JPH10323566A - Photocatalyst and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an excellent photocatalyst by keeping a superfine particle state of titanium oxide and to produce the photocatalyst easily capable of forming a thin film by directly blending it to a ceramic compact by a homogeneous mixing. SOLUTION: An unswelling mica powder is converted to a mica powder by exchanging their intercalation ion to a sodium ion with tetraphenyl sodium boron to coordinate a water molecule between a crystal layer, then heating and cleaving and a metallic ion is deposited on the mica powder with the metallic ion selected among potassium silver, gold, platinum, palladium and ruthenium by an ion exchange or chemical plating, then the mica powder is combined with a titanium oxide obtained by hydrolyzing a titanate soln. In this way, the photocatalyst made to an imbricate state is obtained by combining the unswelling mica carrying the titanium oxide and the metallic ion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocatalyst comprising ultrafine titanium oxide particles and mica, and a method for producing the same.

[0002]

2. Description of the Related Art A photocatalyst using ultrafine particles of titanium oxide is:
It is useful as a substance that excites electrons and holes by light irradiation and exhibits oxidation and reduction actions. The photocatalytic action of titanium oxide is essentially based on ultrafine particles. Therefore, it is used as a powder or sol having a particle size of 50 nm or less at the molecular level, or as a thin film having a thickness of 100 nm or less. However, the structure of titanium oxide ultrafine particles requires advanced technology for particle size control and cohesion prevention, and when mixed with other materials to form a molded product, the particle size difference is large and uniform. A molded product could not be formed.

[0003]

SUMMARY OF THE INVENTION As a result of repeated studies, the present invention has been made to make it possible to easily form a photocatalyst powder with an appropriate particle size by using a combination of titanium oxide and mica as a basic material. It is blended homogeneously in ceramic molded products while maintaining the state of ultrafine particles of titanium oxide,
Another object is to provide a photocatalyst capable of easily forming a thin film and the like and a method for producing the same.

[0004]

For this reason, the photocatalyst of the present invention is characterized in that flaky powder is formed by combining titanium oxide, metal ions and non-swelling mica. In addition,
The metal ion may be at least one or more selected from potassium, silver, gold, platinum, palladium, and ruthenium. Further, the method for producing a photocatalyst of the present invention comprises the steps of exchanging non-swelling mica powder with sodium ions for their interlayer ions with tetraphenylsodium boron to coordinate water molecules between crystal layers, and then heating and cleaving to produce scales. Formed into a fine powder, and carried metal ions by ion exchange or chemical plating with metal ions selected from potassium, silver, gold, platinum, palladium and ruthenium, and then titanium oxide hydrolyzed from a titanium salt solution. The method is to combine them.

[0005] The form in which titanium oxide and mica are bonded is scale powder from the structure of mica. However, by setting the particle size to an appropriate value, it can be easily incorporated into ceramics. Even in the form, since mica is interposed, the titanium oxide does not associate and maintains ultrafine particles. Further, since the modified mica carries metal ions imparting catalytic activity, the photocatalytic function of titanium oxide is promoted.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, titanium oxide is bound to mica modified in the form of ultrafine particles. Therefore, (1) non-swelling mica is modified by chemical treatment to swell it. To obtain well-cleaved mica scales. (2) Potassium is obtained by ion exchange or chemical plating on the obtained mica scales.
It carries a metal ion selected from silver, gold, platinum, palladium and ruthenium. (3) Ultrafine titanium oxide particles are combined with mica scales by hydrolysis of the titanium compound. Hereinafter, the process will be described in detail.

The reason why mica is used here is to form a titanium oxide thin film on mica scales and to carry a metal which promotes its activity. Mica, which is a basic material, belongs to a silicate layered mineral, and has an anisotropic structure having strong covalent bonds in the direction parallel to the crystal axis and weak ionic bonds in the vertical direction of the crystal axis. For this reason, the mica can be peeled off into a thin layer, so that it can be formed into scales or sheets, and is excellent in flexibility, heat resistance, chemical resistance, electrical insulation, and light transmittance.

[0008] Mica can be classified into swellable mica and non-swellable mica based on its reactivity with water. Swellability is the property of swelling by drawing water between the layers of mica crystals.Natural muscovite, phlogopite, synthetic fluorophlogopite, potassium tetrasilicic mica and the like used in ordinary electrical insulating materials are Non-swelling non-swelling mica. On the other hand, due to the composition of the crystal, the bonding strength between the crystal layers is weak, and the interlayer ions coordinated between the layers are Na ⁺ and Li ⁺ with a small ionic radius and a high affinity for water. The mica is called swelling mica. Swellable mica includes sodium (or lithium) teniolite, sodium (or lithium) tetrasilicic mica, the most developed of which produces sols. The swellable mica is a fine scale having a diameter of 5 μm or less and a thickness of 10 nm or less, and its interlayer ions can exchange ions with other metal ions.

[0009] The mica used in the present invention is a non-swelling mica, natural muscovite, phlogopite, synthetic fluorophlogopite,
And potassium silicon mica. Swellable mica has a fine particle size and is difficult to mix with other materials. However, non-swellable mica can be easily mixed with other materials because the particle size can be freely selected by pulverization. The interlayer ions K ⁺ of this non-swelling mica are eluted by treatment with tetraphenyl sodium boron [NaB (C ₆ H ₅ ) ₄ : hereinafter referred to as NaTPB], and instead of Na ⁺ coordination, water molecules are formed. Modification is performed by coordinating 1 to 3 molecular layers ( _{2 to 4} H ₂ O per mica molecule) between crystal phases. Since K ⁺ eluted from mica immediately becomes insoluble KB (C ₆ H ₅ ) ₄ , the reaction is performed because the concentration of K ^{+ in} the aqueous solution is kept low.

The treatment with NaTPB is performed by adding 0.05 to 0.3 mol of NaTPB.
/ l as the main component, and if necessary, NaF 0.5-1.0mol / l, ED
The suspension is adjusted at a ratio of 50 to 100 g of non-swellable mica to 1000 ml of an aqueous solution mixed with 0.05 to 0.1 mol / l of DT, and the treatment reaction is carried out by continuing stirring at room temperature for 3 to 5 hours. It is done. After completion of the reaction, the modified mica obtained by solid-liquid separation is obtained. Although the obtained modified mica varies depending on the bonding strength between the layers, between the crystal phases, a bi-aqueous layer [KMg _2.5 (SiO ₄ ) F ₂ .4H
₂ O], natural phlogopite, muscovite, and synthetic fluorophlogopite, coordinate about 1 water layer (2H ₂ O per molecule). The modified mica has an ion exchange capacity (CEC) of 140 to 185 meq.

When the modified mica is rapidly heated at 500 ° C. or higher, mica scales are cleaved by expansion due to rapid volatilization of water, and scales without flaws are obtained. The degree of cleavage of the mica is desirably 50 or more, preferably 65 or more, in an aspect ratio [root (major axis + minor axis) / wall thickness]. The surface area is 1
It is preferably about 2 to 10 m ² , preferably 3 m ² or more per g.
The degree of fineness of the mica scales is arbitrarily determined according to the application, but generally 70 to 270 mesh as a catalyst powder,
100-400 mesh is used for glaze mixing, and 10-250 mesh is used for porous ceramic.

Further, the specific metal ion is supported by
This is for improving the reaction efficiency by fixing the bond between the electron and the hole, that is, by separating the charge from the electron by fixing to the titanium oxide. That is, in a photocatalytic reaction, electrons and holes generated by excitation by light energy are recombined and consumed as heat or light, and thus may not contribute to the reaction.
In the present invention, this charge separation is intended to improve the photocatalytic reaction.For example, the addition of gold, platinum, palladium, and ruthenium allows the generated electrons to be quickly transferred to metal ions,
The object to be reduced is reduced, and copper and silver have the effect of consuming electrons of titanium oxide to promote oxidation of holes into oxide.

In the present invention, these metal ions are supported by interlayer ion exchange of mica and chemical plating. In the ion exchange, an aqueous solution of a metal compound such as silver (AgNO ₃ ), gold (HAuCl ₄ ), platinum (H ₂ PtCl ₆ ), palladium (PdCl ₂ ), ruthenium is added to a suspension of mica having a solid content of 10% by weight or less. (RuCl
₃ ) The aqueous solution containing a concentration of 5 to 10% is dropped and injected with stirring. For gold, platinum, and the like, in which metal tends to be complex ions, mica is sufficiently immersed and then reduced with a reducing solution such as sodium citrate or formalin.

The chemical plating is performed by a conventional electroless plating method. For example, in the case of silver plating, 5% by weight or less of mica is immersed in a silver nitrate solution having a concentration of 2 to 5%, plating is performed by stirring, and then a reducing solution such as tartrate, formalin, sodium citrate or lactic acid is used. , Alanine, EDTA and other pH buffering agents to add silver ions to the surface of the mica. Precipitation amount of metal ions may, if the mica surface 1 m ² per 10mg or more.

Further, titanium oxide is supported to form a photocatalytic function. As the titanium compound, titanyl sulfate, titanium tetrachloride, titanium alkoxide (TTIP.TTBP) and the like are used. These titanium compound solutions are added dropwise to the mica suspension while stirring under heating, and the titanium oxide generated by the hydrolysis is bound to the mica scales.

The titanium compound is adjusted so that titanium oxide or titanium hydroxide is favorably hydrolyzed. For example, titanyl sulfate is prepared by heating a mica suspension (3% by weight of solid content) to about 70 to 90 ° C.
Hydrolysis is carried out by dropping and pouring while maintaining titanium oxide, and the titanium oxide is combined with mica. Titanium tetrachloride is alkaline and pH
While maintaining the temperature at 6.5 to 7, the solution is dropped into the mica suspension at room temperature, and the titanium oxide is combined with the mica by hydrolysis.

Titanium alkoxide is obtained by diluting titanium isopropoxide or titanium butoxide with aqueous hydrochloric acid and hydrolyzing to bind titanium oxide to mica. The method using titanyl sulfate and titanium tetrachloride has almost the same performance. Titanium oxide or titanium hydroxide produced by hydrolysis is associated with the surface of the anion charge of mica as a cation of the hydrous amorphous body and binds.

In the present invention, the amount of titanium oxide attached to the mica scale is preferably not more than 30 nm, which is the molecular level of the thin film. Therefore mica 1 m ² per titanium oxide coating weight should be less than or equal to 50 mg. The amount of adhesion can be adjusted experimentally using factors such as mica surface area, suspension concentration, amount of hydrolyzed titanium oxide produced, reaction temperature, and reaction time. The surface area of mica is usually 0.5 to 5 m ² / g for muscovite of pulp mica used as an electrical insulating material and ² m ² / g for phlogopite.
-6 m ² / g, in the modified mica according to the present invention, 2-10 m ² / g for muscovite and phlogopite, and 2 to 10 m ² / g for synthetic fluorine mica.
8 m ² / g.

The titanium oxide bonded to mica by hydrolysis is a hydrated amorphous material, so that a baking treatment is performed to adjust the crystal phase. This method involves placing the combined reaction product in a refractory vessel, drying at a temperature up to about 100 ° C, and then at about 300-700 ° C, preferably 300-600 ° C.
By heating at ゜ C for 1 to 2 hours, the hydrous titanium oxide is converted into the form of crystalline titanium oxide, and the titanium oxide is baked on the mica surface.

The crystal phase of titanium oxide varies depending on the titanium compound and the heating temperature. In the case of an inorganic titanium salt, the titanium oxide is anatase at a heating temperature up to about 700 ° C.
At 0 ° C or higher, the transition to rutile starts. In the case of titanium alkoxide, anatase is present at a heating temperature up to about 550 ° C., and most of the alkoxide titanium is transformed to rutile at 600 ° C. or higher.

The band gap of the anatase excited by light energy is 3.2 eV, that of rutile is 3.0 eV,
It is presumed that anatase has higher photoreducing power and photooxidation. Therefore, in the present invention, the heating temperature is controlled so that the crystal phase of titanium oxide becomes anatase as much as possible, but in consideration of the case where part of the titanium oxide becomes rutile, the activity is supplemented by carrying a metal ion that activates the activity. .

Another prior art is a raster pigment in which titanium oxide and mica are combined. This raster pigment is used as an organic paint that develops a red color by light interference between titanium oxide and mica, and a cosmetic pigment that absorbs and blocks ultraviolet rays. The thickness of the titanium oxide is in the range of 90 to 270 nm, and it is composed of a crystalline phase rutile which is stable by heating at about 1000 ° C., which is different from the quantum size level photocatalyst technology as in the present invention.

The titanium oxide-bonded mica of the present invention (hereinafter referred to as “mica”)
The powder photocatalyst based on titania / mica) can be used as a filler to be mixed with another material to produce a coating material or a molded product. For example, it can be baked on the surface of a refractory to form a thin film product, or blended with glaze to produce glazed products such as tiles and tableware. In this case, 20 to 50% by weight of a glass powder having a softening temperature of 700 ° C. or less is added as a sintering binder to prevent rutile.
It is preferable to bake at 50 ° C. or less. However, in combination with an organic material, it is preferable to use a fluorine-based resin or a silicon-based resin having a strong chemical bonding force for decomposing organic substances.

[0024]

According to the first aspect of the present invention, in a structure in which thin film titanium is formed on mica scales, the titanium oxide bonded to the mica scales is titanium oxide-mica scale-titanium oxide-
Due to the geometric form of mica scale-titanium oxide, mutual association of titanium oxide does not occur, and particles at the molecular level can be maintained. It is a photocatalyst that can be adjusted to an appropriate particle size, and can be baked on the surface of a refractory to form a thin film product, and blended with glaze to produce a glazed product such as a tile or a paint. In particular, in the case of a thin film product, scales having excellent elasticity and heat resistance are laminated in parallel with the surface of the base, so that they do not peel off during baking, resulting in a good film. According to the second aspect, there is an effect that the function of the photocatalyst is promoted by supporting the metal. According to the third aspect, a photocatalyst of scale fine powder having excellent activity can be easily produced.

[0025]

【Example】

(A: Adjustment of raw material mica) (A-1) Natural phlogopite: Fineness 30-100 mesh (8
(A-2) synthetic fluorophlogopite (manufactured by Otake Insulators, Ltd.): fineness: 30 to 100 mesh (75%: 40 to 70 mesh), average aspect ratio: 20 (A-3) Synthetic tetrasilicic mica (manufactured by Otake Insulator Co., Ltd.): fineness: 30 to 100 mesh (85% is 40 to 70 mesh), average aspect ratio: 35 Each of the above raw material mica is wet-ground by a ball mill for 24 hours. After rapid stirring by a mixer, the mixture was allowed to stand, the sediment was removed, and the mixture was sieved and collected.

(B: Reforming treatment with NaTPB)
500ml mixed solution of 2mol / l, NaF 1.0mol / l, EDDT 0.1mol / l
The raw mica (A-1), (A-2), (A)
-3) was added in an amount of 25 g, and the mica modification reaction was performed by magnetic stirring at room temperature for 7 hours. After the reaction, the solid phase (mica) is centrifugally separated, and the mica is washed with acetone (concentration 50%) and coexists.
KB (C ₆ H ₅ ) ₄ was dissolved and removed, and further washed with water. The bottom spacing value of the air-dried mica is measured by X-ray diffraction, and the water molecule layer coordinated between the crystal layers (the thickness of the penetrated coordinated water molecule) is measured. Also, by a conventional method, dissolution treatment with hydrofluoric acid,
The amounts of interlayer ions K and Na were measured by flame light analysis.

Next, the air-dried mica was placed in an alumina crucible, housed in an electric furnace previously maintained at 500 to 550 ° C., and heated. In the crucible, the volume of mica increased 3 to 5 times. Then take out the mica from the crucible and rub it in a mortar,
It was loosened to homogeneity. The particle size of the mica was such that the finer particles increased in diameter by 15-20% compared to air-dried mica.
The aspect ratio of each mica due to the rapid heating was 3 to 5 times as determined by SEM photograph. Table 1 shows the properties of the modified mica.

[0028]

[Table 1]

(C1: Carrying Metal Ion / Ion Exchange Method) (C-1: Ag Carrying) The modified (A-1) natural phlogopite and (A-2) fluorine phlogopite are Using each, 200 ml of a suspension in which 3% by weight of each were dispersed was prepared. AgNO ₃ 4.38
g of water dissolved in 250 ml of water is dropped into the mica suspension with stirring, and stirring is continued for about 1 hour to carry out ion exchange. After solid-liquid separation, the solid phase (mica) is washed with water.
Drying at 110 ° C. yielded Ag-phlogopite and Ag-fluorphlogopite.

(C-2: Pd supported) The modified (A-
Using the potassium tetrasilicic mica of 3), prepare 200 ml of a suspension in which 3% by weight is dispersed. 3.34 g of PdCl ₂ 0.1N-HC
l An aqueous solution dissolved in 100 ml is dropped into the mica suspension while stirring, and ion stirring is continued for about 1 hour to perform solid-liquid separation, and then the solid phase (mica) is washed with water.
Drying at ゜ C gave Pd-tetrasilicic mica.

(C-3: Pt supported) The modified (A-
Using 100% potassium tetrasilicic mica of 3), prepare 100 ml of a suspension in which 3% by weight thereof is dispersed. H ₂ PtCl ₆ · 6H ₂ a O 2.65 g of an aqueous solution dissolved in water 100ml was instilled with stirring mica suspension was continued for about 1 hour stirring, Pt ³⁺ exchanged and [PtCl _2] ²⁺ Is allowed to undergo an intercalation (adsorption between layers) reaction. After the completion of the reaction, solid-liquid separation was performed, the solid phase (mica) was collected in another container, 180 ml of a 1% solution of sodium citrate was added, and the mixture was stirred at 70 to 90 ° C. for 20 minutes to perform a reduction treatment. Thereafter, solid-liquid separation was performed, and the solid phase (mica) was washed with water and dried to obtain Pt-tetrasilicon mica.

(C-4: Au supported) The modified (A-
Using 100% potassium tetrasilicic mica of 3), prepare 100 ml of a suspension in which 3% by weight thereof is dispersed. 100 ml of an aqueous solution in which 2 g of HAuCl ₄ .4H ₂ O was dissolved was dropped into the mica suspension while stirring, and stirring was continued for about 1 hour to exchange Au and [AuCl] ^−.
Is subjected to an intercalation reaction. After completion of the reaction, solid-liquid separation was performed, the solid phase (mica) was collected in another container, 180 ml of a 1% solution of sodium citrate was added, and the mixture was reduced at 70 to 90 ° C. for 20 minutes while continuing stirring. After solid-liquid separation, the solid phase (mica) was washed with water and dried to obtain Au-tetrasilicic mica.

(C-5: Ru supported) A suspension 10 in which 3% by weight of the modified fluorophlogopite of (A-2) was dispersed.
Adjust 0 ml. An aqueous solution in which 2.05 g of RuCl ₃ was dissolved in 100 ml of 0.1 N HCl was dropped into the mica suspension while stirring,
Ru ³⁺ exchanged and [RuCl _5] ^2-a to intercalation reaction. After the completion of the reaction, the solid-liquid separation was performed, and the solid phase (mica) was collected in another container.
Was added, and the mixture was stirred at 70 to 90 ° C. for 20 minutes to carry out a reduction treatment. After solid-liquid separation, the solid phase (mica) was washed with water and dried to obtain Ru-fluorphlogopite.

The modified natural phlogopite of (A-1) (C2: by carrying metal ions and by chemical plating)
After cleavage at a temperature of 50 ° C., immersion in KCl ₂ solution for potassium ion exchange, and heating at 700 ° C. for 1 hour, plating with Ag and Pd. (C-6: Ag loading) NH ₄ OH (specific gravity 0.88) water is added to 30 g of AgNO ₃ to form a silver ammonia complex, and further added until the complex is redissolved. Then NaOH 5g, glucose 6
0 g, adjust along the water 2000 ml. The mica is immersed in it, and a plating process is performed with stirring. After completion, solid-liquid separation is performed, the mica is washed with acetone and water, and dried to obtain Ag-phlogopite. The adhesion amount of Ag was 0.2 to 0.3 μm in film thickness.

(D-1: Combination of titanium oxide and mica) The modified mica obtained in the above A was immersed in KCl ₂ to ion-exchange interlayer Na ⁺ to K ⁺ and calcined at 700 ° C. for 1 hour. Natural phlogopite [specific surface area (BET) 5.5 m ² / g], similarly treated and K ⁺ exchanged fluorophlogopite (specific surface area 4.8 m ² / g) are used. A suspension of 3 g of the raw material mica and 120 ml of water was prepared, and the pressure was reduced for 1 hour to remove bubbles, and the mixture was heated and maintained at 70 to 90 ° C.

To this suspension was added a 0.05 ml / l titanium sulfate solution 30
0 ml of 5-10 × 10 ⁻⁷ mol / mi per m ^{2 of} mica surface area
n-drop at 70 ° -90 ° C.
Then, heating is continued to generate hydrous titanium oxide by thermal hydrolysis and bond with mica. At this time, in order to adjust the pH, a slightly excessive amount of aluminum powder than the theoretical sulfate ion was added to the reaction solution.

After the reaction, 500 ml of water was added to the reaction solution for 3 hours.
After leaving it for 0 minutes, the supernatant was discarded, and the liberated TiO.2H ₂ O and generated contaminants were removed. Then, the precipitate was washed by filtration to obtain a wet cake-like hydrous titanium oxide-bound mica. This is 12
After drying at 0 ° C., it was placed in a platinum crucible and calcined at 600 ° C. for 1 hour to obtain titanium oxide-bound mica.

According to the SEM photograph (× 5000) and the X-ray diffraction, the thickness of the titanium oxide film was 3 for both natural phlogopite and fluorophlogopite.
0 nm, and both crystal phases were identified as anatase.

(D-2: Another Example 1 of Bonding of Titanium Oxide and Mica) Ag-phlogopite and Ag- by ion exchange of (C-1)
Fluorphlogopite, (C-2) Pd-tetrasilicic mica, (C-3)
Pt-tetrasilicic mica by (C-4), Ru-fluorphlogopite by (C-5), and Ag-phlogopite by (C-6) chemical plating, (D-
A mica suspension was prepared by the same operation as in 1), and a binding reaction between mica and hydrous titanium oxide by thermal hydrolysis of an aqueous solution of titanium sulfate was performed. Then, the reaction product was heated at 650 ° C. for 1 hour to obtain titania / mica.

In this operation, the conditions for adding the aqueous solution of titanium sulfate were varied according to the surface area of the raw material mica. Table 2 shows the thickness, mica surface area, crystal phase, and the like of the obtained titania / mica titanium oxide.

[0041]

[Table 2]

(D-3: Another Example of Bonding of Titanium Oxide and Mica) 2 g of Pd-tetrasilicon mica according to (C-2) and 3 g of Pt-tetrasilicon mica according to (C-3) were mixed with water. 120 ml was added thereto, and the pressure was reduced for 1 hour. To the defoamed suspension, 500 ml of an aqueous solution in which 10 g of titanium tetrachloride was dissolved was added, and ammonia water was added while stirring at room temperature to keep the pH at 7, and stirring was continued for 2 hours. To produce titanium oxide and bond with mica.

The reaction solution was subjected to solid phase separation, the solid phase was transferred to another container, and about 1 liter of water was added thereto and stirred, followed by solid-liquid separation.
Further washing with acetone gave a combined product of hydrous titanium oxide and mica. The hydrous titanium oxide / mica was dried, placed in a platinum crucible, and calcined at 700 ° C. and 850 ° C., respectively, to obtain titania / mica.

Each product has a titanium oxide film thickness of 25 to 35.
According to X-ray diffraction, the crystal phase was anatase in the calcined product at 700 ° C, and in the calcined product at 850 ° C, each mica was a eutectic phase of rutile and anatase.

(D-4: Another example 3 of bonding of titanium oxide and mica) 1 part by weight of TTIP (titanium and tetraisopropoxide) was added dropwise to ₄ parts by weight of 0.1 mol / l HCl and stirred at room temperature for 2 hours. Thus, a hydrolyzed TiO ₂ sol was prepared. This sol 3
Au-tetrasilicic mica according to (C-4) in 00 ml, (C-5)
300 ml of a suspension of Ru-fluorphlogopite (2% by weight)
Was added, and the mixture was stirred at 50 ° C. for 3 hours to perform a binding reaction with mica. The product obtained is thoroughly washed, dried at 110 ° C and then placed in a platinum crucible at 600 ° C and 8 ° C, respectively.
Calcination was performed at 00 ° C for 1 hour to obtain titania / mica.

According to the X-ray diffraction analysis, the crystal phase was anatase in the calcined product at 600 ° C., and the crystal structure in the calcined product at 800 ° C. was mainly rutile with a small amount of anatase.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B01J 23/48 B01J 23/48 23/66 23/66 37/02 301 37/02 301N 37/30 37/30 C01B 33/42 C01B 33/42

Claims (3)

[Claims] 1. A scaly photocatalyst formed by combining titanium oxide, metal ions and non-swelling mica. 2. The method according to claim 1, wherein the metal ion is at least potassium, silver,
The photocatalyst according to claim 1, wherein the photocatalyst is one or more selected from gold, platinum, palladium, and ruthenium. 3. The method according to claim 3, wherein the non-swellable mica powder is exchanged with sodium ions for its interlayer ions with tetraphenyl sodium boron to coordinate water molecules between the crystal layers.
It is cleaved by heating to form scale fine powder, which contains potassium, silver, gold,
Production of a scaly photocatalyst characterized by supporting metal ions by ion exchange or chemical plating with metal ions selected from platinum, palladium, and ruthenium, and then combining with titanium oxide hydrolyzed from a titanium salt solution. Method.