that a photocatalyst compound or a photocatalyst exhibiting material capable of obtaining a high nitrogen oxide reduction efficiency by the photocatalytic function as described above can be easily produced by the above-mentioned method of mixing the sol.

(1-2) Evaluation Test 1: Influence of Alumina, etc. on Ammonia Reduction Ammonia was also reduced by the same device and method as the nitrogen oxides described above using the comparative example tile, Ti / Al tile, and Ti / Sr tile. I checked the situation. In this case, the test gas flowing into the glass cell 10 was about 4 ppm of ammonia gas, and the concentration of ammonia in the gas passing through the cell was measured by a concentration-side measuring instrument (gas detector tube) downstream of the cell. Then, with respect to the comparative example tile and the example tile (Ti / Al tile, Ti / Sr tile), the ammonia concentration at each elapsed time after the start of the flow of the test gas was plotted. FIG. 6 shows the result.

As shown in FIG. 6, in both the comparative example tile and the example tile, the ammonia concentration was lowered at the start of the test. Then, over the measurement period, the density of the example tile was lower, and after about 10 minutes from the start of the test, the density became almost constant for each tile. 2.5 ppm, and about 2.6 ppm for the Ti / Sr tile. Therefore, the reduction efficiency of ammonia is about 12.5% ((4-3.5) / 4) in the comparative example tile and about 37.5% ((4-2.5) / 4) in the Ti / Al tile. , Ti / Sr tile, about 35% ((4-2.6) / 4). From this, in the tile of the comparative example, the photocatalytic reaction by the titanium dioxide on the surface layer proceeds, and the ammonia is chemically changed to NO, NO _2, etc., and the ammonia is reduced to some extent. In any of the example tiles, the ammonia reduction efficiency was superior to the comparative example tile. The reason is presumed as follows.

If no reaction (chemical change) to convert ammonia to another substance occurs, the test gas flows into the gas detector tube without any reaction, and the measured ammonia concentration is the same as the test gas. However, if ammonia changes to another substance due to a catalytic reaction based on the active oxygen species generated by titanium dioxide in the surface layer, the ammonia concentration decreases from the concentration in the test gas by the changed amount. Therefore, the ammonia concentration of both the comparative example tile and the example tile was reduced immediately after the start of the test. In this case, since ammonia undergoes a catalytic reaction based on active oxygen species, nitrogen constituting ammonia is oxidized, and NO and NO ₂ are generated as intermediate products. Then, the NO is oxidized to NO ₂ by the active oxygen species as described above, when the chemical change this NO ₂ is further oxidized by the active oxygen species to nitric acid, ammonia undergo a catalytic reaction based on active oxygen species It is presumed that the degree of chemical change to NO and NO ₂ increases, and the ammonia reduction efficiency increases.

The example tile is different from the comparative example tile in that alumina and strontium oxide which combine with NO ₂ and do not release NO ₂ from the tile surface are blended as described above. Therefore, in the comparative example tile, since NO ₂ generated from ammonia is released from the tile surface, the reaction of NO ₂ being further oxidized by the active oxygen species and chemically changing to nitric acid does not proceed so much. In contrast, in the example tile, NO ₂ generated from ammonia is not released from the tile surface, and the reaction of oxidizing this NO ₂ to nitric acid by the active oxygen species is promoted. For this reason, in the example tiles, it is considered that the ammonia reduction efficiency was increased as described above, and the ammonia reduction efficiency was superior or inferior.

(1-3) Evaluation Test 1: Influence of Alumina, etc. on Reduction of Sulfur Dioxide Regarding sulfur dioxide, the state of reduction by the comparative example tile and Ti / Al tile is examined using the same device and method as the above-mentioned nitrogen oxide. Was. In this case, the test gas flowing into the glass cell 10 was about 10 ppm of sulfur dioxide gas, and the concentration of sulfur dioxide in the gas passing through the cell was measured by a concentration side meter (gas detector tube) downstream of the cell. Then, with respect to the comparative example tile and the example tile (Ti / Al tile), the sulfur dioxide concentration for each elapsed time after the start of the flow of the test gas was plotted. FIG. 7 shows the result.

  As shown in FIG. 7, in both the comparative example tile and the example tile, the sulfur dioxide concentration decreased with the start of the test. Then, the concentration of the example tile was lower over the measurement period, and after about 30 minutes from the start of the test, the concentration was about 7.7 ppm for the comparative example tile and about 2.7 ppm for the Ti / Al tile. Therefore, the sulfur dioxide reduction efficiency was about 23% ((10-7.7) / 10) for the comparative example tile and about 73% ((10-2.7) / 10) for the Ti / Al tile. . From this, in the tile of the comparative example, the photocatalytic reaction by the titanium dioxide on the surface layer progresses, and the sulfur dioxide is chemically changed into sulfuric acid or sulfurous acid to reduce the sulfur dioxide to some extent. In the case of the tile, the ammonia reduction efficiency superior to that of the comparative tile was exhibited. The reason is presumed as follows.

  For both the comparative example tile and the example tile, the sulfur dioxide concentration decreases as in the case of nitric oxide and ammonia, and the sulfur dioxide undergoes a catalytic reaction based on the active oxygen species generated by the titanium dioxide in the surface layer, and the sulfur dioxide becomes sulfuric acid or sulfuric acid. The reason is that the concentration changes to sulfurous acid, and the ammonia concentration decreases from the concentration in the test gas by the change. Sulfur dioxide, which is a reactant in this evaluation test, is chemically bonded to and absorbed by alumina, which is a basic metal oxide, as described with reference to FIG. Thus, in the comparative tile having no alumina, sulfur dioxide is oxidized by active oxygen species and chemically changed to sulfuric acid or sulfurous acid without being adsorbed on the tile surface, so that this reaction proceeds relatively slowly. On the other hand, in the example tile, sulfur dioxide or sulfurous acid is oxidized by active oxygen species to sulfuric acid or sulfurous acid while adsorbing sulfur dioxide on the tile surface, so that this reaction is promoted. For this reason, in the example tile, it is considered that the sulfur dioxide reduction efficiency was increased as described above, and the sulfur dioxide reduction efficiency was superior or inferior.

  Next, the following two methods were used to evaluate the relationship between the degree of blending of alumina or the like blended with the photocatalyst and the nitrogen oxide reduction effect. In this evaluation, alumina was used as an example.

(2) Evaluation test 2: Influence of alumina content on reduction of nitrogen oxides-Part 1
First, in order to compare with the example product of the present invention, a comparative example tile similar to the evaluation test 1 described above and a photocatalyst function exhibiting tile (example tile) of the example were prepared as follows. The tile of the comparative example is a tile obtained by spray-coating a photocatalytic sol in which titanium dioxide accounts for 7.5% by weight on the tile surface, and firing under the above firing conditions (about 800 ° C. for 60 minutes). In this spray coating, the coating time and the like were determined such that the weight of titanium dioxide on the tile surface after firing was about 3.3 × 10 −4 g / cm ² (the thickness of titanium dioxide was about 0.85 μm). Example tiles are the following Ti / Al tiles.

As for the Ti / Al tile, the mixing ratio determination ratio a / (a + b) is in the range of 0.0001 to 0.8 with respect to the photocatalytic sol in which titanium dioxide occupies 7.5 wt% as in the comparative example tile. Thus, the Ti / Al sol in which the mixing ratio of alumina is adjusted is spray-coated and baked under the same conditions as the above-mentioned comparative example tile. In other words, the weight of titanium dioxide on the tile surface after firing remains the same as that of the comparative example tile at about 3.3 × 10 ⁻⁴ g / cm ² , but the weight of alumina on the tile surface after firing is different from that of the Ti / Al tile. Were fired in various ways, and each Ti / Al tile was used as an example tile in Evaluation Test 2. When the mixing ratio determination ratio a / (a + b) is 0.01, a = b / 99, so that the weight of alumina on the tile surface after firing is about 3.3 × 10 ⁻⁶ g / cm ^2. When the mixing ratio determination ratio a / (a + b) is 0.5, a = b, so that it is about 3.3 × 10 ⁻⁴ g / cm ² . Even in the evaluation test 2, since the comparative example tile exerts a catalytic function as a reference, a fixed amount of photocatalyst was blended by comparing each Ti / Al tie having a different alumina blending amount with the comparative tile. In this case, the effect of the amount of alumina on the improvement of the catalyst function is found.

In this evaluation test 2, using the same test apparatus as the evaluation test 1, after 30 minutes from the start of the test in which the flow of the test gas at a predetermined concentration (about 0.95 ppm) and the lighting of the lamp 20 were started. the NO ₂ concentration and the NOx concentration were measured for Comparative example tile and the example tiles. Then, for each tile, and plotted the amount of NOx removed by subtracting the measured NOx concentration from the NO concentration of the test gas, and a measured NO ₂ concentrations. FIG. 8 shows the result. In addition, since the comparative example tile does not contain any alumina, the mixing ratio determination ratio a / (a + b) is zero.

In FIG. 8, the comparative example tile (a / (a + b) = 0) is plotted on the Y-axis of the graph, and the NO ₂ concentration was about 0.17 ppm and the NOx removal amount was about 0.3 ppm. . The reason why the NOx concentration is the concentration of NO ₂ which has not been included in the test gas of which decreases from the test gas is measured from the photocatalytic reaction proceeds and tile surfaces with titanium dioxide in the surface layer as described above Of NO ₂ is caused.

On the other hand, in the Ti / Al tile in which the mixing ratio determination ratio a / (a + b) is represented by the X-axis coordinate of the graph, the alumina mixing amount is small and the mixing ratio determination ratio a / (a + b) is 0.01. The NO ₂ concentration was about 0.15 ppm, and the NOx removal amount was about 0.4 ppm. Further, in a Ti / Al tile having the same alumina content as titanium dioxide and a mixing ratio determination ratio a / (a + b) of 0.5, the NO ₂ concentration was about 0.14 ppm and the NOx removal amount was about 0.43 ppm. Was. And, in the Ti / Al tile in which the mixing ratio determination ratio a / (a + b) is in the range of 0.05 to 0.2, the NO ₂ concentration is about 0.06 to 0.13 ppm, and the NOx removal amount is about 0.44. ０．４0.46 ppm, and the NO ₂ concentration was remarkably low and the NOx removal amount was large compared to the comparative example tile. It should be noted that even with the Ti / Al tile having the mixing ratio determination ratio a / (a + b) of 0.0001, the result obtained was similar to that of the Ti / Al tile having the mixing ratio determination ratio a / (a + b) of 0.01 (NO ₂ concentration). = About 0.155 ppm, NOx removal amount = about 0.36 ppm), and the X-axis coordinates for plotting the Ti / Al tiles are close to zero and are not shown.

As is evident from these facts, when the mixing ratio determination ratio a / (a + b) is in the range of 0.0001 to 0.5, the release of NO ₂ can be suppressed by adding alumina, It is possible to obtain a higher NO ₂ reduction effect than that of the example tile, and a longer NOx reduction effect. In particular, when the mixing ratio determination ratio a / (a + b) is in the range of 0.05 to 0.2, an extremely high NOx reduction effect can be obtained as compared with the comparative example tile, which is preferable. Then, a high NOx reduction effect could be obtained even with a very small amount of alumina, such as a compounding ratio determination ratio a / (a + b) of 0.0001.

  In addition, each of the Ti / Al tiles having various values of the mixing ratio determination ratio a / (a + b) also had good surface conditions and excellent wear resistance.

(3) Evaluation test 3: Influence of alumina mixing degree on nitrogen oxide reduction-Part 2
In this evaluation test 3, the total amount of titanium dioxide and alumina as photocatalysts (the blended sum of both) was kept constant, and the nitrogen oxide reduction effect when the blended amounts of titanium dioxide and alumina were varied was set. I decided to investigate.

First, in order to compare with the example product of the present invention, a comparative example tile similar to the evaluation test 1 described above and a photocatalyst function exhibiting tile (example tile) of the example were prepared as follows. The comparative example tile is the same tile as the evaluation test 2 described above, and the weight of titanium dioxide on the tile surface after firing is about 3.3 × 10 ⁻⁴ g / cm ² . In addition, the weight of alumina on the tile surface was also about 3.3 × 10 ⁻⁴ g / cm ² for a simple tile (a tile that does not exhibit a photocatalyst) using a blend containing only alumina without any photocatalyst. I prepared something. Example tiles are the following Ti / Al tiles.

The Ti / Al tile has a mixing ratio determination ratio a / (a + b) of 0.05 to 0.95 with respect to the photocatalytic sol in which the total amount of titanium dioxide and alumina occupies 7.5 wt% as in the comparative example tile. The Ti / Al sol in which the blending ratio of alumina was adjusted so as to fall within the range described above was spray-coated and baked under the same conditions as the above-mentioned comparative example tile. In other words, the weight of titanium dioxide on the tile surface after firing was reduced from about 3.3 × 10 ⁻⁴ g / cm ² with the weight of alumina, and various Ti / Al tiles were fired. Example tiles in this evaluation test 3 were used. When the mixing ratio determination ratio a / (a + b) is 0.05, since a + b corresponds to the above 3.3 × 10 ⁻⁴ g / cm ² , the weight a of the alumina on the tile surface after firing is about At 1.65 × 10 ⁻⁵ g / cm ² , the weight b of titanium dioxide is about 3.135 × 10 ⁻⁴ g / cm ² . On the other hand, when the mixing ratio determination ratio a / (a + b) is 0.95, on the contrary, the weight a of alumina is about 3.135 × 10 ⁻⁴ g / cm ² and the weight b of titanium dioxide is about 1. It is 65 × 10 ⁻⁵ g / cm ² . Even in this evaluation test 3, the comparative example tile exerts a catalytic function as a reference. Therefore, by comparing this comparative example tile with each Ti / Al tie having a different blending amount of titanium dioxide and alumina, the catalytic function is obtained. The effect of the blending amount of titanium dioxide and alumina on the improvement of the content is clarified.

  In this evaluation test 3, the same test apparatus as in the evaluation test 1 was used, and the NO2 concentration and the NOx removal amount were plotted as in the evaluation test 2. The result is shown in FIG. In addition, the comparative example tile does not contain any alumina, so the mixing ratio determination ratio a / (a + b) is zero, and the above-mentioned tile that does not exhibit a photocatalyst contains no titanium dioxide. The ratio determination ratio a / (a + b) is 1.

In FIG. 9, the comparative example tile (a / (a + b) = 0) is plotted on the Y-axis of the graph, and the NO ₂ concentration was about 0.17 ppm and the NOx removal amount was about 0.3 ppm. . Although the NOx concentration is lower than the test gas, the concentration of NO ₂ not contained in the test gas is measured as described above for the evaluation test 2. Further, the mere tiles that did not exhibit the photocatalyst were plotted on the X-axis of the graph, and the NO ₂ concentration and the NOx removal amount were naturally zero.

On the other hand, in the Ti / Al tile in which the mixture ratio determination ratio a / (a + b) is represented by the X-axis coordinate of the graph, the alumina mixture amount is small and the mixture ratio determination ratio a / (a + b) is 0.05. The NO ₂ concentration was about 0.07 ppm, and the NOx removal amount was about 0.46 ppm. In a Ti / Al tile in which the amount of alumina is higher than the amount of titanium dioxide and the mixing ratio determination ratio a / (a + b) is 0.8, the NO ₂ concentration is about 0.13 ppm, and the NOx removal amount is about 0.32 ppm. there were. Then, in the Ti / Al tile in which the mixing ratio determination ratio a / (a + b) is in the range of 0.05 to 0.65, the NO ₂ concentration is about 0.07 to 0.09 ppm, and the NOx removal amount is about 0.43. ０．５0.52 ppm, and the NO ₂ concentration was remarkably low and the NOx removal amount was large compared to the comparative example tile. In the case of Ti / Al tiles in which the amount of alumina greatly exceeds the amount of titanium dioxide and the mixing ratio determination ratio a / (a + b) is 0.9 or more, the NO ₂ concentration and the NOx removal amount are equal to or less than those of the comparative example tile. Was.

As is apparent from the above, if the total amount of titanium dioxide and alumina is constant and the mixing ratio determination ratio a / (a + b) is in the range of 0.0001 to 0.8, the addition of alumina makes NO ₂ can be suppressed, and a higher NO ₂ reduction effect and a higher NOx reduction effect than the comparative example tile can be obtained. In particular, when the mixing ratio determination ratio a / (a + b) is in the range of 0.05 to 0.6, an extremely high NOx reduction effect can be obtained as compared with the comparative example tile, which is preferable. When the mixture ratio determination ratio a / (a + b) is less than 0.0001 or larger than 0.8, the same NOx reduction effect as that of the comparative tile can be obtained. When a / (a + b) is 0.9 or more, it is expected that the amount of titanium dioxide as a photocatalyst is too small, the particles are surrounded by alumina particles without gaps and light does not reach, and the photocatalytic function is deteriorated.

  In addition, each of the Ti / Al tiles having various values of the mixing ratio determination ratio a / (a + b) also had good surface conditions and excellent wear resistance.

In the first embodiment, titanium dioxide of anatase type was used as a photocatalyst, and as a metal oxide to be mixed with the photocatalyst, alumina as an amphoteric metal oxide, strontium oxide and barium oxide as basic metal oxides were used. However, it is needless to say that the NOx reduction effect described above can also be obtained by a combination of another photocatalyst and a metal oxide. For example, even if titanium dioxide is used as a photocatalyst, the crystal type may be rutile or brookite. Further, even if a photocatalyst such as ZnO, V ₂ O ₅ , WO ₃ , SnO ₂ , SrTiO ₃ , Bi ₂ O ₃ , and Fe ₂ O ₃ is used, a NOx reduction effect can be obtained. Further, as metal oxides replacing alumina, strontium oxide and barium oxide, zinc oxide, tin oxide (above, amphoteric metal oxide), magnesium oxide, calcium oxide, rubidium oxide, sodium oxide, potassium oxide (above, basic oxide) Even if metal oxide) is used, a NOx reduction effect can be achieved. When the basic gas is to be reduced, phosphorus oxide (acid metal oxide) can be used in addition to the amphoteric metal oxide.

  Next, a second embodiment will be described. In the second embodiment, the procedure for forming a surface layer composed of a photocatalyst compound having a photocatalyst such as titanium dioxide and a specific metal oxide such as alumina on the tile surface is different. In the embodiment of the second embodiment, first, a base material for forming a surface layer is prepared. The base material may be ceramic, resin, metal, glass, pottery wood, silica plate, concrete plate, cement plate, cement extruded and shaped plate, gypsum board or autoclave-cured lightweight concrete plate, etc., for buildings, houses and bridges. A base material used for a building structure such as a road noise barrier is preferable because environmental pollutants such as nitrogen oxides can be reduced on the surface of the building structure to purify the atmosphere.

  Next, a binder layer is formed on the surface of the prepared base material. The binder layer is formed by selecting a binder material whose softening temperature is lower than the deterioration temperature of the base material and using the binder material by an appropriate method suitable for the properties of the binder. For example, when the base material is a tile, an enamel, or a porcelain, a glaze layer or a printed layer for coloring the surface can be used as a binder layer as it is. After the formation of the binder layer, the surface of the binder layer is coated or printed with the sol such as the Ti / Al sol in the first embodiment, or the titanium dioxide particles obtained by removing the solvent from the sol and alumina. A mixed particle with the particles is sprayed to form a photocatalyst compound layer to be a surface layer later. Alternatively, a photocatalyst compound layer may be formed on a separately prepared binder layer, and the binder layer may be placed on the surface of the base material. In these cases, the photocatalyst compound layer only needs to be formed on the binder layer so as not to be separated from the binder layer during the subsequent firing.

  Thereafter, when the binder layer is a glaze layer made of glaze, the temperature is higher than the softening temperature of the binder material (glaze) in the range of 30 ° C. to 300 ° C. and lower than the deterioration temperature of the base material. Heat treatment. Through this heat treatment, the binder material (glaze) is melted and solidified, the binder layer is firmly fixed on the tile surface, and a surface layer is formed from the photocatalyst compound layer. At this time, at the boundary with the binder layer, the particles of the photocatalyst compound (titanium dioxide particles, alumina particles) in the surface layer settle in the binder layer in the process of melting the binder material, and the particles are buried in the binder layer. It is held and firmly fixed to the binder layer. In addition, in the photocatalyst compound layer, adjacent particles are bonded by sintering due to intermolecular force between particles and sintering, and a surface layer is formed. In this surface layer, each of titanium dioxide and alumina is formed on the surface. Expose the particles. Therefore, the surface layer can be firmly fixed to the binder layer, and the respective particles of titanium dioxide and alumina can be effectively brought into contact with the outside air. Therefore, according to the manufacturing method in the second reference example, it is possible to easily manufacture a building structure material having a surface layer capable of causing a photocatalytic reaction with high efficiency.

  In this case, since the heating temperature is higher than the softening temperature of the binder material by 30 ° C. or more, the softening of the binder material by heating does not require a carelessly long time, which is preferable, and does not hinder the sedimentation / holding of titanium dioxide or alumina particles. It is preferable because it does not cause messy. In addition, since the heating temperature is not higher than the transformation temperature of the binder by more than 300 ° C., it is possible to avoid rapid melting of the binder material, excessive precipitation of titanium dioxide and alumina particles, generation of uneven surfaces, and generation of pinholes. This is preferable because defects such as the above can be suppressed. The heating temperature is preferably higher than the softening temperature of the binder material in the range of 50 ° C. or more and 150 ° C. or less.

Even in the second embodiment, as the photocatalyst, titanium dioxide having a crystal type of rutile or brookite, ZnO, V ₂ O ₅ , WO ₃ , SnO ₂ , SrTiO ₃ , Bi ₂ O ₃ , Fe ₂ O ₃ Etc. may be used. In addition, as a metal oxide instead of alumina, if the reduction target is an acidic gas such as NOx, zinc oxide, tin oxide (above, amphoteric metal oxide), magnesium oxide, calcium oxide, rubidium oxide, sodium oxide, Potassium oxide (above, a basic metal oxide) may be used, and when the basic gas is to be reduced, phosphorus oxide (an acidic metal oxide) may be used in addition to the amphoteric metal oxide described above. Good.

Next, another embodiment will be described. In the first and second embodiments, the reactant (for example, NO) or the intermediate product (for example, NO ₂ ) is held in the catalytic reaction system by the photocatalyst and the above-mentioned specific compound, This is to ensure the opportunity for the reactants to be used for the catalytic reaction and the opportunity for the intermediate products to be further used for this catalytic reaction, and to obtain the effect of reducing harmful substances such as NOx. In this embodiment, the NOx reduction effect is further improved or a new effect is obtained by adding a substance other than the specific compound described above.

First, a third embodiment will be described. The third embodiment relates to a photocatalytic function-executing material having not only the efficiency of the catalytic reaction as described above but also the antibacterial function exhibited by the photocatalyst generating active oxygen species. In the production, a Ti / Al sol in which alumina is blended with titanium dioxide at the above-mentioned blending ratio determining ratio which can achieve the efficiency of the catalytic reaction, and copper (Cu) or its oxide or silver (Ag) or its A third sol in which particles such as oxides are dispersed is prepared. Next, a Ti / Al sol is applied to the tile surface and baked to form a Ti / Al layer. Thereafter, a third sol is applied to the surface of the Ti / Al layer on the tile surface, and the third sol component is fixed to the surface by a method such as photoreduction. This tile is a tile of the third embodiment. The tile of the third embodiment has a surface layer on which titanium dioxide serving as a photocatalyst is fixed together with alumina on the surface thereof, and particles such as Cu are fixed on the upper surface thereof. It becomes the tile which was done. In applying the third sol, the application amount is adjusted so that the photocatalyst is sufficiently irradiated with light. For example, it is sufficient that the weight of Cu after firing is about 0.8 to 2.0 μg / cm ² . The following antibacterial properties were evaluated for the third example tile and the comparative example tile used in the above evaluation test. The evaluation was made based on the presence or absence of a bactericidal effect on Escherichia coli (Escherichiacoil w3110 strain).

First, the surfaces of both the example tile and the comparative example tile of the third example were sterilized with 70% ethanol, and then 0.15 ml (1 to ⁵ × 10 ⁴ CFU) of Escherichia coli was dropped on the tile surface. A glass plate was placed on the tile surface, and Escherichia coli was brought into close contact with the tile surface. This was used as a sample, and a pair of this sample was prepared for each tile. Next, one sample of the example tile and the comparative example tile of the third example was irradiated with a fluorescent lamp through a glass plate, and the other sample was placed in a light-shielded environment. Then, as the irradiation time elapses, the viability of E. coli in the sample under fluorescent light irradiation (under a light place) and the sample under light shielding (under a dark place) was measured, and the antibacterial rate (E. coli was killed) converted from this viability was measured. Or the rate at which growth was stopped) was plotted against elapsed time. The result is shown in FIG. At the time of measurement, the bacterial solution of each sample was wiped with sterile gauze, collected in 10 ml of physiological saline, and the survival rate of Escherichia coli in this physiological saline was measured, and this was defined as the survival rate in the sample.

  As is clear from FIG. 10, under the fluorescent lamp irradiation, a high antibacterial effect was obtained in both the example tile of the third example and the comparative example tile. This is considered to be because titanium dioxide in the surface layer actively generated reactive oxygen species under the irradiation of a fluorescent lamp, and Escherichia coli was killed or stopped growing by the decomposition of the organic components contained in the reactive oxygen species. However, under the light-shielded state, the comparative example tile has almost no antibacterial effect because no active oxygen species is generated, while the tile of the third embodiment has a relatively high antibacterial effect even under the light-shielded state. Was done. This is because particles such as Cu fixed on the surface exerted an antibacterial function even under light shielding. Therefore, according to the example tile of the third embodiment, the antibacterial function that titanium dioxide, which is a photocatalyst, cannot exhibit because it is under light shielding can be performed by the particles of Cu or the like under light shielding, and the photocatalyst performs. It can complement antibacterial function.

Even in the third embodiment, as the photocatalyst, titanium dioxide having a crystal type of rutile or brookite, ZnO, V ₂ O ₅ , WO ₃ , SnO ₂ , SrTiO ₃ , Bi ₂ O ₃ , Fe ₂ O ₃ May be used. As a metal oxide instead of alumina, zinc oxide, tin oxide (above, amphoteric metal oxide), magnesium oxide, calcium oxide, rubidium oxide, sodium oxide, potassium oxide (above, basic metal oxide) ) And phosphorus oxide (acidic metal oxide). Further, instead of Cu, an oxide thereof, silver (Ag) or an oxide thereof, or a metal such as Pd, Ni, Co, Pt, Au, Al, Fe, Zn, Cr, Rh, or Ru, It is preferable to use a metal that has an antibacterial action even if it is slight.

  Next, fourth and fifth embodiments will be described. This fourth embodiment uses a photocatalyst and the above-mentioned metal oxides such as alumina (amphoteric metal oxide, basic metal oxide, and acidic metal oxide) as in the first and second embodiments. It is a quaternary compound in which other compounds are used in combination with a metal such as Cu or Ag as in the third embodiment. The fifth embodiment is a three-component system in which a photocatalyst and the above-described metal oxide such as alumina (amphoteric metal oxide, basic metal oxide, and acidic metal oxide) are used in combination with other compounds.

  If the metal used in the fourth embodiment is a metal having a reduction potential equal to or higher than the potential (−3.2 V) of the free electrons generated by titanium dioxide as a photocatalyst, the metal is supported on titanium dioxide by the reduction potential (reduction supported). ) Is preferred. Specifically, it is a transition metal such as Ag, Cu, Pd, Fe, Ni, Cr, Co, Pt, Au, Li, Ca, Mg, Al, Zn, Rh, and Ru. Among them, Ag, Cu, Pd, Pt, and Au are particularly preferable because the reduction potential has a positive value, so that reduction carrying easily occurs. A method for supporting the metal on the photocatalyst when using these metals together will be described. The following methods can be used as a method for supporting the metal on the photocatalyst.

1) Simple mixing method: A method in which an aqueous solution of a metal salt containing a target metal species is added to a photocatalytic sol, the two are mixed, and the metal ions are supported by adsorption on the surface of the photocatalytic particles.
2) Coprecipitation method: After adding an aqueous solution of a metal salt containing a target metal species to a photocatalytic sol, a metal salt and a photocatalyst are simultaneously precipitated by adding or heating a precipitant to coprecipitate the metal ions and photocatalyst particles. A method of supporting on the surface.
3) Pre-photoreduction supporting method: a method of adding a metal salt aqueous solution containing a target metal species to a photocatalyst sol and irradiating with ultraviolet energy to carry out the photoreduction of metal ions on the surface of photocatalytic particles using photoreduction.
4) Post-photoreduction loading method: A method of applying a metal salt aqueous solution containing the target metal species on the photocatalyst film, irradiating it with ultraviolet energy, and using the photoreduction of metal ions on the photocatalyst film surface to carry it. .
5) Evaporation method: A method of supporting metal particles or metal compounds by chemical or physical evaporation.
6) Others: A method in which ions of the target metal species are added before granulating the photocatalyst particles using the sol-gel method, and then the particles of the photocatalyst / metal ions are formed by a coprecipitation method or the like.

The compound used in combination with the photocatalyst and the above-mentioned metal oxide such as alumina was silicon dioxide (silica: SiO ₂ ). Note that an oxide such as ZrO ₂ , GeO ₂ , ThO ₂ , or ZnO can be used instead of silica.

  In the fourth embodiment, the above-described simple mixing method, the supporting method before photoreduction or the coprecipitation method was employed, and a photocatalyst supporting a metal by this method was used.

The tile exhibiting the photocatalytic function of the fourth embodiment (example tile) uses a photocatalytic sol in which a photocatalyst (titanium dioxide) supporting Ag and Cu is dispersed by a simple mixing method, a pre-reduction supporting method or a coprecipitation method, Following the steps described in the evaluation test 1 of the first embodiment described above, the sol of the other two components (alumina, silica) is mixed and stirred with this metal-loaded photocatalyst sol (photocatalyst / metal). It was manufactured through spray coating and baking of the mixed sol. The four-component tile of the photocatalyst / metal (Ag or Cu) / alumina / silica thus produced is the example tile of the fourth example. At this time, a tile (reference tile) was also manufactured for a two-component system of a photocatalyst / metal (Ag or Cu) in order to grasp the effects of the newly added metal and silica. The example tile of the fifth embodiment uses the same photocatalyst (titanium dioxide) sol as in the first embodiment, and follows the steps described in the evaluation test 1 of the first embodiment. A sol of the other two components (alumina, silica) was mixed and stirred with the photocatalytic sol, and the mixed sol was manufactured by spray coating and firing. The three-component photocatalyst / alumina / silica tile thus manufactured is the example tile of the fifth example. Then, the NOx reduction efficiency was examined for the example tiles of the fourth and fifth examples, the reference tile, the example tile of the first example, and the comparative example tile. Note that the example tile and the comparative example tile of the first example are as described in the evaluation test 1 of the first example, and the mixing ratio determination ratio of the example tile of the first example is a / (a + b). ) Is 1/11. Further, the mixing ratio determination ratio (SIO ₂ / (TiO ₂ + Al ₂ O ₃ + SiO ₂ )) of the example tile of the fourth example is 1/11, and the mixing ratio determination ratio of the example tile of the fifth example is (Al ₂ O ₃ / (TiO ₂ + Al ₂ O ₃ + SiO ₂ )) is 1/11. In the two-component reference tile, the weight ratio of metal to TiO ₂ is 0.001 (Ag / TiO ₂ ) for the two-component reference tile containing Ag, and 0.01 for the two-component reference tile containing Cu. (Cu / TiO ₂ ).

With respect to these tiles, CNO / out and CNO ₂ / out were measured using the test device shown in FIG. 4 as described in the evaluation test 1 of the first embodiment. Then, based on the measured CNO / out, CNO ₂ / out, and the known test gas concentration (CNO / in), the value of (CNO / in−CNO / out), CNO ₂ / Out and NOx reduction efficiency were determined. Table 1 shows the results.

(CNO / in-CNO / out) is the amount of NO oxidized to NO ₂ or NO ₃ ⁻ (NO reduction amount), and is a value that is an index of NO oxidizing power. CNO ₂ / out is the amount of by-products of NO ₂ out of the system. The smaller the value of CNO ₂ / out, the more the NO ₂ is not released out of the system, that is, the stronger the adsorption power of NO _2. It represents that. Therefore, as is clear from Table 1, according to the example tile of the fourth example, the NO oxidizing power equal to or higher than that of the first example could be exhibited, and a high NOx reduction efficiency could be obtained. In particular, in the embodiment the tiles of the fourth embodiment was blended Ag, high NO oxidizing power by large (CNO / in-CNO / out ), since a powerful NO ₂ adsorptive force by a small CNO ₂ / out, It was possible to achieve both oxidizing power and adsorption power.

  Also, from the results of the reference tiles, if the pre-reduction supporting method is adopted, even with a two-component system of titanium dioxide and metal, the same NO oxidizing power and NOx reduction efficiency as in the first embodiment can be obtained. Was. Further, from the results of the example tile of the fifth example, even if silica was blended, the same NO oxidizing power and NOx reduction efficiency as those of the first example could be obtained. It was found that there was no problem due to the silica compounding.

Even in the fourth and fifth embodiments, titanium dioxide having a crystal type of rutile or brookite, ZnO, V ₂ O ₅ , WO ₃ , SnO ₂ , SrTiO ₃ , Bi ₂ O ₃ , Fe _{2 2} O ₃ or the like may be used. As a metal oxide instead of alumina, if the reduction target is an acidic gas such as NOx, zinc oxide, tin oxide (above, amphoteric metal oxide), magnesium oxide, calcium oxide, rubidium oxide, sodium oxide, and potassium oxide (Above, a basic metal oxide) may be used, and when a basic gas is to be reduced, phosphorus oxide (an acidic metal oxide) may be used in addition to the above amphoteric metal oxide. Further, each of the above metals may be used instead of Ag or Cu, or each of the above oxides may be used instead of silica.

  Next, sixth and seventh embodiments will be described. In the sixth embodiment, as in the fourth embodiment, a photocatalyst represented by titanium dioxide, an amphoteric or basic or acidic metal oxide represented by alumina, Cu, Ag, Pd, Fe, Ni , Cr, Co, Pt, Au, Rh, Ru, etc., the metal described in the fourth embodiment and the other compounds (oxides), such as silica, described in the fourth embodiment in a four-component system. It is. The seventh embodiment is a three-component system in which a photocatalyst, an amphoteric or basic or acidic metal oxide represented by alumina, and another compound (oxide) described in the fourth embodiment such as silica are used in combination. Things. In the sixth and seventh embodiments, the improvement of the decomposing ability including the decomposing ability of the environmental pollutants such as NOx and the prevention of the pollution are aimed at.

  In the sixth embodiment, as in the fourth embodiment, a photocatalytic sol in which a photocatalyst (titanium dioxide) carrying Ag and Cu is dispersed by the simple mixing method or the pre-photoreduction supporting method is used. Then, even in the example tile of the sixth example, as in the fourth example, it was manufactured by following the steps described in the evaluation test 1 of the first example. Similar to the fifth embodiment, the tile of the seventh embodiment was manufactured by mixing and stirring a sol of another component (alumina, silica) with the photocatalytic sol, spraying and firing the mixed sol. In order to grasp the effects of newly added metal and silica, two-component system of photocatalyst / metal (Ag or Cu), two-component system of photocatalyst / silica, and three components of photocatalyst / metal (Ag or Cu) / silica Tile (reference tile) was also manufactured for the system. In this case, when applying the photocatalytic sol to the substrate (tile), a technique such as spin coating or dip coating can be employed instead of spray coating. Further, the fixation of the photocatalyst sol to the substrate surface is performed by baking as in the process described in the evaluation test 1 of the first embodiment (baking type), or a silicone resin is mixed with the photocatalyst sol at a relatively low temperature. A technique (paint type) of curing this silicone resin was employed. Then, the example tiles, reference tiles, and comparative example tiles of the sixth and seventh examples were evaluated. The comparative example tile is as described in the evaluation test 1 of the first example.

The mixture ratio determination ratio (SIO ₂ / (TiO ₂ + Al ₂ O ₃ + SiO ₂ )) of the example tile of the sixth embodiment is 1/10, and the mixture ratio determination ratio (Al ₂ O ₃ / (TiO ₂ + Al ₂ O ₃ + SiO ₂ )) is 1/10. The determination ratio (SIO ₂ / (TiO ₂ + SiO ₂ )) of the blend ratio of the two-component reference tile of photocatalyst / silica is 1/5. In the photocatalyst / metal two-component reference tile, the weight ratio of metal to TiO ₂ is 0.001 (Ag / TiO ₂ ) for the Ag-containing two-component reference tile, and the two-component reference tile for the Cu mixing. Is 0.01 (Cu / TiO ₂ ). In the three-component reference tile of photocatalyst / metal / silica, the weight ratio of metal to TiO ₂ is the same as the above reference tile (0.001 (Ag / TiO ₂ ), 0.01 (Cu / TiO ₂ )). Yes, and the mixing ratio determination ratio (SIO ₂ / (TiO ₂ + SiO ₂ )) is 1/5.

First, a photocatalyst / metal (Ag or Cu) two-component reference tile will be described in order to grasp the effect of a newly blended metal. In the case of the baking type, this two-component reference tile is prepared by adding various metal salts (special grade of Wako Pure Chemical Reagent) to titanium oxide sol (Ishihara STS-11) and 0.001 to titanium oxide solid content in the titanium oxide sol. It was blended to be 10%. Then, Ag or Cu was previously supported on the photocatalyst by a simple mixing method, a supporting method before photoreduction, or a coprecipitation method. In the pre-reduction supporting method, a metal salt aqueous solution of Ag or Cu was mixed with the titanium oxide sol, and then irradiated with ultraviolet light at an intensity of 1 mW / cm ² for 2 hours to obtain a photocatalytic sol supporting the metal. In the coprecipitation method, a TiOSO ₄ solution was used as a starting material, and an aqueous solution of a metal salt was added to this solution to hydrolyze the solution to obtain a metal-supported photocatalytic sol. Thereafter, these photocatalyst sols are spray-coated on the tile surface so that the film thickness after firing becomes about 0.8 μm, and fired at 600 to 900 ° C. (about 800 ° C. in this reference tile) to obtain a two-component system. A reference tile (baked type) was obtained.

  In the paint type, various metal salts (special grade of Wako Pure Chemical Reagent) were mixed with titanium oxide sol (Nissan Chemical TA-15) so as to be 0.001 to 1% based on the solid content of titanium oxide in the titanium oxide sol. Then, a photocatalyst sol having Ag or Cu supported thereon by a simple mixing method or a supporting method before photoreduction and a silicone resin as a binder are mixed such that the solid content ratio of titanium oxide and the silicone resin is 7: 3. Then, the tile surface was spin-coated and heated at 150 ° C. to obtain a two-component reference tile (paint type).

The following evaluation tests were performed on the two-component reference tiles (baking type and paint type) to evaluate the decomposing ability of chemical substances. Decomposition power can be directly evaluated by antibacterial power and oil decomposition rate. Here, the antibacterial activity is based on the antibacterial activity against Escherichia coli (Escherichiacoil w3110 strain) described in the third embodiment, and the antibacterial activity exerted by a tile having a photocatalytic layer composed of a single photocatalyst (titanium dioxide) is defined as 1. evaluated. The oil decomposition rate was determined as follows. 1 mg / 100 cm ^{2 of} salad oil was applied to the test body, and ultraviolet rays of 1 mW / cm ² were irradiated for 7 days. Then, the gloss was measured before oil application, immediately after oil application, and at the end of irradiation, and the value obtained from the following equation 1 was defined as the oil decomposition rate.

The decomposition of a chemical substance by a photocatalyst is mainly due to the oxidizing effect of the active oxygen species released from the photocatalyst upon photoexcitation to the substance. It is possible to use force. Here, as a model reaction, the NO oxidizing power of various photocatalytic thin films was also evaluated based on the conversion amount from oxidation of nitrogen monoxide (NO) to nitrogen dioxide (NO ₂ ). The NO oxidizing power was measured by using the test apparatus shown in FIG. 4 and measuring CNO / out as described in the evaluation test 1 of the first embodiment. Then, from the measured CNO / out and the known test gas concentration (CNO / in), (CNO / in-CNO / out) for each elapsed time after light irradiation is obtained, and one hour elapses from the start of light irradiation. The number of moles of the total NO oxidized up to this was calculated from the above (CNO / in-CNO / out), and this was defined as the NO oxidizing power. However, at that time, the flow of the NO gas (test gas) was performed at 2 liter / min, and the size of the sample piece was 5 cm × 50 cm.

  Table 2 shows the antibacterial activity, oil decomposition rate, and NO oxidation activity of the two-component reference tiles (baked type and paint type). In addition, the antibacterial activity, the oil decomposition rate, and the NO oxidizing activity in Table 2 are obtained when the tile is in a light place, as is clear from the above description.

From Table 2, in the baking type reference tile, in the Cu-added system, Cu prepared by the pre-photoreduction supporting method with 1% supported on TiO ₂ has antibacterial activity, oil decomposition rate, NO oxidation activity. Is the best. In the Ag-added system, the supporting method before photoreduction is also the most excellent in antibacterial activity, oil decomposition rate and NO oxidizing activity as compared with the simple mixing method. Antibacterial activity by addition of any metal in the table, the oil decomposition rate, with NO oxidation force from the fact that improved compared to that of no addition, Cu supported on TiO _2, Ag, Pd, Fe, etc. It was found that the metal contributed to the improvement of the decomposition power of TiO ₂ . The Cu addition system in baked type, showing the highest antibacterial activity that the Cu adjusted by photoreduction front supporting method carries 0.1% to 1% with respect to TiO _2. It was also found that the Ag-added system exhibited higher antibacterial activity than the Cu-added system.

From the above results, it can be seen that in the baking type and paint type reference tiles, the decomposition power is improved by supporting metals such as Cu, Ag, Pd, and Fe on TiO ₂ . That is, it can be concluded that the above metals have a function of improving the decomposition power of TiO ₂ . In addition, it can be seen that the supporting method before photoreduction is superior to the simple mixing method as a supporting method of the metal species with respect to the decomposing power. Further, it can be said that by adjusting the amount of the metal carried, the decomposition power of TiO ₂ can be changed.

We also examined the antimicrobial activity when placed Reference tile of a two-component system of the baking type in the dark in the reference tile was 0.1% carrying Cu TiO ₂ with a simple mixing method, the antibacterial The force was about 0.3. In addition, the antibacterial activity of the reference tile in which 1% of Cu was supported on TiO ₂ by the simple mixing method was about 0.3. Furthermore, the antibacterial activity of the reference tile in which 0.1% of Ag was supported on TiO ₂ by the simple mixing method was about 0.3. As described above, in a dark place, the photocatalyst is not activated, and its antibacterial activity is nothing but the effect of the supported metal itself. Considering that non-metal-added tiles, that is, photocatalysts only, have almost zero antibacterial activity in a dark place, these reference tiles exhibit the antibacterial activity exhibited by the metal itself and the tiles containing only the photocatalyst. The antibacterial activity exceeding the antibacterial activity (1 in Table 2) can be exhibited in a light place. For example, antibacterial photopic under reference tile was 0.1% carrying Cu TiO ₂ with a simple mixing method, but it is 1.5 from Table 2, the value of Cu itself exhibits antimicrobial Exceeds the sum of the force (0.3) and the tile antibacterial activity (1) of the photocatalyst alone. Therefore, it can be said that the Cu By carrying to TiO _2, it is possible to obtain a large effect than that simply combining Cu and TiO _2.

  Here, the example tiles of the sixth and seventh examples will be described based on the effects of the reference tile described above. In the sixth and seventh examples, a new evaluation item, hydrophilicity, was also evaluated. First, the relationship between hydrophilicity and surface contamination will be described prior to a hydrophilicity test or the like.

  In recent years, it has been found that soiling of the surface can be prevented by making the surface hydrophilic (Polymer, Vol. 44, May 1995, p. 307). The hydrophilicity can be converted into a contact angle with water. The smaller the contact angle, the better the wettability to water, and the less water that contacts the hydrophilic surface is less likely to remain on the contact surface. Then, if the water does not easily stop, the dirt components such as urban dust contained in the rainwater flow down from the hydrophilic surface together with the water, and the dirt prevention effect is enhanced.

  For this reason, it has been proposed to apply a graft polymer imparted with hydrophilicity to an outer wall of a building or the like so as to prevent contamination with a coating film of the graft polymer. However, hydrophilicity calculated by a contact angle with water has been proposed. Since the water resistance is about 30 ° to about 40 °, water tends to remain on the surface relatively easily, and the stain prevention effect and the antifogging effect are not always sufficient. In addition, since inorganic dust represented by clay mineral has a contact angle with water of about 20 to about 50 °, it exhibits an affinity with the graft polymer having the above-mentioned contact angle and easily adheres to the surface of the graft polymer. . In conjunction with this, it has been difficult for the coating film or film of the graft polymer to exhibit a high stain-preventing effect, particularly against inorganic dust.

  If the contact angle is made smaller than the contact angle of inorganic dust such as urban dust or clay mineral containing a large amount of lipophilic component, the dust does not exert an affinity on the base material surface, and The prevention effect can be further enhanced. In addition, as the contact angle approaches zero degree, the hydrophilicity increases, and the water diffuses in a film form on the surface of the base material and flows easily. Therefore, not only the above-mentioned urban dust but also the inorganic dust easily flows down with water from the base material surface. In this case, in order to enhance the stain prevention effect, it is more preferable that the contact angle is approximately 20 ° or less and a value close to zero.

  Examinations of the examples (sixth and seventh examples) of the present invention using a photocatalyst based on such a problem show that the hydroxyl radical / OH is generated by the catalytic reaction exhibited by the photocatalyst. As described above, the contact angle with water as an index of hydrophilicity was examined. The outline of the test is as follows.

Regarding the above-described example tiles of the sixth and seventh examples, two-component and three-component reference tiles, and comparative example tiles, baking-type tiles were prepared, and sample pieces of appropriate sizes were prepared. . Then, the contact angle of the water droplet dropped on the sample piece is measured by using a lamp (irradiation amount of the sample piece is about 1 mW / cm ² at a wavelength of 320 to 380 nm) for irradiating the ultraviolet ray after manufacturing the tile for about 24 hours. The measurement was performed after irradiation (under a light place) and after being left in a dark place for a time sufficient to completely stop the activity of the photocatalyst (under a dark place). Table 3 shows the measurement results.

  From the results shown in Table 3, as in the case of the two-component reference tile in which the effect of the metal composition was investigated, even in the four-component example tile (sixth embodiment), the metals such as Cu and Ag in the table were used. By blending the compound, the antibacterial power, the oil decomposition power, and the NO oxidation power were improved, and the decomposition power was increased. Moreover, an antibacterial activity exceeding the sum of the antibacterial activity exhibited by the metal itself in the table, such as Cu and Ag, and the antibacterial activity of the comparative tile or the three-component tile of the photocatalyst alone could be obtained. Moreover, the Mohs hardness of the surface layer is equivalent to the Mohs hardness of a mere tile having no surface layer, and has practicality as a tile.

Further, since the contact angles of the sixth and seventh examples were smaller than the comparative example tiles regardless of whether they were bright or dark, the SiO ₂ compounded with TiO _{2 in} the surface layer or Al ₂ O It was revealed that ₃ or both contributed to the improvement of the hydrophilicity of the tile surface through the adsorption of hydroxyl groups as described above. In addition, it was found that the addition of the metals listed in the table, such as Cu and Ag, did not cause an increase in the contact angle, that is, a decrease in the hydrophilicity. From these facts, a functional thin film having both decomposing power and hydrophilicity or a functional material having such a thin film can be used for Cu, Ag, Pd, Fe, Ni, Cr, Co, Pt, and Au which contribute to improving the decomposing power. , Rh, Ru and the like can be produced by supporting the metal on TiO ₂ and blending SiO ₂ or Al ₂ O ₃ or both of them with TiO ₂ which contributes to the improvement of hydrophilicity.

Further, since the tiles of the sixth and seventh embodiments contain Al ₂ O ₃ in addition to TiO ₂ in the surface layer, nitrogen oxides are used as described in the first and second embodiments. Of course, it has the effect of reducing harmful substances such as substances. In addition, although the NO oxidation power of the three-component example tile of the seventh embodiment containing no metal is equal to that of the comparative example tile, in the example tiles of the sixth and seventh examples, As described in the first and second embodiments, the intermediate product (NO ₂ ) is chemically changed to nitric acid to reduce NO ₂ . Therefore, according to the example tiles of the sixth and seventh examples, there is no contradiction that the total harmful substance containing NO and NO ₂ can be reduced.

It was examined whether or not the above-described effect of improving the decomposing power can be obtained also in the paint-type tiles of the sixth and seventh examples. The results are shown in Table 4. Therefore, even in the case of the paint type, according to the example tiles of the sixth and seventh examples, it is possible to improve the antibacterial power, the oil decomposition power, and the NO oxidation power to increase the decomposition power by blending the metals in the table. Proof of what was possible. Even in the paint-type tiles according to the sixth and seventh embodiments, similarly to the above-described baking-type tiles, the hydrophilicity of the tile surface is improved through hydroxyl group adsorption by SiO ₂ blended with TiO _2. Of course. Even with this paint type, the surface layer had a pencil hardness of 4H, so that it had utility as a tile.

Here, the mixing amounts of Cu, Ag, and the like described above will be described by taking an example tile of the sixth embodiment of the four-component system of photocatalyst / metal / alumina / silica as an example. In the example tile of the sixth example, the mixing ratio determination ratio (SIO ₂ / (TiO ₂ + Al ₂ O ₃ + SiO ₂ )) was fixed at 1/10, the weight of metal was c, and the weight of TiO ₂ was d. In the case where it was expressed, those prepared so as to have various values of c / d (metal mixing ratio) were prepared. Then, for each example tile, the relationship between the metal compounding ratio and the antibacterial activity was examined. The results are shown in FIGS. 11 and 12 for the baking type and the paint type. The antibacterial activity in this case is expressed as 1 as the antibacterial activity exhibited by the tile of Example 7 of the three-component system of photocatalyst / alumina / silica.

As can be seen from FIGS. 11 and 12, in both the baking type and the paint type, if any metal of Ag, Pd, Pt, Cu, and Cr has a metal compounding ratio of about 0.00001 or more, “Value” Antimicrobial activity of 1 or more was obtained. Further, in the case of Ag, Pd, and Pt, the antibacterial activity peaked at a metal compounding ratio of about 0.001, and peaked at approximately 0.01 in Cu and Cr, and thereafter, the antibacterial activity tended to decrease. Therefore, it was found that metals such as Ag, Pd, Pt, Cu, and Cr should be blended so that the metal blending ratio becomes a value of about 0.00001 to 0.05. In other words, if these metals are blended at a metal blending ratio of 0.00001 or more, it will not occur that the amount of the metals is too small and does not contribute to the improvement of the antibacterial activity at all. It is preferable because the metal does not become excessive with respect to (TiO ₂ ) and adversely affects the catalytic reaction of the photocatalyst. In addition, it was found that the example tile of the surface layer containing Ag, Pd, and Pt as the fourth component had higher antibacterial activity than the example tile of the surface layer containing Cu and Cr as the fourth component.

Here, regarding the surface properties of the surface layer formed on the tile surface using the photocatalyst sol described above, the four-component photocatalyst / metal / alumina / silica example of the sixth example tile and the photocatalyst / alumina / silica were used. An example tile of the seventh embodiment of the three-component system will be described. In this case, in the tiles of the sixth and seventh embodiments, the mixture ratio determination ratio (SIO ₂ / (TiO ₂ + Al ₂ O ₃ + SiO ₂ )) is constant at 1/10, and is one of the surface properties. Those having a surface layer having various thicknesses were prepared. Then, for each example tile, the relationship between the thickness of the surface layer and the contact angle, antibacterial power, oil decomposition power or NO oxidizing power was examined. The results are shown in FIGS.

  FIGS. 13 to 16 show the tile (printing type) according to the sixth embodiment of the four-component system. FIG. 13 is a graph showing the relationship between the surface layer thickness and the light contact angle, FIG. 14 is a graph showing the relationship between the surface layer thickness and the antibacterial activity, and FIG. FIG. 16 is a graph showing the relationship between the oil decomposition power and FIG. 16 is a graph showing the relationship between the surface layer thickness and the NO oxidation power. In this case, the antibacterial activity in the case where the tile having the surface layer containing photocatalyst / alumina / silica exerts 1 as the antibacterial activity. FIG. 17 is a graph showing the relationship between the surface layer thickness and the bright contact angle in the example tile (baked type) of the seventh example of the three-component system. Note that the four-component example tiles were assumed to contain Ag, Pd, Pt, Cu, and Cr in the surface layer, respectively, and were examined for those having a thickness of 0.005 to 3 μm.

In the three-component and four-component example tiles, since the surface layer contained SiO ₂ which contributes to the improvement of hydrophilicity through the adsorption of hydroxyl groups as described above, the surface layer contained SiO _2. (Improved hydrophilicity) is required. The improvement in hydrophilicity in this case can be confirmed by the presence or absence of a low contact angle as described above, and the contact angle is preferably 20 ° or less. Considering FIG. 13 and FIG. 17 from this viewpoint, in the case of the baking-type three-component and four-component example tiles, if the thickness of the surface layer is about 0.01 μm or more, a small contact angle of 20 ° or less is obtained. Is obtained, and an effect of preventing contamination through improvement in hydrophilicity is obtained, which is preferable. When the surface layer thickness is about 0.01 μm or more, a contact angle of 20 ° or less is obtained because the film (surface layer) is not too thin, even if the substrate has a large contact angle. This is considered to be because the contact angle of the surface layer itself formed on the base material (tile) can be exhibited.

  As shown in FIGS. 13 and 17, when the thickness of the surface layer is about 0.5 μm or more, the contact angle remains small. On the other hand, as the surface layer thickness increases, the weight per contact area of the surface layer increases, so if the surface layer thickness is too thick, the adhesion between the base material and the surface layer decreases, and the surface layer becomes May peel off. Therefore, the thickness of the surface layer is preferably about 3 μm or less from the viewpoint of maintaining the adhesion between the substrate and the surface layer. When the thickness of the surface layer is too large, ultraviolet light does not penetrate into the lower layer of the surface layer at all, and the function as a photocatalyst cannot be exhibited by the entire surface layer. Therefore, the thickness of the surface layer is preferably about 3 μm or less. It can also be said.

  Then, as shown in FIGS. 14 to 16, if the surface layer thickness is determined as described above (about 0.01 to about 3 μm), the antibacterial power, oil decomposition power, and NO oxidation power are surely improved. And is preferred.

  In addition to the above surface layer thickness, the following surface properties were examined.

When irradiated with ultraviolet rays, excited electrons are generated together with hydroxyl radicals by a photocatalyst. Therefore, by specifying the phenomenon that occurs in the surface layer due to the excited electrons and observing the state, the state of generation of the excited electrons, that is, the state of generation of hydroxyl radicals / OH can be determined. In the tiles of the sixth and seventh embodiments, since the surface layer contains SiO ₂ that adsorbs and retains hydroxyl groups, hydroxyl radicals / OH generated by the photocatalyst are retained in this SiO _2. . Therefore, it is considered that the larger the amount of excited electrons generated by the photocatalyst, the larger the amount of hydroxyl radicals / OH generated. As a result, the hydroxyl group density on the surface of SiO ₂ increases, the contact angle of water decreases, and the hydrophilicity increases. Can be Therefore, if ultraviolet irradiation is performed with the silver nitrate solution adhered to the surface layer, the charge of silver ions in the silver nitrate solution adhered to the surface layer changes due to the excitation electricity, a color reaction occurs, and before and after ultraviolet irradiation. And a color difference ΔE is observed. Since the color difference ΔE increases as the number of excited electrons involved in the reaction increases, it becomes an index indicating the degree of hydrophilicity. Therefore, the color difference ΔE was observed as follows.

In the measurement of the color difference ΔE, a general 1% silver nitrate solution was used as a reagent that exhibits a color reaction. Silver ions contained in this solution react with excited electrons (e ⁻ ) generated by the photocatalyst and are precipitated as silver. The reaction formula is as follows. By the precipitation of silver in this manner, the surface of the silver nitrate solution adheres to brown or black, and a color difference ΔE is clearly obtained.

Ag ^{+ +} e ^- → Ag ↓

Accordingly, a 1% silver nitrate solution is applied to the surface layer of the paint type tiles of the sixth embodiment (four components) and the seventh embodiment (three components), and in this state, ultraviolet irradiation is performed. The color difference ΔE was measured. Ultraviolet rays were irradiated on the surface layer so as to have an intensity of 1.2 mW / cm ² , and the irradiation time was 5 minutes. Then, the relationship between the measured color difference ΔE and the contact angle, antibacterial power, oil decomposition power or NO oxidizing power was examined. The results are shown in FIGS. When measuring the color difference ΔE, the residual aqueous solution on the tile surface was wiped off with a Kim towel, and the difference between the silver color amount on the tile surface in this state and the silver color amount before the test (before ultraviolet irradiation) was determined. . Then, the measurement of the silver coloring amount was performed according to JISZ8729 (1980) and JISZ8730 (1980) using a color difference meter ND300A of Nippon Shokuhin Kogyo Co., Ltd.

  FIGS. 18 to 21 relate to the tile (paint type) of the sixth embodiment of the four-component system. FIG. 18 is a graph showing the relationship between the color difference ΔE and the light contact angle, FIG. 19 is a graph showing the relationship between the color difference ΔE and the antibacterial activity, and FIG. FIG. 21 is a graph showing the relationship between the color difference ΔE and the NO oxidizing power. In this case, the antibacterial activity of the tile having the surface layer containing the photocatalyst / alumina / silica is expressed as 1 as the antibacterial activity. FIG. 22 is a graph showing the relationship between the color difference ΔE and the light contact angle in the three-component system tile (paint type) of the seventh embodiment. The four-component example tiles were assumed to contain Ag in the surface layer, and the tiles having a color difference ΔE of 0 to 60 were examined. In this case, a tile having a color difference ΔE of zero is simply a tile that does not generate excited electrons (a tile having only a surface layer composed of only paint).

18 and 22, when the color difference ΔE is 1 or more, a small contact angle of 20 ° or less can be obtained, and a stain prevention effect through improvement in hydrophilicity can be obtained, which is preferable. If the color difference ΔE is about 10 or more, the contact angle remains at a small value. Meanwhile, since the generation amount is Fuere if excited electrons of the photocatalyst becomes active, the color difference △ Although E increases, the photocatalyst to the total amount of components other than the photocatalyst (Al ₂ O _3, SiO ₂ or those with the above metal) It is considered that as the amount of the photocatalyst increases and the amount of the photocatalyst increases, the adhesion to the substrate decreases, and the peeling of the surface layer easily occurs. Therefore, when the color difference ΔE is 50 or less, the amount of the photocatalyst is not too large relative to the total amount of the components other than the photocatalyst, which is preferable from the viewpoint of suppressing the surface layer peeling.

  Then, as shown in FIGS. 19 to 21, if the color difference ΔE is in the range (about 1 to about 50) determined as described above, the antibacterial, oil-decomposing and NO-oxidizing powers can be reliably improved. Is preferred.

Next, the improvement of the superhydrophilic function by the addition of another component (metal oxide) such as SiO ₂ or Al ₂ O ₃ which contributes to the improvement of the hydrophilicity of TiO ₂ will be described. First, a description will be given of a printing type embodiment (eighth embodiment).

1) Procurement of photocatalyst and metal oxide sol;
Photocatalytic substance /
TiO ₂ sol: average particle diameter of about 0.02 μm (Ishihara STS-11) or average particle diameter of about 0.01 μm (Taki Chemical A-6L)
SnO ₂ sol: average particle size about 0.002 μm (Taki Chemical)

In the eighth embodiment, in addition to the harmless, chemically stable and inexpensive anatase TiO ₂ , SnO ₂ sol was used, but other photocatalytic substances such as crystalline TiO ₂ , SrTiO ₃ , ZnO, SiC, can be used GaP, CdS, CdSe, and _{MoS 3, V 2 O 5,} WO 3, SnO 2, Bi 2 O 5, Fe 2 O 3 as an alternative material.

Metal oxide /
SiO ₂ sol: average particle size of about 0.007 to about 0.009 μm (Nissan Chemical Snowtex S)
Al ₂ O ₃ sol: average particle diameter of about 0.01 μm × about 0.1 μm (Nissan Chemical Alumina Sol 200, amorphous) or average particle diameter of about 0.01 to about 0.02 μm (Nissan Chemical Alumina Sol 520, boehmite)
SiO ₂ + K ₂ O sol: (Nissan Chemical Snowtex K · SiO ₂ / K ₂ O molar ratio 3.3 to 4.0)
SiO ₂ + LiO ₂ sol: (Nissan Chemical Lithium Silicate 35, SiO ₂ / LiO ₂ molar ratio 3.5)
ZrO ₂ sol: average particle size about 0.07 μm (Nissan Chemical NZS-30B)

All the above sols were commercially available, but as a starting material, a hydrolysis inhibitor such as hydrochloric acid or ethylamine was added to the metal alkoxide, diluted with an alcohol such as ethanol or propanol, and then partially hydrolyzed. Or a solution in which hydrolysis has completely proceeded. For example, in the case of titanium alkoxide, tetraethoxytitanium, tetraisopropoxytitanium, tetra-n-propoxytitanium, tetrabutoxytitanium, tetramethoxytitanium and the like can be mentioned. In addition, other organic metal compounds (chelates and acetates), and inorganic metal compounds such as TiCl ₄ and Ti (SO ₄ ) ₂ can be used as starting materials.

2) Adjustment of hydrophilicity imparting material;
The sol of the photocatalytic substance and the metal oxide is diluted in advance so that the concentration of the solid content is 0.4% by weight, and the respective sols are mixed at a ratio shown in Table 5 described below and sufficiently stirred. did. The solid content weight ratio after mixing is the liquid weight ratio of each sol used.

3) Preparation of tiles exhibiting hydrophilicity;
A glazed tile (AB06E11 made by TOTO) was prepared as a base material, and a predetermined amount of the mixed sol was spray-coated on the surface of the tile so as to have a film thickness of about 0.5 μm. This was fired at a maximum temperature of about 700 ° C. to 900 ° C. for 60 minutes in an RHK (roller hearth kiln) to produce an eighth example tile. In the tile of the eighth embodiment, spray coating was performed. However, as a coating method, flow coating, spin coating, dip coating, roll coating, brush coating, and other coating methods can be used. In the eighth embodiment, a tile is used as a base material. In addition, a metal, ceramics, ceramics, glass, plastics, wood, stone, cement, concrete, a combination thereof, or a laminate thereof is used. Is possible. In the eighth embodiment, since the sol to be used is the one described in the above-mentioned procurement of the sol, a photocatalyst, an amphoteric or basic or acidic metal oxide represented by alumina, and a second It is a two-component or three-component system in which other compounds (oxides) described in the fourth embodiment are combined. However, as shown in Table 5 below, a plurality of compounds (metal oxides) may be used as one component in some cases.

4) Evaluation;
The hydrophilicity was evaluated by the static contact angle of water. First, the test tiles (the eighth example tile and the comparative example tile) were irradiated with a BLB fluorescent lamp (black light lamp manufactured by Sankyo Electric Co., Ltd., FL20BLB) having an ultraviolet intensity of about 1.5 mW / cm ² for 24 hours, and then contacted with water. The corner was measured. After that, it was stored for 72 hours in a light-shielded state (stored in a dark place), and the contact angle with water was measured again. The results are shown in the above table. The film strength was evaluated using Mohs hardness. Table 5 shows the results.

In Table 5 No. 2-No. From FIG. 14, it can be seen that in the hydrophilicity by ultraviolet irradiation, the contact angle with water is 10 degrees or less in the range of TiO ₂ / (TiO ₂ + SiO ₂ + Al ₂ O ₃ ) ≧ 0.4, and sufficient hydrophilicity is achieved. . In addition, after storage in a dark place, if the amount of TiO ₂ is the same, it can be seen that the higher the amount of Al ₂ O ₃ added, the higher the hydrophilicity is maintained. It is also found that the hardness increases by adding SiO ₂ and by increasing the amount of SiO ₂ added. From these facts, by adding SiO ₂ and Al ₂ O ₃ to the photocatalyst (TiO ₂ ), the hydrophilicity under light irradiation is improved as compared with the photocatalyst alone, and the hydrophilicity maintaining power in a dark place is also improved. It was also confirmed that the film hardness and the density were improved. Among these effects, when the sol shown in this example is used, it is considered that the improvement in hydrophilicity is mainly brought about by the addition of Al ₂ O ₃ , and the improvement in film hardness is brought about by the addition of SiO _2. Can be Note that, in Table 4, No. No. 1 is the result of the above glazed tile, No. 2 is a result about the tile only of a photocatalyst (comparative example tile).

No. 5 in Table 5. 15-No. No. 18 was obtained by performing the same test, except that a part of SiO ₂ was replaced with K ₂ O. Similarly, the results show that the addition of SiO ₂ , K ₂ O, and Al ₂ O ₃ achieves an improvement in the hydrophilicity function and an increase in the film hardness in a firing temperature range of about 700 to about 800 degrees. No. Reference numeral 19 denotes a test in which a part of SiO ₂ was replaced with LiO ₂ , which also achieved improvement in hydrophilicity and film hardness.

  No. 17 and No. No. 18 examined the raw material shape of the alumina sol, and it was confirmed that the use of alumina sol having an amorphous and feather-like structure further improved the hydrophilicity function. It is considered that a tissue having more hydrophilic groups than a particle-like structure is particularly effective in improving the hydrophilic function.

No. 20 shows the result when ZrO ₂ is added to TiO ₂ . This indicates that ZrO _{2 is} also effective in improving hydrophilicity.

No. 21 and no. 22 shows the result of a test using SnO ₂ as a photocatalyst. Even with SnO ₂ alone, a hydrophilizing effect was observed, and improvement of hydrophilicity was confirmed by adding Al ₂ O ₃ . At this time, there was no decrease in film hardness, and it was confirmed that SnO ₂ itself also had a function as a binder.

No. 3-No. From 14, it can be seen that as the amount of Al ₂ O ₃ added increases, the contact angle decreases and the hydrophilicity improves. Therefore, the degree of hydrophilicity can be changed by adjusting the amount of Al ₂ O ₃ added. From the results in Table 2, considering that the decomposition power of TiO ₂ can be changed by adjusting the amount of the metal such as Cu, Ag, Pd, and Fe supported on the photocatalyst, the addition of Al ₂ O ₃ is considered. By adjusting the amount and the amount of the metal carried, the balance between hydrophilicity performance and decomposition power (decomposition performance) can be adjusted. As a result, when a strong decomposing power is required, it can be said that the required strong decomposing power can be exerted while maintaining the hydrophilicity at the same level as that which can be exhibited by the photocatalyst.

  Combining hydrophilicity and decomposition performance in this way has the following advantages. By a two-step process of removing stains based on hydrophilicity and removing stains based on decomposition performance, it is possible to significantly improve the efficiency of removing attached stains and improve the removal speed. In this case, depending on the type of the stain, the adhesion strength of the slight stain left after the removal of the stain based on the hydrophilicity may be high. Even small stains with high adhesion strength can be removed. Further, since the dirt is removed as described above, the light to the photocatalyst is not blocked, and the amount of light applied to the photocatalyst can be increased. Therefore, the stain removal based on the hydrophilicity and the stain removal based on the decomposition performance can be maintained extremely efficiently.

In summary, it has been found that the addition of SiO ₂ , Al ₂ O ₃ , and ZrO ₂ to the photocatalyst improves the contact angle under light irradiation and the ability to maintain hydrophilicity after holding in a dark place. This effect is believed to be caused by the hydrophilic nature of these substances, wet heat can be mentioned as an index indicating the hydrophilicity of the material, heat of wetting preferred TiO ₂ as a photocatalyst is anatase type three hundred and twenty to five hundred and twelve × 10 ^-3 Jm ^-2, is 293~645 × 10 ^-3 Jm ^-2 rutile. For this reason, the compound is preferably a compound having a heat of wetting of 500 × 10 ⁻³ Jm ⁻² or more, and includes GeO ₂ , ThO ₂ , and ZnO in addition to the above three types of metal oxides. It has been found that these metal oxides have not only a crystalline structure but also an amorphous one, and the particle size range is 0.1 μm or less. It was also found that the film hardness was improved by adding SiO ₂ . By making K ₂ O or LiO ₂ a part of the added amount of SiO _2, the film hardness could be improved even at a low firing temperature. In particular, as the range in which the above effects can be expected, the conditions of TiO ₂ / (total solid content of hydrophilicity-imparting modifier) ≧ 0.5 and SiO ₂ / (total solid content of hydrophilicity-imparting modifier) ≦ 0.5 are set. This is the case.

Next, the addition of another component (metal oxide) such as SiO ₂ or Al ₂ O _3, which contributes to the improvement of the hydrophilicity of TiO ₂ , improves the superhydrophilic function and improves other functions (film hardness). The presence / absence will be described for a paint type embodiment (ninth embodiment).

1) Procurement of photocatalyst and metal oxide sol;
Photocatalytic substance /
TiO ₂ sol: (Nissan Chemical TA-15)
In the ninth embodiment, SnO ₂ sol was used in addition to harmless, chemically stable and inexpensive anatase TiO ₂ , but other photocatalytic substances such as crystalline TiO ₂ , SrTiO ₃ , ZnO, SiC, may be used GaP, CdS, CdSe, and _{MoS 3, V 2 O 5,} WO 3, SnO 2, Bi 2 O 5, Fe 2 O 3 as an alternative material.

Metal oxide /
SiO ₂ sol: (Glaska T2202 made by Japan Synthetic Rubber)
Al ₂ O ₃ sol: average particle size of about 0.01 to about 0.02 μm (Nissan Chemical Alumina Sol 520 Boehmite)

Although a commercial product was used for SiO _2, it is possible to use a film-forming element composed of silicone (organopolysiloxane) or a precursor of silicone. Commercially available TiO ₂ and Al ₂ O ₃ sols were also used, but as in the above-described eighth embodiment, a hydrolysis inhibitor such as hydrochloric acid or ethylamine was added to a metal alkoxide as a starting material. It is also possible to prepare these sols through the above-mentioned steps.

2) Adjustment of hydrophilicity imparting material;
After mixing the above raw materials at a fixed ratio, the mixture was diluted three times with ethanol to obtain a coating liquid. The composition ratio of the prepared coating liquid is shown in Table 6 below.

3) Preparation of tiles exhibiting hydrophilicity;
As in the eighth embodiment, a glazed tile was prepared as a base material, coated by a spin coating method, and heated at 150 ° C. for 30 minutes to cure the coating film. In the ninth embodiment, spin coating is performed, but flow coating, spray coating, dip coating, roll coating, brush coating, and other coating methods can be used as the coating method. Also in this ninth embodiment, in addition to tiles, metal, ceramics, ceramics, glass, plastics, wood, stone, cement, concrete or a combination thereof, or a laminate thereof can be used as a base material. is there. In the ninth embodiment, the photocatalyst was used because the sol to be used was the one described in the procurement of the above sol and the components shown in Table 5 were TiO ₂ , SiO ₂ or Al ₂ O _3. A two-component or three-component system obtained by combining an amphoteric, basic or acidic metal oxide represented by alumina, and other compounds (oxides) such as silica described in the fourth embodiment. .

4) Evaluation;
Regarding film hardness, a pencil hardness test (JISK5400 paint general test) was performed on test tiles (ninth example tile and comparative example tile). Table 7 shows the results. As for the hydrophilicity, the static contact angle of water was measured for the test tiles (the ninth example tile and the comparative example tile) in the same manner as in the eighth example. Table 8 shows the results. In this case, the ultraviolet intensity was about 1.2 mW / cm ² , and the irradiation time was 12 hours.

From Table 7, it was found that those having a ratio of SiO ₂ / TiO ₂ of 0.1 or less were insufficient in binder (SiO ₂ sol), resulting in a decrease in film strength. Also, from Table 8, it can be seen that, when SiO ₂ / TiO ₂ is in the range of 1/5 to ₂ and Al ₂ O ₃ / TiO ₂ is in the range of 1/12 to 2, the effect of improving the hydrophilic speed by adding alumina is exhibited. There was found. This effect, as mentioned in the eighth embodiment, but are considered to be caused by the hydrophilicity of Al ₂ O _3, wet heat can be mentioned as an index indicating the hydrophilicity of the material, preferred TiO ₂ as a photocatalyst heat of wetting in anatase 320~512 × 10 ^-3 Jm ^-2, is 293~645 × 10 ^-3 Jm ^-2 rutile. For this reason, it is preferable that the compound has a heat of wetting of 500 × 10 ⁻³ Jm ⁻² or more, and even in this example, ZrO ₂ , GeO ₂ , ThO ₂ , and ZnO are mentioned. These metal oxides may be not only those having a crystal structure but also amorphous ones.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described examples and embodiments, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention. is there.

  For example, in producing a tile capable of replenishing the antibacterial function by fixing particles such as copper and oxides thereof, a Ti / Al sol is applied to the tile surface and baked beforehand to form a surface layer composed of a photocatalyst compound. May be manufactured, and the third sol may be applied again to the surface layer of the tile and fired.

When oxidizing nitrogen oxides with titanium dioxide as a photocatalyst, the state of progress of the catalytic reaction when alumina is blended with this titanium dioxide and the state of bonding of the intermediate product of the catalytic reaction by alumina are schematically shown. FIG. FIG. 4 is an explanatory view schematically showing a state of bonding of an intermediate product of a catalytic reaction by alumina when alumina is blended with titanium dioxide when oxidizing sulfur oxides with titanium dioxide as a photocatalyst. FIG. 4 is an explanatory diagram schematically showing a state of bonding of an intermediate product of a catalytic reaction by alumina when alumina is blended with titanium dioxide when carbon monoxide is oxidized by titanium dioxide as a photocatalyst. The schematic block diagram of the test apparatus used for the measurement of the nitrogen oxide reduction effect by the example tile in the 1st Example of this invention. 7 is a graph showing a result of a nitrogen oxide reduction effect of the example tile in the first example. Graph for explaining the effect of reducing ammonia by the example tile in the first example. 7 is a graph for explaining the effect of reducing sulfur dioxide by the example tile in the first example. 7 is a graph showing a result of a nitrogen oxide reduction effect of the example tile in the first example. 7 is a graph showing a result of a nitrogen oxide reduction effect of the example tile in the first example. 9 is a graph showing the results of the antibacterial effect of the example tile according to the third example of the present invention. Relationship between c / d (metal compounding ratio) and antimicrobial activity when the weight of the metal carried on the tile (baked type) of the sixth embodiment of the four-component system is represented by c and the weight of TiO ₂ is represented by d A graph showing. 4 relationship component sixth the weight of the example tiles metal carrying in (paint type) of Example c of, c / d (metal formulation ratio) when the weight of TiO ₂ was expressed as d and the antimicrobial activity A graph showing. 13 is a graph showing the relationship between the surface layer thickness and the light contact angle in a four-component tile (baked type) of Example 6 of Example 6; 13 is a graph showing the relationship between the surface layer thickness and the antibacterial activity of the four-component tile (baked type) of the sixth example of the sixth example. 13 is a graph showing the relationship between the surface layer film thickness and the oil decomposition power in the example tile (baked type) of the sixth example of the four-component system. 13 is a graph showing the relationship between the thickness of the surface layer and the NO oxidizing power in the example tile (baked type) of the sixth example of the four-component system. 13 is a graph showing the relationship between the surface layer thickness and the bright contact angle in the example tile (baked type) of the seventh example of the three-component system. 16 is a graph showing the relationship between the color difference ΔE and the light contact angle in the example tile (paint type) of the sixth example of the four-component system. 14 is a graph showing the relationship between the color difference ΔE and the antibacterial activity of the four-component tile (paint type) of the sixth embodiment. 13 is a graph showing the relationship between the color difference ΔE and the oil decomposition power in the example tile (paint type) of the sixth example of the four-component system. 13 is a graph showing the relationship between the color difference ΔE and the NO oxidizing power in the example tile (paint type) of the sixth example of the four-component system. 13 is a graph showing the relationship between the color difference ΔE and the light contact angle in a three-component tile (paint type) of the seventh embodiment of the seventh embodiment.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 10 Glass cell 12 Cylinder 14 Air pump 15 Humidity adjuster 16 Flow control valve 18 NOx sensor 20 Lamp

Claims (38)

A photocatalyst compound comprising a photocatalyst functioning as a catalyst when irradiated with light and another compound,
The other compound is
When the reactant subjected to a catalytic reaction involving the photocatalyst undergoes the catalytic reaction and undergoes a chemical change and changes to a final product defined by the structure of the reactant and the catalytic reaction, the photocatalyst and A photocatalyst compound, which is a compound that functions to enhance the degree of transition from the reactant to the final product in the presence of A photocatalyst formulation according to claim 1,
The other compound is
A photocatalyst formulation, wherein the reactant or a compound that chemically reacts with an intermediate product generated before the reactant undergoes the catalytic reaction and transforms into the final product. A photocatalyst formulation according to claim 1 or claim 2,
The photocatalyst is a photocatalyst that generates excited electrons and holes by the energy of irradiated light and generates active oxygen species by the excited electrons and holes in the presence of oxygen and moisture on the catalyst surface. object. A photocatalyst formulation according to claim 3, wherein
The other compound is an amphoteric metal oxide, a basic metal oxide or an acidic metal oxide chemically bonded to the reactant or the intermediate product subjected to the catalytic reaction based on the active oxygen species. A photocatalyst formulation that is at least one metal oxide. A photocatalyst formulation according to claim 4, wherein
The amphoteric metal oxide as the other compound is at least one metal oxide selected from Al ₂ O ₃ , ZnO, SnO, and SnO ₂ , and the basic metal oxide is SrO, BaO, MgO , CaO, a Rb ₂ O, Na ₂ O, at least one metal oxide selected from K ₂ O, the acidic metal oxide is P ₂ O _5, photocatalyst formulation. A photocatalyst formulation according to any one of claims 2 to 5, wherein
The photocatalyst composition, wherein the other compound is formulated such that a / (a + b) is about 0.0001 to 0.8 when the weight is represented by a and the weight of the photocatalyst is represented by b. The photocatalyst composition according to any one of claims 2 to 6, wherein
A photocatalyst composition, wherein the photocatalyst and the other compound are adjusted and blended in a particle size range of about 0.005 to 0.5 μm. A photocatalyst formulation according to any one of claims 1 to 7, wherein
In addition to the photocatalyst and the other compound, a compound having a property of chemically adsorbing a hydroxyl group is provided as a third component,
A photocatalyst formulation, wherein the hydroxyl group is chemically adsorbed and retained on the surface of the photocatalyst and the compound as the third component, and the retained hydroxyl group exhibits hydrophilicity. A photocatalyst formulation according to claim 8, wherein
The compound as the third component is a compound having a heat of wetting equal to or higher than that of the photocatalyst. A photocatalyst formulation according to claim 9, wherein
The photocatalyst composition, wherein the compound as the third component is at least one metal oxide selected from SiO ₂ , Al ₂ O ₃ , ZrO ₂ , GeO ₂ , ThO ₂ , and ZnO. The photocatalyst formulation according to any one of claims 8 to 10, wherein
In addition to the photocatalyst, the other compound and the compound as the third component, a metal exhibiting antibacterial properties is compounded as a fourth component, and
A photocatalyst formulation, wherein the metal as the fourth component is supported on the photocatalyst. A photocatalyst formulation according to claim 11, wherein
The photocatalyst formulation, wherein the metal as the fourth component is a metal having a reduction potential equal to or higher than the potential of free electrons emitted by the photocatalyst. A photocatalyst formulation according to claim 12, wherein
The metal as the fourth component is at least one metal selected from Ag, Cu, Pd, Fe, Ni, Cr, Co, Pt, Au, Li, Ca, Mg, Al, Zn, Rh, and Ru. There is a photocatalyst formulation. A photocatalyst formulation according to claim 13,
When the weight of the metal selected as the fourth component is represented by c and the weight of the photocatalyst is represented by d, the photocatalyst composition is formulated such that c / d is about 0.00001 to 0.05. . A photocatalyst-containing material having a photocatalyst that functions as a catalyst when irradiated with light,
A photocatalyst-containing material, wherein the photocatalyst composition according to any one of claims 1 to 7 is mixed and dispersed in a paint or glaze. A photocatalyst-containing material having a photocatalyst that functions as a catalyst when irradiated with light,
A photocatalyst-containing material, wherein the photocatalyst composition according to any one of claims 8 to 14 is mixed and dispersed in a paint or glaze. A material having a base layer and a surface layer formed on the surface thereof, and exhibiting a photocatalytic function when irradiated with light,
As the surface layer,
A photocatalyst exhibiting material having a surface layer comprising the photocatalyst composition according to claim 1 or a surface layer comprising the photocatalyst-containing material according to claim 15. A material having a base layer and a surface layer formed on the surface thereof, and exhibiting a photocatalytic function when irradiated with light,
As the surface layer,
A photocatalytic function exhibiting material having a surface layer comprising the photocatalyst composition according to any one of claims 8 to 14, or a surface layer comprising the photocatalyst-containing material according to claim 16. It is a photocatalytic function exhibiting material according to claim 18,
The surface layer has a surface property satisfying one of the following conditions (1) and (2).
(1) Surface layer thickness: about 0.01 to about 3.0 μm
(2) In the state where a 1% silver nitrate solution is adhered to the surface layer, the ultraviolet ray intensity on the surface layer is 1.2 mW / cm ² , and the ultraviolet ray is irradiated on the surface layer for 5 minutes before and after ultraviolet irradiation. Color difference of surface layer after irradiation ΔE: 1 to 50 A material having a base layer and a surface layer formed on the surface thereof, and exhibiting a photocatalytic function when irradiated with light,
The surface layer,
15. A photocatalytic function-executing material, wherein the photocatalyst composition according to any one of claims 1 to 14 is a surface layer formed on the surface of the base material layer with a binder interposed therebetween. It is a photocatalytic function exhibiting material according to claim 20,
The photocatalytic function-exhibiting material, wherein the binder is a binder that bonds or polymerizes or melts the photocatalyst composition to the surface of the base material layer at a temperature equal to or lower than the transformation temperature of the base material of the base material layer. The photocatalytic function-exhibiting material according to claim 20 or claim 21,
The photocatalytic function-exhibiting material, wherein the binder is either glaze or paint. A material having a base layer and a surface layer formed on the surface thereof, and exhibiting a photocatalytic function when irradiated with light,
The surface layer, in addition to TiO ₂ as a photocatalyst, Al ₂ O _3, and SiO _2, which contains a metal which exhibits antimicrobial, photocatalytic exhibited material. The photocatalytic function-exhibiting material according to any one of claims 17 to 23,
The base material layer is formed of any base material of ceramic, resin, metal, glass, pottery, wood, silica plate, concrete plate, cement plate, cement extrusion shaping plate, gypsum board or autoclave-cured lightweight concrete plate. , Photocatalyst function material. The photocatalytic function-exhibiting material according to any one of claims 17 to 24,
The photocatalytic function exhibiting material, wherein the surface layer is formed by heat treatment. It is a photocatalytic function exhibiting material according to any one of claims 17 to 25,
A photocatalytic material, wherein a metal or a metal compound exhibiting antibacterial properties is fixed to the surface of the surface layer. A method for producing a material having a substrate layer and a surface layer formed on the surface thereof, and exhibiting a photocatalytic function when irradiated with light,
Preparing a photocatalyst composition according to any one of claims 1 to 14 or a photocatalyst composition dispersion sol in which the photocatalyst composition is dispersed;
An arrangement step of arranging the photocatalyst composition or the photocatalyst composition dispersion sol in a layer on the surface of the base material layer,
Forming the surface layer. The manufacturing method according to claim 27,
The disposing step includes:
When disposing the photocatalyst composition or the photocatalyst composition dispersion sol in a layer on the surface of the substrate layer, the photocatalyst composition or the photocatalyst composition dispersion sol is placed in a layer on the surface of the substrate layer, A method for producing a photocatalytic function exhibiting material, comprising a step of applying or printing. A method for producing a material having a substrate layer and a surface layer formed on the surface thereof, and exhibiting a photocatalytic function when irradiated with light,
Preparing a photocatalyst composition according to any one of claims 1 to 14 or a photocatalyst composition dispersion sol in which the photocatalyst composition is dispersed;
A step of disposing a binder in a layer on the surface of the base material layer to form a binder layer,
An arrangement step of disposing the photocatalyst composition or the photocatalyst composition dispersion sol in a layer on the surface of the binder layer,
Heat-treating the surface layer according to the properties of the binder to form the surface layer. The method according to claim 29, wherein
The binder is a glaze, and in forming the surface layer, the temperature is higher than the softening temperature of the glaze in a range of 30 ° C. or more and 300 ° C. or less, and lower than the deterioration temperature of the base material of the base material layer. A method for producing a photocatalytic function-exhibiting material that is heat-treated under the following conditions. The method according to claim 29, wherein
The method for producing a photocatalytic function-executing material, wherein the binder is a paint, and a heat treatment is performed in a temperature environment equal to or lower than a deterioration temperature of the base material of the base material layer when forming the surface layer. 31. The method according to claim 30, wherein
A method for producing a photocatalytic function-executing material, wherein heat treatment is performed in a temperature environment of about 150 to about 1300 ° C. to form the surface layer. The manufacturing method according to any one of claims 27 to 32,
Following the step of forming the surface layer, a step of applying a solution in which a metal or metal compound exhibiting antibacterial properties is dispersed on the surface of the formed surface layer, and applying the metal or metal oxide to the surface layer. A method for producing a photocatalytic function-exhibiting material, comprising a step of fixing the material to a surface of a photocatalyst. The manufacturing method according to any one of claims 27 to 32,
The disposing step includes:
After arranging the photocatalyst composition or the photocatalyst composition dispersion sol in a layer, a step of applying a solution in which a metal or a metal compound exhibiting antibacterial properties is dispersed,
The step of forming the surface layer,
A method for producing a photocatalytic function exhibiting material, comprising a step of fixing the metal or metal oxide to the surface of the surface layer simultaneously with the formation of the surface layer. The manufacturing method according to any one of claims 27 to 32,
Following the step of forming the surface layer, a step of applying a metal salt aqueous solution containing a metal ion exhibiting antibacterial properties to the surface of the formed surface layer, and irradiating the surface layer with ultraviolet light to form the metal A method for producing a photocatalytic function-executing material, comprising a step of supporting and fixing the metal on a photocatalyst in the surface layer using photoreduction of ions to a photocatalyst. The method for producing a photocatalyst compound according to claim 11, wherein a photocatalyst that functions as a catalyst when irradiated with light, the other compound, the compound as the third component, and a metal as the fourth component are mixed. And
Preparing a photocatalyst-dispersed sol in which at least the photocatalyst is dispersed among the photocatalyst, the other compound, and the compound as the third component;
Mixing a metal salt aqueous solution containing an ion of a metal exhibiting antibacterial properties with the photocatalyst-dispersed sol, and supporting the metal as a fourth component on the photocatalyst. . The method for producing a photocatalyst compound according to claim 11, wherein a photocatalyst that functions as a catalyst when irradiated with light, the other compound, the compound as the third component, and a metal as the fourth component are mixed. And
Preparing a photocatalyst-dispersed sol in which at least the photocatalyst is dispersed among the photocatalyst, the other compound, and the compound as the third component;
After mixing an aqueous solution of a metal salt containing ions of a metal exhibiting antibacterial properties with the photocatalyst-dispersed sol, co-precipitating the salt of the metal and the photocatalyst, and loading the metal as a fourth component on the photocatalyst; A method for producing a photocatalyst composition, comprising: The method for producing a photocatalyst compound according to claim 11, wherein a photocatalyst that functions as a catalyst when irradiated with light, the other compound, the compound as the third component, and a metal as the fourth component are mixed. And
Preparing a photocatalyst-dispersed sol in which at least the photocatalyst is dispersed among the photocatalyst, the other compound, and the compound as the third component;
A metal salt aqueous solution containing a metal ion exhibiting antibacterial properties is mixed with the photocatalyst-dispersed sol, and then irradiated with ultraviolet light, and the metal is loaded on the photocatalyst as a fourth component by utilizing photoreduction of the metal ions. And a process for producing a photocatalyst composition.

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