JP4120856B2 - Photocatalyst - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photocatalyst body.
[0002]
[Prior art]
It is known to use a photocatalytic film for deodorizing, antifouling and / or antibacterial.
[0003]
When the photocatalyst film is irradiated with ultraviolet rays and absorbs the light energy, electrons and holes are generated in the semiconductor that constitutes the photocatalyst film and exhibits a photocatalytic action. Electrons and holes react with oxygen and water on the film surface to generate active oxygen and other active radicals, and are said to be oxidized and reduced by decomposing organic contaminants and odorous components.
[0004]
Of the substances having photocatalytic activity, titanium oxide is currently most promising. This is because titanium oxide has a remarkable photocatalytic action, is a safe and industrially reasonable price, and can be obtained in a necessary amount.
[0005]
In recent years, attention has been focused on the usefulness of photocatalytic films, and active efforts are being made to form photocatalytic films on a wide range of articles such as building materials, lighting fixtures, and lamps.
[0006]
Although there are various methods for producing a photocatalytic film, a so-called dip method and an ultrafine particle dispersion coating method are generally used.
[0007]
The so-called dip method is a method in which a metal alkoxide constituting a photocatalyst film is applied to a substrate, for example, when the photocatalyst film is titanium oxide, a coating solution containing titanium alkoxide is applied and baked at a temperature of 400 to 500 ° C. This is a method of forming a film. The photocatalyst film obtained by this production method is durable because of its excellent film strength.
[0008]
The ultrafine particle dispersion coating method is a method in which a photocatalytic film is obtained by coating a substrate with a water-soluble dispersion in which photocatalytic ultrafine particles such as titanium oxide are dispersed in a solution made of water, alcohol, or the like, and baking it. . The photocatalytic film obtained by this production method has high crystallinity and excellent photocatalytic properties.
[0009]
If the photocatalyst film obtained by the so-called dip method is not baked at a high temperature for a long time, there is a problem that the crystallinity on the film surface is insufficient and the photocatalytic property is low. In the case where the substrate is a soft glass such as soda lime glass, the glass has a relatively low softening temperature and cannot be fired at a required high temperature, so that it is difficult to obtain sufficient photocatalytic properties.
[0010]
Further, when the photocatalyst film is formed by the above manufacturing method, the photocatalyst film mainly composed of titanium oxide is larger in refractive index than that of glass. There is also a problem that the rate decreases.
[0011]
On the other hand, in the ultrafine particle dispersion coating method, it is difficult to obtain sufficient adhesion to the substrate, and when an organic binder is used, cracks are likely to occur in the binder. When cracks occur in the binder, there is a problem that the transmittance decreases due to white turbidity. The applicant improved the photocatalyst film formation by the ultrafine particle dispersion coating method, and formed the metal oxide ultrafine particles formed on the substrate and the porous metal oxide composed of the Si compound on the underlying layer. In the photocatalyst formed with the photocatalyst film mainly composed of the ultrafine particles of titanium oxide, the metal oxide ultrafine particles contained in the underlayer are made of an oxide of Al, Zr, and Si, and the average particle size is 10 to 40 nm. And a photocatalyst having a molar ratio of 40 to 90% has been filed. In addition, an application has been filed to provide a highly functional photocatalyst that further improves the decomposition effect of such a photocatalyst, and a lamp and a luminaire using the photocatalyst, which have high decomposition characteristics.
[0012]
[Problems to be solved by the invention]
However, even with such a photocatalyst having high decomposition characteristics, high decomposition characteristics are still required. Moreover, there is no need for sintering at a high temperature as in the prior art, and the selection range of the substrate on which the photocatalyst film is formed is not narrowed, and the photocatalyst body is firmly bound while maintaining good compatibility with the substrate. In addition, a photocatalyst having high film strength and excellent scientific durability has been pursued.
[0013]
In addition, such a high-decomposable photocatalyst is highly decomposable, but also has a high adsorptivity to dirt substances and gases, and depending on the use conditions, the amount of dirt attached is more than the amount decomposed by the photocatalytic action. In this case, it has been found that the desired effect cannot be obtained. In addition, if there is a region where light is not irradiated with a desired intensity on the photocatalyst film, the region has a larger amount of dirt and gas than the portion where the photocatalyst film is not formed. There is.
[0014]
The adhesion of this dirt is affected by the surface state of the photocatalytic film. A highly decomposable photocatalyst has a high hydrophilicity in the film itself, and the photocatalytic film having a higher hydrophilicity tends to have higher dirt adhesion and adsorbability.
[0015]
  The present invention has been made in view of the above problems, and an object of the present invention is to provide a photocatalyst that has high degradability and can suppress adhesion and adsorption of dirt substances.
[Means for achieving the object]
  The photocatalyst of claim 1 comprises a substrate; TiOR₂Organometallic compound comprising (R is a chelate compound)Is applied to the surface of the substrate, and the TiOR is applied by heat treatment in a temperature range of 100 to 500 ° C. ₂ Organometallic compound consisting ofAnd a photocatalytic film made of an amorphous metal compound formed on the substrate so as to have a C / O ratio of 1 or less. And
[0016]
In the present claims and the following claims, the definitions and technical meanings of terms are as follows unless otherwise specified.
[0017]
As a result of various studies on the material for forming the photocatalyst film, the present inventor has found that the photocatalyst film is very high by making Ti, O, and C, which have not been known so far, the main component and the C / O ratio being 1 or less. It has been found that it has a decomposing power and can be formed at a low temperature. In addition, by performing heat treatment of this photocatalyst film at a relatively high temperature, a photocatalyst film mainly composed of titanium oxide having excellent film strength, adhesion strength to the substrate, and durability can be obtained while maintaining high decomposition power. I also discovered that. In particular, the average C / O ratio of the entire film is in the range of 0.01 to 0.3, and the C / O ratio on the surface is particularly preferably 0.1 or less. This is presumably because if the C content is increased, light is absorbed by the photocatalytic film and the transmittance of the film decreases. For this reason, said range became the optimal value.
[0018]
The substrate supports the photocatalyst film, and is allowed to be a functional material formed not only for the purpose of supporting the photocatalyst film but also for other functions not originally intended for supporting the photocatalyst. To do. Examples of the functional material used as the substrate include building materials such as tiles, window glass, and ceiling panels, kitchen and sanitary equipment, home appliances, lighting equipment, deodorizing or dust collecting filters, and the like. In addition to those listed above, a desired member can be used as the substrate as long as it can exhibit a photocatalytic action.
[0019]
Examples of the base material include metals, glass, ceramics (including porcelain), ceramics, stones, synthetic resins, and wood. However, since the photocatalytic film is formed by thermal decomposition, the substrate needs to have heat resistance that can withstand the heating temperature during the thermal decomposition. By this thermal decomposition, the photocatalyst film is firmly fixed to the substrate.
[0020]
Further, the photocatalyst is provided with a photocatalytic function by forming a base having a particle size of 1.0 μm to several hundreds μm made of metal, metal oxide, ceramics, etc., and forming a photocatalytic film on the surface of the particle. It can be a granular material. The particulate material having a photocatalytic function can be used as a deodorizing filter for an air purifier or used as an additive for a water purifier, or can be mixed into a paint to form a photocatalytic coating agent. Further, it is allowed to dispose the particles so as to form a film.
[0021]
When the substrate is formed by baking the photocatalyst film at a high temperature, the substrate needs to have heat resistance capable of withstanding the baking.
[0022]
The C / O ratio can be controlled by adjusting the amount of oxygen mixed in the atmosphere during film formation, but may be controlled by other methods.
[0023]
Experiments have confirmed that when the C / O ratio of the photocatalyst film is 1 or less, the resolving power of the photocatalytic film is good, and when it exceeds 1, the resolving power is greatly reduced.
[0024]
  Photocatalysts using amorphous titanium oxide have not been known so far, but have been found to have a very high decomposing power and can be heat-treated at a relatively high temperature. It was possible to obtain a photocatalyst film having good adhesion strength to the film, substrate, and durability while maintaining the above.Therefore, according to invention of Claim 1, it is possible to maintain the decomposition power of a photocatalyst film in a high state..
[0025]
  The photocatalyst of claim 2 comprises a substrate; TiOR₂Organometallic compound comprising (R is a chelate compound)Is applied to the surface of the substrate, and the TiOR is applied by heat treatment in a temperature range of 100 to 500 ° C. ₂ Organometallic compound consisting ofAnd heat-treating a film made of an amorphous metal compound, which is mainly formed of Ti, O, and C and has a C / O ratio of 1 or less, at a temperature exceeding 600 ° C. And a photocatalyst film that has been converted into a photocatalyst film.
[0026]
  Claims 1 and 2The photocatalytic film acts as follows.
(1) A photocatalytic film having high photocatalytic activity can be obtained by drying or firing in a relatively low temperature region.
(2) By subjecting the photocatalytic film of (1) to heat treatment in a relatively high temperature region (above 300 ° C.), titanium oxide (TiO 2)₂), A photocatalytic film that maintains higher decomposability, has high adhesion strength to the substrate and high film strength, and has chemical durability.
(3) The compatibility between the substrate and the photocatalyst film is good, and the photocatalyst film can be firmly bound to the substrate.
(4) It has been confirmed that the surface of the photocatalyst is hydrophobic in a normal state. By providing this hydrophobic property, adhesion and adsorption of dirt substances and gases are greatly reduced.
[0027]
  Claims 1 and 2According to the invention, since the photocatalyst film is formed from the amorphous metal compound mainly composed of Ti, O, and C, a photocatalyst having a high decomposing power can be formed at a low temperature.
[0028]
  The photocatalyst of claim 2 isMade of amorphous metal compoundCoveredCrystallize film by heat treatmentdidThe main feature is titanium oxide. Crystallization allows anatase structure, rutile structure and mixtures thereof.
[0029]
  Claim2According to the invention, since the photocatalyst film made of an amorphous metal compound containing Ti, O, and C as a main component is heat-treated, the photocatalyst film is crystallized, while maintaining a high decomposition force, A photocatalyst having high film strength and chemical durability can be obtained.
[0030]
  Claims 1 and 2Photocatalyst ofIsThe photocatalytic film is TiOR₂(R is a chelate compound)Consist ofFormed by pyrolyzing organometallic compoundsRu.
[0031]
This photocatalytic film is TiOR₂It can be formed by applying a solution obtained by dissolving (R is a chelate compound) in water, an organic solvent or a mixed solution thereof under a desired condition, followed by drying or heat treatment. It is also possible to form a solution based on an organic titanium compound such as titanium alkoxide by a CVD method under specific conditions, and to perform thermal decomposition.
[0032]
  Claims 1 and 2Photocatalyst ofIs, Amorphous metal compound is TiOR₂It is formed by thermally decomposing an organometallic compound using (R is a chelate compound) as a raw material.
[0033]
  TiOR₂(R is a chelate compound)Consist ofAmorphous metal compound mainly composed of Ti, O, and C obtained by pyrolyzing organometallic compoundFormed fromAlthough it was confirmed by experiments that the photocatalytic film has extremely high photocatalytic activity, the detailed mechanism by which the photocatalytic activity becomes high is unknown.
[0034]
However, it is considered that the amount of OH groups produced on the surface particularly affects the photocatalytic activity during the photocatalytic film formation process. Titanium alkoxide (TiOR)_FourIn the case of forming a photocatalyst film using as a raw material, first, a hydrolysis reaction partially occurs, and a large number of OH groups are formed.₂). The conventional photocatalyst film thus formed contains a large amount of OH groups, and many crystal defects are generated.
[0035]
  In contrast, the TiOR of this claim₂(R is a chelate compound)By pyrolyzing an organometallic compound consisting ofIn the case of film formation, this raw material hardly undergoes hydrolysis reaction and is directly thermally decomposed, which is considered to be because the amount of OH groups produced is very small.
[0036]
  The photocatalyst of claims 1 and 2 comprisesAmorphous metal compoundFormed fromThe photocatalytic film is TiOR₂ Consist ofSince it is formed by pyrolyzing the organometallic compound, the photocatalytic activity can be further increased.
[0037]
  Claim3Claims1 or 2In the photocatalyst described, TiOR₂ Consist ofOrganometallic compoundsInA photocatalytic film is formed by adding at least one of a group consisting of Si, Zr, Y, and Al or a mixture thereof, an alkoxide, a chelate, and a modified product thereof.
[0038]
  Claim3According to the invention of TiOR₂ Consist ofOrganometallic compoundsInAlthough at least one alkoxide, chelate, and its modified substance are added from the group consisting of Si, Zr, Y, and Al, the photocatalytic film contains C, although some absorption in the visible region occurs. The film formability and photocatalytic activity can be improved.
[0039]
  the aboveIn the photocatalyst, TiOR₂ Consist ofAdd metal oxide fine particles to organometallic compoundsMay.
[0040]
  thisAccording to TiOR₂ Consist ofSince metal oxide fine particles are added to the organometallic compound, the film forming property and the photocatalytic activity can be improved.
[0041]
  Claim4Claims1Or3In any one photocatalyst body, TiOR₂ Consist ofA silicone resin or a modified product thereof is added to an organometallic compound.
[0042]
  Claim4According to the invention of TiOR₂ Consist ofSince a silicone resin or a modified product thereof is added to the organometallic compound, the film formability and photocatalytic activity can be improved.
[0043]
  Claim5Claims1Or4In any one photocatalyst body, TiOR₂ Consist ofBy pyrolyzing organometallic compounds in an atmosphere mainly composed of inert gasTi, O, C as the main components, so that the C / O ratio is 1 or lessA photocatalytic film is formed.
[0044]
  Claim5According to the invention of TiOR₂ Consist ofSince the organometallic compound is thermally decomposed in an atmosphere mainly containing an inert gas, the photocatalytic activity can be maintained while improving the film formability.
[0045]
  Claim6Claims1Or5In any one of the photocatalyst bodies, R is acetylacetone (C_FiveH₇O₂), Cyclopentadienyl (C_FiveH_Five) Or dipivaloylmethane (C₁₁H₁₉O₂) At least one kind.
[0046]
  Claim6According to this photocatalyst body, it is possible to form a photocatalyst film with a chelate compound that is relatively inexpensive and easy to handle.
[0047]
  the aboveIn the photocatalyst, TiOR_xR ’_y(R: chelate compound, R ′: alkyl group, hydroxyl group, alkoxy group or carboxy group), and x + y = 2 and y ≦ 1May.
[0048]
TiOR_xR ’_yOf the chelate compound (R) bonded to titanium oxide (TiO) is substituted on one chelate compound (R ′) with an alkyl group, a hydroxyl group, an alkoxy group or a carboxy group, so that the substrate surface is wetted. This improves the adhesion and improves the adhesion of the film and the film formability. Thus, as a method of substituting one chelate compound (R), a known chemical reaction can be used.
[0049]
  ThisAccording to the photocatalyst body, TiOR_xR ’_yOf the chelate compounds (R) bonded to titanium oxide (TiO), one of the chelate compounds (R ′) is substituted with an alkyl group, a hydroxyl group, an alkoxy group or a carboxy group. The wettability is improved and the film adhesion and film formability can be improved.
[0050]
  the aboveIn the photocatalyst, TiOR₂ Consist ofAn organic metal compound is dissolved in a solvent, and further TiO₂AlO₃, SiO₂A photocatalytic film is prepared by applying a solution prepared by dispersing at least one ultrafine particle selected from the above to a substrate and then performing thermal decomposition.May form.
[0051]
  TiO₂AlO₃, SiO₂The at least one kind of ultrafine particles selected from the above has an average particle diameter of 2 to 100 nm, preferably 4 to 10 nm. TiO₂AlO₃, SiO₂At least one kind of ultrafine particles selected from the group consisting of TiOR and a solution dispersed in an organic solvent such as water or ethanol₂ Consist ofAn appropriate amount is mixed with an organometallic compound. The mixing ratio at this time is titanium oxide TiO.₂The mass conversion ratio of the material of the formed film is converted to TiO₂/ TiOR₂Is preferably ¼ to 4/5.
[0052]
  Thus, TiOR₂ Consist ofTiO as organometallic compound₂AlO₃, SiO₂By mixing an appropriate amount of at least one kind of ultrafine particles selected from the above, the film formability can be improved and the visible light transmittance can be increased. This is TiO₂AlO₃, SiO₂It is considered that at least one kind of ultrafine particles selected from the above is dispersed and mixed in the photocatalytic film, so that the difference in the mixed refractive index is reduced and the light interference is reduced.
[0053]
  the aboveAccording to the photocatalyst, TiOR₂ Consist ofTiO as organometallic compound₂AlO₃, SiO₂Since an appropriate amount of at least one kind of ultrafine particles selected from the above is mixed, the film formability of the photocatalyst film is improved and the visible light transmittance can be increased.
[0054]
  Also,The photocatalyst is a base; a photocatalyst film mainly composed of Ti, O, and C formed on the base and having a C / O ratio of 1 or less.₂AlO₃, SiO₂At least one kind of ultrafine particles selected from the above are mixed, and the amount thereof is 30 to 90 wt% as the oxide equivalent amount of the photocatalyst film.May be.
[0055]
The photocatalyst film mainly composed of Ti, O, and C has advantages such as forming a photocatalyst having high decomposing power at a low temperature as in claim 1, but the transmittance is reduced due to the effect of containing C, etc. A bug is raised. Therefore, as a result of examining various additives, TiO₂AlO₃, SiO₂By mixing at least one kind of ultrafine particles selected from the above, the transmittance was high and high decomposability was exhibited, particularly TiO.₂The oxide film is reduced to 30 to 90 wt% as an oxide reduction, so that the property film is good, the film can be formed at a low temperature, and a photocatalyst having a high transmittance can be formed.
[0056]
  The photocatalyst isThe film thickness of the formed photocatalyst is 30 to 350 nm and the average visible light transmittance of 500 to 600 nm is 86% or more.Preferably.
[0057]
  This is due to the high C content.catalystMembranes are required for membrane permeability and photocatalytic degradation performance because light is absorbed by the membrane and membrane permeability decreases.ThicknessStipulatedAboveDefine the transmittance. Thus, the C content necessary for the activation of the photocatalyst is defined by the transmittance.
[0058]
  This photocatalystTherefore, by defining the transmittance at the film thickness necessary for the decomposition performance of the photocatalyst, the optimal decomposition performance of the photocatalyst can be obtained.
[0059]
  Claim7Claims 1 to6In any one of the photocatalyst bodies, the photocatalyst film is hydrophobic.
[0060]
Here, “hydrophobic” means that the contact angle with water is 60 ° or more in an equilibrium state in an air atmosphere.
[0061]
The surface of the film containing titanium oxide as a main component varies somewhat depending on the production method, but generally has a hydrophilic contact angle of about 45 to 50 ° or less, and is irradiated with ultraviolet rays. In some cases, the contact angle is further lowered to become hydrophilic.
[0062]
As described above, a film containing titanium oxide as a main component generally has a strong hydrophilic tendency, and a photocatalytic film having higher hydrophilicity tends to have higher adhesion and adsorption of dirt.
[0063]
  Inventor is TiOR₂ Consist ofThe photocatalytic film formed by pyrolyzing organic compounds has a hydrophobic surface, which greatly reduces the adhesion of dirt and provides very high decomposition characteristics.Butfound.
[0064]
The details of the mechanism that exhibits hydrophobicity are unknown, but the photocatalytic film is formed by thermal decomposition without hydrolysis, so that the titanium oxide is close to a perfect crystal with few defects up to the film surface, and the OH group It seems that it is difficult to combine.
[0065]
When the surface of the photocatalyst film is hydrophobic, adhesion and adsorption of dirt substances and gases are greatly reduced, and the photocatalyst film has high decomposition characteristics, so that the cleaning effect of the photocatalyst is further promoted. In particular, the photocatalyst film of the photocatalyst according to claim 10 is hydrophilic immediately after film formation, but exhibits a hydrophobicity with a contact angle with respect to water of about 70 to 90 ° when left as it is or when water is attached thereto.
[0066]
  Claim7According to the invention, when the photocatalyst film is hydrophobic, the adsorption or adhesion of dirt substances and gases is reduced even when compared with the substrate surface on which the photocatalyst film is not formed. It can be set as the photocatalyst body provided with both the effects which suppress adhesion of a substance.
[0067]
  the aboveIn the photocatalyst, the substrate has a porous surfacePreferably.
[0068]
  the aboveIn the photocatalyst, a porous metal oxide film is formed on the substrate, and a photocatalyst film is formed on the surface of the porous metal oxide film.May.
[0069]
It has been found that the photocatalytic properties are further improved by forming a photocatalytic film made of an amorphous metal compound mainly composed of Ti, O, and C when a metal, ceramics or the like is used as a base and the surface is porous. In this case, even if the film thickness of the photocatalyst film is as small as several nanometers to several tens of nanometers, the decomposability becomes very high.
[0070]
For example, silica (SiO 2)₂) And alumina (Al₂O_ThreeThe same effect can be obtained even when a porous metal oxide film made of, for example, is formed.
[0071]
In the dip method using a general organic titanium compound or the like, the photocatalytic activity is almost lost at a constant film thickness, for example, 10 nm or less, whereas the photocatalytic film of the present invention maintains a relatively high photocatalytic activity even at a film thickness of 10 nm or less. For example, even if it was 2 to 3 nm, it was only slightly reduced. This seems to be due to the fact that the surface area of the photocatalytic film increases because the substrate has a porous surface.
[0072]
  This photocatalystTherefore, by making the substrate surface porous, a photocatalyst having high photocatalytic activity can be obtained even if the film thickness is reduced.
[0073]
  the aboveIn the photocatalyst body, the substrate is metal oxide particles, and a photocatalyst film is formed on the particle surface.May.
[0074]
When the photocatalyst film is fired in a relatively low temperature region, the SO in the atmosphere_xOr NO_xFor example, the photocatalytic activity may be reduced. Such a decrease in photocatalytic activity is greatly improved by high-temperature heat treatment, but the substrate material is limited because high-temperature heat treatment is required.
[0075]
Therefore, for example, silica (SiO₂) And alumina (Al₂O_ThreeThese are improved by forming a photocatalyst layer on the surface of the metal oxide particles consisting of, for example, and directly or by depositing the metal oxide particles on the substrate, and a photocatalyst with high photocatalytic activity can be obtained. .
[0076]
The metal oxide fine particles may be not only titanium oxide fine particles of 4 to 100 nm which are usually used, but also those having almost no other photocatalytic activity such as glass, alumina and zirconia, and those having a diameter of several mm such as beads. But it ’s okay. This is the raw material TiOR₂A suitable amount of metal oxide fine particles (particle size: 16 nm) made of alumina are mixed in a solution of 2 to 10% by mass (R is acetylacetone) dissolved in water and ethanol (50:50), dried, and then heat treated at 100 to 500 ° C. in a timely manner. Further, it is formed by forming a suitable secondary shape by pulverizing or the like.
[0077]
A coating film that has only been naturally dried dissolves in water, organic solvents, etc., and its film strength is very weak. However, the photocatalytic film is obtained by partially thermally decomposing the raw material by heat treatment at a low temperature (100 ° C. to 500 ° C.). Form.
[0078]
  This photocatalystAccording to the surface of metal oxide fine particlesInSince the photocatalyst film is formed, a photocatalyst film having practical film strength and durability and having a very high decomposability even when the photocatalyst film is used alone can be obtained at a low temperature. It can be used as a photocatalyst in the form of an appropriate secondary shape by decomposing a substance to be decomposed or by depositing the fine particles on a substrate on a film or particles.
[0079]
  The photocatalyst is, Substrate; MO on substrate_XC_Y(M is at least one of Si, Zr, Al, and Ga) A photocatalytic film was formed on the surface of the layer formed at 5 to 150-nm.May be.
[0080]
MO_XC_YIn the above, M is at least one of Si, Zr, Al, and Ga, or a mixture thereof, and is formed on the substrate. Moreover, it can be set as the photocatalyst body which has especially high decomposability to make Y / X into the range of 0.02-0.2.
[0081]
MO like this_XC_YThe layer can be formed by applying and drying at least one of Si, Zr, Al, and Ga in which alkoxide, chelate, and their metamorphosis are dissolved. At this time, the film thickness is preferably 5 to 150 nm. For example, ZrC can be formed in a film thickness of 70 nm by applying Zr acetylacetonate dissolved in 1 to 5 wt% alcohol and heating to 150 ° C.
[0082]
  thisAccording to the photocatalyst film, unevenness in film formability and decomposability, which is sensitive to the surface state of the substrate, and suppresses unevenness and decrease in film formability and decomposability regardless of the surface state of the photocatalyst film, which is likely to be deteriorated. be able to.
[0083]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0084]
FIG. 1 is a conceptual schematic diagram showing an enlarged cross section of a photocatalyst body in the first embodiment of the present invention.
[0085]
In each figure, 10 is a photocatalyst body, 1 is a substrate, and 2 is a photocatalyst film. The substrate 1 is made of rectangular plate-shaped soda lime glass having a thickness of 3 mm and a side length of about 50 mm.
[0086]
The photocatalytic film of this embodiment is formed from an amorphous titanium oxide-based metal compound containing Ti, O, and C as main components.
[0087]
A method for forming the photocatalytic film 2 will be described.
[0088]
  For example,TiOR₂(R is acetylacetone (C_FiveH₇O₂)) Is prepared by dissolving 2 to 10% by mass in a solvent composed of water and ethanol (50:50), and this solution is applied to the substrate 1 and dried naturally.
[0089]
The coating film thus obtained dissolves in water or an organic solvent and has a very low film strength. However, a photocatalytic film made of an amorphous metal compound mainly composed of Ti, O, and C is obtained by subjecting the coating film raw material to partial thermal decomposition by heat-treating the coating film in a relatively low temperature region (100 to 500 ° C.). 2.
[0090]
Thus, by forming the photocatalyst film 2 from an amorphous metal compound mainly composed of Ti, O, and C, the photocatalyst film 2 having practical film strength, excellent durability, and very high decomposing power. Can be obtained. In addition, since the photocatalytic film 2 can be formed at a relatively low temperature, the heat-resistant temperature of the substrate 1 is not restricted, and the photocatalytic film itself can be prevented from being thermally deteriorated.
[0091]
It was confirmed that the photocatalyst film 2 thus formed had an amorphous structure by X-ray diffraction if the heat treatment was 600 ° C. or lower.
[0092]
Moreover, when the photocatalyst film 2 heat-treated in a relatively high temperature region exceeding 600 ° C. was observed by X-ray diffraction, the photocatalyst film 2 had few lattice defects to the surface and was close to a perfect crystal (TiO2)₂The photocatalyst film 2 having higher adhesion strength to the substrate 1, film strength, and chemical durability was obtained while maintaining a very high decomposing power.
[0093]
In addition, the photocatalytic film 2 of the present embodiment is hydrophilic immediately after the film formation, but if left as it is or once water is attached, the contact angle with respect to water becomes about 70 to 90 ° and exhibits hydrophobicity.
[0094]
When the photocatalyst film 2 exhibits hydrophobicity, the adsorption of dirt substances and gases is reduced as compared with the substrate surface on which the photocatalyst film is not formed. Therefore, it is possible to obtain the photocatalyst body 2 having both a high decomposing power and a reduction effect of dirt adhesion.
[0095]
Photocatalytic film 2 is TiOR₂Is applied mainly in water, an organic solvent or a mixed solution thereof and dried or heat-treated, R is acetylacetone (C_FiveH₇O₂), Cyclopentadienyl (C_FiveH_Five) Or dipivaloylmethane (C₁₁H₁₉O₂The similar photocatalyst film 2 can also be formed.
[0096]
TiOR₂When using, the film-forming property at the time of the coating film is poor, and uneven color and unevenness of decomposition are likely to occur. TiOR to improve this₂When an average of 1 or less of R in the formula is substituted with another alkyl group, hydroxyl group, alkoxy group or carboxyl group, the film-forming property can be improved while maintaining a high decomposing power.
[0097]
  In addition, TiOR₂ Consist ofOrganometallic compoundsInWhen a very small amount (30% or less) of a material to which at least one alkoxide, chelate and its modified substance are added from the group consisting of Si, Zr, Y and Al is mixed, the film formability can be improved while maintaining a high decomposing power. .
[0098]
  TiOR₂ Consist ofEven when a small amount of metal oxide fine particles is added to the organometallic compound or a small amount of silicone or a modified product thereof is added, the film formability can be improved while maintaining a high decomposition force.
[0099]
For example, TiOR₂(R is acetylacetone (C_FiveH₇O₂)) Dissolves in water or an organic solvent and has a low reactivity with them, and hardly reacts with these various additives. Therefore, the addition of a small amount has little effect on the decomposability.
[0100]
Next, a second embodiment will be described. In the present embodiment, only the photocatalyst film formation process is different, and the basic configuration is the same as that shown in FIG.
[0101]
The photocatalyst film 2 of the present embodiment is also formed from an amorphous titanium oxide-based metal compound mainly composed of Ti, O, and C, but titanium alkoxide (TiOR) is used as a raw material for film formation._Four) Is different from the first embodiment.
[0102]
That is, titanium alkoxide (TiOR_Four) As a raw material for film formation,₂The photocatalytic film 2 made of an amorphous titanium oxide-based metal compound mainly composed of Ti, O, and C can be formed by thermal decomposition at 300 ° C. or higher in an atmosphere mainly composed of an inert gas. However, titanium alkoxide (TiOR_Four) As a raw material for film formation, it is necessary to adjust the decomposition temperature (heating temperature), the input source amount, and the added oxygen amount to desired conditions. When the input source amount is small, the photocatalytic film of this embodiment cannot be formed, and a conventional titanium oxide film containing a large amount of OH groups is formed. Therefore, the photocatalyst body 10 of the present embodiment can be formed by introducing a source amount several to several tens of times that of the prior art and performing thermal decomposition in a state close to supersaturation.
[0103]
In addition, when a small amount of oxygen is mixed in the atmosphere, the C / O ratio in the photocatalyst film is controlled by adjusting the oxygen mixing amount. When the C / O ratio is 1 or less, the decomposing power of the photocatalytic film 2 is good, and when it exceeds 1, the decomposing power is greatly reduced.
[0104]
When heat treatment is performed in a relatively high temperature region, it is desirable to perform heat treatment so that the titanium oxide of the photocatalytic film 2 has an anatase crystal structure. Titanium oxide has a rutile form and anatase form as crystal structures, and it is considered that the anatase form is superior in photocatalytic action, and the film strength, durability, and the like are also improved.
[0105]
However, in practice, there are many cases where a rutile form is mixed with an anatase form, and a practical photocatalytic action can still be obtained. Therefore, in this embodiment, a mixed form of both is allowed.
[0106]
The photocatalyst of the present invention can also be applied as a lamp. In this case, the light emission principle of the lamp does not matter. For example, when a glass bulb is used as a substrate, a photocatalytic film is formed on the surface of the glass bulb. The glass bulb may be an embodiment that surrounds the discharge medium, or an outer tube that further surrounds the arc tube containing the light emitting part. That is, the lamp is allowed to be an incandescent bulb, a discharge lamp, etc., and in the case of an incandescent bulb, the filament is a heat generating part, and in the case of a discharge lamp, a discharge medium or phosphor layer that emits a bright line by discharge is a light emitting part. It corresponds to each. In the case of LED, the light emitting semiconductor chip corresponds to the light emitting portion, and the mold resin corresponds to the glass bulb. Therefore, the bulb is not limited to glass in a broad sense.
[0107]
In the case of an incandescent light bulb, a halogen light bulb having a higher color temperature has a higher light emission ratio at a wavelength of 400 nm or less than a light bulb for general lighting, but it may be an incandescent light bulb for general lighting.
[0108]
In the case of a discharge lamp, either a low pressure discharge lamp or a high pressure discharge lamp may be used.
[0109]
An example of the low-pressure discharge lamp is a fluorescent lamp. The phosphor used for the fluorescent lamp can be selected to appropriately increase the emission of 400 nm or less. Such a fluorescent lamp is suitable as a lamp for activating a photocatalyst because it has a relatively small decrease in visible light and has a better activation effect of the photocatalyst than a fluorescent lamp for general illumination. However, the present invention allows a fluorescent lamp using a three-wavelength-type phosphor or a calcium halophosphate phosphor that has been widely used for general illumination.
[0110]
In addition, germicidal lamps, black lights, chemical lamps, and the like for the purpose of mainly using light emission of 400 nm or less are allowed. On the other hand, as the high-pressure discharge lamp, for example, a mercury lamp, a metal halide lamp, a high-pressure sodium lamp and the like are allowed.
[0111]
Since the photocatalyst film is formed using the glass bulb of the lamp as a base, the photocatalyst film can be sufficiently activated even if the amount of emitted light of 400 nm or less generated by the lamp is small.
[0112]
When the lamp is used, since the organic dirt substances such as cigarette fat and soot and the like adhering to the glass bulb are decomposed by the photocatalytic action, the decrease in the luminous flux due to the dirt on the glass bulb is reduced. For this reason, while being able to perform favorable illumination over a long period of time, the cleaning interval of a lamp can be lengthened.
[0113]
Further, heat generated as the lamp is turned on generates heat convection around the lamp and convection of the room air. Deodorization and sterilization of the air in contact with the lamp is performed. Therefore, the indoor air can be deodorized and sterilized by using the lamp of the present invention.
[0114]
The photocatalyst of the present invention can also be used as a lighting fixture. In the case of a luminaire, the light control means or reflector of the luminaire body may be used as a base, and a photocatalytic film may be formed on at least a part of the light control means. The lighting fixture may be outdoor or indoor.
[0115]
The light control means is allowed to be used in one kind or a combination of any plural kinds such as a reflector, a globe, a shade, a translucent cover, and a louver. Further, the photocatalytic film may be formed on the entire light control means, or may be formed on a part thereof.
[0116]
The light control means, when dirt made of organic matter such as smoke or cigarette oil adheres to it, the optical performance as a lighting fixture is lowered, but the dirt is decomposed by forming a photocatalytic film. Therefore, it is possible to suppress a decrease in optical performance.
[0117]
Moreover, indoor deodorization and sterilization can also be performed by decomposing or sterilizing odorous substances in the air that come into contact with the light control means.
[0118]
  Furthermore, not only the photocatalyst is formed into a film, but also the grain shapeofIt can be formed into various types such as forming a film, and as a use, it is sized and structured so that it can be stored in a refrigerator, an air conditioner, an air purifier, etc. in addition to a lighting fixture, and disposed in these devices. It can also be a deodorizing or sterilizing means.
[0119]
【The invention's effect】
  The present invention has the following effects.
(1)TiOR ₂ While pyrolyzing the organometallic compound consisting of (R is a chelate compound)Ti, O, C as the main componentAnd an amorphous metal compound formed on the substrate so that the C / O ratio is 1 or less.When a photocatalyst film is formed, a photocatalyst having a high decomposability can be formed at a low temperature.
(2) TiOR₂ Consist ofThermal decomposition of organic compoundsIn addition, the film made of an amorphous metal compound, which is mainly formed of Ti, O, and C and has a C / O ratio of 1 or less, is heat-treated at a temperature exceeding 600 ° C. and crystallized.When the photocatalyst film is formed, a photocatalyst having a high cleaning effect can be obtained, which is difficult to be soiled due to the decomposition power having a high photocatalytic action.
[Brief description of the drawings]
FIG. 1 is a conceptual schematic view showing an enlarged cross section of a photocatalyst in first and second embodiments of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Base | substrate, 2 ... Photocatalyst film | membrane, 10 ... Photocatalyst body

Claims (7)

A substrate;
TiOR ₂ (R is a chelate compound) A solution of the organometallic compound consisting of coating the surface of the substrate, Ti with pyrolysis of organometallic compounds comprising the TiOR ₂ by heat treatment temperature range of 100~500 ℃, O, C And a photocatalytic film made of an amorphous metal compound formed on the substrate so that the C / O ratio is 1 or less;
The photocatalyst body characterized by comprising. A substrate;
TiOR ₂ (R is a chelate compound) A solution of the organometallic compound consisting of coating the surface of the substrate, Ti with pyrolysis of organometallic compounds comprising the TiOR ₂ by heat treatment temperature range of 100~500 ℃, O, C A photocatalyst film crystallized by heat-treating a film made of an amorphous metal compound on the substrate so as to have a C / O ratio of 1 or less at a temperature exceeding 600 ° C .;
The photocatalyst body characterized by comprising. Si organometallic compound consisting TiOR _2, Zr, at least one alkoxide selected from the group consisting of Y and Al, chelates and claim 1 or 2, wherein its modified product is added, characterized in that the formation of the photocatalytic film Photocatalyst body. The photocatalyst according to any one of claims 1 to 3, wherein a silicone resin or a modified product thereof is added to an organometallic compound comprising TiOR ₂ . A photocatalytic film was formed by thermally decomposing an organometallic compound composed of TiOR _{2 in} an atmosphere mainly composed of an inert gas so that the main component was Ti, O, and C, and the C / O ratio was 1 or less. The photocatalyst according to any one of claims 1 to 4, wherein Claim R is characterized in that at least one of acetylacetone _{(C 5 H 7 O 2)} , cyclopentadienyl (C ₅ H ₅₎ or dipivaloylmethane _{(C 11 H 19 O 2)} 1 The photocatalyst as described in any one of 5 to 5.   The photocatalyst according to any one of claims 1 to 6, wherein the photocatalyst is hydrophobic.

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