JP2013184100A - Visible light-responsive photocatalyst composition and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a visible light-responsive photocatalyst composition that contains a photocatalyst, on which a promoter is not deposited, and the promoter and that has high visible light responsibility and to provide a method for producing the visible light-responsive photocatalyst composition.SOLUTION: The visible light-responsive photocatalyst composition comprises a mixture including a metal oxide (A) having photocatalytic activity and a promoter-deposited metal oxide (B) obtained by depositing the promoter (b) on a metal oxide (b) having no photocatalytic activity. The method for producing the visible light-responsive photocatalyst composition comprises: a step of adding the metal oxide (b) to a solution of the promoter (b) to contact the promoter (b) with the metal oxide (b) and produce the promoter-deposited metal oxide (B); and a mixing step of mixing the promoter-deposited metal oxide (B) with the metal oxide (A).

Description

  The present invention relates to a visible light responsive photocatalyst composition that exhibits photocatalytic activity under irradiation with visible light, and a method for producing the same. The present invention also relates to a coating agent, a photocatalyst film, an article with a photocatalyst film containing the composition, and a method for producing the article. In this specification, “photocatalytic activity” means not only ultraviolet light, visible light, and infrared light, but also a property that exhibits a catalytic function by light in at least one wavelength region, and has photocatalytic activity. The substance is called “photocatalyst”.

A photocatalyst with low or no photocatalytic activity under visible light irradiation (sometimes referred to as “visible light responsiveness”) is used as a photocatalyst with high photocatalytic activity under visible light irradiation (sometimes referred to as “visible light responsive photocatalyst”). As a technique for conversion, a technique has been reported in which a promoter such as platinum, copper, or iron is supported on the surface of a metal oxide such as titanium oxide or tungsten oxide having low visible light response.
For example, Patent Document 1 describes a photocatalytic material in which a copper compound or a chromium compound is supported on titanium oxide or zirconium oxide. In this Patent Document 1, interfacial charge transfer occurs to the promoter component supported on the surface of the metal oxide semiconductor by photoexcitation, and the valence band of the metal oxide semiconductor moves to the promoter component or the promoter component. It is described that electrons move from the catalyst component to the conduction band of the metal oxide semiconductor. Patent Documents 2 and 3 describe photocatalytic materials in which a copper compound is supported on tungsten oxide. Patent Documents 4 and 5 describe photocatalytic materials in which platinum is supported on tungsten oxide. Patent Document 6 describes that VOC decomposition performance is improved by combining a tungsten oxide photocatalyst particle carrying platinum with a porous material such as silica carrying platinum.

Further, instead of the method of supporting the promoter on the surface of the photocatalyst as described above, a method of simply mixing the photocatalyst and the promoter is also reported.
For example, Patent Document 7 describes a visible light responsive photocatalyst powder obtained by mixing a CuO powder with a tungsten oxide powder.

Although the photocatalyst carrying a cocatalyst as in Patent Documents 1 to 6 is excellent in visible light responsiveness, there is a problem that it is not easy to produce. That is, if the amount of the cocatalyst supported is small, the visible light responsiveness is inferior. If the amount of the cocatalyst is large, the photocatalyst activity is reduced due to inhibition of light irradiation to the photocatalyst due to the surface of the photocatalyst being too covered with the cocatalyst. There is a problem that there is a restriction on the amount of loading because of fear. In addition, since tungsten oxide is dissolved in an alkaline solution, when tungsten oxide is used as a photocatalyst, there is a problem that the impregnation support method from an alkaline solution cannot be used.
On the other hand, a visible light responsive photocatalyst obtained by simply mixing a cocatalyst and a photocatalyst as in Patent Document 7 is easy to manufacture, but has a problem of low visible light responsiveness.
Thus, in order to sufficiently improve the visible light responsiveness of the photocatalyst using the cocatalyst, it is common technical knowledge that the cocatalyst needs to be supported on the photocatalyst.

WO2008 / 149889 JP 2009-226299 A JP 2011-101876 A Japanese Patent No. 4772818 JP 2011-20009 JP 2011-72961 A JP 2008-149312 A

  Under such circumstances, an object of the present invention is to provide a visible light responsive photocatalyst composition that is easy to manufacture and has high visible light responsiveness, and a method for manufacturing the same. It is another object of the present invention to provide a coating agent, a photocatalyst film, an article with a photocatalyst film, and a method for producing the article containing the composition.

As a result of intensive studies to achieve the above-mentioned object, the present inventors supported a cocatalyst on a metal oxide other than the photocatalyst and mixed it with the photocatalyst to support the cocatalyst on the photocatalyst. It has been found that the visible light responsiveness can be sufficiently improved without doing so.
The present invention has been completed based on such findings.

That is, the present invention provides the following [1] to [13].
[1] A mixture containing a metal oxide (A) having photocatalytic activity and a promoter-supported metal oxide (B) in which a promoter (b ₂ ) is supported on a metal oxide (b ₁ ) having no photocatalytic activity A visible light responsive photocatalyst composition comprising:
[2] The visible light responsive photocatalytic composition according to [1], wherein the metal oxide (A) having photocatalytic activity is a metal compound having low or no visible light responsiveness.
[3] The visible light responsive photocatalytic composition according to [1], wherein the metal oxide (A) is at least one of titanium oxide and tungsten oxide.
[4] The metal oxide (b ₁ ) is at least one selected from silica, alumina, magnesia, cerium oxide, silica alumina, silica magnesia, zeolite, and titanosilicate [1] to [3 ] The visible light responsive photocatalyst composition in any one of.
[5] The cocatalyst (b ₂ ) is at least one selected from platinum, palladium, ruthenium, gold, copper, iron, chromium, nickel, cerium, tungsten, and tungsten carbide. 4] The visible light responsive photocatalyst composition described in any one of [4].
[6] The metal oxide (A) is tungsten oxide, the metal oxide (b ₁ ) is at least one of silica and alumina, and the promoter (b ₂ ) is copper. [5] The visible light responsive photocatalyst composition according to any one of [5].
[7] The cocatalyst (b ₂₎ a solution of the metal oxides in the (b ₁₎ was added, the cocatalyst (b ₂₎ and the metal oxide (b ₁₎ and a cocatalyst-supported metal oxide contacting the The visible light response according to any one of [1] to [6], comprising a production step of (B) and a mixing step of mixing the promoter-supported metal oxide (B) and the metal oxide (A). Type photocatalyst composition manufacturing method.
[8] A coating agent comprising the visible light responsive photocatalyst composition according to any one of [1] to [6] and a binder.
[9] A photocatalytic film containing the visible light responsive photocatalytic composition according to any one of [1] to [6].
[10] An article with a photocatalyst film comprising a base material and the photocatalyst film according to [9] provided on a surface of the base material.
[11] The article with a photocatalyst film according to [10], wherein the photocatalyst film is a fired body of the visible light responsive photocatalyst composition according to any one of [1] to [6].
[12] The article with a photocatalyst film according to [10], wherein the photocatalyst film is a dried product of the coating agent according to [8].
[13] The article with a photocatalyst film according to [11], comprising a step of attaching the visible light responsive photocatalyst composition according to any one of [1] to [6] to a surface of a base material and firing the composition. Production method.

  According to the present invention, using a photocatalyst not supporting a cocatalyst and a metal oxide other than the photocatalyst supporting the cocatalyst, the visible light responsive photocatalyst composition having a small number of manufacturing steps and excellent visible light responsiveness Things can be provided.

It is a schematic diagram of the evaluation container of visible light responsiveness. It is an emission spectrum of blue LED irradiated in the evaluation container of FIG. It is a graph which shows the evaluation result of visible light responsiveness in Examples 1-4 and the comparative example 1. FIG. It is a graph which shows the evaluation result of visible light responsiveness in Examples 5-6 and Reference Example 3.

[Visible light responsive photocatalyst composition]
The visible light responsive photocatalyst composition of the present invention comprises a metal oxide (A) having photocatalytic activity and a promoter-supporting metal in which a promoter (b ₂ ) is supported on a metal oxide (b ₁ ) having no photocatalytic activity. It consists of a mixture containing an oxide (B).

<Metal oxide (A) having photocatalytic activity>
The metal oxide (A) having photocatalytic activity is not particularly limited as long as it is a metal oxide known as a semiconductor photocatalyst material. Here, the “metal oxide known as a semiconductor photocatalytic material” refers to a metal oxide that can absorb light and excite electrons from the valence band to the conduction band. Examples of the metal oxide (A) include titanium oxide (TiO ₂ ), tungsten oxide (WO ₃ ), strontium titanate (SrTiO ₃ ), niobium oxide (Nb ₂ O ₅ ), tantalum oxide (Ta ₂ O ₅ ), Examples thereof include zirconium oxide (ZrO ₂ ), bismuth oxide (Bi ₂ O ₃ ), and iron oxide (Fe ₂ O ₃ ). These may be used alone or in combination of two or more. Among these, titanium oxide (TiO ₂ ) and tungsten oxide (WO ₃ ) are more preferable from the viewpoint of price, availability, and performance.
The above metal oxide is a metal oxide with low or no visible light responsiveness, but is mixed with the promoter-supported metal oxide (B) to form the visible light responsive photocatalyst composition of the present invention. Visible light responsiveness can be increased. For example, when titanium oxide (TiO ₂ ) is evaluated for visible light responsiveness described in Examples described later, the amount of CO ₂ generated after 6 hours is less than 0.5 μmol, and the visible light responsiveness is low or absent. It is a metal oxide. In addition, when tungsten oxide (WO ₃ ) is evaluated for visible light responsiveness as described in Examples described later, the amount of CO ₂ generated after 6 hours becomes undetectable, and metal oxidation with low or no visible light responsiveness occurs. It is a thing. However, the visible light responsive photocatalyst composition of the present invention using these titanium oxide (TiO ₂ ) and tungsten oxide (WO ₃ ) as the metal oxide (A) is more visible than the metal oxide (A) alone. Photoresponsiveness becomes remarkably high.

The BET specific surface area of the metal oxide (A) is preferably 1 to 200 m ² / g. When it is 1 m ² / g or more, since the BET specific surface area is large, the photocatalytic activity is excellent. When it is 200 m ² / g or less, the handleability is excellent. From these viewpoints, BET specific surface area of the metal oxide (A) is more preferably 3~100m ² / g, and more preferably 4~70m ² / g, even more preferably 8~50m ² / g.
Here, the BET specific surface area is a value measured by the BET method by nitrogen adsorption. For example, the BET specific surface area can be measured using a fully automatic BET specific surface area measuring device “Macsorb, HM model-1208” manufactured by Mountec Co., Ltd.

The average primary particle diameter (D _BET ) of the metal oxide (A) by the _BET one-point method is preferably 0.01 to 1.0 μm. When it is 0.01 μm or more, handling is easy, and when it is 1.0 μm or less, the photocatalytic activity is excellent. In this respect, the average particle size is more preferably 0.02 to 0.5 μm, and still more preferably 0.05 to 0.3 μm.
Here, the average primary particle size (D _BET ) (nm) is a specific surface area S (m ² / g) of titanium oxide measured by the _BET single point method, and the following formula D _BET = 6000 / (S × ρ)
It is a value calculated from Here, ρ represents the density (g / cm ³ ) of titanium oxide.

(Titanium oxide (TiO ₂ ))
Titanium oxide is not particularly limited, and any of rutile type titanium oxide, anatase type titanium oxide and brookite type titanium oxide may be used, but from the viewpoint of photocatalytic activity, rutile type titanium oxide is preferable.
The titanium oxide is preferably obtained by a vapor phase method (a method of obtaining titanium oxide by vapor phase reaction between titanium tetrachloride and oxygen) using titanium tetrachloride as a raw material. Titanium oxide obtained by the vapor phase method has a uniform particle size and at the same time a high temperature process during production, so that the crystallinity is high, and as a result, the photocatalytic activity of the resulting composition is good It will be something.
As titanium oxide, it is more advantageous to use commercially available titanium oxide as it is in view of the catalyst preparation step. Commercially available titanium oxide includes those produced by the liquid phase method and those produced by the vapor phase method, but those produced by the liquid phase method have a large specific surface area and low rutile crystallinity. For this reason, it is necessary to calcinate the titanium oxide to have an optimum specific surface area and crystallinity. If it goes through such a firing step, it will take extra time and cause high costs. Moreover, the trouble that it colors at the time of baking may also generate | occur | produce. Also from such a viewpoint, it is preferable to use a commercial product of titanium oxide obtained by a vapor phase method (for example, rutile titanium oxide manufactured by Showa Titanium Co., Ltd.) having appropriate crystallinity and specific surface area as it is. .

(Tungsten oxide (WO ₃ ))
There is no restriction | limiting in particular in tungsten oxide, A commercial item can be used suitably. Since tungsten oxide may be partially reduced to a V value, it is preferably used after being oxidized to a VI value by baking at a high temperature. The crystal structure of tungsten oxide is not particularly limited, but a monoclinic system is preferable.

<Metal oxide not having photocatalytic activity (b ₁ )>
The metal oxide (b ₁ ) having no photocatalytic activity is not particularly limited as long as it is a metal oxide that does not meet the definition of the metal oxide (A) having photocatalytic activity. For example, silica (SiO ₂ ), alumina (Al ₂ O ₃ ), magnesia (MgO), cerium oxide (CeO ₂ ), zirconia (ZrO ₂ ), silica alumina (composite oxide composed of silicon and aluminum), silica magnesia ( A composite oxide composed of silicon and magnesium), zeolite, titanosilicate, and the like. These may be used alone or in combination of two or more. Among these, silica (SiO ₂ ), alumina (Al ₂ O ₃ ), silica alumina, and zeolite are preferable from the viewpoint of price and availability.
By using those in the form of a porous material as the metal oxide, a function of improving the decomposition performance of the volatile organic compound (VOC) can be imparted as an adsorption aid.
Silica, alumina, silica alumina, zirconia, and the like also function as a binder when forming the photocatalytic component into a film. Thereby, a photocatalyst film | membrane can also be formed, without adding a binder separately.

The average primary particle diameter (D _BET ) of the metal oxide (b ₁ ) by the _BET one-point method is preferably 0.005 to 0.5 μm. When it is 0.005 μm or more, handling is easy, and when it is 0.5 μm or less, the photocatalytic activity of the visible light-responsive photocatalyst obtained in the present invention is excellent. From this viewpoint, the average particle size according to the BET one-point method is more preferably 0.008 to 0.3 μm, and still more preferably 0.01 to 0.2 μm.
Metal oxide (b ₁₎ the ratio of the average primary particle diameter (D _BET) a metal oxide average primary particle diameter (D _BET) of (A) of (b ₁ / A) is visible photoresponsive From the viewpoint, it is preferably 0.01 to 1, more preferably 0.02 to 0.5, and still more preferably 0.05 to 0.3.
The BET specific surface area of the metal oxide (b ₁ ) is preferably 10 to 400 m ² / g. When it is 10 m ² / g or more, since the BET specific surface area is large, the function as the adsorption aid is excellent. When it is 400 m ² / g or less, the handleability is excellent. From these viewpoints, BET specific surface area of the metal oxide (b ₁₎ is more preferably 50~350m ² / g, more preferably from 100~330m ² / g, even more preferably 150 to 300 m ² / G.

<Cocatalyst (b ₂ )>
The promoter (b ₂ ) is not particularly limited as long as it is a substance known to improve the activity of the photocatalyst. Examples thereof include platinum, palladium, ruthenium, gold, copper, iron, chromium, nickel, and cerium. , Tungsten, tungsten carbide and the like. Among these, platinum, palladium, ruthenium, copper, iron, and tungsten carbide are preferable. Moreover, copper and iron are more preferable from a viewpoint that it is cheap and versatility is high.
The cocatalyst (b ₂ ) may be supported on the metal oxide (b ₁ ) in the above-described metal state, or may be supported on the metal oxide (b ₁ ) in the state of a metal compound. Examples of the metal compound include halides such as chlorides, bromides and iodides of the above metals; conjugate bases of acids such as acetates, nitrates and sulfates; hydroxides and oxides. A metal, a hydroxide, or an oxide is preferable.

<Cocatalyst-supported metal oxide (B)>
The promoter-supported metal oxide (B) is a product in which the promoter (b ₂ ) is supported on the metal oxide (b ₁ ).
From the viewpoint of the visible light responsiveness of the visible light responsive photocatalyst obtained by the present invention, the supported amount of the promoter (b ₂ ) in terms of metal with respect to 100 parts by mass of the metal oxide (b ₁ ) is preferably 0.01 to 5 parts by mass, more preferably 0.02 to 1 part by mass, and still more preferably 0.03 to 0.5 parts by mass. This supported amount can be calculated from the amount charged in the production of the metal oxide (B), and the sample is heated in a hydrofluoric acid solution to be completely dissolved, and the extract is quantified by ICP emission spectroscopic analysis. You can also

<Method for producing promoter-supported metal oxide (B)>
There is no restriction | limiting in particular in the manufacturing method of a cocatalyst carrying | support metal oxide (B). For example, a metal oxide in an aqueous solution of co-catalyst (b ₂₎ a (b ₁₎ was added, and a method for filtering another after adsorbed metal oxide (b ₁₎ to cocatalyst (b _2), cocatalyst ( A method is known in which a metal oxide (b ₁ ) is added to an aqueous solution of b ₂ ) and heated to evaporate water to dryness. In addition, when the metal oxide (b ₁ ) has ion exchange ability, a method of supporting the promoter (b ₂ ) by ion exchange is also known.
Next, a preferred method for producing the promoter-supported metal oxide (B) will be described.
In this production example, the co-catalyst (b ₂ ) feedstock, metal oxide (b ₁ ), solvent, and optionally a mixture containing an alkaline substance are stirred to assist the metal oxide (b ₁ ). The catalyst (b ₂ ) is bound or adsorbed and supported. In this way, the promoter-supported metal oxide (B) is obtained.

(Feed for cocatalyst (b ₂ ))
The co-catalyst (b ₂₎ the feedstock (precursor) of the chloride of the metal constituting the co-catalyst (b _2), a bromide, halides such as iodides; acetate, nitrate, acid such as sulfuric acid salt Conjugated bases; hydroxides and the like.
The feedstock (precursor) of the cocatalyst (b ₂ ) may be an anhydride or a hydrate.

(solvent)
Water is used as the solvent, but it may further contain a polar solvent other than water. Examples of polar solvents other than water include those that dissolve the cocatalyst (b ₂ ) feedstock, water and alkaline substances, and examples thereof include alcohols, ketones, and mixtures thereof. Examples of alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, others, dimethylformamide, tetrahydrofuran, or a mixed solution thereof.

(Alkaline substance)
Examples of the alkaline substance include sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, triethylamine, trimethylamine, ammonia, and a basic surfactant. Sodium hydroxide is preferred.
The concentration of the alkaline solution to be added is preferably 0.1 to 5 mol / L, more preferably 0.3 to 4 mol / L, and still more preferably 0.5 to 3 mol / L. If it exceeds 5 mol / L, the precipitation becomes non-uniform when added, which is not preferable.

(Mixing and stirring)
There are no particular restrictions on the order of mixing and stirring the metal oxide (b ₁ ), the starting material of the cocatalyst (b ₂ ), the solvent, and, if necessary, the alkaline substance. For example, it is preferable to first mix the metal oxide (b ₁ ) with the solvent and stir as necessary, then mix the starting material of the cocatalyst (b ₂ ) and stir these. However, first, the starting material of the cocatalyst (b ₂ ) may be mixed with the solvent and stirred as necessary, then the metal oxide (b ₁ ) may be mixed, and these may be stirred. Further, the metal oxide (b ₁ ) and the cocatalyst (b ₂ ) may be mixed in the solvent at the same time and stirred.
In the case of adding an alkaline substance, it may be added at least one of the following three timings before, during and after mixing the metal oxide (b ₁ ) and / or the promoter (b ₂ ) with the solvent. Although it is good, it is preferable to add the metal oxide (b ₁ ) and the cocatalyst (b ₂ ) in a solvent after sufficiently stirring.
There is no restriction | limiting in particular in stirring time, For example, it is 5 to 120 minutes, Preferably it is about 10 to 60 minutes. Moreover, although there is no restriction | limiting in particular in stirring temperature, For example, it is room temperature-about 70 degreeC.
The pH at which these mixtures are stirred is preferably 8 to 11 at the reaction temperature. When the pH is 8 to 11, the cocatalyst (b ₂ ) is favorably supported on the surface of the metal oxide (b ₁ ) and the amount of alkaline substance used is reduced, so that the waste liquid treatment becomes easy. From this viewpoint, the pH is more preferably 9 to 11, and further preferably 9.5 to 10.5. The measurement is preferably performed with a pH meter.

(Separation of the obtained promoter-supported metal oxide (B))
The promoter-supported metal oxide (B) obtained as described above can be separated from the mixed solution as a solid content. This separation method is not particularly limited, and examples thereof include filtration, sedimentation separation, centrifugation, and evaporation to dryness.
The separated promoter-supported metal oxide (B) is washed with water, dried, pulverized, classified, etc. as necessary.

<Method for producing visible light responsive photocatalyst composition>
Visible-light-responsive photocatalyst composition, the addition of co-catalyst (b ₂₎ a solution of the metal oxides in the (b _1), contacting a co-catalyst (b ₂₎ and the metal oxide (b ₁₎ It can be suitably produced by a production method having a production process of the promoter-supported metal oxide (B) and a mixing process of mixing the promoter-supported metal oxide (B) and the metal oxide (A). . According to this production method, the visible light responsive photocatalyst composition can be easily produced with few production steps.
There are no particular restrictions on the method of physical mixing. For example, there are a method in which two or more types of powder are added to a container such as a beaker and agitation, and a method in which two or more types of powder are placed in a bag and shaken. . In order to mix them better, a method of grinding two kinds of powders in a mortar or a method of mixing in a pulverizer or a mill is also suitable.
The ratio of the metal oxide (A) to the total of the metal oxide (A) and the promoter-supported metal oxide (B) is preferably 10 to 50% by mass, more preferably 20 to 40% by mass, and 25 to 35%. More preferred is mass%. When the metal oxide (A) is 10% by mass or more, visible light responsiveness is sufficient. On the other hand, when the metal oxide (A) is 50% or less, the VOC adsorption force is improved and the visible light responsiveness is improved.

[Coating agent]
The coating agent of the present invention has the above-described visible light responsive photocatalyst composition and a binder.
As the binder, either an organic binder or an inorganic binder may be used, but an inorganic binder is preferably used in order to avoid decomposition of the binder by the photocatalytic substance. The kind of binder is not specifically limited. For example, an arbitrary binder such as a polymer binder capable of forming a thin film by polymerization or solvent volatilization can be used in addition to an inorganic binder such as silica that is usually used for fixing the photocatalytic substance on the substrate surface. In the case where the metal oxide (b ₂₎ to function as a binder may not be contained separately binder may decrease the content correspondingly.

[Photocatalyst film, article with photocatalyst film and method for producing the same]
The photocatalyst film of the present invention contains the visible light responsive photocatalyst composition. Moreover, the article with a photocatalyst film of the present invention has a base material and a photocatalyst film provided on the surface of the base material.
There is no restriction | limiting in particular in the method of forming a photocatalyst film | membrane on the surface of this base material. For example, the visible light responsive photocatalyst composition may be attached to the surface of the base material and fired, or the coating agent may be applied to the surface of the base material and dried, and the dried product may be fired. Also good. Alternatively, the visible light responsive photocatalyst composition may be fired to produce a sputtering target, and the target may be sputtered to form a photocatalytic film on the substrate surface.
Examples of the substrate include, but are not limited to, a substrate made of a general single member such as metal, ceramic, and glass, and a composite substrate made of two or more members.

[Application form]
The application form of the visible light responsive photocatalyst composition of the present invention is not particularly limited, and is in the presence of water (for example, in water or seawater), in a dry state (for example, in a low humidity state in winter, etc.), or in a high humidity state. Visible light responsiveness can be expressed even in the state or in the presence of organic substances.
For example, in addition to walls, floors, ceilings, etc., buildings such as hospitals and factories, machine tools and measuring devices, interiors and parts of electrical appliances (refrigerators, washing machines, dishwashers, etc., and filters for air cleaners Etc.) and can be applied to any object.

EXAMPLES Hereinafter, although an Example, a comparative example, and a reference example demonstrate this invention concretely, this invention is not limited to these examples.
Various characteristics were determined according to the following methods.

(Visible light response)
An evaluation container (container volume 275 cm ³ ) having the shape shown in FIG. 1 was used. 10 ml of a 1% by volume acetone aqueous solution was placed in the lower part of the container, and a 0.1 g sample was placed on a glass filter paper having a diameter of 55 mm, and the container was sealed. After replacing the inside of the container with synthetic air (mixed gas of 79% nitrogen and 21% oxygen), a blue LED (“LP-3024RA” manufactured by Hayashi Watch Industry Co., Ltd., emission wavelength 400-600 nm, light intensity 7.7 mW / cm) ² ), the gas in the evaluation container was measured with a gas chromatograph, and the CO ₂ concentration generated by decomposing acetone was quantified. Visible light response was evaluated by the amount of carbon dioxide generated during a predetermined time. The emission spectrum of the blue LED used is shown in FIG.

<Example 1>
(Preparation of copper-supported silica)
1.0 g of silica (manufactured by Sigma Aldrich Japan Co., Ltd., No. 236810, BET specific surface area: 274 m ^{2 /} g) is placed in an evaporating dish (made of glass, outer diameter 60 mm, capacity 30 cm ³ ) as a cocatalyst feedstock. 42.4 mg / ml copper (II) chloride (manufactured by Kanto Chemical Co., Inc., prepared from copper chloride (II) dihydrate, special grade) 50 μl aqueous solution (0.1 parts by mass as copper with respect to 100 parts by mass of silica) And about 2.5 ml of distilled water was added. Then, it stirred using the glass rod for about 0.5 hour, evaporating water with a 60 degreeC vapor | steam. Then, it dried overnight in 120 degreeC drying machine. In this way, 0.1 part by mass of copper-supporting silica was obtained as particles B.
(Preparation of visible light responsive photocatalyst composition)
Tungsten oxide (WO ₃ , manufactured by Kojundo Chemical Laboratory Co., Ltd., BET specific surface area: 6.5 m ² / g) (particle A) was ground in an agate mortar to obtain particles A. 0.3 g of this tungsten oxide powder and 0.7 g of copper-supporting silica particles B were added to an agate mortar and mixed for 10 minutes while grinding with a pestle. In this way, a visible light responsive photocatalyst composition was obtained.

<Example 2>
The same operation as in Example 1 was carried out except that the silica of Example 1 was replaced with alumina (Catalyst Society Reference Catalyst ALO-8, BET specific surface area: 150 m ² / g) to make particles B. The results are shown in Table 1 and FIG.
<Example 3>
Instead of the copper chloride (II) dihydrate of Example 1, copper nitrate (II) trihydrate (Cu (NO ₃ ) ₂ .3H ₂ O, manufactured by Kanto Chemical Co., Inc., purity 99.9% by mass) The same operation as in Example 1 was performed except that particles B were used. The results are shown in Table 1 and FIG.
<Example 4>
Instead of the copper chloride (II) dihydrate of Example 1, copper acetate (II) monohydrate ((CH ₃ COO) ₂ Cu · H ₂ O, manufactured by Kanto Chemical Co., Ltd., deer special grade) was used. Then, the same operation as in Example 1 was performed except that the particles B were obtained. The results are shown in Table 1 and FIG.

<Reference Example 1>
(Preparation of copper-supported tungsten oxide)
Tungsten oxide (manufactured by Kojundo Chemical Laboratory Co., Ltd.) was ground in an agate mortar. After adding 5.0 g of this tungsten oxide powder to 200 ml of a 0.026 mg / ml copper (II) chloride aqueous solution (corresponding to 0.05 parts by mass as copper with respect to 100 parts by mass of tungsten oxide), the mixture was heated to 90 ° C., Stir for 1 hour. The obtained powder was subjected to suction filtration, washed with distilled water, and then dried overnight in a 120 ° C. dryer. In this way, 0.05 mass part copper carrying | support tungsten oxide was obtained.
About the obtained copper carrying | support tungsten oxide, the same measurement as Example 1 was performed. The results are shown in Table 1.
<Reference Example 2>
0.05 g of copper-supported tungsten oxide powder 0.3 g obtained in Reference Example 1 and 0.7 g of silica (manufactured by Sigma-Aldrich Japan Co., Ltd., No. 236810) were placed in an agate mortar and ground, Mix for 10 minutes. Thus, a mixed powder of copper-supported tungsten oxide and silica was obtained.
About the obtained sample, the same measurement as Example 1 was performed. The results are shown in Table 1.

<Comparative Example 1>
Copper oxide powder (manufactured by Kanto Chemical Co., Inc., purity 99.9% by mass, BET specific surface area: 3 m ² / g) to 2% by weight with respect to tungsten oxide of particle A (manufactured by Kojundo Chemical Laboratory Co., Ltd.) Then, the mixture was thoroughly ground and mixed in an agate mortar.
About the obtained sample, the same measurement as Example 1 was performed. The results are shown in Table 1 and FIG.

<Example 5>
As particle A, rutile type titanium oxide (manufactured by Showa Titanium Co., Ltd., Super Titania (registered trademark) F-10, BET specific surface area: 12 m ^{2 /} g) 0.3 g and particle B were obtained in Example 1. 0.1 part by mass of copper-supporting silica 0.7 g was put in an agate mortar and mixed for 10 minutes while grinding with an agate pestle. Thus, a mixture of titanium oxide and copper-supported silica was obtained.
About the obtained sample, the same measurement as Example 1 was performed. The results are shown in Table 2 and FIG.
<Example 6>
Preparation of iron-supported silica Iron (III) chloride hexahydrate (FeCl ₃ .6H ₂ O, manufactured by Kanto Chemical Co., Inc., purity 99.9 mass%) was used instead of copper (II) chloride in Example 1. Then, 0.05 part by mass of iron-supporting silica was obtained as particles B by the same preparation method as in Example 1.
Further, in the same manner as in Example 5 except that iron-supporting silica was used instead of the copper-supporting silica in Example 5, rutile titanium oxide (Showa Titanium Super Titania (registered trademark) F-10) of particle A was used. ).
About the obtained sample, the same measurement as Example 1 was performed. The results are shown in Table 2 and FIG.
<Reference Example 3>
Preparation Method of Copper-Supported Titanium Oxide 5.0 g of Rutile Type Titanium Oxide (Super Titania (registered trademark) F-10, manufactured by Showa Titanium Co., Ltd.), 200 ml of 0.026 mg / ml copper (II) chloride aqueous solution (100 titanium oxide) In addition to 0.05 parts by mass as copper with respect to parts by mass), the mixture was heated to 90 ° C. and stirred for 1.5 hours. The obtained mixture was filtered, washed with distilled water, and then dried overnight in a 120 ° C. dryer to obtain 0.05 part by mass of copper-supported titanium oxide particles (sample).
About the obtained sample, the same measurement as Example 1 was performed. The results are shown in Table 2 and FIG.

<Evaluation results (Examples 1 to 4, Reference Examples 1 to 2 and Comparative Example 1)>
In the examples, reference examples, and comparative examples in Table 1, tungsten oxide or copper-supported tungsten oxide is used as the particles A and the like.
As is clear from the comparison between Examples 1 to 4 and Comparative Example 1, the metal oxide (silica) was used rather than the case where the cocatalyst (copper compound) was simply mixed with the photocatalyst (tungsten oxide) (Comparative Example 1). (Alternatively, it was found that the responsiveness to visible light was better when the mixture was supported on alumina) (Examples 1 to 4).
Further, as is clear from comparison between Examples 1 to 4 and Reference Examples 1 to 2, a promoter is prepared by mixing a promoter-supported metal oxide (copper-supported silica or copper-supported alumina) with a photocatalyst (tungsten oxide). It was found that the visible light responsiveness equivalent to the case where is supported on the photocatalyst can be obtained.

<Evaluation results (Examples 5 to 6 and Reference Example 3)>
In the examples and reference examples in Table 2, titanium oxide or copper-supported titanium oxide is used as the particles A and the like.
As is clear from the comparison between Examples 5 to 6 and Reference Example 3, the promoter is supported on the photocatalyst by mixing the promoter-supported metal oxide (copper-supported silica or iron-supported silica) with the photocatalyst (titanium oxide). It was found that the visible light responsiveness equivalent to that of the case can be obtained.

Claims (13)

Visible comprising a mixture comprising a metal oxide (A) having photocatalytic activity and a promoter-supported metal oxide (B) having a promoter (b ₂ ) supported on a metal oxide (b ₁ ) having no photocatalytic activity Photoresponsive photocatalytic composition.   The visible light responsive photocatalyst composition according to claim 1, wherein the metal oxide (A) having photocatalytic activity is a metal compound having low or no visible light responsiveness.   The visible light responsive photocatalyst composition according to claim 1, wherein the metal oxide (A) is at least one of titanium oxide and tungsten oxide. The metal oxide (b ₁ ) is at least one selected from silica, alumina, magnesia, cerium oxide, silica alumina, silica magnesia, zeolite, and titanosilicate. The visible light responsive photocatalyst composition described. It said cocatalyst (b _2), platinum, palladium, ruthenium, gold, copper, iron, is at least one chromium, is selected from nickel, cerium, tungsten, and tungsten carbide, claim 1 The visible light responsive photocatalyst composition described in 1. The metal oxide (A) is tungsten oxide, the metal oxide (b ₁ ) is at least one of silica and alumina, and the promoter (b ₂ ) is copper. The visible light responsive photocatalyst composition according to claim 1. The cocatalyst (b ₂₎ a solution of the metal oxides in the (b ₁₎ was added, the cocatalyst (b ₂₎ and the metal oxide (b ₁₎ and a cocatalyst-supported metal oxide contacting (B) Manufacturing process,
The manufacturing method of the visible light responsive photocatalyst composition in any one of Claims 1-6 which has a mixing process which mixes a promoter-supported metal oxide (B) and a metal oxide (A).   The coating agent which has a visible light responsive photocatalyst composition in any one of Claims 1-6, and a binder.   A photocatalyst film containing the visible light responsive photocatalyst composition according to claim 1.   An article with a photocatalyst film comprising a base material and the photocatalyst film according to claim 9 provided on a surface of the base material.   The article with a photocatalyst film according to claim 10, wherein the photocatalyst film is a fired body of the visible light responsive photocatalyst composition according to any one of claims 1 to 6.   The article with a photocatalyst film according to claim 10, wherein the photocatalyst film is a dried product of the coating agent according to claim 8.   The manufacturing method of the article | item with a photocatalyst film | membrane of Claim 11 including the process of making the visible light responsive photocatalyst composition in any one of Claims 1-6 adhere to the surface of a base material, and baking.

Images