JP2002346394A - Highly efficient photocatalyst composition, paint and substrate using the same and method for coating object using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly efficient photocatalyst composition capable of widening the wavelength region of light capable of being utilized by a photocatalytic semiconductor, capable of converting the light energy from a light source to exciting energy to enhance energy efficiency and exciting the photocatalytic semiconductor even after the completion of irradiation with the light from the light source to realize energy saving. SOLUTION: The highly efficient photocatalyst composition is provided by a combination of the photocatalytic semiconductor with a light emitting body having an absorbing band in a wavelength region not exciting the photocatalytic semiconductor and excited itself to emit light having a wavelength for exciting the photocatalytic semiconductor. The highly efficient photocatalyst composition capable of achieving the reduction of irradiation energy by a combination of the photocatalytic semiconductor with a luminous body emitting light containing the exciting wavelength of the photocatalytic semiconductor after the completion of irradiation with light from an exciting light source is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a composition for activating a photocatalytic reaction of a photocatalytic semiconductor material.

[0002]

2. Description of the Related Art A photocatalytic semiconductor material is irradiated with light having an energy greater than the band gap to generate electrons in a conduction band and holes in a valence band by photoexcitation, which diffuses into the particle surface and comes into contact with oxygen and water. As a result, electrons reduce adsorbed oxygen to generate superoxide anions, and holes oxidize water to generate hydroxyl radicals. It is known that all of these products have strong bactericidal power, organic substance decomposing power, and superhydrophilicity through the oxidation-reduction reaction.
As a light emitting source of light having energy equal to or greater than the band gap, there are sunlight, various lamps, ultraviolet rays, X-rays, various electromagnetic wave pulses, light emitting diodes, and the like. Each of these energy sources emits light having a wavelength that is absorbed by the photocatalytic semiconductor material, but is often not a practical light source because of low absorption efficiency or high running cost.
In addition, the light source may be limited depending on the fixed state of the photocatalytic semiconductor material, and such a point also hinders simple practical use. For example, titanium oxide (TiO)
In order to obtain the band gap energy (wavelength of 380 nm or less) of 2) from sunlight, only about 2% of the light can be used. Also, considering the excitation energy absorption efficiency of TiO2, only about 2% of sunlight can be used, and only one-tenth of the energy is absorbed as excitation energy in consideration of quantum efficiency. It has been known.

If a photocatalytic semiconductor material that absorbs a wavelength in the visible region of 400 to 800 nm, which is the main constituent wavelength of sunlight, is made instead of TiO2, the absorption efficiency should be improved. However, the energy at a wavelength of 400 to 800 nm is 3.0 to 1.4 eV, and there are photocatalytic semiconductor materials having a band gap energy in this range. However, a semiconductor having a small band gap energy has recombination of electrons and holes. Likely (the rate of recombination of electrons and holes at the particle surface decreases exponentially with the magnitude of the bandgap energy). That is, most of the oxygen and water are diffused to the surface of the particles and redoxed before the oxidation and reduction, so that no catalytic activity is exhibited. In addition, photocatalytic semiconductor materials (CdSe,
CdS, WO3, Fe2O3, GaP, etc.)
The crystal is oxidized by its own holes generated by the excitation energy and causes a dissolution phenomenon, and thus many of them lack practicality.

As a stable photocatalytic semiconductor material capable of producing a strong oxidation-reduction reaction by absorbing a radiation energy that can be used on a daily basis and easily used by humans, Ti
O2 is known, but as described above, it is excited only by light having a wavelength of 380 nm or less, so that the reaction efficiency is poor.

[0005] As an improvement measure, for example, (1) a photocatalytic semiconductor material such as WO3 having an absorption wavelength in the visible light region and Ti
A method using O2 in combination, (2) adding a small amount of ruthenium or chromium to TiO2, or adding chromium ions to Ti
A method of reducing the bandgap energy by accelerating the O2 particles to form an implanted impurity level to enable excitation in the visible light range; (3) Ti in a reducing atmosphere
Methods for forming an absorption band in the visible light region, such as a method for generating O2, have been proposed.

In the case of (1), the band gap energy of WO3 is 2.5 eV (wavelength 480 nm), and the holes generated by excitation in the visible light region oxidize oxygen on the TiO2 crystal surface, and the resulting oxygen It is stated that hydrophilic domains are generated by the adsorption of water on the defects, and a superhydrophilic coating can be obtained. This proposal is not a proposal aimed at improving the oxidation-reduction power by activating TiO2 due to the magnitude of the excitation energy and the resulting effects.
Another feature of O2 is that the contact angle with water, which is another feature of O2, is set to 0 degree to obtain superhydrophilicity, and to prevent fogging, water droplet formation, antistatic and the like of an object such as a glass plate. In the case of (2), there is a report that absorption also appears in the visible light range, but it has not been confirmed again and has not yet been proved. Further, in the case of (3), as in the case of (2), although the effect was reported, it was not reproducible and was not sufficiently verified.

That is, the practical use of a conventional photocatalytic semiconductor material is premised on the fact that the photocatalytic semiconductor is used as fine particles in order to secure a large specific surface area in order to secure the catalytic efficiency of the photocatalytic semiconductor. Therefore, in order to maintain the recovery efficiency of the particulate photocatalytic semiconductor and to enhance the efficiency of the oxidation-reduction reaction on the target object, how to fix it to the substrate In order to maintain the catalytic reaction described above, a proposal has been made on a binder to a substrate, a binder composition for paint, and the like. Numerous proposals have been made for the immobilization of such a photocatalytic semiconductor on a substrate. For example, methods for fixing aqueous silica sol, alkoxysilane, and silicone polymer are disclosed in JP-A-2-187147 and JP-A-20-187147.
00-107608, JP-A-10-146251,
JP-A-11-188271, JP-A-8-131842
JP-A-4-284851 and JP-A-9-1724
JP-A-9-208438, JP-A-11-6104
4, JP-A-11-315223, JP-A-2000-1
91960, JP-A-10-287846, JP-A-1
It is shown in the official gazettes such as 1-2235550. Also, regarding the fixing method using hydraulic cement, see JP-A-2000-
233134, JP-A-2000-219546, JP-A-2000-189801, JP-A-2000-11711
7, JP-A-2000-73046, JP-A-22820
No. 4 and the like. The fixing method using an alkali silicate, an alkaline earth silicate or a phosphate is disclosed in JP-A-8-318166 and JP-A-8-1137.
No. 54, Japanese Unexamined Patent Publication No. 9-10582, Japanese Unexamined Patent Publication No. 11-188
No. 271, etc. Further, for example, with respect to a fixing method using a high light-resistant fluororesin, JP-A-4-284851, JP-A-8-131842,
It is proposed in Japanese Patent Application Laid-Open No. H11-188271.

[0008]

As described above, at present, no proposal has been made in terms of the efficient administration of light energy from a light source to a photocatalytic semiconductor, and therefore, a large amount of energy including visible light is required. A photocatalytic semiconductor material that efficiently absorbs has not been put to practical use. On the other hand, when irradiating ultraviolet light with various lamps, the ultraviolet region has a large amount of absorbing medium, and it is difficult to quantitatively secure a desired irradiation amount. For example, when ultraviolet light is irradiated through an acrylic plate or a normal glass plate, the acrylic plate has a transmittance of 95% at a wavelength of 400 nm, a transmittance of 75% at a wavelength of 380 nm, and a wavelength of 360 nm.
In this case, the transmittance becomes 0%. For a normal glass plate, the wavelength is 4
The transmittance decreases from around 00 nm and the transmittance becomes 0 at 300 nm.
%become. In addition, absorption by water vapor and oxygen in the air also occurs. Also, a lamp containing a lot of ultraviolet light with a wavelength of 360 nm or less cannot be used in a space where people live and live due to the influence of human body, and it can be used in isolated areas or at night when human activities stop. Therefore, the catalyst reaction time cannot be sufficiently secured.

A photocatalytic semiconductor material having a high band gap energy, an absorption band in the ultraviolet region, and a strong oxidative decomposition power is attractive in its bactericidal power and organic substance decomposition power. It is difficult to select a light source, and because it is a short-wavelength ultraviolet ray, it is necessary to consider the effect on the human body, and it is difficult to select a practical and effective light source and maintain effective catalytic reaction efficiency together. Was.

The present invention has been made in view of the above-mentioned conventional problems, and one of its objects is to secure a light source of a photocatalytic semiconductor material having a bactericidal power by a strong oxidation-reduction power and an organic substance decomposition power. While the light energy for exciting the photocatalytic semiconductor material can be utilized without relying on a special light source, a large amount of energy including visible light can be used, the absorption of the excitation light can be reduced, and the excitation energy can be efficiently irradiated. A composition that activates a photocatalytic reaction that can efficiently absorb and use the energy of an external irradiation light source and can continue to supply excitation energy by self-emission after irradiation is completed, paints and coating materials using the same And a method of coating a substrate using the same.

[0011]

Means for Solving the Problems As a result of intensive studies from the above viewpoint, the present inventors have found that a luminous body, which is a substance that is excited and emits light by being irradiated with light, in the vicinity of a photocatalytic semiconductor material. It was found that light energy could be used efficiently if it existed. That is, the composition for activating the photocatalytic reaction of the present invention is a composition comprising a photocatalytic semiconductor material and a luminous body as basic materials, and dramatically improves the catalytic activity.

That is, in order to achieve the above object, the present invention activates a photocatalytic reaction in which a powdery photocatalytic semiconductor material is mixed with a powdery luminescent substance that activates the photocatalytic reaction. Composed of a highly efficient photocatalytic composition.

At this time, the luminescent material is preferably any one of a phosphor, a phosphor, a phosphor, and an electroluminescence, which emits and emits light in the form of light by converting the absorbed electromagnetic wave energy into quantum light.

The luminescent substance may be a substance which emits and emits light in the form of light by converting the absorbed electromagnetic wave energy into quantum light.

Further, it is preferable that the light emitting substance contains a phosphor, a phosphor, a phosphor, and electroluminescence.

Preferably, the photocatalytic semiconductor material is made of titanium oxide (Ti02) or strontium titanate (SrTiO) which absorbs light of a predetermined wavelength and is excited to cause a catalytic reaction.
3), silicon titanate (SiTiO3), potassium titanate (K2TiO3), titanium peroxide (TiO2)
), Molybdenum sulfide (MoS2), bismuth oxide (B
i2O3), ferric titanate (Fe2TiO3), indium oxide (In2O3), ruthenium oxide (Ru)
O2), cadmium oxide (CdO), ferric oxide (F
e2 O3), tungsten oxide (WO3), niobium oxide (Nb2 O5), cadmium selenide (CdS)
e), potassium tantalate (KTaO3), cadmium sulfide (CdS), (silicon) Si, zirconium oxide (ZrO2), gallium phosphide (GaP), gallium arsenide (GaAs), zinc oxide (ZnO), tin oxide (SnO)
It is preferable that at least one member selected from the group of 2) is used.

The average particle diameter of the photocatalytic semiconductor material is 3
It is preferably from nm to 30 μm.

The mixed composition of the photocatalytic semiconductor material and the luminescent substance is used in a weight ratio of 20 to 20%.
It is preferable to mix 90 wt% and 10 to 50 wt% of the luminous body.

Further, the light source for exciting the photocatalytic semiconductor material and the luminescent substance may be a fluorescent lamp, sunlight, an electromagnetic wave pulse, an electron beam, an ultraviolet ray, or an X-ray. Good.

Further, the present invention comprises a paint containing the high-efficiency photocatalyst composition according to any one of claims 1 to 8.

Further, the present invention comprises a substrate on which the high-efficiency photocatalyst composition according to any one of claims 1 to 8 is fixed by a required fixing method.

The present invention also provides a photocatalytically active composition obtained by dispersing a luminescent substance in a sol of a photocatalytic semiconductor material, applying the photocatalytically active composition to an object, and coating the object after high-temperature baking. Composed of methods.

Further, the luminescent substance is excited by an electron beam for CRT, ultraviolet ray or visible light, and activated silver and nickel excited by ultraviolet ray or ultraviolet ray, visible ray excited by silver or nickel, silver and aluminum and activated silver alone. Zinc “ZnS: A
g +, (NiorAlor simple substance)] Silver-activated zinc sulfide and copper and aluminum-activated zinc cadmium sulfide [ZnS: Ag ++ (Zn, Cd) S: Cu2
+, Al3 +] Zinc sulfide activated with chlorine and silver and cadmium sulfide activated with copper and aluminum [ZnS: Ag +, Cl − + (Zn,
Cd) S: Cu2 +, Al3 +] Cerium-activated yttrium aluminate [YAlO3:
Ce3 +] Calcium tungstate [CaWO4] Lead activated calcium tungstate [CaWO4: Pb
2+] Lead activated barium silicate [BaSi2 O6: Pb2 +] Lead activated strontium barium magnesium [(Sr, Ba, Mg) Si2 O7: Pb2 +] Cerium activated calcium magnesium [CaMg
Si2O7: Ce3 +] Yttrium silicate activated with cerium and terbium [Y2
SiO6: Ce3 +, Tb3 +] Cerium-activated yttrium silicate [Y2 SiO5: C
e3 +] Terbium activated yttrium silicate [Y2 SiO5:
Tb3 +] Europium activated yttrium sulfide oxide [Y2O2
S: Eu2 +] Manganese-activated zinc silicate [Zn2 SiO4: Mn2
+] Europium activated strontium phosphate [Sr2 P2
O7: Eu2 +] Europium-activated strontium magnesium phosphate [(Sr, Mg) 2 P2O7: Eu2 +] Europium-activated strontium phosphate [Sr3 (P
O4): Eu2 +] Europium-activated aluminum strontium barium silicate [(Sr, Ba) Al2 Si2 O8: Eu2
+] Europium activated barium magnesium silicate [Ba3
MgSi2O8: Eu2 +] Europium activated strontium fluoroborate [SrB
4 O7 F: Eu2 +] Europium activated barium chloride iodine [BaF
(Cl, I): Eu2 +] Europium-activated strontium silicate, strontium chloride [(Sr2 Si3 O8.2SrCl2: Eu
2+] Europium and manganese activated magnesium barium aluminate [BaMgAl16O27: Eu2 +, Mn]
Preferably, any one of the above fluorescent compounds is used.

The luminescent substance is sodium-activated cesium iodide [CsI: Na +] europium-activated barium sulfate [BaSO4: Eu2] excited by X-rays.
+] Europium activated barium fluoride chloride [BaFCl: E
u2 +] or any other fluorescent compound.

Further, the luminescent substance is excited by europium-activated calcium tungstate [CaWO] which is excited by short-wavelength ultraviolet light for plasma display.
4: Eu3 +] Europium activated magnesium barium aluminate [B
aMgAl14O23: Eu2 +] Any one of fluorescent compounds such as europium-activated magnesium strontium silicate [SrMg (SiO4): Eu2 +] may be used.

The luminescent substance is neodymium and europium activated calcium aluminate [CaAl2O3: Eu2 +, Nd] dysprosium and europium activated strontium aluminate [Sr4Al14O25: Eu2 +, Dy] dysprosium and europium activated strontium aluminate [ [SrAl2O3: Eu2 +, Dy] may be any one of the luminous or phosphorescent compounds.

[0027]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a powdery photocatalytic semiconductor material, a powdery luminescent substance for activating a photocatalytic reaction,
And a high-efficiency photocatalyst composition in which is mixed. That is, by mixing a photocatalytic semiconductor material composed of a particulate powder and a particulate luminescent substance and arranging these substance particles in close proximity to each other, light energy is efficiently used.

Since the photocatalytic semiconductor material and the light emitting substance are arranged and dispersed in the form of particles in close proximity, absorption by oxygen or water vapor in the air is small, and the light energy of the light emitting substance efficiently acts on the photocatalytic semiconductor. Excite this. In particular, the luminescent substance absorbs light energy having a wavelength not used to excite the photocatalytic semiconductor material, and when excited, emits light having a wavelength corresponding to the band of the excitation light of the photocatalytic semiconductor material at a particle position close to the photocatalytic semiconductor material. And activate it effectively.

A photocatalytic semiconductor material is a substance which is excited by light and can give its energy to other materials. When light having a band gap energy or more is absorbed, electrons in the valence band are excited into the conduction band to be excited. Holes are generated in the band, and the holes and electrons cause bactericidal, deodorizing, organic matter decomposing, or superhydrophilic washing and antifogging effects through oxidation and reduction reactions.

The photocatalytic semiconductor material is titanium oxide (TiO 0
2), strontium titanate (SrTiO3), silicon titanate (SiTiO3), potassium titanate (K2TiO3), titanium peroxide (TiO2), molybdenum sulfide (MoS2), bismuth oxide (Bi2O3)
), Ferric titanate (Fe2TiO3), indium oxide (In2O3), ruthenium oxide (RuO2)
), Cadmium oxide (CdO), ferric oxide (Fe2
O3), tungsten oxide (WO3), niobium oxide (Nb2O5), cadmium selenide (CdSe),
Potassium tantalate (KTaO3), cadmium sulfide (CdS), (silicon) Si, zirconium oxide (Zr
O2), gallium phosphide (GaP), gallium arsenide (Ga
As), zinc oxide (ZnO), tin oxide (SnO2)
It is preferably at least one selected from the group of The average particle size is preferably 3 nm to 30 μm, more preferably 5 nm to 100 nm, and a commercially available material can be easily obtained and applied. However, it is not limited to these. In particular, titanium oxide is an anatase type, a rutile type crystalline titanium oxide, of which anatase type high-purity titanium oxide fine particles have strong photocatalytic performance in terms of self-purification, antibacterial and the like,
Moreover, it is preferable in that it is expressed for a long period of time.

The luminous body includes a phosphor, a phosphor, a phosphor, and an electroluminescence which emits and emits light in the form of light by converting the absorbed electromagnetic wave energy into a quantum optical form. Phosphors include, for example, sulfides and oxides of zinc and cadmium or sulfides of alkaline earth metals containing extremely small amounts of heavy metals in their crystals, and these are excited by electromagnetic waves using copper, manganese, etc. as active substances, It emits unique fluorescence. When the excited electrons return to their original orbit, luminescence emits energy obtained from outside as light. The phosphor continues to emit light even after the irradiation of the electromagnetic wave stops. Electroluminescence is an electroluminescent material in which free electrons accelerated by an electric field excite electrons of a specific impurity, which serves as a luminescent center, present in a luminescent material, and emits energy when it returns to its original state. . The light storage body is obtained by adding a rare earth element europium to an oxide such as strontium or aluminum, and emits light when the stored energy is gradually released by irradiating high energy light such as ultraviolet light. It is believed to be something.
Therefore, even at night or the like, it is possible to self-emit light and emit excitation energy light of the photocatalyst semiconductor arranged in close proximity.

As the phosphor, the following compounds that are excited by electron beam excitation for CRT and ultraviolet or visible light are suitably selected. However, the luminous body is not limited to the following compounds. Silver-nickel, silver-aluminum, and silver-activated zinc sulfide "ZnS: Ag +, (NiorAlor alone)" Silver-activated zinc sulfide and copper and aluminum-activated zinc cadmium sulfide [ZnS: Ag ++ (Zn, Cd) S: Cu2
+, Al3 +] Zinc sulfide activated with chlorine and silver and cadmium sulfide activated with copper and aluminum [ZnS: Ag +, Cl − + (Zn,
Cd) S: Cu2 +, Al3 +] Cerium-activated yttrium aluminate [YAlO3:
Ce3 +] Calcium tungstate [CaWO4] Lead activated calcium tungstate [CaWO4: Pb
2+] Lead activated barium silicate [BaSi2 O6: Pb2 +] Lead activated strontium barium magnesium [(Sr, Ba, Mg) Si2 O7: Pb2 +] Cerium activated calcium magnesium [CaMg
Si2O7: Ce3 +] Yttrium silicate activated with cerium and terbium [Y2
SiO6: Ce3 +, Tb3 +] Cerium-activated yttrium silicate [Y2 SiO5: C
e3 +] Terbium activated yttrium silicate [Y2 SiO5:
Tb3 +] Europium activated yttrium sulfide oxide [Y2O2
S: Eu2 +] Manganese-activated zinc silicate [Zn2 SiO4: Mn2
+] Europium activated strontium phosphate [Sr2 P2
O7: Eu2 +] Europium-activated strontium magnesium phosphate [(Sr, Mg) 2 P2O7: Eu2 +] Europium-activated strontium phosphate [Sr3 (P
O4): Eu2 +] Europium-activated aluminum strontium barium silicate [(Sr, Ba) Al2 Si2 O8: Eu2
+] Europium activated barium magnesium silicate [Ba3
MgSi2O8: Eu2 +] Europium activated strontium fluoroborate [SrB
4 O7 F: Eu2 +] Europium activated barium chloride iodine [BaF
(Cl, I): Eu2 +] Europium-activated strontium silicate, strontium chloride [(Sr2 Si3 O8.2SrCl2: Eu
2+] Europium and manganese activated magnesium barium aluminate [BaMgAl16O27: Eu2 +, Mn]

As the luminous body, the following compounds which are excited by X-ray irradiation are suitably selected. However, the luminous body is not limited to the following compounds. Sodium activated cesium iodide [CsI: Na +] Europium activated barium sulfate [BaSO4: Eu2
+] Europium activated barium fluoride chloride [BaFCl: E
u2 +] etc.

Further, the luminous body is a europium-activated calcium tungstate [CaWO] which is excited by short-wavelength ultraviolet light for plasma display.
4: Eu3 +] Europium activated magnesium barium aluminate [B
aMgAl14O23: Eu2 +] It is preferable to use europium-activated magnesium strontium silicate [SrMg (SiO4): Eu2 +]. However, the luminous body is not limited to these compounds.

As the luminous body, the following may be selected as the luminous body and the phosphor. However, the luminous body is not limited to these compounds. Neodymium and europium activated calcium aluminate [CaAl2O3: Eu2 +, Nd] Dysprosium and europium activated strontium aluminate [Sr4Al14O25: Eu2 +, Dy] Dysprosium and europium Activated strontium aluminate [SrAl2O3: Eu2 +, Dy]

The average particle diameter of these phosphors is 0.1 μm.
m to 100 μm, more preferably 1 μm to 5 μm.
0 μm, and commercially available materials can be used.

The proportion of the mixed composition of the particulate photocatalyst semiconductor material and the particulate light emitter is preferably 20 to 90 wt% for the photocatalytic semiconductor material and 10 to 50 wt% for the light emitter.

A high-efficiency photocatalyst composition obtained by mixing a particulate photocatalytic semiconductor material and a particulate light-emitting substance is used as it is as a particulate mixture, by disposing it in the passage of water or another liquid, or cleaning air. be able to.

The high-efficiency photocatalyst composition can be immobilized on the substrate by using any of the previously disclosed methods for immobilizing a photocatalyst material on a substrate. For example, the composition is internally added and applied as an inorganic adhesive, fixing agent, coating agent or paint. For example, it may be mixed with an aqueous silica sol, alkoxysilane, or silicone polymer and applied as a paint, a coating material, an adhesive, a fixing material, or a coating material. Further, it can be kneaded with hydraulic cement and applied as an adhesive, a fixing agent, or a coating agent to an object. Further, the high-efficiency photocatalyst composition may be fixed to the substrate using an alkali silicate, an alkaline earth silicate, or a phosphate. Further, the composition may be applied by internally adding it to an organic adhesive, fixing agent, coating agent or paint. In this case, it is preferable to use a fluorine resin as the organic substance so that the binder or the like of the organic paint is hardly decomposed with time due to the oxidation-reduction action of the photocatalytic semiconductor. As the substrate, for example, ceramics, inorganic materials such as glass, plastic, rubber,
The present invention can be applied to articles made of organic materials such as wood and paper, articles made of metal such as metal such as aluminum, and alloys such as steel.

The amount of the composition added to an inorganic or organic binder (including an adhesive, a fixing agent, a coating agent, and a paint) is preferably 3 wt% to 50 wt%, more preferably 5 wt% to 30 wt%. It is good.

Further, a light-emitting substance is dispersed in a sol of a photocatalytic semiconductor material to obtain a photocatalytic active composition, and the photocatalytic active composition is applied to a substrate, sprayed, coated, and fired at a high temperature to be brought into close contact. And applied as a coating material.

[0042]

EXAMPLES The contents of the present invention will be described in more detail with reference to the following examples. However, these examples are merely examples, and the scope of the present invention is not limited to these examples.

Example 1 10 g of TiO2 (anatase type average particle size 7 nm), aqueous silica sol (average particle size 5
nm) 50 g with 150 g of 3 mm glass beads for 30
The mixture was placed in a 0 ml plastic container, and dispersed with a paint conditioner manufactured by Red Devil Co. for 1 hour to form a paint. Further, 6 g of the luminous body CaAl2O4: Eu2 +, Nd (average particle size 2.5 ± 1 .mu.m) and 0.1 g of the nonionic surfactant.
3 g was added and the mixture was stirred for 1 hour to obtain a paint containing the high-efficiency photocatalyst composition. The obtained paint is applied to a 100 cm 2 glass plate degreased with acetone to a thickness of 5 μm via a primer.
200 ° C 1 after painting with a roll coater
After drying for a period of time, Sample A coated with the highly efficient photocatalyst composition of the present invention was obtained.

Example 2 A sample B was obtained in the same manner as in Example 1 except that the average particle size of TiO 2 (anatase type) was changed to 20 nm.

Example 3 Sample C was obtained in the same manner as in Example 1 except that the amount of TiO 2 (anatase type average particle diameter 7 nm) was changed to 20 g.

[Embodiment 4] Phosphor CaAl2 of Embodiment 1
O4: Eu2 +, Nd (average particle size 2.5 ± 1 μm)
Was changed to 12 g to obtain a sample D.

[Comparative Example 1] A sample E was prepared by applying a coating material to which no luminous body was added to the coating material of Example 1 on a glass plate in the same manner as in Example 1.

[Comparative Example 2] A glass plate not subjected to the surface treatment was used as Sample F.

[Evaluation] Using the samples obtained in Examples 1 to 4 and Comparative Examples 1 and 2, a decomposition test of formaldehyde was carried out by the following method. (Test Method 1) Samples A to F were placed in a Pyrex (registered trademark) glass container (completely sealed inner volume: 30 liters), and irradiation with a UV intensity of 1 mW / cm2 was started while injecting 50 ppm of formaldehyde and stirring. FIG. 1 shows the concentration change over time. In Samples A to E, a decrease in formaldehyde concentration is observed, but in Sample F, the concentration hardly changes. (Test method 2) Pyrex glass container (fully sealed)
Samples A to E were placed in an internal volume of 20 l), 50 pmm of formaldehyde was injected, and the mixture was allowed to stand for 1 hour in a room (under sunlight and a fluorescent lamp under an illuminance of about 1000 lx) with stirring to measure the concentration. Thereafter, the container was moved to a dark room, and the results of measuring the formaldehyde concentration at each time are shown in FIG. In Samples A to D, a decrease in density under daylight is observed, and a decrease in density in a dark room thereafter is also observed. This is a result of CaAl2O3: Eu2 +, Nd, which is a phosphorescent phosphor, emitting light in a dark room to excite the photocatalytic semiconductor material and activate the catalytic reaction. Sample E does not show any activity after being transferred to a dark room although a decrease in concentration under daylight is observed. Sample F hardly changed

[Comparative Example 3] 10 g of TiO2 (anatase type average particle diameter: 20 nm), 100 g of aqueous silica sol (average particle diameter: 5 nm), and 1 g of nonionic surfactant were mixed in 3 m.
The mixture was shaken with a paint shaker for 3 hours together with 100 g of the glass beads of m to obtain a paint. The thickness of the coating film is set to 1 on a glass plate 100 cm 2 degreased from the obtained paint through a primer.
After coating with a roll coater so that the thickness becomes 0 μm, 200
The sample was dried at ℃ 1 hour to obtain a sample G.

Example 5 Ba3M was added to the paint of Comparative Example 3.
gSi2O8: 3 g of Eu2 + (average particle diameter 2 [mu] m),
0.3 g of nonionic surfactant was added, and the mixture was shaken with 150 g of 3 mm glass beads for 2 hours to obtain a highly efficient photocatalyst composition paint. A roll coater was applied to a glass plate 100 cm 2 via a primer so that the coating thickness became 10 μm. And dried at 200 ° C. for 1 hour to obtain a sample H.

[Embodiment 6] Ba3 MgSi of Embodiment 5
SrB4O7 F: Eu instead of 2O8: Eu2 +
A sample I was obtained by adding 3 g of 2+ (average particle size: 5 μm) to form a paint and applying the same paint as above.

[Evaluation] Using the samples GI obtained in the above Comparative Examples and Examples, a decomposition test of formaldehyde was carried out by the following method. "Test method 3" Samples G to I were placed in a Pyrex glass container (completely closed, inner volume: 30 l),
50 ppm of formaldehyde was injected, and the concentration was measured indoors (sunlight, illuminance under fluorescent lamp about 500 lx) with stirring. The results are shown in FIG.

In the same manner as described above, after irradiation with formaldehyde, irradiation was performed at an ultraviolet intensity of 1 mW / m 2 with stirring, and the concentration change with time was measured. FIG. 4 shows the results.

Under the sunlight and fluorescent light, the sample H has the highest activity. Ba3MgSi2O8 used for sample H:
Eu2 + has an excitation spectrum of 200 nm or less to 400 nm.
nm, followed by broad, especially around 370 nm
Since the excitation efficiency up to around 420 nm is high and the peak of the emission spectrum is at 380 nm to 400 nm,
It can be seen that adjacent TiO2 is excited by its own light emission. In particular, close proximity to TiO2 reduces the absorption by oxygen and water vapor in the air and efficiently excites, thereby promoting the decomposition of formaldehyde.

From this, Ba3 MgSi2 O8
: Eu2 + was not used to excite TiO2 42
It absorbs a wavelength of 0 nm or less (especially 380 nm to 420 nm) and emits light having a wavelength corresponding to the absorption band of TiO2 by being excited, thereby exciting TiO2 more effectively by emitting it at a position close to TiO2. It is understood that.

At an ultraviolet intensity of 1 mW / cm 2, sample I has the highest activity. SrB4 O used for sample I
7: Eu2 + has an excitation spectrum of about 200 nm or more.
It is similar to Ba3MgSi2O8: Eu2 + described above in that it continues broadening to around 400 nm, but the excitation efficiency in the short wavelength ultraviolet region below 340 nm is high. Further, the peak of the emission spectrum is 36
Since it is in the range of 0 nm to 370 nm, it is possible to excite the adjacent TiO2 more strongly. Therefore, the decomposition of formaldehyde is promoted.

[0058]

According to the high efficiency photocatalyst composition of the present invention, a luminous body excited from a wide wavelength band including visible light can emit light having a wavelength corresponding to the band gap energy of a photocatalytic semiconductor material without relying on a special light source. Therefore, the light energy from the light source can be used more efficiently.

Further, since the luminous body is located close to the photocatalytic semiconductor material, the excitation energy from the luminous body can be directly applied without being absorbed or reflected by another substance.

If a luminous body is selected as the luminous body,
By continuing to emit light for several hours to several tens of hours after the end of the light irradiation, it is possible to continue to excite the photocatalytic semiconductor material. Until now, the photocatalytic semiconductor material did not undergo an oxidation-reduction reaction because it was not excited during the period of no light irradiation (at night or after the light was turned off). However, the oxidation-reduction reaction continues for several hours to over ten hours. That is, the oxidation-reduction reaction can be continued day and night, and power consumption can be suppressed.

[Brief description of the drawings]

FIG. 1 is a graph showing evaluation test results of Examples 1 to 4 and Comparative Examples 1 and 2.

FIG. 2 is a graph showing other evaluation test results of Examples 1 to 4 and Comparative Examples 1 and 2.

FIG. 3 is a graph showing evaluation test results of Comparative Example 3 and Examples 5 and 6.

FIG. 4 is a graph showing other evaluation test results of Comparative Example 3 and Examples 5 and 6.

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Claims (11)

[Claims] 1. A high-efficiency photocatalytic composition for activating a photocatalytic reaction in which a powdery photocatalytic semiconductor material is mixed with a powdery luminescent substance for activating a photocatalytic reaction. 2. A phosphor that emits and emits light in the form of light by converting the absorbed electromagnetic wave energy into quantum light,
The high-efficiency photocatalyst composition according to claim 1, which is any one of a phosphorescent material, a phosphor, and electroluminescence. 3. The high-efficiency photocatalyst composition according to claim 1, wherein the luminescent substance is a substance which emits and emits light in the form of light by converting the absorbed electromagnetic wave energy into quantum light. 4. The light-emitting substance is a phosphor, a phosphor, a phosphor,
The high-efficiency photocatalyst composition according to any one of claims 1 to 3, which is at least one kind of electroluminescence. 5. A photocatalytic semiconductor material is titanium oxide (Ti02) that absorbs light of a predetermined wavelength and is excited to cause a catalytic reaction.
), Strontium titanate (SrTiO3), silicon titanate (SiTiO3), potassium titanate (K
2 TiO3), titanium peroxide (TiO2), molybdenum sulfide (MoS2), bismuth oxide (Bi2O3)
), Ferric titanate (Fe2TiO3), indium oxide (In2O3), ruthenium oxide (RuO2)
), Cadmium oxide (CdO), ferric oxide (Fe2
O3), tungsten oxide (WO3), niobium oxide (Nb2O5), cadmium selenide (CdSe),
Potassium tantalate (KTaO3), cadmium sulfide (CdS), (silicon) Si, zirconium oxide (Zr
O2), gallium phosphide (GaP), gallium arsenide (Ga
5) at least one selected from the group consisting of As), zinc oxide (ZnO), and tin oxide (SnO2).
The high-efficiency photocatalyst composition according to any one of the above. 6. The photocatalytic semiconductor material has an average particle size of 3 nm.
The high-efficiency photocatalyst composition according to any one of claims 1 to 5, which has a thickness of from 30 to 30 µm. 7. The mixed composition of a photocatalyst semiconductor material and a luminescent substance may have a weight ratio of 20 to 90, respectively.
The high-efficiency photocatalyst composition according to any one of claims 1 to 6, wherein the high-efficiency photocatalyst composition is blended in an amount of 10% to 50% by weight. 8. The high efficiency according to claim 1, wherein the light source for exciting the photocatalytic semiconductor material and the luminescent substance includes a fluorescent lamp, sunlight, an electromagnetic pulse, an electron beam, an ultraviolet ray, and an X-ray. Photocatalyst composition. 9. A paint containing the high-efficiency photocatalyst composition according to any one of claims 1 to 8. 10. A substrate on which the high-efficiency photocatalyst composition according to claim 1 is fixed by a required fixing method. 11. A method for coating an object which is obtained by dispersing a light emitting substance in a sol of a photocatalytic semiconductor material to obtain a photocatalytic active composition, applying the photocatalytic active composition to the object, and baking at a high temperature.