JP5182665B2 - Organic photocatalyst - Google Patents

Description

  The present invention relates to an organic photocatalyst used for decomposing an organic substance or an inorganic substance containing nitrogen, sulfur, phosphorus, etc. under light irradiation, particularly under visible light irradiation, a method for producing the same, and an application of the organic photocatalyst.

  A photocatalyst is a catalyst material that decomposes harmful substances using the oxidizing power and reducing power generated by the input of light energy. This photocatalyst does not use toxic chemicals or fossil fuels, Various chemical substances that are difficult to be decomposed can be safely and easily decomposed only by using them, and thus are attracting attention as environmentally friendly environmental purification materials.

At present, photocatalysts made of inorganic compounds such as titanium oxide (TiO ₂ ), zinc oxide, and tungsten oxide are known as photocatalyst materials. Among them, titanium oxide is the size and safety of its photocatalytic action, It is the most excellent material from the viewpoint of cost, has been extensively studied, and has been put into practical use (see Non-Patent Document 1).

  This titanium oxide exhibits photocatalytic activity by light in the ultraviolet region, but only ultraviolet light corresponding to an energy density of 3% of natural light is used. Therefore, from the viewpoint of solar energy conversion efficiency, a photocatalyst that can effectively use visible light that occupies about half of the natural light energy density is desired.

  Further, when titanium oxide is used as a pigment for a paint, there is a problem that an organic component of the paint is decomposed by the titanium oxide to cause a choking phenomenon.

By the way, about the photocatalyst which consists of an organic compound, there is almost no report example so far, and only polyparaphenylene, its derivative (s), etc. are reported (refer nonpatent literature 2). These are ultraviolet light-responsive materials and have problems such as difficulty in use in a gas (wet air) phase or a liquid phase containing water.
Illustrated All photocatalysts (supervised by Kazuhito Hashimoto and Akira Fujishima), Industrial Research Committee (2003) J. Chem. Soc. Faraday Trans., 93, 221 (1997)

  In view of the above problems of the prior art, the present invention efficiently decomposes organic substances or inorganic substances containing nitrogen, sulfur, phosphorus, etc. under light (particularly visible light) irradiation in a gas phase or a liquid phase containing water. It is an object to provide an organic photocatalyst to be obtained and a method for producing the same. Moreover, an object of this invention is to provide the use of this organic photocatalyst.

  As a result of intensive studies to achieve the above object, the present inventors irradiate a material composed of a specific p-type organic semiconductor and a specific n-type organic semiconductor with visible light (wavelength: 400 to 750 nm). As a result, it has been found that a photocatalytic oxidation-reduction reaction occurs through unidirectional photo-induced electron transfer. Further, it has been found that the material exhibits photocatalytic activity under light irradiation in a gas phase or a liquid phase, and can efficiently decompose an organic substance or an inorganic substance containing nitrogen, sulfur, or phosphorus. Based on these findings, the present inventor has further developed and completed the present invention.

  That is, this invention provides the following organic photocatalysts, its manufacturing method, and the use of this organic photocatalyst.

  Item 1. An organic photocatalyst containing a p-type organic semiconductor and an n-type organic semiconductor, which is used for decomposing an organic substance or an inorganic substance containing nitrogen, sulfur or phosphorus under light irradiation.

  Item 2. The organic photocatalyst according to Item 1, having a two-layer structure in which a p-type organic semiconductor layer and an n-type organic semiconductor layer are laminated.

  Item 3. The organic photocatalyst according to Item 1, wherein the p-type organic semiconductor layer has a thickness of about 20 to 500 nm and the n-type organic semiconductor layer has a thickness of about 50 to 800 nm.

  Item 4. The organic photocatalyst according to Item 1, wherein the organic photocatalyst has a three-layer structure including a co-evaporated layer of a p-type organic semiconductor and an n-type organic semiconductor between the p-type organic semiconductor layer and the n-type organic semiconductor layer.

  Item 5. The organic photocatalyst according to Item 1, having a two-layer structure in which a p-type organic semiconductor layer and an n-type organic semiconductor layer are laminated on a substrate.

  Item 6. The organic photocatalyst according to Item 1, wherein the organic photocatalyst has a three-layer structure including a co-deposited layer of a p-type organic semiconductor and an n-type organic semiconductor between the p-type organic semiconductor layer and the n-type organic semiconductor layer on the substrate.

  Item 7. The organic photocatalyst according to Item 1, wherein the material of the p-type organic semiconductor is a macrocyclic ligand compound or a metal complex thereof.

  Item 8 The organic photocatalyst according to Item 7, wherein the material of the p-type organic semiconductor is at least one selected from the group consisting of phthalocyanine derivatives, naphthalocyanine derivatives, and porphyrin derivatives.

  Item 9 The organic photocatalyst according to Item 8, wherein the material of the p-type organic semiconductor is a phthalocyanine derivative.

  Item 10. The organic photocatalyst according to Item 1, wherein the material of the n-type organic semiconductor is a polycyclic aromatic compound.

  Item 11. The material according to Item 10, wherein the material of the n-type organic semiconductor is at least one selected from the group consisting of fullerenes, carbon nanotubes, a conductive polymer doped with an electron donor, a perylene derivative, and a naphthalene derivative. Organic photocatalyst.

  Item 12. The organic photocatalyst according to Item 11, wherein the material of the n-type organic semiconductor is at least one selected from the group consisting of fullerenes and perylene derivatives.

  Item 13 A method for producing the organic photocatalyst according to Item 5, wherein an n-type organic semiconductor layer and a p-type organic semiconductor layer are laminated on a substrate to form a two-layer structure.

  Item 14. A method for producing an organic photocatalyst according to Item 6, wherein an n-type (or p-type) organic semiconductor layer is formed on a substrate, and an n-type organic semiconductor and a p-type organic semiconductor are co-deposited thereon. Forming a co-evaporated layer and forming a p-type (or n-type) organic semiconductor layer thereon to form a three-layer structure.

  Item 15 A method for decomposing an organic substance in a gas phase or an aqueous phase or an inorganic substance containing nitrogen, sulfur or phosphorus, wherein the organic photocatalyst according to Item 1 is converted into an organic substance or an inorganic substance containing nitrogen, sulfur or phosphorus under light irradiation. Decompose by contacting.

  Item 16 A coating composition comprising the organic photocatalyst according to Item 1 and a coating material.

  Item 17 A method of treating water by dispersing the organic photocatalyst of Item 1 in water to be treated containing an organic substance or an inorganic substance containing nitrogen, sulfur, or phosphorus, and irradiating it with light.

  Item 18: The water treatment method according to Item 17, wherein the organic photocatalyst is recovered by filtration after the treatment, and again subjected to water treatment.

Hereinafter, the present invention will be described in detail.
I. Organic Photocatalyst The organic photocatalyst of the present invention includes a p-type organic semiconductor and an n-type organic semiconductor. Specifically, it has a structure in which a portion made of a p-type organic semiconductor (bulk layer) and a portion made of an n-type organic semiconductor (bulk layer) are in contact with each other. The organic photocatalyst of the present invention generates unidirectional photoinduced electron transfer at the interface where the p-type organic semiconductor material and the n-type organic semiconductor material are in contact with light, and this is an organic substance or an inorganic substance containing nitrogen, sulfur or phosphorus. Used for decomposition. Therefore, this organic photocatalyst is used for decomposing an organic substance or an inorganic substance containing nitrogen, sulfur or phosphorus under light irradiation in a gas phase or a liquid phase.

Examples of the p-type organic semiconductor include a macrocyclic ligand compound or a metal complex thereof. The macrocyclic ligand compound is a cyclic compound that contains an atom having an unpaired electron on the ring and can be a metal ligand, and the metal complex is the macrocyclic ligand. And a metal complex consisting of metal atoms. As an atom which has an unpaired electron, a nitrogen atom and an oxygen atom are mentioned, for example, A nitrogen atom is preferable. As a metal atom, each metal element of 1-15 group of a periodic table is mentioned, Preferably it is a 4-14 group metal element. In addition, the metal complex may be any metal as long as the metal atom and the macrocyclic ligand compound are 1: 1 (molar ratio) and form a planar four-coordinate complex.

  Specific examples of the macrocyclic ligand compound or the metal complex thereof include phthalocyanine derivatives, naphthalocyanine derivatives, porphyrin derivatives, and the like.

  A phthalocyanine derivative means a compound having a basic phthalocyanine skeleton. Specifically, for example, the following formula (1A) or (1B):

(In the formula, M ¹ represents a metal atom selected from the group consisting of groups 4 to 14 of the periodic table or an atomic group containing the metal atom, and a dotted line represents a coordinate bond)
The phthalocyanine derivative represented by these is mentioned.

Preferably among the Periodic Table 4-14 metals atom represented by M ^1, Group 4 (especially, Ti), Group 5 (in particular, V), Group 6 (in particular, Mo), Group 7 (especially, Mn ), Group 8 (Fe, Ru, Os), Group 9 (Co, Rh, Ir), Group 10 (Ni, Pd, Pt), Group 11 (particularly Cu), Group 12 (particularly Zn), Group 13 (Especially Al) and group 14 (especially Pb). In addition, the atomic group containing the metal atom means a group (for example, Ti—O) in which another ligand (for example, oxygen or cyano group) is coordinated to the metal.

Among the above, phthalocyanine represented by the formula (1A), or M ¹ in the formula (1B) is Ti, Co, Pt, Os, Mn, Ir, Fe, Rh, Cu, Zn, Ni, Pd or Ru. Phthalocyanine derivatives are preferable, and (1A) metal-free phthalocyanine, (1B) iron phthalocyanine, and cobalt phthalocyanine are particularly preferable from the viewpoint of photocatalytic activity for decomposition of organic substances or inorganic substances containing nitrogen, sulfur, or phosphorus. These compounds are either commercially available or can be easily produced by those skilled in the art.

  A naphthalocyanine derivative means a compound having a basic skeleton of naphthalocyanine. Specifically, for example, the following formula (2A) or (2B):

(In the formula, M ² represents a metal atom selected from the group consisting of groups 4 to 14 of the periodic table or an atomic group containing the metal atom, and a dotted line represents a coordinate bond)
The naphthalocyanine derivative represented by these is mentioned.

Preferably among the Periodic Table 4-14 metals atom represented by M ^2, Group 4 (especially, Ti), Group 5 (in particular, V), Group 6 (in particular, Mo), Group 7 (especially, Mn ), Group 8 (Fe, Ru, Os), Group 9 (Co, Rh, Ir), Group 10 (Ni, Pd, Pt), Group 11 (particularly Cu), Group 12 (particularly Zn), Group 13 (Especially Al) and group 14 (especially Pb). In addition, the atomic group containing the metal atom means a group (for example, Ti—O) in which another ligand (for example, oxygen or cyano group) is coordinated to the metal.

Among the above, naphthalocyanine represented by the formula (2A) or M ² in the formula (2B) is Ti, Co, Pt, Os, Mn, Ir, Fe, Rh, Cu, Zn, Ni, Pd or Ru. Naphthalocyanine derivatives are preferable, and (2A) metal-free naphthalocyanine, (2B) iron naphthalocyanine, and cobalt naphthalocyanine are particularly preferable from the viewpoint of photocatalytic activity for decomposition of organic substances or inorganic substances containing nitrogen, sulfur, or phosphorus. These compounds are either commercially available or can be easily produced by those skilled in the art.

  A porphyrin derivative means a compound having a basic skeleton of porphyrin. Specifically, for example, the following formula (3A) or (3B):

(Wherein R ³ represents a hydrogen atom, an alkyl group, an aryl group or a heteroaryl group, M ³ represents a metal atom selected from the group consisting of groups 4 to 14 of the periodic table or an atomic group containing the metal atom) The dotted line shows the coordination bond)
The porphyrin derivative represented by these is mentioned.

Here, examples of the alkyl group represented by R ³ include a C _1-20 linear or branched alkyl group, and a C _1-10 alkyl group is preferable. Specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, n-pentyl, n-hexyl, n-heptyl, n-octyl and the like.

Moreover, as an aryl group shown by said R < ³ >, a monocyclic or bicyclic aryl group is mentioned, Specifically, a phenyl, a naphthyl, etc. are mentioned.

In addition, examples of the heteroaryl group represented by R ³ include pyridyl and pyrazinyl.

Of the metal atoms of groups 4 to 14 of the periodic table represented by M ³ , group 4 (especially Ti), group 5 (particularly V), group 6 (particularly Mo), group 7 (particularly Mn) are preferred. ), Group 8 (Fe, Ru, Os), Group 9 (Co, Rh, Ir), Group 10 (Ni, Pd, Pt), Group 11 (particularly Cu), Group 12 (particularly Zn), Group 13 (Especially Al) and group 14 (especially Pb). In addition, the atomic group containing the metal atom means a group (for example, Ti—O) in which another ligand (for example, oxygen or cyano group) is coordinated to the metal.

Among the above, porphyrin represented by the formula (3A), or in the formula (3B), M ³ is Ti, Co, Pt, Os, Mn, Ir, Fe, Rh, Cu, Zn, Ni, Pd or Ru, R ^A porphyrin derivative in which ³ is phenyl or a hydrogen atom is preferable. In particular, (3A) a metal-free porphyrin or (3B) an iron porphyrin or cobalt porphyrin from the viewpoint of photocatalytic activity for decomposition of an organic substance or an inorganic substance containing nitrogen, sulfur or phosphorus. Is preferred. These compounds are either commercially available or can be easily produced by those skilled in the art.

Examples of n-type organic semiconductors and n-type organic semiconductors include polycyclic aromatic compounds. The polycyclic aromatic compound may be partially saturated. A polycyclic aromatic compound is a compound having a structure in which at least two aromatic rings are condensed, or a structure in which a plurality of aromatic rings are bonded via unsaturated bonds (double bonds, triple bonds, etc.). It means the compound etc. which have. In addition to the benzene ring and the like, the aromatic ring includes a heteroaromatic ring such as a pyrrole ring, an imidazole ring, a pyridine ring, and a quinoxaline ring (all of the rings may be partially saturated).

  The polycyclic aromatic compound may have various substituents within a range that does not adversely affect the present invention. Examples of the substituent include an electron withdrawing group, and specific examples include a carbonyl group, a sulfone group, and a sulfoxide group.

Specific examples of the polycyclic aromatic compound include fullerenes such as C ₆₀ , C ₇₀ , C ₇₆ , C ₈₂ and C ₈₄ ; carbon nanotubes; electron donors (phenylenediamine, tetraaminoethylene, tris (2, 2-bipyridine) ruthenium etc.) doped conducting polymers (polyimide, polyphenylene vinylene, polyparaphenylene, polypyrrole, etc.); perylene derivatives; naphthalene derivatives. Among these, perylene derivatives, naphthalene derivatives, fullerenes (C _{60 and the} like) are preferably used, and perylene derivatives and fullerenes (C _{60 and the} like) are particularly preferable.

  A perylene derivative means a compound having a basic skeleton of perylene. Specifically, for example, the following formulas (4A) to (4C):

(Wherein R ¹ represents an alkyl group or an aryl group)
The perylene derivative represented by these is mentioned.

  A naphthalene derivative means a compound having a basic skeleton of naphthalene. Specifically, for example, the following formula (5A):

(Wherein R ² represents an alkyl group or an aryl group)
The naphthalene derivative represented by these is mentioned.

Here, examples of the alkyl group represented by R ¹ or R ² include a C _1-20 linear or branched alkyl group, and a C _1-10 alkyl group is preferable. Specific examples include methyl, ethyl, n-propyl, isopropyl, sec-butyl, isobutyl, n-pentyl, n-hexyl, n-heptyl, n-octyl and the like.

Moreover, as an aryl group shown by said R < ¹ > or R < ² >, a monocyclic or bicyclic aryl group is mentioned, Specifically, a phenyl, a naphthyl, etc. are mentioned.

Organic Photocatalyst The organic photocatalyst of the present invention comprises the above p-type organic semiconductor and n-type organic semiconductor. Although there is no particular limitation on the bonding mode of the p-type organic semiconductor and the n-type organic semiconductor in the organic photocatalyst, it is preferable to bond them so that the contact area between them increases from the viewpoint of photocatalytic activity (ie, quantum yield). When the contact area between the n-type organic semiconductor and the n-type organic semiconductor increases, photo-induced electron transfer occurs efficiently when light is irradiated, and an effective photocatalytic redox reaction occurs. Because.

  Specific examples of the organic photocatalyst of the present invention include a laminated (film) structure in which a p-type organic semiconductor and an n-type organic semiconductor are laminated.

  The stacked structure is preferably, for example, a two-layer structure in which a p-type organic semiconductor and an n-type organic semiconductor are stacked. This may be a film having a two-layer structure itself, or may have a two-layer structure of an n-type organic semiconductor and a p-type organic semiconductor on a substrate.

  When the organic photocatalyst is a film having a two-layer structure or a substrate having a two-layer structure, the thickness of each layer is not particularly limited. For example, the thickness of the n-type organic semiconductor layer is about 50 to 800 nm. The p-type organic semiconductor layer has a thickness of about 20 to 500 nm, preferably about 30 to 350 nm. Adopting such a thickness is preferable because the photocatalytic activity is optimized.

  The laminated structure may be a three-layer structure in which a co-evaporated layer formed by co-evaporating an n-type organic semiconductor and a p-type organic semiconductor is sandwiched between the p-type organic semiconductor layer and the n-type organic semiconductor layer. Of course, the substrate may have this three-layer structure.

  When the organic photocatalyst has a three-layer structure on a film having a three-layer structure or a substrate, the thickness of each layer is not particularly limited. For example, the thickness of the n-type organic semiconductor layer is about 50 to 800 nm. The co-deposition layer is about 5 to 10 nm, and the thickness of the p-type organic semiconductor layer is about 20 to 500 nm, preferably about 30 to 350 nm. Adopting such a thickness is preferable because the photocatalytic activity is optimized.

  In order to increase the activity of the photocatalyst, a transition metal catalyst (for example, Ag, Cu, Ni, Pd, Pt, Ir catalyst, etc.) may be added to the organic photocatalyst of the present invention as necessary.

  Note that the base material on which the laminated structure is formed is selected from materials and shapes according to the purpose.

  Furthermore, the organic photocatalyst of the present invention may be in the form of a powdery product (particles, fine particles, etc.) that is easily dispersed in a medium, for example, by further crushing and cutting the film having the above laminated structure.

  The organic photocatalyst described above (for example, a substrate (carrier) having a laminated structure, a powdered material, etc.) can be dispersed in a liquid medium (for example, water) and can be recovered by filtration or the like. Therefore, they can be dispersed in a medium (for example, water) containing an object to be processed such as an organic substance, decomposed by light irradiation, and after treatment, only the photocatalyst can be separated by filtration or the like and reused. is there.

The organic photocatalyst of the present invention can decompose organic substances or inorganic substances containing nitrogen, sulfur, phosphorus and the like by absorbing natural light and visible light efficiently in the gas phase or liquid phase under light irradiation. The organic photocatalyst of the present invention has high catalytic efficiency and can effectively use light in the visible region contained in natural light as an energy source. Furthermore, since the organic photocatalyst of the present invention is an organic compound, it has excellent processability and moldability, and is stable in water.
II. Production Method of Organic Photocatalyst The production method of the organic photocatalyst of the present invention will be described below, but is not limited thereto.

  As the p-type organic semiconductor, those described above can be used, and typical examples include phthalocyanine derivatives, naphthalocyanine derivatives, and porphyrin derivatives. More preferably, the compound represented by Formula (1A), (1B), (2A), (2B), (3A), (3B) is mentioned. In particular, a metal-free phthalocyanine of the formula (1A), an iron phthalocyanine of the formula (1B), or a cobalt phthalocyanine of the formula (1B) is preferable.

As the n-type organic semiconductor, those described above can be used, and those having a good pn junction relationship with the p-type organic semiconductor are used. Typical examples of the n-type organic semiconductor include perylene derivatives, naphthalene derivatives, and fullerenes. More preferably, the compound represented by Formula (4A), (4B), (4C), (5A) is mentioned. In particular, from the viewpoint of efficient carrier generation, a perylene derivative (3,4,9,10-perylenetetracarboxyl-bisbenzimidazole) or a fullerene (C ₆₀ or the like) represented by the formula (4A) is preferably used. .

  The organic photocatalyst of the present invention includes a transition metal catalyst (for example, Ag, Cu, Ni, Pd) as necessary in addition to the n-type organic semiconductor and the p-type organic semiconductor in order to increase the activity of the photocatalyst. , Pt, Ir catalyst, etc.) may be added.

  The organic photocatalyst of the present invention is not particularly limited as long as it has a form in which a n-type organic semiconductor and a p-type organic semiconductor have a pn junction so as to increase the contact area and can form such a junction form. .

  For example, when the organic photocatalyst is a two-layer structure film in which an n-type organic semiconductor and a p-type organic semiconductor are stacked, a two-layer structure is formed by stacking an n-type organic semiconductor and a p-type organic semiconductor on a substrate, It can be produced by peeling the two-layer structure film from the substrate. In this case, the material of the substrate is not particularly limited as long as the formed two-layer structure film can be easily peeled off. For example, a glass substrate is mentioned. The obtained two-layer structure film can be used as it is as a photocatalyst, but if necessary, an adhesive layer is provided on the two-layer structure film and attached to the substrate, or pulverized and cut into a powder form. It is also possible.

  Alternatively, an organic photocatalyst layer can be provided on a base by directly laminating an n-type (or p-type) organic semiconductor and a p-type (or n-type) organic semiconductor on a specific base from the beginning. In this case, the base material may be any material as long as the organic photocatalyst of the present invention can be laminated. For example, ceramics (silica, alumina, zirconia, etc.), metal, alloy, wood, activated carbon, pumice, concrete, paper, fiber And filter paper. In addition, the shape of the substrate may be any depending on the application.

  As a method of laminating an n-type organic semiconductor and a p-type organic semiconductor on a substrate, a known method can be adopted. For example, a method such as a vacuum deposition method, a sputtering method, an electrochemical coating (electrodeposition), or a coating method can be used. Can be mentioned. Among these, with respect to the perylene derivative / phthalocyanine derivative system, the vacuum deposition method is preferable because a uniform coating film can be obtained.

  When the organic semiconductor has a two-layer structure, the thickness of each layer is not particularly limited, but is preferably set appropriately in the above-described range. That is, the thickness of the p-type organic semiconductor layer is about 20 to 500 nm, preferably about 30 to 350 nm, and the thickness of the n-type organic semiconductor layer is about 50 to 800 nm, preferably about 100 to 650 nm. is there.

  When the organic semiconductor has a three-layer structure, a p-type (or n-type) organic semiconductor layer is formed on the substrate, and a co-deposition layer composed of the p-type organic semiconductor and the n-type organic semiconductor is formed thereon. Furthermore, it is good also as an organic photocatalyst which laminates | stacks an n-type (or p-type) organic-semiconductor layer on it, and has a three-layer structure on a base | substrate. Furthermore, the three-layer structure film can be formed by peeling the three-layer structure film from the substrate. In addition, said lamination | stacking method can be employ | adopted for a lamination | stacking method, and a co-deposition layer can also be formed using a well-known method.

  When the organic semiconductor has a three-layer structure, the thickness of each layer is not particularly limited, but is preferably set appropriately in the above-described range. That is, the thickness of the n-type organic semiconductor layer is about 50 to 800 nm, preferably about 100 to 650 nm, the co-deposited layer is about 5 to 10 nm, and the thickness of the p-type organic semiconductor layer is 20 to 500 nm. About nm, preferably about 30 to 350 nm.

Furthermore, in addition to the laminated structure, further on the outer layer, using an electrolytic deposition method, a suspension casting method, etc., a transition metal catalyst (for example, Ni, Pd, Pt, Ag, Ir catalyst, etc., preferably (Ag or IrO ₂ catalyst) may be supported. The transition metal catalyst to be supported need not be completely covered with the outer layer, and may be dispersed and supported. The average particle diameter of the transition metal catalyst may be fine particles having a particle size of about 5 to 800 nm (preferably about 10 to 100 nm).
III. Photocatalytic action and use The organic photocatalyst of the present invention can be decomposed by contacting with an organic substance contained in a gas phase or an aqueous phase or an inorganic substance containing nitrogen, sulfur or phosphorus under light irradiation. .

  The light used in the organic photocatalyst of the present invention can be light having a wide range of wavelengths (wavelength of about 220 to 1200 nm). As the light source, for example, one type selected from natural light (sunlight), fluorescent lamp, halogen lamp, high pressure mercury lamp, low pressure mercury lamp, black light, excimer laser, deuterium lamp, xenon lamp, Hg-Zn-Pb lamp, etc. Or two types of light sources having different wavelength ranges can be used. In particular, the organic photocatalyst of the present invention is extremely practical in that it can use natural light (wavelength of 300 to 800 nm), particularly visible light (wavelength of 400 nm or more, particularly about 400 to 750 nm). Titanium oxide used as an inorganic photocatalyst is extremely meaningful considering that an ultraviolet light source is necessary indoors.

  Moreover, the organic photocatalyst of this invention can decompose | disassemble organic substance or the inorganic substance containing nitrogen, sulfur, or phosphorus only by light irradiation efficiently. In this regard, the method of decomposing organic matter by irradiating the photocatalyst with light while applying an electrochemical bias (for example, ChemPhysChem 2004, 5, 716-720) is a clear line. In the electrochemical decomposition method, for example, negative charges (electrons) generated by oxidative decomposition on the catalyst surface are removed through the electrodes. In the organic photocatalyst of the present invention, the electrons are received by oxygen present in the processing medium. It is considered to be removed. Therefore, the decomposition reaction proceeds more efficiently when oxygen is present in a high concentration in the gas phase or liquid phase (water phase). For example, in the gas phase, the oxygen concentration is preferably 20% by volume, more preferably 25% by volume or more. Moreover, in the liquid phase (for example, water), it is preferable to supply air (oxygen-containing gas) (bubbling or the like) or to react the liquid phase while stirring.

  Substances to be decomposed in the gas phase or in the water phase include malodorous substances, dust, microorganisms, viruses, sick house syndrome causative substances (formaldehyde, etc.), odor components (cigarette odor, pet odor, etc.), toxic substances (dioxins, PCB, etc.), agricultural chemicals, ethylene gas, nitrogen compounds (ammonia, NOx, etc.), sulfur compounds (mercaptan, sulfide, etc.), and phosphorus compounds (organic phosphorus, etc.).

  Further, the organic photocatalyst of the present invention is excellent in processing or moldability because both the p-type organic semiconductor and the n-type organic semiconductor are composed of an organic substance. Although titanium oxide as an inorganic photocatalyst has difficulty in workability or moldability, the organic photocatalyst of the present invention solves such a problem. Therefore, it is used for a very wide range of applications that exceed the applications of titanium oxide.

  The organic photocatalyst of the present invention can be used as a surface material of various filters that filter and decompose the decomposition target in the gas phase or aqueous phase. As a method for fixing the organic photocatalyst of the present invention to the filter substrate, a method such as the above-described vacuum deposition method, sputtering method, electrochemical coating (electrodeposition), coating or the like may be used.

  In addition, the organic photocatalyst of the present invention is dispersed in water to be treated containing an organic substance or an inorganic substance containing nitrogen, sulfur or phosphorus, subjected to a decomposition treatment by light irradiation, and further filtered and separated and recovered after the treatment. And can be subjected to water treatment again.

  Moreover, the organic photocatalyst of this invention can be mixed in a coating material, and can be set as the coating composition which has photocatalytic activity. In the coating composition, since the organic photocatalyst has a high affinity for the coating, it is possible to uniformly disperse the catalyst.

  Since the organic photocatalyst of the present invention is stable against water, the water containing the decomposition target can also be efficiently treated. For example, the powder is dispersed in water to be treated, and light is irradiated to treat the water. After the treatment, the powder is filtered to obtain treated water, and the powder can be easily recovered. The water phase (treated water) includes, for example, industrial circulating water, industrial wastewater, industrial wastewater, clean water, sewage, soil and groundwater, ponds, pools, domestic wastewater, residual agricultural chemicals, baths, water storage Examples include tanks, lakes, and dams. These aqueous phases are not particularly limited in pH, hardness and the like, and can be treated efficiently. In particular, the pH is preferably about 7 to 11.

  The organic photocatalyst comprising the p-type organic semiconductor and the n-type organic semiconductor titanium oxide of the present invention has a high catalytic activity against the decomposition of organic substances and the like by visible light irradiation. In particular, the organic photocatalyst of the present invention is a photocatalyst that can use light energy in the entire visible light region, and is particularly effective in that sunlight (natural light) can be sufficiently used.

  Unlike the inorganic photocatalyst, the organic photocatalyst of the present invention is obtained by simply laminating a p-type organic semiconductor and an n-type organic semiconductor, and has a very high practicality because it is extremely easy to mold.

  Although organic materials are generally easily oxidatively decomposed, the organic photocatalyst of the present invention functions stably in the gas phase or liquid phase. Of course, it can be used indoors as well as outdoors.

It is a schematic diagram of the test cell for photocatalytic reactions using the organic photocatalyst used in Example 1 and 2. 3 is a schematic diagram of a test cell for a photocatalytic reaction using an organic photocatalyst used in Comparative Example 1. FIG. 4 is a graph showing the relationship between the reaction time (minutes) and the methylene blue concentration (μM) in the photocatalytic reactions of Examples 1 and 2 and Comparative Example 1. It is a graph which shows the relationship between the reaction time (minute) and the methylene blue density | concentration (micromol) in the photocatalytic reaction of Examples 3 and 4 and Comparative Examples 2-4.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.

Example 1 (Evaluation of activity of organic photocatalyst during visible light irradiation)
(1) As organic photocatalytic materials, 3,4,9,10-perylenetetracarboxyl-bisbenzimidazole (hereinafter referred to as “PV”) which is an n-type semiconductor and metal-free phthalocyanine (hereinafter referred to as “H” which is a p-type semiconductor). ₂ Pc ”). In the present invention, those purified by sublimation were used.
(2) Preparation of the double layer film used as an organic photocatalyst element was performed by the vacuum evaporation method. First, PV was laminated on a glass substrate with a thickness of 220 nm, and then H ₂ Pc was laminated on the PV with a thickness of 70 nm.
(3) The configuration and method of the experimental apparatus were as follows. First, a test cell as shown in FIG. 1 was produced. As a cylindrical test rod, a multifoam made by Marumoto Struers (inner diameter 40 mm, height 30 mm (code: EFOPY, No: 40300046)) was used. The bottom of the cell was made by laying a polypropylene sheet on a glass plate. In order to seal between the cylindrical test rod and the polypropylene sheet, silicon grease (for high vacuum and chemical resistance) was applied to the contact portion. (Reference: Photocatalyst Product Forum, wet decomposition performance test method for photocatalyst products (revised on May 28, 2004))
(4) Methylene blue trihydrate was a special grade reagent stipulated in JIS K 8897, and purified water conforming to the 14th Japanese Pharmacopoeia standard was used. A fresh methylene blue aqueous solution (10 μmol / l) was prepared and adjusted to pH 10 using sodium hydroxide or potassium hydroxide. The double layer film produced in the above (2) was peeled off from the glass substrate using a methylene blue aqueous solution and allowed to stand on the top of the test bowl. The effective area of the organic photocatalyst at this time was about 12.5 cm ² , and the test bowl was filled with 35 ml of methylene blue aqueous solution. The upper part of the cylindrical test cell was closed with a cut-off filter (L-42, manufactured by HOYA, 5 × 5 cm ² ).
(5) The organic photocatalytic reaction was performed by irradiating visible light (wavelength: 400 to 750 nm) having an intensity of about 60 mWcm ⁻³ for 3 hours using a halogen lamp (manufactured by Nihon PI Corporation) as a light source. At this time, light irradiation was performed from the upper part of the test cell. When 180 minutes passed from the start of the reaction, the visible absorption spectrum of the methylene blue aqueous solution was measured, and the amount of decomposition was quantified. The visible absorption spectrum is measured using Shimadzu MultiSpec-1500, the spectrophotometer measurement cell is made of resin and has an optical path length of 10 mm, and the transmittance of light in the wavelength range of 600 to 700 nm is 80% or more. The thing of was used.
(6) As a result of the above (5), a decrease in absorbance was observed as the decomposition of methylene blue progressed. After 180 minutes, the concentration of the methylene blue aqueous solution decreased by about 0.5 μmol / l, confirming that about 5% decomposition of the initial concentration occurred. The results are shown in FIG.

Example 2 (Evaluation of activity of organic photocatalyst during visible light irradiation)
(1) PV as an n-type semiconductor and iron phthalocyanine (hereinafter referred to as “FePc”) as a p-type semiconductor were used as organic photocatalytic materials. In the present invention, those purified by sublimation were used.
(2) Preparation of the double layer film used as an organic photocatalyst element was performed by the vacuum evaporation method. First, PV was laminated on a glass substrate with a thickness of 130 nm, and then FePc was laminated on the PV with a thickness of 70 nm.
(3) The configuration and method of the experimental apparatus were the same as (3) to (5) of Example 1.
(4) As a result of the experiment, a decrease in absorbance was observed as methylene blue was decomposed. After 180 minutes, the concentration of the methylene blue aqueous solution decreased by about 1.2 μmol / l, confirming that about 12% decomposition of the initial concentration occurred.

  On the other hand, when an experiment was performed under the same conditions as in Example 1 except that no organic photocatalyst was used, no decomposition of methylene blue was confirmed even under light irradiation.

  From the results of Examples 1 and 2, it was found that the decomposition reaction of methylene blue occurred using an organic photocatalyst that absorbs a wide range of visible light. The results are shown in FIG.

Comparative Example 1 (Activity evaluation of titanium oxide photocatalyst during irradiation with visible light)
(1) Using a titanium oxide photocatalyst, a methylene blue decomposition test was performed by the method according to Examples 1 and 2.
(2) As a titanium oxide photocatalyst, a photocatalyst standard sample (50SQC, manufactured by Photocatalyst Laboratory Inc.) was used. This was obtained by coating a titanium oxide photocatalyst on a glass plate, and a titanium oxide having a thickness of 0.5 μm and a glass plate size of 50 mm × 50 mm × (thickness) 1.8 mm was used.
(3) Since titanium oxide has the property of adsorbing methylene blue on its surface, the surface was saturated and adsorbed with methylene blue. The reagents and water used were the same as in Examples 1 and 2. Adsorption onto the titanium oxide surface was performed in a test cell as shown in FIG. 2 using a 20 μmol / l methylene blue aqueous solution adjusted to pH 10. After adsorbing for 12 hours, the liquid was taken out and the absorbance was measured. As a result, the concentration of the methylene blue aqueous solution was lowered. Therefore, the adsorption was carried out for another 12 hours using a 20 μmol / l methylene blue aqueous solution. Since the concentration of the methylene blue aqueous solution at this time was 10 μmol / l or more, titanium oxide having methylene blue saturated and adsorbed on the surface was used for the photocatalytic reaction.
(4) A photocatalytic reaction was carried out using a test cell as shown in FIG. A multifoam made by Marumoto Struers (inner diameter 40 mm, height 30 mm (code: EFOPY, No: 40300046)) was used as a test rod. The test cell was filled with a fresh aqueous methylene blue solution adjusted to pH 10 (10 μmol / l, 35 ml).
(5) The photocatalytic reaction was performed by irradiating visible light (wavelength: 400 to 750 nm) having an intensity of about 60 mWcm ⁻³ for 3 hours using a halogen lamp (manufactured by Nippon P ^- I Co., Ltd.) as a light source. At this time, light irradiation was performed from the lower part of the test cell. At the time when 20 minutes, 40 minutes, 60 minutes, 80 minutes, 100 minutes, 120 minutes, 140 minutes, 160 minutes, and 180 minutes have elapsed since the start of the reaction, the visible absorption spectrum of the methylene blue aqueous solution was measured, and the amount of decomposition was determined. Quantified. The visible absorption spectrum measuring apparatus and the measurement cell are the same as in Examples 1 and 2.
(6) As a result of the above (5), no progress of decomposition of methylene blue was observed.

Moreover, when it experimented on the same conditions as the comparative example 1 except not using a titanium oxide photocatalyst, decomposition | disassembly of methylene blue was not confirmed even under visible light irradiation.

  From the results of Examples 1 and 2 and Comparative Example 1, it can be seen that the organic double layer film is a photocatalyst having a wide range of visible light responsiveness, and is superior to conventional titanium oxide in that it can effectively use visible light. The photocatalyst was confirmed. The results are shown in FIG.

Example 3 (Activity evaluation of organic photocatalyst during irradiation with visible light)
(1) As organic photocatalyst materials, n-type semiconductor 3,4,9,10-perylenetetracarboxyl-bisbenzimidazole (PV) and p-type semiconductor metal-free phthalocyanine (H ₂ Pc) were used. In the present invention, those purified by sublimation were used.
(2) Preparation of the double layer film used as an organic photocatalyst element was performed by the vacuum evaporation method. First, PV was laminated with a thickness of 200 nm on a glass substrate, and then H ₂ Pc was laminated with a thickness of 120 nm on the PV.
(3) The configuration and method of the experimental apparatus were as follows. First, a glass cell (1 cm × 1 cm × 5 cm) was filled with a predetermined concentration of methylene blue aqueous solution.
(4) Methylene blue trihydrate was a special grade reagent stipulated in JIS K 8897, and purified water conforming to the 14th Japanese Pharmacopoeia standard was used. A fresh methylene blue aqueous solution (10 μmol / l) was prepared and adjusted to pH 10 with sodium hydroxide. The photocatalyst carrying substrate prepared in the above (2) was placed on the side surface of the cell so that the catalyst surface was inside. At this time, the area of the organic photocatalyst was about 5 cm ² , and the test bowl was filled with 5 ml of methylene blue aqueous solution. The upper part is open and in contact with the atmosphere. The bottom of the cell is stirred with a magnetic stirrer.
(5) The organic photocatalytic reaction was performed by irradiating visible light (wavelength: 400 to 750 nm) for 3 hours using a halogen lamp (manufactured by Nihon PI Corporation, 100 mWcm ⁻² ) as a light source. At this time, light irradiation was performed from the side of the test cell. The irradiation area is 1 cm ² . During the reaction, white light of 1 μWcm ⁻² was irradiated from the right-angle direction, and the visible absorption spectrum of the methylene blue aqueous solution was measured from the transmission amount, and the decomposition amount was quantified. For measurement of the visible absorption spectrum, MPCD-7000 manufactured by Otsuka Electronics was used.
(6) As a result of the above (5), a significant decrease in absorbance was observed with the progress of the decomposition of methylene blue. The results are shown in FIG.

Example 4 (Activity evaluation of organic photocatalyst during irradiation with visible light)
(1) PV as an n-type semiconductor and FePc as a p-type semiconductor were used as organic photocatalytic materials. In the present invention, those purified by sublimation were used.
(2) Preparation of the double layer film used as an organic photocatalyst element was performed by the vacuum evaporation method. First, PV was laminated with a thickness of 200 nm on a glass substrate, and then FePc was laminated with a thickness of 50 nm on the PV. For FePc, a method of casting from a solution was also employed.
(3) The configuration and method of the experimental apparatus were the same as (3) to (5) of Example 3.
(4) As a result of the experiment, a significant decrease in absorbance was observed as methylene blue was decomposed. The results are shown in FIG.

Comparative example 2 (blank test at the time of visible light irradiation without a catalyst)
Visible light was irradiated in the same manner as in Example 3 except that no organic photocatalyst was used. As a result of the experiment, it was found that the absorbance of methylene blue gradually decreased by light irradiation. The results are shown in FIG. This is considered that methylene blue reacted with dissolved oxygen and decomposed by light irradiation.

Comparative Example 3 (blank test without catalyst without light irradiation)
Example 3 was the same as Example 3 except that no organic photocatalyst was used and no light was irradiated (tested in a dark room). As a result of the experiment, the absorbance of methylene blue did not change at all and no decomposition occurred. The results are shown in FIG.

Comparative Example 4 (PV activity evaluation during visible light irradiation)
(1) As an organic photocatalyst material, only sublimated and purified PV was used.
(2) As an organic photocatalyst element, PV was vapor-deposited with a thickness of 200 nm on a glass substrate by a vacuum vapor deposition method.
(3) The configuration and method of the experimental apparatus were the same as (3) to (5) of Example 3.
(4) As a result of the experiment, although the decomposition of methylene blue progressed, the decrease in absorbance was equivalent to that of the blank test of Comparative Example 2, and it was found that the photocatalytic reaction hardly proceeded with PV alone. The results are shown in FIG.

Claims (12)

An organic photocatalyst in which a p-type organic semiconductor of a phthalocyanine derivative and an n-type organic semiconductor of a perylene derivative are laminated, and an organic substance or an inorganic substance containing nitrogen, sulfur, or phosphorus under light irradiation without applying an electrochemical bias. Organic photocatalyst used to decompose.   The organic photocatalyst according to claim 1, having a two-layer structure in which a p-type organic semiconductor layer and an n-type organic semiconductor layer are laminated.   The organic photocatalyst according to claim 1, wherein the thickness of the p-type organic semiconductor layer is 20 to 500 nm, and the thickness of the n-type organic semiconductor layer is 50 to 800 nm.   The organic photocatalyst according to claim 1, wherein the organic photocatalyst has a three-layer structure including a co-deposited layer of a p-type organic semiconductor and an n-type organic semiconductor between the p-type organic semiconductor layer and the n-type organic semiconductor layer.   The organic photocatalyst according to claim 1, having a two-layer structure in which a p-type organic semiconductor layer and an n-type organic semiconductor layer are laminated on a substrate.   2. The organic photocatalyst according to claim 1, wherein the organic photocatalyst has a three-layer structure including a co-deposited layer of a p-type organic semiconductor and an n-type organic semiconductor between the p-type organic semiconductor layer and the n-type organic semiconductor layer on the substrate.   6. A method for producing an organic photocatalyst according to claim 5, wherein an n-type organic semiconductor layer and a p-type organic semiconductor layer are laminated on a substrate to form a two-layer structure.   A method for producing an organic photocatalyst according to claim 6, wherein an n-type (or p-type) organic semiconductor layer is formed on a substrate, and an n-type organic semiconductor and a p-type organic semiconductor are co-deposited thereon. A manufacturing method characterized by forming a co-deposition layer and forming a p-type (or n-type) organic semiconductor layer thereon to form a three-layer structure.   A method for decomposing an organic substance in a gas phase or an aqueous phase or an inorganic substance containing nitrogen, sulfur or phosphorus, wherein the organic photocatalyst according to claim 1 is converted into an organic substance or an organic substance under light irradiation without applying an electrochemical bias. A method of decomposing by contacting with an inorganic substance containing nitrogen, sulfur or phosphorus.   A paint composition comprising the organic photocatalyst according to claim 1 and a paint.   The organic photocatalyst according to claim 1 is dispersed in water to be treated containing an organic substance or an inorganic substance containing nitrogen, sulfur, or phosphorus, and the water is treated by irradiating light without applying an electrochemical bias. how to. Furthermore, the water treatment method of Claim 11 which filters and collect | recovers this organic photocatalyst after a process, and uses for water treatment again.

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