JP2013150972A - Semiconductor hetero particle and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide semiconductor hetero particles including two different kinds of semiconductor particles and exhibiting a photocatalyst function in a comparatively wide pH range without using a solution type electronic mediator.SOLUTION: Semiconductor hetero particles include first semiconductor particles 2a, second semiconductor particles 2b, metallic particles 3, and an organic group 1. The potential of the conduction band lower end of the first semiconductor particles 2a is more negative than the potential of the valence electron band upper end of the second semiconductor particles 2b. The metallic particles 3 are joined to either one of the first and second semiconductor particles 2a, 2b, and the organic group 1 is bonded to the other of the first and second semiconductor particles 2a, 2b. The organic group 1 has a metal bond functional group, and the metal bond functional group is bonded to the metallic particles 3.

Description

  The present invention relates to a semiconductor heteroparticle and a method for producing the same, and more particularly to a semiconductor heteroparticle comprising two different types of semiconductor particles and a method for producing the same.

  When the semiconductor is irradiated with light having energy greater than or equal to the band gap, electrons in the valence band are excited to the conduction band and holes are generated in the valence band. Thus generated electrons have a strong reducing power and holes have a strong oxidizing power. Therefore, molecules can be reduced or oxidized on the semiconductor surface and in the vicinity thereof. Development of technologies such as conversion of solar energy into chemical energy, organic synthesis, and decomposition of toxic substances has been extensively performed using the photocatalytic action of semiconductors.

For example, a technique for generating hydrogen from water using a semiconductor photocatalyst has been extensively studied for the purpose of producing clean energy, and such a technique is also one of techniques using a photocatalytic reaction. In the conventional hydrogen generation technology using a semiconductor photocatalyst, one kind of semiconductor photocatalyst needs to function as a catalyst for both the oxidation reaction and the reduction reaction of water, so that the potential at the upper end of the valence band is O ₂ / OH ⁻ (in basic solution) or O ₂ / H ₂ O (in neutral or acidic solution) positive (noble, ie, more distant from the vacuum level) than the redox potential, and lower end of conduction band Is more negative than the redox potential of H ₂ O / H ₂ (in neutral or basic solution) or H ⁺ / H ₂ (in acidic solution) (base, ie closer to the vacuum level) It was necessary. For this reason, in the hydrogen generation technology using the conventional photocatalyst, the semiconductor photocatalyst which can be utilized was limited to the thing which satisfy | fills the said conditions.

  Therefore, a composite reaction system has been proposed in which two types of semiconductor photocatalysts are used, one of the semiconductor photocatalysts performs a water oxidation reaction, and the other semiconductor photocatalyst performs a water reduction reaction (hydrogen generation reaction). In this composite reaction system, each semiconductor photocatalyst has only to have a potential that allows an oxidation reaction and a reduction reaction to proceed. Compared to the case of using one kind of semiconductor photocatalyst, the available semiconductor photocatalyst can be used. The selection range is expanded.

For example, Japanese Unexamined Patent Application Publication No. 2005-199187 (Patent Document 1) discloses a photocatalyst system in which an oxygen generation photocatalyst and a hydrogen generation photocatalyst are combined. In this photocatalyst system, an Fe compound forming an Fe ³⁺ / Fe ²⁺ redox system is added to promote electron transfer between the photocatalysts. Such an Fe compound is called a solution-type electron mediator and has an electron transfer function. However, since solution-type electron mediators depend on the type of photocatalyst used, even if the range of available semiconductor photocatalysts is expanded, the types of available solution-type electron mediators tend to be limited. Further, since the electron transfer by the solution-type electron mediator is caused by the diffusion of the solution-type electron mediator in the solution, there is a limit to the improvement of the reaction rate.

  Y. Sasaki et al. Have proposed a photocatalyst obtained by electrostatically aggregating an oxygen-generating photocatalyst and a hydrogen-generating photocatalyst in an acidic atmosphere (Non-patent Document 1). This photocatalyst enables direct electron transfer between the oxygen generating photocatalyst and the hydrogen generating photocatalyst without using an electron mediator. However, even in this photocatalyst, there is a problem that the pH at which the photocatalytic function is manifested is limited to a range in which both photocatalysts attract each other.

  In addition, A. Iwase et al. Have proposed a photocatalyst in which an oxygen-generating photocatalyst and a hydrogen-generating photocatalyst are combined using graphene oxide obtained by photoreduction (Non-patent Document 2). In this photocatalyst, the graphene oxide acts as a solid electron mediator. However, this photocatalyst has a problem that the pH at which the photocatalytic function is expressed is limited to a range in which both photocatalysts are attracted to each other.

JP 2005-199187 A

Y. Sasaki et al. Phys. Chem. C, 2009, 113, 17536-17542 A. Iwase et al. Am. Chem. Soc. 2011, 133, 11054-11057.

  The present invention has been made in view of the above-described problems of the prior art, has two different types of semiconductor particles, and does not use a solution-based electron mediator, and exhibits a photocatalytic function in a relatively wide pH range. An object is to provide semiconductor hetero particles and a method for producing the same.

  As a result of intensive studies to achieve the above object, the present inventors can obtain semiconductor hetero particles that exhibit a photocatalytic function by joining two different types of semiconductor particles through metal particles and organic groups. As a result, the present invention has been completed.

That is, the first semiconductor heteroparticle of the present invention is
A first semiconductor particle, a second semiconductor particle, a metal particle, and an organic group;
The potential at the lower end of the conduction band of the first semiconductor particles is more negative than the potential at the upper end of the valence band of the second semiconductor particles;
The metal particles are bonded to one of the first and second semiconductor particles;
The organic group is bonded to the other semiconductor particle of the first and second semiconductor particles;
The organic group has a metal bond functional group, and the metal bond functional group is bonded to the metal particle. In the first semiconductor heteroparticle, it is preferable that the metal particle is supported on one of the first and second semiconductor particles.

The second semiconductor heteroparticle of the present invention is
A first semiconductor particle, a second semiconductor particle, a first metal particle, a second metal particle, and an organic group;
The potential at the lower end of the conduction band of the first semiconductor particles is more negative than the potential at the upper end of the valence band of the second semiconductor particles;
The first and second metal particles are bonded to the first and second semiconductor particles, respectively;
The organic group has a first metal binding functional group and a second metal binding functional group, and the first and second metal binding functional groups bind to the first and second metal particles, respectively. It is characterized by that. In the second semiconductor heteroparticle, it is preferable that the first and second metal particles are supported on the first and second semiconductor particles, respectively.

Furthermore, the third semiconductor heteroparticle of the present invention is
A first semiconductor particle, a second semiconductor particle, a first organic group, a second organic group, and a metal particle;
The potential at the lower end of the conduction band of the first semiconductor particles is more negative than the potential at the upper end of the valence band of the second semiconductor particles;
The first and second organic groups are bonded to the first and second semiconductor particles, respectively;
The first and second organic groups have first and second metal binding functional groups, respectively, and the metal particles are in the first metal binding functional group and the second metal binding functional group, respectively. It is characterized by being connected.

The method for producing the first semiconductor heteroparticle of the present invention comprises:
A first semiconductor particle, a second semiconductor particle, a metal particle, and an organic group, wherein the potential at the lower end of the conduction band of the first semiconductor particle is higher than the potential at the upper end of the valence band of the second semiconductor particle. A method for producing negative semiconductor heteroparticles, comprising:
Bonding metal particles to one of the first and second semiconductor particles;
The other semiconductor particle of the first and second semiconductor particles is mixed with an organic molecule having a metal bond functional group to prepare a semiconductor particle to which the organic group having a metal bond functional group is bonded. Process,
Mixing the semiconductor particles to which the metal particles are bonded and the semiconductor particles to which the organic groups having the metal bonding functional groups are bonded to bond the metal particles to the metal bonding functional groups; It is characterized by including.

  In the step of joining the metal particles in the method for producing the first semiconductor heteroparticle, it is preferable to support the metal particles on one of the first and second semiconductor particles.

In addition, the second method for producing a semiconductor heteroparticle of the present invention includes:
1st semiconductor particle, 2nd semiconductor particle, 1st metal particle, 2nd metal particle, and organic group are provided, and the electric potential of the conduction band lower end of said 1st semiconductor particle is said 2nd semiconductor A method for producing a semiconductor heteroparticle that is more negative than the potential at the top of the valence band of the particle,
Bonding the first metal particles to the first semiconductor particles;
Bonding the second metal particles to the second semiconductor particles;
One of the first and second semiconductor particles to which the metal particles are bonded is mixed with an organic molecule having a first metal-bonded functional group and a second metal-bonded functional group, The metal particles are bonded to one of the first and second metal-bonding functional groups, the metal particles are bonded, and the metal particles are bonded to the first and second metal-bonding functional groups. Preparing a semiconductor particle to which an organic group having the other metal-bonded functional group of the group is bonded;
The other semiconductor particle of the first and second semiconductor particles bonded to the metal particle is bonded to the organic group bonded to the metal particle and having the other metal-bonded functional group. Mixing the semiconductor particles being bonded, and bonding the metal particles bonded to the other semiconductor particles and the other metal-binding functional group;
It is characterized by including.

  In the step of bonding the first metal particles in the method for producing the second semiconductor heteroparticle, it is preferable that the first metal particles are supported on the first semiconductor particles, and the second metal particles are bonded. In the caulking step, it is preferable to support the second metal particles on the second semiconductor particles.

Furthermore, the third method for producing a semiconductor heteroparticle of the present invention is as follows.
1st semiconductor particle, 2nd semiconductor particle, 1st organic group, 2nd organic group, and metal particle are provided, and the electric potential of the conduction band lower end of said 1st semiconductor particle is said 2nd semiconductor A method for producing a semiconductor heteroparticle that is more negative than the potential at the top of the valence band of the particle,
Mixing first semiconductor particles and organic molecules having a first metal-binding functional group to prepare first semiconductor particles to which the first organic group having the metal-binding functional group is bonded; ,
Mixing second semiconductor particles and organic molecules having a second metal-bonded functional group to prepare second semiconductor particles to which the second organic group having the metal-bonded functional group is bonded; ,
Mixing the semiconductor particles and the metal particles to which one organic group of the first and second organic groups is bonded, and bonding the metal-bonded functional group in the organic group and the metal particles; Preparing a semiconductor particle to which the organic group is bonded and the metal particle is bonded to a metal bonding functional group in the organic group;
The semiconductor particle to which the other organic group of the first and second organic groups is bonded, the organic group is bonded, and the metal particle is bonded to the metal bonding functional group in the organic group. And mixing the semiconductor particles to bond the metal particles to the metal-bonded functional group in the other organic group.

  In the present invention, “bond” is a concept including “adsorption”, and the “adsorption” generally means irreversible without desorption.

  The reason why the photocatalytic function is manifested in the semiconductor heteroparticle of the present invention is not necessarily clear, but the present inventors speculate as follows. That is, in the semiconductor heteroparticle of the present invention, it is assumed that the two kinds of semiconductor particles are in contact or close to each other due to the interaction between the metal particles joining the two kinds of semiconductor particles and the organic group. The When the semiconductor heteroparticle in such a state is irradiated with light, the electron excited in one semiconductor particle (first semiconductor particle) has a valence band compared to the potential at the lower end of the conduction band of the first semiconductor particle. It is presumed that the potential at the upper end moves efficiently to positive semiconductor particles (second semiconductor particles). As a result, a photo-oxidation reaction is likely to occur at the surface of the first semiconductor particle and its vicinity, and a photoreduction reaction by electrons photoexcited by the second semiconductor particle at and near the surface of the second semiconductor particle. Since it is likely to occur, it is presumed that the photocatalytic function is expressed in the semiconductor heteroparticle of the present invention including the first and second semiconductor particles.

  According to the present invention, it is possible to develop a photocatalytic function in a relatively wide pH range without using a solution-based electron mediator in a semiconductor heteroparticle having two different types of semiconductor particles. Moreover, it becomes possible to easily manufacture such semiconductor hetero particles.

It is a conceptual diagram which shows the suitable one embodiment of the semiconductor heteroparticle of this invention. It is a conceptual diagram which shows other suitable one Embodiment of the semiconductor heteroparticle of this invention. It is a conceptual diagram which shows another suitable one Embodiment of the semiconductor heteroparticle of this invention. 2 is a high-resolution field emission scanning electron micrograph showing a reflected electron image of Au-supported nitrogen-doped tantalum oxide particles. It is a graph which shows the FT-IR spectrum of the particle | grains measured by ATR method.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.

<Semiconductor heteroparticle>
First, the semiconductor heteroparticle of the present invention will be described. The first semiconductor heteroparticle of the present invention comprises a first semiconductor particle, a second semiconductor particle, a metal particle, and an organic group. The second semiconductor heteroparticle of the present invention includes the first semiconductor particle, the second semiconductor particle, the first metal particle, the second metal particle, and an organic group. Furthermore, the 3rd semiconductor heteroparticle of this invention is equipped with a 1st semiconductor particle, a 2nd semiconductor particle, a 1st organic group, a 2nd organic group, and a metal particle.

(Semiconductor particles)
The 1st-3rd semiconductor heteroparticle of this invention is equipped with two types of different semiconductor particles, a 1st semiconductor particle and a 2nd semiconductor particle. In the first and second semiconductor particles, the potential at the lower end of the conduction band of the first semiconductor particle is more negative than the potential at the upper end of the valence band of the second semiconductor particle (base, that is, closer to the vacuum level). Preferably, the potential difference is 0.1 eV or more. Since the potential at the lower end of the conduction band of the first semiconductor particle and the potential at the upper end of the valence band of the second semiconductor particle have such a potential difference, electrons photoexcited in the first semiconductor particle are converted into the second semiconductor. A two-stage photoexcitation system is formed in which the particles move to the valence band of the particles and the electrons are photoexcited again to the conductor of the second semiconductor particle.

  Although there is no restriction | limiting in particular as a band gap of the semiconductor particle concerning this invention, 4.0 eV or less is preferable. Semiconductor particles having such a band gap can absorb light having a wavelength of 300 to 1000 nm to form electrons and holes. The semiconductor particles according to the present invention may be an n-type semiconductor or a p-type semiconductor.

  Examples of such semiconductor particles include oxides of various metals (including those in which the metal is partially oxidized), composite oxides (including those in which the metal is partially oxidized), nitrides ( Including those in which the metal is partially nitrided), oxynitrides (including those in which the metal oxide is partially nitrided, and those in which the metal nitride is partially oxidized), sulfides (including Including those in which the metal is partially sulfided), oxysulfides (including those in which the metal oxide is partially sulfided, and those in which the metal sulfide is partially oxidized), nitrogen fluorides (Including those in which metal nitrides are partially fluorinated, those in which metal fluorides are partially nitrided), oxyfluorides (in which metal oxides are partially fluorinated, metals Including those in which the fluoride is partially oxidized), oxynitride fluoride (metal oxynitridation) Including partially fluorinated, metal oxyfluoride partially nitrided, metal oxyfluoride partially oxidized, and carbide (metal is partially carbonized) Carbon-containing oxides (including those in which the metal is partially oxidized), phosphorus compounds, silicide compound semiconductors, and the like. Moreover, the semiconductor particles according to the present invention may be doped with at least one element among nitrogen, sulfur, carbon, phosphorus, and metal elements.

More specific semiconductor particles include titanium compounds, tantalum compounds, iron compounds, zinc compounds, copper compounds, and the like. It is not particularly limited, but as the titanium _compound, TiO 2, M-TiO ₂ (represents TiO ₂ where the element M doped, as the element M, N, S, F, Ni, Ru, Rh, Fe, Cu, Co, etc.), SrTiO ₃ , M-SrTiO ₃ (represents SrTiO ₃ doped with the element M, and examples of the element M include Cr, Mn, Ru, Rh, Ir, etc.), CaTiO ₃ , Sr ₃ Ti ₂ O ₇ , Sr ₄ Ti ₃ O ₇ , K ₂ La ₂ Ti ₃ O ₁₀ , Rb ₂ La ₂ Ti ₃ O ₁₀ , Cs ₂ La ₂ Ti ₃ O ₁₀ , CsLaTi ₂ NbO ₁₀ , La ₂ TiO ₅ La ₂ Ti ₃ O ₉ , La ₂ Ti ₂ O ₇ , Na ₂ Ti ₆ O ₁₃ , K ₂ Ti ₆ O ₁₃ , KTiNbO _{5 and the} like.

It is not particularly limited as the tantalum _{compound, Ta 2 O 5, N-} Ta 2 O 5 ( nitrogen-doped tantalum _{oxide), TaON, Ta 3 N 5} , CaTaO 2 N, SrTaO 2 N, BaTaO 2 N, LaTaO 2 _{N, Y 2 Ta 2 O 5} N, InTaO 4, Ni-TaO 4 ( nickel doped TaO _4), and the like. Is not particularly limited as the iron compound _{represents Fe 2 O 3, M-Fe} 2 O 3 (Fe 2 O 3 in which the element M doped, as the element M, N, Zn, (N , Zn), Cu, Ni, Ti, Si, Nb, etc.), CaFe ₂ O ₄ , CuFe ₂ O ₄ , CuFeO ₂ , ZnFe ₂ O _{4 and the} like.

Although there is no restriction | limiting in particular as said zinc compound, ZnS, Ni-ZnS (nickel dope zinc sulfide) etc. are mentioned. Is not particularly limited as the copper _{compound, Cu 2 O, CuO, CuBi} 2 O 4, CuI, Cu (InGa) S 2, Cu (InGa) Se 2, CuGaS 2, CuGaSSe, CuGaSe 2, Cu-Zn- S-based compound, Cu-ZnS-based compound, Cu-Zn-Sn-S-based compound, Cu-Sn-S-based compound, Cu-In-Ga-Se-based compound, Cu-In-Ga-S-based compound, Cu- In-Se compounds are exemplified.

In addition, metal oxides such as WO ₃ , BiVO ₄ , Bi ₂ MoO ₆ , Nb ₂ O ₅ , NiO, ZnO, SnO ₂ , ZrO ₂ , CeO ₂ , ZrO ₂ / CeO ₂ solid solution, InP, InAs, GaP, Compound semiconductors such as GaAs, GaAsP, GaN, GaInAsP, GaSb, CdS, CdSe, Si, SiC, Ge, SiC, and silicides of various metals (Mo, W, Ti, Co, Ni, Fe, etc.) also apply to the present invention. It can be used as semiconductor particles.

  Although there is no restriction | limiting in particular as an average primary particle diameter of the semiconductor particle concerning this invention, 100 micrometers or less are preferable and 10 micrometers or less are more preferable. When the average primary particle diameter exceeds the upper limit, the specific surface area of the particles decreases, and the contact probability between the particles tends to decrease. The lower limit of the average primary particle diameter is not particularly limited, but is usually 1 nm or more. The primary particle diameter of the semiconductor particles can be measured by a known method such as X-ray diffraction (XRD) measurement, transmission electron microscope (TEM) observation, or scanning electron microscope (SEM) observation. In the present invention, the shape of the semiconductor particles is not particularly limited.

Moreover, there is no restriction | limiting in particular as a specific surface area of the semiconductor particle concerning this invention, However, 5 m < ² > / g or more is preferable. When the specific surface area is less than the lower limit, the contact probability between particles and the photocatalytic activity tend to decrease.

  In the semiconductor heteroparticle of the present invention, the content of the first and second semiconductor particles is not particularly limited, but the mass ratio of the first semiconductor particle to the second semiconductor particle is first: first. 2 = 1: 20 to 20: 1 is preferable, and 1:10 to 10: 1 is more preferable. When the mass ratio between the first semiconductor particles and the second semiconductor particles deviates from the above range, the electrons photoexcited by the first semiconductor particles tend to be difficult to efficiently move to the second semiconductor particles.

(Metal particles)
In the first semiconductor hetero particles of the present invention, metal particles are bonded (preferably supported) to one of the first and second semiconductor particles. In the second semiconductor heteroparticle of the present invention, the first and second metal particles are bonded (preferably supported) to the first and second semiconductor particles, respectively. Furthermore, in the third semiconductor heteroparticle of the present invention, metal particles are bonded to both metal bonding functional groups of the first and second organic groups described later, and are directly bonded to the semiconductor particles. Absent.

  Examples of these metal particles include metals belonging to Groups 8 to 11 of the periodic table, and specifically include Cu, Ag, Au, Ni, Pd, Pt, Fe, Ru, Os, Co, Rh, and Ir. Can be mentioned. Among these metals, Au, Pd, Ag, and Pt are preferable from the viewpoint that electrons can be efficiently moved. In the metal particle concerning this invention, these metals may be contained individually by 1 type, or 2 or more types may be contained. In the second semiconductor heteroparticle of the present invention, the first and second semiconductor particles may be made of the same kind of metal or different kinds of metals.

  In the semiconductor heteroparticle of the present invention, all of such metals may exist in a metal state, or a part of them may be changed to a state other than a metal state such as an oxide or a hydroxide. Good.

  Although there is no restriction | limiting in particular as content of such a metal particle, In 1st and 2nd semiconductor heteroparticle, it is 0.05-60 mass with respect to 100 mass parts of each semiconductor particle which the metal particle has joined. Part is preferable, and 0.1 to 50 parts by mass is more preferable. Moreover, in 3rd semiconductor heteroparticle, 0.05-30 mass parts is preferable with respect to a total of 100 mass parts of 1st and 2nd semiconductor particles, and 0.1-25 mass parts is more preferable. When the content of the metal particles is less than the lower limit, the electrons photoexcited by the first semiconductor particles tend to be difficult to efficiently move to the second semiconductor particles. On the other hand, when the content exceeds the upper limit, Light absorption tends to be inhibited.

  Further, in the first and second semiconductor hetero particles, the metal particles are preferably bonded (preferably supported) in a state of being uniformly dispersed on the surface of the semiconductor particles, but are biased to a part of the surface of the semiconductor particles. It may be bonded (preferably supported) in a state (that is, nonuniformly).

  Although there is no restriction | limiting in particular as an average particle diameter of such a metal particle, 200 nm or less is preferable and 20 nm is more preferable. When the average particle diameter of the metal particles exceeds the upper limit, the coverage of the metal particles on the surface of the semiconductor particles becomes too high, and the light absorption of the semiconductor particles tends to be inhibited. The lower limit of the average particle diameter of the metal particles is not particularly limited, but is usually 0.5 nm or more. The metal particles preferably have a uniform particle size (that is, the particle size distribution is monodisperse), but metal particles having different particle sizes may be mixed at a certain ratio. Further, in the second semiconductor hetero particles, the average particle diameters of the first and second metal particles may be the same or different. The particle diameter of the metal particles should be measured by a known method such as X-ray diffraction (XRD) measurement, transmission electron microscope (TEM) observation, scanning electron microscope (SEM) observation, light scattering method, CO pulse adsorption method, etc. Can do. In the present invention, the shape of the metal particles is not particularly limited.

(Organic group)
The organic group according to the present invention connects the semiconductor particles and the metal particles, or connects the metal particles to each other, whereby the photoexcited electrons in the first semiconductor particles move to the valence band of the second semiconductor particles. It is possible to do.

Specifically, in the first semiconductor heteroparticle of the present invention, as shown in FIG. 1, the organic group 1 binds to the first semiconductor particle 2a (including adsorption; the same applies hereinafter), and the first. The first semiconductor particle 2a and the second semiconductor particle 2b are connected to each other through the organic group 1 and the metal particle 3 by being bonded to the metal particle 3 bonded to the second semiconductor particle 2b. The electron e ⁻ photoexcited in the semiconductor particle 2a moves to the valence band of the second semiconductor particle 2b. In the first semiconductor heteroparticle of the present invention, the organic group 1 is bonded to the second semiconductor particle 2b and also to the metal particle 3 bonded to the first semiconductor particle 2a. Similarly to the above, the electron e ⁻ photoexcited in the first semiconductor particle 2a moves to the valence band of the second semiconductor particle 2b.

Further, in the second semiconductor heteroparticle of the present invention, as shown in FIG. 2, the organic group 1 is bonded to the metal particle 3a bonded to the first semiconductor particle 2a and the second semiconductor particle 2b. The first semiconductor particle 2a and the second semiconductor particle 2b are connected to each other through the organic group 1 and the metal particles 3a and 3b by being bonded to both of the metal particles 3b. The photoexcited electron e ⁻ moves to the valence band of the second semiconductor particle 2b.

Further, in the third semiconductor heteroparticle of the present invention, as shown in FIG. 3, the first organic group 1a is bonded to the first semiconductor particle 2a, is bonded to the metal particle 3, and the second When the organic group 1b is bonded to the second semiconductor particle 2b and is bonded to the metal particle 3, the first semiconductor particle 2a and the second semiconductor particle 2b are bonded to the first and second organic groups 1a and 1a. Electrons e ⁻ coupled through 1b and the metal particles 3 and photoexcited in the first semiconductor particles 2a move to the valence band of the second semiconductor particles 2b.

(Organic group in the first semiconductor heteroparticle)
The organic group in the first semiconductor heteroparticle is formed by bonding an organic molecule with the semiconductor particle and with the metal particle. Such an organic molecule is not particularly limited as long as it can be bonded to one of the first and second semiconductor particles and can be bonded to a metal particle bonded to the other semiconductor particle. However, it has a functional group (metal-binding functional group) that can be chemically bonded to metal particles. As an organic molecule having such a metal binding functional group, for example, the following formula (1):
^{X 1 -R 1 -Y 1 (1} )
The thing represented by is mentioned.

X ¹ in the formula (1) represents a metal-bonded functional group. One or more such metal-bonded functional groups may be contained in the organic molecule. The form of bonding with the metal particles is not particularly limited as long as it can be chemically bonded, and examples thereof include coordination bonding and ionic bonding. Such bonding forms may be present alone or in combination of two or more in the semiconductor heteroparticle.

  Such a metal-bonded functional group is preferably a functional group containing at least one heteroatom selected from a sulfur atom, an oxygen atom, a nitrogen atom, a phosphorus atom and an arsenic atom, a mercapto group, a hydroxyl group, a carboxyl group, an aldehyde group , Cyano group, nitro group, amino group, ester group, amide group, formyl group, ketone group, phosphoric acid group, sulfonic acid group, pyridyl group, carboxylic acid ester group, phosphoric acid ester group, phosphine group, phosphine oxide group, Examples include amine oxide groups, carbonyl groups, phosphoric acid amide groups, phosphoric acid triamide groups, sulfoxide groups, imino groups, aromatic amino groups (pyridinyl groups, imidazolyl groups, etc.), and chelate functional groups thereof. Moreover, these metal bond functional groups may form the ring. Such metal-bonded functional groups may be included in the organic molecule alone or in combination of two or more.

Y ¹ in the formula (1) represents a functional group (anchor group) that can be bonded to the surface of the semiconductor particle. One or two or more such anchor groups may be contained in the organic molecule. In addition, there are no particular restrictions on the form of bonding with the surface of the semiconductor particles. Complex bond (adsorption), and depends on the type of anchor group. Such bonding forms may be present alone or in combination of two or more in the semiconductor heteroparticle.

  Examples of such anchor groups include silyl groups, carboxyl groups, phosphoryl groups, sulfonic acid groups, hydroxyl groups, silanol groups, mercapto groups, aldehyde groups, cyano groups, nitro groups, amino groups, ester groups, amide groups, formyl groups, Ketone group, phosphate group, pyridyl group, carboxylate group, phosphate group, phosphine group, phosphine oxide group, amine oxide group, carbonyl group, phosphate amide group, phosphate triamide group, sulfoxide group, imino group, Examples thereof include aromatic amino groups (pyridinyl group, imidazolyl group, etc.), chelate functional groups thereof, functional groups derived from these functional groups, and the like. Among such anchor groups, a carboxyl group, a phosphate group, and a phosphoryl group are preferable when the semiconductor particle is a metal oxide, and a functional group (phosphoryl group) having a morpholyl group (P = O) in the case of a compound semiconductor. , Phosphoric acid group, phosphoric acid ester group, phosphine oxide group, phosphoric acid amide group). Such an anchor group is usually present on the surface of the semiconductor particle in a state where protons are desorbed, but in a state where the oxygen atom of the anchor group is coordinated to the metal on the surface of the semiconductor particle. Also good. Moreover, only one type of anchor group may be contained in the organic molecule or two or more types may be contained.

  Examples of the silyl group include alkoxysilyl groups. Examples of the alkoxysilyl group include trialkoxysilyl groups having three alkoxy groups, dialkoxysilyl groups having two alkoxy groups, and monoalkoxysilyl groups having one alkoxy group. By bonding such a silyl group to an oxygen atom on the surface of the semiconductor particle, a semiconductor particle in which the organic group according to the present invention is chemically bonded can be obtained. Accordingly, the alkoxy group is not particularly limited, but from the viewpoint of reactivity with semiconductor particles, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, etc. having a relatively small number of carbon atoms in the alkoxy group (more preferably Is preferably an alkoxysilyl group having 1 to 4 carbon atoms. Moreover, only 1 type may be contained in the organic molecule, or 2 or more types may be contained in the organic molecule.

R ¹ in the formula (1) can form an organic molecule by chemically linking the metal-bonding functional group and the anchor group, and the first semiconductor particle and the second semiconductor according to the length thereof. It is a group (spacer group) that can adjust the distance to the particles. Such a spacer group is not particularly limited, but preferably has a stable chemical structure that is not dissociated or eliminated by light irradiation or a redox reaction. As such a spacer group, for example, a saturated hydrocarbon group, an unsaturated hydrocarbon group, an aromatic hydrocarbon group, and a part of carbon atoms of these hydrocarbon groups are heteroatoms (N, O, S, Si Etc.) and a heterocyclic group substituted with a heterocyclic group. The saturated hydrocarbon group, unsaturated hydrocarbon group, and hetero group may be linear or branched. In the present invention, when the metal binding functional group and the anchor group can be directly bonded to form an organic molecule, a spacer group may not be included in the organic molecule.

  The length of the spacer group is not particularly limited, but the average terminal group distance is preferably 30 mm or less. When the average terminal group distance exceeds the upper limit, the distance between the first semiconductor particles and the second semiconductor particles becomes too long, and the electron transfer between the two tends to hardly occur. Examples of the spacer group having such an average terminal distance include alkyl groups having 1 to 18 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a decyl group, and an octadecyl group, a methenyl group, and an ethenyl group. , Propenyl group, butenyl group, hexenyl group, decenyl group, octadecenyl group and other unsaturated aliphatic hydrocarbon groups having 1 to 18 carbon atoms, phenyl group, aromatic hydrocarbon groups having 6 to 12 carbon atoms such as naphthyl group, And a heterocyclic group or a heterocyclic group in which a part of carbon atoms of these hydrocarbon groups is substituted with a heteroatom (N, O, S, Si, etc.). Such a spacer group may be included in the organic molecule alone or in combination of two or more.

  Examples of organic molecules having such metal-bonded functional groups and anchor groups include known organic alkoxysilanes such as organic trimethoxysilane and organic triethoxysilane. As organic trimethoxysilane, mercaptomethyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, mercaptophenyltrimethoxysilane, hydroxymethyltrimethoxysilane, N-hydroxymethyl-N-methylaminopropyltrimethoxysilane, 2-cyanoethyl Trimethoxysilane, 3-cyanopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 4-aminobutyltrimethoxysilane, N- (6-aminohexyl) aminomethyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3- [2- (2-aminoethylamino) ethylamino] propyltrimethoxysilane, p-aminophenyltrimethoxysilane, m-aminophenyltrimethoxy Run, 3- (m-aminophenoxy) propyl trimethoxy silane, acetoxy silane, acetoxy methyltrimethoxysilane, and the like acetoxyethyl trimethoxysilane.

  Examples of the organic triethoxysilane include mercaptomethyltriethoxysilane, 3-mercaptopropyltriethoxysilane, mercaptophenyltriethoxysilane, hydroxymethyltriethoxysilane, N-hydroxymethyl-N-methylaminopropyltriethoxysilane, 2 -Cyanoethyltriethoxysilane, 3-cyanopropyltriethoxysilane, 3-aminopropyltriethoxysilane, 4-aminobutyltriethoxysilane, N- (6-aminohexyl) aminomethyltriethoxysilane, N- (2-amino) Ethyl) -3-aminopropyltriethoxysilane, 3- [2- (2-aminoethylamino) ethylamino] propyltriethoxysilane, p-aminophenyltriethoxysilane, m-aminophenyltrie Kishishiran, 3- (m-aminophenoxy) propyl triethoxysilane, acetoxy triethoxy silane, acetoxymethyl triethoxysilane, and the like acetoxyethyl triethoxysilane.

  Examples of other organic molecules having a metal binding functional group and an anchor group include mercaptoacetic acid, 3-mercaptopropionic acid, mercaptobenzoic acid, mercaptophenol, mercaptoethanol, 4-hydroxybenzenethiol, 4-aminobenzoic acid, 3-aminobenzoic acid, 2-aminobenzoic acid, 4-aminobenzenethiol, 3-aminobenzenethiol, 2-aminobenzenethiol, 4-aminophenol, 3-aminophenol, 2-aminophenol, 2,4-dihydroxy Examples include aniline, 2,3-diaminophenol, aminomethanoic acid, 2-aminoethanoic acid, 3-aminopropionic acid, (1-aminoethyl) phosphonic acid, and the like.

  Although there is no restriction | limiting in particular as content of the organic group in a 1st semiconductor heteroparticle, The coverage of the organic group with respect to the surface of the 1st and 2nd semiconductor particle is 0.1 to 80% (more preferably, 0 0.5 to 60%), it is preferable that the organic group is bonded to the semiconductor particle and bonded to the metal particle. When the coverage of the organic group is less than the lower limit, the bonding ratio between the first semiconductor particles and the second semiconductor particles via the metal particles is decreased, and the formation ratio of the semiconductor hetero particles is decreased. It tends to be difficult for electrons to move. On the other hand, if the organic group coverage exceeds the above upper limit, light absorption of the semiconductor particles is inhibited, or the reduction / reduction sites of the semiconductor are covered, so that the electron transfer efficiency between the semiconductor particles tends to decrease. .

(Organic group in the second semiconductor heteroparticle)
The organic group in the second semiconductor heteroparticle is formed by bonding an organic molecule to both metal particles bonded to the first and second semiconductor particles. Such an organic molecule is not particularly limited as long as it can be bonded to both the first and second metal particles bonded to the first and second semiconductor particles. And a functional group that can be chemically bonded to the second metal particle (second metal-bonding functional group). For example, the following formula (2):
^{X 1 -R 1 -X 2 (2} )
The thing represented by is mentioned.

X ¹ and X ² in the formula (2) represent the first and second metal binding functional groups, respectively, and may be the same or different. X ¹ may be contained in the organic molecule or may be contained in two or more, and the same applies to X ² . The form of bonding between the metal bonding functional group and the metal particle in the second semiconductor heteroparticle and the type of the metal bonding functional group are the same as the metal bonding functional group in the first semiconductor heteroparticle. Further, R ¹ in the formula (2) has the same meaning as R ¹ in the formula (1) in the first semiconductor heterostructure particles.

  Examples of the organic molecule having at least two metal-bonded functional groups include methanedithiol, 1,2-ethyldithiol, 1,3-propanedithiol, 2-aminoethanethiol, 3-aminopropanethiol, 1 , 4-benzenedithiol, 2-mercaptoethanol, 3-mercaptopropanol, 4-aminobenzenethiol, 3-aminobenzenethiol, 2-aminobenzenethiol, 1,4-phenylenediamine, 4-hydroxybenzenethiol, 4-carboxy Examples include benzaldehyde, 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 2-hydroxybenzoic acid, 4-mercaptobenzoic acid, 3-mercaptobenzoic acid, 2-mercaptobenzoic acid, and isophthalic acid.

  Although there is no restriction | limiting in particular as content of the organic group in a 2nd semiconductor heteroparticle, The coverage of the organic group with respect to the surface of a 1st and 2nd semiconductor particle is 0.1-80% (more preferably, 0 0.5 to 60%), it is preferable that the organic group is bonded to the metal particles bonded to the semiconductor particles. When the organic group coverage is less than the lower limit, the bonding ratio between the first semiconductor particles and the second semiconductor particles via the metal particles decreases, and the first semiconductor particles as shown in FIG. There is a tendency that a structure in which the first metal particles and the second metal particles bonded to the second semiconductor particles are bonded via an organic group is difficult to form. On the other hand, if the organic group coverage exceeds the above upper limit, light absorption of the semiconductor particles is inhibited, or the reduction / reduction sites of the semiconductor are covered, so that the electron transfer efficiency between the semiconductor particles tends to decrease. .

(Organic group in the third semiconductor hetero particle)
The first and second organic groups in the third semiconductor heteroparticle are formed by combining the first and second organic molecules with the first and second semiconductor particles and the same metal particle, respectively. It is what is done. Such organic molecules are not particularly limited as long as they are capable of binding to semiconductor particles and capable of binding to metal particles, but the first and second organic molecules can be chemically bonded to metal particles. Having first and second functional groups (first and second metal-binding functional groups), respectively. For example, as the first organic molecule capable of forming the first organic group, the following formula (1):
^{X 1 -R 1 -Y 1 (1} )
The thing represented by is mentioned. Moreover, as a 2nd organic molecule which can form a 2nd organic group, following formula (3):
^{X 3 -R 2 -Y 2 (3} )
The thing represented by is mentioned. Such a first organic molecule and a second organic molecule may be the same or different.

X ¹ in the formula (1) and X ³ in the formula (3) represent the first and second metal-binding functional groups, respectively, and may be the same or different. Moreover, one or more metal binding functional groups may be contained in the organic molecule. The form of bonding between the metal bonding functional group and the metal particle in the third semiconductor heteroparticle and the type of the metal bonding functional group are the same as those of the metal bonding functional group in the first semiconductor heteroparticle.

Y ¹ in the formula (1) and Y ² in the formula (3) are respectively the first and second functional groups (first and second functional groups) that can be bonded to the surfaces of the first and second semiconductor particles. Second anchor group), which may be the same or different. One or more such anchor groups may be contained in the organic molecule. The bonding form between the anchor group and the surface of the semiconductor particle in the third semiconductor heteroparticle and the type of the anchor group are the same as the anchor group in the first semiconductor heteroparticle.

R ¹ in the formula (1) and R ^{2 in} (3) can form an organic molecule by chemically linking the metal-bonding functional group and the anchor group. This is a group capable of adjusting the distance between the semiconductor particles and the second semiconductor particles (first and second spacer groups, respectively). R ¹ and R ² may be the same spacer group or different spacer groups. The type of spacer group in the third semiconductor heteroparticle is the same as the spacer group in the first semiconductor heteroparticle.

  Examples of such organic molecules having a metal-bonded functional group and an anchor group include the organic molecules exemplified in the first semiconductor heteroparticle, such as organic alkoxysilane, mercaptoacetic acid, 3-mercaptopropionic acid, mercaptobenzoic acid, and mercapto. Phenol, mercaptoethanol, 4-hydroxybenzenethiol, 4-aminobenzoic acid, 3-aminobenzoic acid, 2-aminobenzoic acid, 4-aminobenzenethiol, 3-aminobenzenethiol, 2-aminobenzenethiol, 4-amino Phenol, 3-aminophenol, 2-aminophenol, 2,4-dihydroxyaniline, 2,3-diaminophenol, aminomethanoic acid, 2-aminoethanoic acid, 3-aminopropionic acid, (1-aminoethyl) phosphonic acid, etc. Is mentioned.

  Although there is no restriction | limiting in particular as content of the organic group in a 3rd semiconductor heteroparticle, The coverage of the organic group with respect to the surface of a 1st and 2nd semiconductor particle is 0.1-80% (more preferably, 0 0.5 to 60%), it is preferable that the organic group is bonded to the semiconductor particle and bonded to the metal particle. When the coverage of the organic group is less than the lower limit, the bonding ratio between the first semiconductor particles and the second semiconductor particles via the metal particles is decreased, and the formation ratio of the semiconductor hetero particles is decreased. It tends to be difficult for electrons to move. On the other hand, if the organic group coverage exceeds the above upper limit, light absorption of the semiconductor particles is inhibited, or the reduction / reduction sites of the semiconductor are covered, so that the electron transfer efficiency between the semiconductor particles tends to decrease. .

(Cocatalyst)
In the semiconductor heteroparticle of the present invention, it is preferable to support a reaction promoter on at least one of the first and second semiconductor particles in order to improve the reaction efficiency as a photocatalyst. Such a co-catalyst is not particularly limited as long as it is a catalyst having a composition different from that of the metal particles supported on the semiconductor particles, and examples thereof include a catalyst containing a metal exemplified as the metal particles, an organic catalyst, and the like. Examples of the catalyst to be included include a metal inorganic catalyst and a metal complex catalyst. Moreover, these promoters may be used individually by 1 type, or may use 2 or more types together.

As the metal inorganic catalyst, metals belonging to Groups 2 to 14 of the periodic table (for example, Pt, Pd, Rh, Ru, Ni, Au, Fe, Mg, Ti, Mn, Co, Cu, Ga, Ag, Cd, In) , Ce, Ta, W, Ir, Pb), intermetallic compounds of this metal, alloys (eg, Ni—Mo—Zn alloys), and oxides thereof (eg, MnO, MnO ₂ , Mn ₂ O ₃ , Mn) ₃ O ₄ , CoO, Co ₃ O ₄ , RuO ₂ , Rh ₂ O ₃ , IrO ₂ , NiO), composite oxide (eg, NiCo ₂ O ₄ ), nitride, oxynitride, sulfide, oxysulfide , Carbides, phosphorus compounds (for example, phosphorus-containing Co compounds), and the like. These metal inorganic catalysts may be used individually by 1 type, or may use 2 or more types together.

  The metal complex catalyst is not particularly limited as long as it is a compound that exhibits oxidation activity or reduction activity by utilizing holes or electrons. For example, at least selected from metals belonging to Groups 6 to 10 of the periodic table One type of metal complex, for example, a complex of a metal and a ligand such as Cr, Mo, W, Ru, Re, Mn, Fe, Os, Co, Rh, Ir, Ni, Pd, and Pt, can be given. Such a complex may be mononuclear or multinuclear with two or more nuclei. Also, two or more metals may be included.

The ligand in the metal complex catalyst is not particularly limited. For example, typical main ligands include nitrogen-containing heterocyclic compounds, oxygen-containing heterocyclic compounds, oxygen-containing compounds, and sulfur-containing heterocyclic compounds. Examples of auxiliary ligands include CO, halogen, and phosphines. The auxiliary ligand is partly dissociated by contact with CO ₂ , base, or water in the course of the reaction, and converted to a side ligand (solvent molecule such as acetonitrile, dimethylformamide, water, alcohol, acetone). Also good. These ligands may be used alone or in combination of two or more. In such a ligand, the element coordinated to the metal is not particularly limited, and examples thereof include O, N, C, P, S, Si, and halogen. As for such an element, 11 types may coordinate, or 2 or more types may coordinate.

  Examples of the nitrogen-containing heterocyclic compound include pyridine, bipyridine, phenanthroline, terpyridine, pyrrole, indole, carbazole, imidazole, pyrazole, quinoline, isoquinoline, acridine, pyridazine, pyrimidine, pyrazine, phthalazine, quinazoline, quinoxaline and the like. Examples of the oxygen-containing heterocyclic compound include furan, benzofuran, oxazole, pyran, pyrone, coumarin, and benzopyrone. Examples of the oxygen-containing compound include polyoxometalates, and examples of the sulfur-containing heterocyclic compound include thiophene, thionaphthene, and thiazole. Such a ligand may be used individually by 1 type, or may use 2 or more types together.

  The organic catalyst is not particularly limited as long as it is a compound that exhibits oxidation activity or reduction activity by utilizing holes or electrons by utilizing holes or electrons. For example, a porphyrin skeleton, a phthalocyanine skeleton, Electronic carriers such as a compound containing a corrole skeleton, a chlorin skeleton, a flavin skeleton, a viologen skeleton, a pyridine skeleton (which may further contain a metal atom), Meldola Blue, 1-methoxy-5-methylphenazinium methyl sulfate Examples include organic compounds used as compounds, biocatalysts such as enzymes.

  Although there is no restriction | limiting in particular as the load of such a promoter, 0.01-50 mass parts is preferable with respect to 100 mass parts of semiconductor particles to carry | support, 0.03-40 mass parts is more preferable. When the amount of the cocatalyst supported is less than the lower limit, sufficient effects due to the cocatalyst tend not to be obtained. On the other hand, when the amount exceeds the upper limit, the cocatalyst itself absorbs and scatters light. The catalyst activity tends to decrease because it prevents light absorption or acts as a recombination center. Further, when the cocatalyst coats or contacts the metal particles, the electron transfer efficiency is lowered and the catalytic activity tends to be lowered.

<Method for producing semiconductor hetero particles>
Next, the manufacturing method of the semiconductor heteroparticle of this invention is demonstrated.

  In the method for producing semiconductor heteroparticles according to the present invention, first and second semiconductor particles are selected in which the potentials of the conduction band and the valence band have the relationship described above. That is, two types of semiconductor particles are selected in which the potential at the lower end of the conduction band of the first semiconductor particles is more negative (preferably the potential difference is 0.1 eV or more) than the potential at the upper end of the valence band of the second semiconductor particles.

  The semiconductor particles used in the present invention may be commercially available semiconductor particles or semiconductor particles synthesized in advance by a known method. Such semiconductor particles may be subjected to treatment such as pulverization and polishing in advance in order to reduce the particle diameter. Further, in order to smoothly join the metal particles and bond the organic groups, the semiconductor particles may be pretreated in advance. Furthermore, in order to improve the catalytic activity, the semiconductor particles may be previously subjected to a doping treatment.

<Method for Producing First Semiconductor Heteroparticle>
In the first method for producing a semiconductor heteroparticle of the present invention, metal particles are bonded (preferably supported) to one of the first and second semiconductor particles selected as described above (step). (1-1)), the other semiconductor particle of the first and second semiconductor particles is mixed with an organic molecule having a metal bond functional group, and the organic group having the metal bond functional group is bonded. Semiconductor particles are prepared (step (1-2)). Thereafter, the semiconductor particles to which the metal particles are bonded are mixed with the semiconductor particles to which the organic groups having the metal bonding functional groups are bonded to bond the metal particles and the metal bonding functional groups (steps). (1-3)). Thereby, the 1st semiconductor heteroparticle of this invention in which the 1st semiconductor particle and the 2nd semiconductor particle were joined via the organic group and the metal particle is obtained.

(Process (1-1))
In the step (1-1), the method for joining the metal particles to the semiconductor particles is not particularly limited, and is a photodeposition method (sometimes called a photo-deposition method, a photo-deposition method, a photoreduction deposition support method), impregnation. Examples thereof include a supporting method, a deposition-precipitation method, a nanoparticle supporting method, and a physical vapor deposition method (PVD method).

  In the photodeposition method, semiconductor particles and a metal salt are allowed to coexist in a solution, and this is irradiated with light. Thereby, the metal salt is reduced, and metal particles or metal compound particles are deposited on the surface of the semiconductor particles. In addition, you may add a sacrificial reagent to a solution as needed.

  In the impregnation supporting method, first, semiconductor particles are added to a solution in which a metal salt is dissolved, and the solvent is removed under heating or reduced pressure. Thereby, the metal salt is supported on the surface of the semiconductor particles. Thereafter, by firing or reducing the metal salt, semiconductor particles carrying metal particles or metal compound particles can be obtained.

  In the deposition method, first, metal particles are reduced in a solution to produce metal particles. Next, the semiconductor particles are added to the obtained dispersion and stirred to support the metal particles on the surface of the semiconductor particles.

  In the nanoparticle support method, first, a metal colloid solution is prepared by a laser ablation method or a colloid method using an organic polymer as a protective group. Next, the colloidal solution and the semiconductor particles are mixed, and the solvent is removed by filtration, heating or distillation under reduced pressure. Thereby, metal nanoparticles are supported on the surface of the semiconductor particles. Examples of the PVD method include a vacuum deposition method, a sputtering method, an ion plating method, and a pulse laser deposition method (PLD method).

  There is no restriction | limiting in particular as a metal salt used by this process (1-1), For example, the hydroxide, sulfate, halide (chloride, etc.) of a metal to join, nitrate, carbonate, organic acid salt, phosphorus Examples thereof include acid salts and ammonium salts. Moreover, these metal salts may be used individually by 1 type, or may use 2 or more types together.

  In the manufacturing method of the 1st semiconductor heteroparticle of this invention, it is also possible to implement simultaneously the synthesis | combination of a semiconductor particle, and this process (1-1). In addition, when preparing semiconductor particles on which a cocatalyst is supported, the cocatalyst can be supported at any stage before, after, and simultaneously with this step (1-1). The cocatalyst loading method is not particularly limited, and examples thereof include an adsorption loading method, an impregnation loading method, a photoprecipitation method (sometimes called a photodeposition method or a photodeposition method), a deposition precipitation method, a nanoparticle loading method, Examples include physical vapor deposition (PVD method). Two or more of these supporting methods may be used in combination. In addition, when the metal complex is supported, in addition to the adsorption support method, the metal complex may be directly synthesized after adsorbing the ligand to the semiconductor particles.

(Process (1-2))
In the step (1-2), semiconductor particles having an organic group having a metal binding functional group bonded thereto are prepared by binding organic molecules having a metal binding functional group to the surface of the semiconductor particle. Examples of the bonding method include a chemical bonding (adsorption) method, a physical adsorption method, and a composite bonding (adsorption) method thereof, and the chemical bonding (adsorption) method is particularly preferable.

  In the chemical adsorption method, first, the organic molecules are dissolved in a solution such as an organic solvent or water, and semiconductor particles are added and dispersed in the obtained solution. Then, the organic molecules are chemisorbed on the surface of the semiconductor particles by stirring the dispersion for 1 to 24 hours. In addition to stirring, chemical adsorption can be performed by shaking, rotation using a rotator, ultrasonic treatment, or the like. Moreover, as long as chemical adsorption is possible, it may be left still.

  On the other hand, in the chemical bonding method, it is necessary that the organic molecule has an anchor group (reactive anchor group) that is reactive to the surface of the semiconductor particle in addition to the metal-bonding functional group. . Although there is no restriction | limiting in particular as such a reactive anchor group, From a reactive viewpoint with respect to the surface of a semiconductor particle, an alkoxy silyl group and an alkoxy titanium group are preferable, and an alkoxy silyl group is more preferable. Examples of such an organic molecule having a reactive anchor group include a silane coupling agent having a metal binding functional group and a titanium coupling agent having a metal binding functional group.

  In the chemical bonding method, first, organic molecules having a metal-bonding functional group and a reactive anchor group are dissolved in an organic solvent such as toluene, and semiconductor particles are added and dispersed in the obtained solution. Thereafter, the dispersion is heated at a temperature (for example, 70 to 100 ° C.) at which the hydroxyl groups on the surface of the semiconductor particles react with the reactive anchor groups in an inert gas atmosphere, thereby reacting with the hydroxyl groups on the surface of the semiconductor particles. An organic group having a metal-binding functional group is bonded to the surface of the semiconductor particle by reacting with the anchor group.

  Furthermore, in this step (1-2), first, an inorganic molecule such as ammonia is adsorbed on the surface of a semiconductor particle (preferably a compound semiconductor containing Si, Ge, Ga, etc.), and an amino group is formed on the surface of the semiconductor particle. Reactive functional groups such as are introduced. Then, the organic group which has a metal bond functional group can be chemically bonded to the surface of a semiconductor particle by making this reactive functional group and the organic molecule which has a metal bond functional group react.

  Further, in this step (1-2), first, a coupling agent is chemically bonded to the surface of the semiconductor particle, and the coupling agent and an organic molecule having a metal-bonded functional group are reacted, whereby the semiconductor particle of the semiconductor particle is reacted. An organic group having a metal-binding functional group can be bonded to the surface.

  In the manufacturing method of the 1st semiconductor heteroparticle of this invention, it is also possible to implement simultaneously the synthesis | combination of a semiconductor particle, and this process (1-2). In addition, when preparing semiconductor particles carrying a cocatalyst, the cocatalyst can be carried at any of the stages before, after, and simultaneously with this step (1-2). In the case of carrying out a calcination treatment when supporting the catalyst, it is preferable to support the promoter before this step (1-2). The cocatalyst loading method is not particularly limited, and examples thereof include an adsorption loading method, an impregnation loading method, a photoprecipitation method (sometimes called a photodeposition method or a photodeposition method), a deposition precipitation method, a nanoparticle loading method, Examples include physical vapor deposition (PVD method). Two or more of these supporting methods may be used in combination. In addition, when the metal complex is supported, in addition to the adsorption support method, the metal complex may be directly synthesized after adsorbing the ligand to the semiconductor particles.

  Moreover, it is also possible to convert the metal bond functional group of the organic group bonded to the semiconductor particles prepared in this way into another metal bond functional group. For example, when the metal-bonded functional group after preparation is a mercapto group, it can be converted to a sulfonic acid group by oxidation with hydrogen peroxide. Moreover, when the metal bond functional group after preparation is a cyano group, it can convert into a carboxyl group by hydrolyzing with a sulfuric acid.

(Process (1-3))
In the step (1-3), the semiconductor particles obtained in the step (1-1) and the semiconductor particles obtained in the step (1-2) are mixed and stirred. Thereby, a metal particle and a metal bond functional group couple | bond together, and the semiconductor heteroparticle of this invention can be obtained. At this time, the semiconductor particles obtained in the step (1-1) and the semiconductor particles obtained in the step (1-2) may be mixed in advance in a solution to be composited. The semiconductor hetero particles of the present invention exhibiting the photocatalytic function can be formed even by directly mixing in them.

<Method for Producing Second Semiconductor Heteroparticle>
In the second method for producing a semiconductor heteroparticle of the present invention, the first and second metal particles are bonded (preferably supported) to the first and second semiconductor particles selected as described above (steps), respectively. (2-1) and (2-2)), one of the first and second semiconductor particles to which the metal particles are bonded, the first metal-binding functional group, and the second metal An organic molecule having a binding functional group is mixed to bond the metal particle and one of the first and second metal binding functional groups, the metal particle is bonded, and the Semiconductor particles are prepared in which an organic group having the other metal-bonded functional group of the first and second metal-bonded functional groups is bonded to the metal particles (step (2-3). 1st and 2nd semiconductor grain which are joined And the other semiconductor particles are mixed with the semiconductor particles bonded to the metal particles and bonded to the metal particles with an organic group having the other metal-binding functional group. The bonded metal particles are bonded to the other metal-binding functional group (step (2-4)).

(Steps (2-1) and (2-2))
In the steps (2-1) and (2-2), in the same manner as in the step (1-1), the first metal particles are used as the first semiconductor particles, and the second metal is used as the second semiconductor particles. Each particle can be joined. Further, in the same manner as in the step (1-1), if necessary, the cocatalyst is supported before, after, and simultaneously with these steps (2-1) and (2-2). be able to.

(Process (2-3))
In the step (2-3), the first semiconductor particles to which the first metal particles obtained in the step (2-1) are bonded and the second semiconductor particles obtained in the step (2-2) are used. One of the second semiconductor particles to which the metal particles are bonded is mixed with an organic molecule having the first metal-bonding functional group and the second metal-bonding functional group and stirred. Thereby, the semiconductor particle which the said metal particle joined and the organic group which has the other metal bond functional group of the said 1st and 2nd metal bond functional group has couple | bonded with this metal particle is obtained.

  For example, the first semiconductor particles to which the first metal particles obtained in the step (2-1) are bonded, the organic molecules having the first metal-bonding functional group and the second metal-bonding functional group, Are mixed and stirred, the first metal particles and the first metal-bonding functional group are bonded, the first metal particles are bonded, and the organic group having the second metal-bonding functional group is the first metal particle. First semiconductor particles bonded to the metal particles are obtained.

  In the step (2-3), as in the case of the step (1-2), the cocatalyst is added at any stage before, after, or at the same time as necessary in the step (2-3). It can be supported.

(Process (2-4))
In the step (2-4), the first semiconductor particles to which the first metal particles obtained in the step (2-1) are bonded and the second semiconductor particles obtained in the step (2-2) are used. The other semiconductor particle of the second semiconductor particles bonded to the metal particle is bonded to the metal particle obtained in the step (2-3), and the first and second particles are bonded to the metal particle. The semiconductor particles to which the organic group having the other metal-bonded functional group among the metal-bonded functional groups is bonded are mixed and stirred. As a result, the metal particles bonded to the other semiconductor particle and the other metal-bonding functional group are bonded to each other, and the semiconductor heteroparticle of the present invention can be obtained.

  For example, as described above, the first metal particle is bonded to the first metal particle in the step (2-3) and the organic group having the second metal bond functional group is bonded to the first metal particle. When semiconductor particles are prepared, the other semiconductor particle is a second semiconductor particle to which the second metal particle obtained in the step (2-2) is bonded. When these semiconductor particles are mixed and stirred, the second metal particles and the second metal-bonding functional group are bonded, and the semiconductor heteroparticle of the present invention can be obtained. At this time, the first semiconductor particles obtained in the step (2-3) and the second semiconductor particles obtained in the step (2-2) may be mixed in a solution in advance to be combined. Although it is good, the semiconductor heteroparticle of the present invention that exhibits a photocatalytic function can be formed only by directly mixing in the catalytic reaction solution.

<Method for Producing Third Semiconductor Heteroparticle>
In the third method for producing a semiconductor heteroparticle of the present invention, the first semiconductor particle selected as described above and an organic molecule having a first metal-bonding functional group are mixed and stirred, and the metal-bonding function is mixed. First semiconductor particles to which a first organic group having a group is bonded are prepared (step (3-1)). Similarly, the second semiconductor particles selected as described above and the organic molecule having the second metal bonding functional group are mixed and stirred, and the second organic group having the metal bonding functional group is bonded. Second semiconductor particles are prepared (step (3-2)). Next, a semiconductor particle to which one organic group of the first and second organic groups is bonded and a metal particle are mixed, and the metal-bonded functional group in the organic group and the metal particle are mixed. Bonding is performed to prepare semiconductor particles in which the organic group is bonded and the metal particle is bonded to the metal bonding functional group in the organic group (step (3-3)). Thereafter, the semiconductor particle to which the other organic group of the first and second organic groups is bonded, the organic group is bonded, and the metal particle is bonded to the metal bonding functional group in the organic group. The semiconductor particles are mixed to bond the metal-bonded functional group in the other organic group to the metal particles (step (3-4)).

(Steps (3-1) and (3-2))
In step (3-1), in the same manner as in step (1-2), the first metal is bonded to the surface of the first semiconductor particle by bonding an organic molecule having a first metal-binding functional group. First semiconductor particles to which an organic group having a binding functional group is bonded are prepared. Similarly, in the step (3-2), the organic group having the second metal-bonded functional group is bonded to the surface of the second semiconductor particle by bonding an organic molecule having the second metal-bonded functional group. Second semiconductor particles that are bonded are prepared. Further, in the same manner as in the step (1-2), if necessary, the cocatalyst is supported before, after, and simultaneously with these steps (3-1) and (3-2). be able to.

(Process (3-3))
In the step (3-3), the first semiconductor particles to which the organic group having the first metal-binding functional group obtained in the step (3-1) is bonded and the step (3-2) are obtained. One of the second semiconductor particles to which the organic group having the second metal-bonding functional group is bonded is mixed with the metal particles and stirred. Thereby, the semiconductor particle which the said organic group couple | bonded and the said metal particle has couple | bonded with the metal bond functional group in this organic group is obtained.

  For example, the first semiconductor bond obtained by mixing and stirring the first semiconductor particles and the metal particles to which the organic group having the first metal bond functional group obtained in the step (3-1) is bonded is mixed. A first semiconductor particle in which the functional group and the metal particle are bonded, the organic group is bonded, and the metal particle is bonded to the first metal-bonded functional group in the organic group is obtained.

  In the step (3-3), as in the step (1-2), the cocatalyst is added at any stage before, after and at the same time as the step (2-3) as necessary. It can be supported.

(Process (3-4))
In the step (3-4), the first semiconductor particles to which the organic group having the first metal-binding functional group obtained in the step (3-1) is bonded and the step (3-2) are obtained. The other semiconductor particle of the second semiconductor particles to which the organic group having the second metal-bonding functional group is bonded is bonded to the organic group obtained in the step (3-3) and The semiconductor particles in which the metal particles are bonded to the metal bond functional group in the organic group are mixed and stirred. Thereby, the metal-bonding functional group in the organic group couple | bonded with the said other semiconductor particle and the said metal particle are couple | bonded, and the semiconductor heteroparticle of this invention can be obtained.

  For example, as described above, first semiconductor particles in which the organic group is bonded in the step (3-3) and the metal particles are bonded to the first metal-bonding functional group in the organic group are prepared. In this case, the other semiconductor particle is a second semiconductor particle to which an organic group having a second metal-bonded functional group obtained in the step (3-2) is bonded. When these semiconductor particles are mixed and stirred, the metal particles and the second metal-bonding functional group are bonded, and the semiconductor heteroparticles of the present invention can be obtained. At this time, the first semiconductor particles obtained in the step (3-3) and the second semiconductor particles obtained in the step (3-2) may be mixed in a solution in advance to be combined. Although it is good, the semiconductor heteroparticle of the present invention that exhibits a photocatalytic function can be formed only by directly mixing in the catalytic reaction solution.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example. The semiconductor particles used in the examples and comparative examples were prepared by the following method.

(Preparation Example A-1)
<Preparation of nitrogen-doped titanium oxide (N-TiO ₂₎ particles>
Titanium oxide (“ST-01” manufactured by Ishihara Sangyo Co., Ltd.) was heat-treated at 575 ° C. for 3 hours in a mixed gas stream of ammonia and argon (NH ₃ / Ar = [400 ml / min] / [200 ml / min]). As a result, yellow nitrogen-doped titanium oxide (N—TiO ₂ ) particles were obtained.

(Preparation Example A-2)
<Nitrogen-doped tantalum oxide _(N-Ta 2 _{O 5)} Preparation of particles>
5 g of tantalum chloride was dissolved in 100 ml of ethanol, and 5% NH ₃ aqueous solution was added to make up to 300 ml. This solution was stirred for 5 hours to obtain white tantalum oxide (Ta ₂ O ₅ ) particles. The tantalum oxide particles were baked at 800 ° C. for 6 hours to crystallize, and then 6% at 575 ° C. in a mixed gas stream of ammonia and argon (NH ₃ / Ar = [400 ml / min] / [200 ml / min]). Time heat treatment was performed to obtain yellow nitrogen-doped tantalum oxide (N—Ta ₂ O ₅ ) particles.

(Preparation Example A-3)
<Preparation of calcium iron oxide (CaFe ₂ O ₄ ) particles>
Calcium acetate monohydrate _{(Ca (CH 3 COO) 2} · H 2 O, manufactured by Wako Pure Chemical Industries, Ltd.) and iron (III) nitrate nonahydrate _{(Fe (NO 3) 3 ·} 9H 2 O, Wako Pure Chemical Industries, Ltd.) were mixed so that the molar ratio of calcium and iron was Ca: Fe = 1: 2. The solution was heated at 120 ° C. with stirring to evaporate and dry the water, then calcined at 450 ° C. for 1 hour, and further calcined at 1000 ° C. for 6 hours to obtain calcium iron oxide (CaFe ₂ O ₄ ). Particles were obtained.

(Preparation Example A-4)
<Preparation of zinc-doped iron oxide (Zn—Fe ₂ O ₃ ) particles>
Zinc nitrate hexahydrate _{(Zn (NO 3) 2 ·} 6H 2 O, manufactured by Wako Pure Chemical Industries, Ltd.) and iron (III) nitrate nonahydrate _{(Fe (NO 3) 3 ·} 9H 2 O, the sum Komatsu Pure Chemical Industries, Ltd.) were mixed so that the molar ratio of zinc and iron was Zn: Fe = 1: 20. This solution was heated at 120 ° C. with stirring to evaporate and dry the water, and then calcined at 550 ° C. for 2 hours to obtain zinc-doped iron oxide (Zn—Fe ₂ O ₃ ) particles.

(Preparation Example A-5)
<Preparation of tantalum oxynitride (TaON) particles>
6 at 820 ° C. in tantalum oxide powder (Ta ₂ O ₅ , manufactured by Wako Pure Chemical Industries, Ltd.) in a mixed gas flow of ammonia and argon (NH ₃ / Ar = [400 ml / min] / [200 ml / min]). Temporal heat treatment was performed to obtain tantalum oxynitride (TaON) particles.

(Preparation Example A-6)
<Preparation of bismuth vanadate (BiVO ₄ ) particles>
Bismuth oxide (Bi ₂ O ₃ , manufactured by Kanto Chemical Co., Inc.) and ammonium metavanadate (NH ₄ VO ₃ , manufactured by Kanto Chemical Co., Ltd.) were mixed so that the molar ratio of bismuth and vanadium was equimolar. . This mixture was baked in the atmosphere at 900 ° C. for 5 hours to obtain bismuth vanadate (BiVO ₄ particles).

(Preparation Example A-7)
<Preparation of Ta ₃ N ₅ particles>
Tungsten oxide powder (Ta ₂ O ₅ , manufactured by Wako Pure Chemical Industries, Ltd.) and mixed gas (NH ₃ / Ar = [400 ml / min] / [200 ml / min]) of ammonia and argon at 850 ° C. A time heat treatment was performed to obtain Ta ₃ N ₅ particles.

(Preparation Example B-1)
<Preparation of mercaptopropyl silyl-group-modified titanium oxide (MPSi-TiO ₂₎ particles>
² g of titanium oxide (“ST-01” manufactured by Ishihara Sangyo Co., Ltd., primary particle size: 7 nm, specific surface area: 320 m ² / g), 0.550 g of mercaptopropyltrimethoxysilane (MP-TMS), 100 ml of dehydrated toluene The mixture was mixed and stirred at 90 ° C. for 15 hours under an argon atmosphere. The dispersion after the reaction is cooled and filtered, and the filter cake is washed with toluene and methanol, and then dried at 45 ° C. for 6 hours and 90 ° C. for 12 hours to oxidize the mercaptopropylsilyl group bonded to the surface. titanium was obtained (MPSi-TiO ₂₎ particles.

(Preparation Example B-2)
<Preparation of mercaptomethyl silyl-group-modified titanium oxide (MMSi-TiO ₂₎ particles>
A mercaptomethylsilyl group was bonded to the surface in the same manner as in Preparation Example B-1, except that 0.471 g of mercaptomethyltrimethoxysilane (MM-TMS) was used instead of mercaptopropyltrimethoxysilane (MP-TMS). Titanium oxide (MMSi-TiO ₂ ) particles were obtained.

(Preparation Example B-3)
<Preparation of Mercapto benzoic acid-modified titanium oxide (MBA-TiO ₂₎ particles>
0.5 g of titanium oxide (“ST-01” manufactured by Ishihara Sangyo Co., Ltd.), 0.216 g of 4-mercaptobenzoic acid (MBA) and 5 ml of methanol were mixed and stirred overnight at room temperature. The obtained dispersion was filtered, and the filter cake was washed with methanol, and then dried at 45 ° C. for 6 hours and 90 ° C. for 12 hours. Titanium oxide (MBA-TiO ₂ ) with mercaptobenzoic acid bound to the surface was then obtained. ) Obtained particles.

(Preparation Example B-4)
<Preparation of Mercaptopropionic Acid-Modified Titanium Oxide (MPA-TiO ₂ ) Particles>
Titanium oxide (MPA-) having mercaptopropionic acid bonded to the surface in the same manner as in Preparation Example B-3, except that 122 μl of 3-mercaptopropionic acid (MPA) was used instead of 4-mercaptobenzoic acid (MBA). TiO ₂ ) particles were obtained.

(Preparation Example B-5)
<Preparation of Mercaptophenol-Modified Titanium Oxide (MPhOH-TiO ₂ ) Particles>
Titanium oxide (MPhOH-TiO ₂ ) with mercaptophenol bound to the surface in the same manner as Preparation Example B-3 except that 0.177 g of 4-mercaptophenol was used instead of 4-mercaptobenzoic acid (MBA). Particles were obtained.

(Preparation Example B-6)
<Preparation of aminopropyl silyl-group-modified titanium oxide (APSi-TiO ₂₎ particles>
In the same manner as in Preparation Example B-1, except that 0.502 g of aminopropyltrimethoxysilane (AP-TMS) was used instead of mercaptopropyltrimethoxysilane (MP-TMS), an aminopropylsilyl group was bonded to the surface. and which titanium oxide was obtained (aPSi-TiO ₂₎ particles.

(Preparation Example B-7)
<Preparation of aminophenyl silyl-group-modified titanium oxide (APhSi-TiO ₂₎ particles>
An aminophenylsilyl group is formed on the surface in the same manner as in Preparation Example B-1, except that 0.597 g of p-aminophenyltrimethoxysilane (APh-TMS) is used instead of mercaptopropyltrimethoxysilane (MP-TMS). Bonded titanium oxide (APhSi—TiO ₂ ) particles were obtained.

(Preparation Example B-8)
<3- (2-aminoethylamino) propyl silyl group-modified titanium oxide (AEAPSi-TiO ₂₎ Preparation of particles>
Instead of mercaptopropyltrimethoxysilane (MP-TMS), 3- (2-aminoethylamino) propyltrimethoxysilane (AEAP-TMS) 0.889 g was used, and the amount of titanium oxide was changed to 0.7 g for dehydration. Titanium oxide (AEAPSi-TiO ₂ ) particles having 3- (2-aminoethylamino) propylsilyl groups bonded to the surface are obtained in the same manner as in Preparation Example B-1, except that the amount of toluene is changed to 50 ml. It was.

(Preparation Example B-9)
<Preparation of mercaptopropyl silyl-group-modified _{N-TiO 2 (MPSi-N} -TiO 2) particles>
Preparation Example B except that 1 g of N-TiO ₂ particles obtained in Preparation Example A-1 was used instead of titanium oxide (“ST-01” manufactured by Ishihara Sangyo Co., Ltd.) and the amount of dehydrated toluene was changed to 50 ml. In the same manner as in -1, N-TiO ₂ (MPSi-N-TiO ₂ ) particles having a mercaptopropylsilyl group bonded to the surface were obtained.

(Preparation Example B-10)
<Preparation of Mercaptobenzoic Acid Modified N—TiO ₂ (MBA-N—TiO ₂ ) Particles>
Except for using 0.5 g of N-TiO ₂ particles obtained in Preparation Example A-1 instead of titanium oxide (“ST-01” manufactured by Ishihara Sangyo Co., Ltd.), the same as Preparation Example B-3, N-TiO ₂ (MBA-N-TiO ₂ ) particles having mercaptobenzoic acid bonded to the surface were obtained.

(Preparation Example B-11)
<Preparation of mercaptopropylsilyl group-modified zinc oxide (MPSi-ZnO) particles>
Instead of titanium oxide (“ST-01” manufactured by Ishihara Sangyo Co., Ltd.), 1 g of zinc oxide powder (ZnO, manufactured by Wako Pure Chemical Industries, Ltd., particle size: 0.02 μm) was used, and the amount of dehydrated toluene was 50 ml. Zinc oxide (MPSi-ZnO) particles having a mercaptopropylsilyl group bonded to the surface thereof were obtained in the same manner as in Preparation Example B-1, except for changing to.

(Preparation Example B-12)
<Preparation of Mercapto benzoic acid-modified tungsten oxide (MBA-WO ₃₎ particles>
Tungsten oxide _(WO 3, Ltd. Kojundo Chemical Laboratory) instead of titanium oxide (Ishihara Sangyo Kaisha Ltd. "ST-01") except for using 0.5g, same manner as in Preparation Example B-3 a manner, tungsten oxide mercapto benzoic acid is bound to the surface (MBA-WO ₃₎ to obtain particles.

(Preparation Example B-13)
<Preparation of Mercaptobenzoic Acid Modified N—Ta ₂ O ₅ (MBA-N—Ta ₂ O ₅ ) Particles>
Similar to Preparation Example B-3 except that 0.5 g of N-Ta ₂ O ₅ particles obtained in Preparation Example A-2 were used instead of titanium oxide (“ST-01” manufactured by Ishihara Sangyo Co., Ltd.). Thus, N-Ta ₂ O ₅ (MBA-N-Ta ₂ O ₅ ) particles having mercaptobenzoic acid bonded to the surface were obtained.

(Preparation Example B-14)
<Preparation of mercaptopropyl silyl-group-modified _{N-Ta 2 O 5 (MPSi} -N-Ta 2 O 5) particles>
Except for using 2 g of N-Ta ₂ O ₅ particles obtained in Preparation Example A-2 instead of titanium oxide (“ST-01” manufactured by Ishihara Sangyo Co., Ltd.), the same as Preparation Example B-1, N-Ta ₂ O ₅ (MPSi-N-Ta ₂ O ₅ ) particles having mercaptopropylsilyl groups bonded to the surface were obtained.

(Preparation Example B-15)
<Preparation of mercaptopropyl silyl-group-modified tantalum oxide _(MPSi-Ta 2 _{O 5)} particles>
Preparation example except using 2 g of tantalum oxide (Ta ₂ O ₅ ) particles prepared as a precursor before nitrogen doping in Preparation Example A-2 instead of titanium oxide (“ST-01” manufactured by Ishihara Sangyo Co., Ltd.) In the same manner as in B-1, tantalum oxide (MPSi-Ta ₂ O ₅ ) particles having mercaptopropylsilyl groups bonded to the surface were obtained.

(Preparation Example C-1)
<Preparation of Au-supported N—Ta ₂ O ₅ (Au / N—Ta ₂ O ₅ ) Particles by Photodeposition Method>
1 g of N-Ta ₂ O ₅ particles obtained in Preparation Example A-2, 162 g of methanol and 0.033 g of chloroauric acid (HAuCl ₄ ) aqueous solution (30% by mass) were mixed and stirred, and further triethanolamine (TEOA) ) After adding 18 g, irradiation with light having a wavelength of 420 nm or more was performed for 30 minutes using a 500 W mercury lamp. The obtained dispersion was filtered, and the filter cake was washed with methanol, and then dried at 45 ° C. for 12 hours, so that N—Ta ₂ O ₅ (Au / N—Ta ₂ O ₅ with Au supported on the surface). ) Obtained particles.

(Preparation Example C-2)
<Preparation of Au bearing _N-Ta 2 O 5 by impregnation and rear nitriding _{(Au / N-Ta 2 O} 5) particles>
5 g of tantalum chloride was dissolved in 100 ml of ethanol, and 5% NH ₃ aqueous solution was added to make up to 300 ml. The solution was stirred for 5 hours to obtain white tantalum oxide (Ta ₂ O ₅ ) particles, and then fired at 800 ° C. for 6 hours to crystallize. 1 g of the crystallized tantalum oxide particles and 100 ml of an aqueous solution to which 0.033 g of chloroauric acid (HAuCl ₄ ) aqueous solution (30% by mass) was added were mixed and then concentrated under reduced pressure at 55 ° C. to completely remove moisture. . Then, after drying at 45 ° C. for 12 hours, firing was performed at 400 ° C. for 2 hours in an air atmosphere to obtain tantalum oxide (Au / Ta ₂ O ₅ ) particles having Au supported on the surface. The Au / Ta ₂ O ₅ particles were heat-treated at 575 ° C. for 6 hours in a mixed gas stream of ammonia and argon (NH ₃ / Ar = [400 ml / min] / [200 ml / min]). N-Ta ₂ O ₅ (Au / N-Ta ₂ O ₅ ) particles on which is supported.

(Preparation Example C-3)
<Preparation of Au bearing _{N-Ta 2 O 5 (Au} / N-Ta 2 O 5) particles by nanoparticles supporting method>
After mixing 0.8 g of N-Ta ₂ O ₅ particles obtained in Preparation Example A-2 and 34 ml of Au nanocolloid solution prepared by the laser ablation method, water was completely removed by concentration under reduced pressure at 55 ° C. . Then dried at 45 ° C. 12 h, Au nanoparticles was obtained _{N-Ta 2 O 5 (Au} / N-Ta 2 O 5) particles carried on the surface.

(Preparation Example C-4)
<Preparation of Pt—Au-supported N—Ta ₂ O ₅ (Pt—Au / N—Ta ₂ O ₅ ) Particles>
After mixing 0.6 g of N-Ta ₂ O ₅ particles obtained in Preparation Example A-2, 0.0794 g of Pt—P salt nitric acid solution (4.531% by mass) and 24 ml of water, the mixture was stirred at room temperature for 1 hour. Let stand for 1 hour. After removing the supernatant, the precipitate was dried at 45 ° C. overnight to obtain N—Ta ₂ O ₅ (Pt / N—Ta ₂ O ₅ ) particles carrying Pt.

Instead of _N-Ta 2 _{O 5} particles, except for using the Pt / _N-Ta 2 _{O 5} particles 1g are allowed carrying Au similarly by light precipitation method as in Preparation Example C-1, Pt on a surface and Au N-Ta ₂ O ₅ (Pt—Au / N—Ta ₂ O ₅ ) particles on which is supported.

(Preparation Example C-5)
<Preparation of Ag-supported N—Ta ₂ O ₅ (Ag / N—Ta ₂ O ₅ ) Particles by Photodeposition Method>
0.00394 g of silver nitrate (AgNO ₃ ) is used instead of the chloroauric acid aqueous solution, 81 g of water is used instead of methanol, the amount of N-Ta ₂ O ₅ particles is 0.5 g, and the amount of triethanolamine (TEOA) is N-Ta ₂ O ₅ (Ag / N-Ta ₂ O ₅ ) particles carrying Ag on the surface were obtained in the same manner as in Preparation Example C-1, except that the amount was changed to 9 g.

(Preparation Example C-6)
<Preparation of Pd-supported N—Ta ₂ O ₅ (Pd / N—Ta ₂ O ₅ ) Particles by Photodeposition Method>
In the same manner as in Preparation Example C-5 except that 50 μl of a palladium nitrate (Pd (NO ₃ ) ₂ ) solution (Pd content: 100.19 g / L) was used instead of silver nitrate (AgNO ₃ ), Pd was formed on the surface. Supported N—Ta ₂ O ₅ (Pd / N—Ta ₂ O ₅ ) particles were obtained.

(Preparation Example C-7)
<Preparation of Au-supported calcium iron oxide (Au / CaFe ₂ O ₄ ) particles by photodeposition method>
Instead of N-Ta ₂ O ₅ particles, 0.5 g of the calcium iron oxide particles obtained in Preparation Example A-3 were used, and 45 g of water and 45 g of methanol were used instead of 162 g of methanol. Except that the amount of triethanolamine was changed to 9 g in 0.025 g, calcium iron oxide (Au / CaFe ₂ O ₄ ) particles having Au supported on the surface were obtained in the same manner as in Preparation Example C-1.

(Preparation Example C-8)
<Preparation of Au-supported copper (I) (Au / Cu ₂ O) particles by photodeposition method>
Instead of N-Ta ₂ O ₅ particles, 1 g of copper (I) oxide powder (Cu ₂ O, manufactured by Wako Pure Chemical Industries, Ltd.) was used, and 81 g of water and 81 g of methanol were used instead of 162 g of methanol. Except that the amount of the aqueous solution was changed to 0.05 g, copper (I) (Au / Cu ₂ O) particles having Au supported on the surface were obtained in the same manner as in Preparation Example C-1.

(Preparation Example C-9)
<Preparation of Au-supported Zn—Fe ₂ O ₃ (Au / Zn—Fe ₂ O ₃ ) Particles by Photodeposition Method>
Zn carrying Au on its surface in the same manner as in Preparation Example C-8, except that 1 g of Zn—Fe ₂ O ₃ particles obtained in Preparation Example A-4 was used instead of the copper (I) oxide powder. _{-Fe 2 O 3 (Au / Zn} -Fe 2 O 3) particles were obtained.

(Preparation Example C-10)
<Preparation of Au-supported zinc oxide (Au / ZnO) particles by photodeposition method>
Instead of copper (I) oxide powder, 1 g of zinc oxide powder (ZnO, manufactured by Wako Pure Chemical Industries, Ltd., particle size: 0.02 μm) was used, and the amount of water was changed to 90 g and the amount of methanol was changed to 90 g. In the same manner as in Preparation Example C-8 except that triethanolamine was not added, zinc oxide (Au / ZnO) particles having Au supported on the surface were obtained.

(Preparation Example C-11)
<Preparation of Au-supported tungsten oxide (Au / WO ₃ ) particles by photodeposition method>
Tungsten oxide (Au 3 on which Au is supported on the surface) in the same manner as in Preparation Example C-10 except that 1 g of tungsten oxide (WO ₃ , manufactured by Kojundo Chemical Laboratory Co., Ltd.) was used instead of zinc oxide powder. / WO ₃₎ to obtain particles.

(Preparation Example C-12)
<Preparation of Au-supported tantalum oxynitride (Au / TaON) particles by photodeposition method>
Instead of calcium iron oxide particles, 0.5 g of the tantalum oxynitride particles obtained in Preparation Example A-5 were used, and Au was added to the surface in the same manner as Preparation Example C-7, except that triethanolamine was not added. Supported tantalum oxynitride (Au / TaON) particles were obtained.

(Preparation Example C-13)
<Preparation of Au-supported bismuth vanadate (Au / BiVO ₄ ) particles by photodeposition method>
Instead of calcium iron oxide particles, 0.5 g of bismuth vanadate particles obtained in Preparation Example A-6 were used, and Au was added to the surface in the same manner as Preparation Example C-7, except that triethanolamine was not added. The supported bismuth vanadate (Au / BiVO ₄ ) particles were obtained.

(Preparation Example C-14)
<Preparation of Au-supported Ta ₃ N ₅ (Au / Ta ₃ N ₅ ) particles by photodeposition method>
Instead of calcium iron oxide particles, 0.5 g Ta ₃ N ₅ particles obtained in Preparation Example A-7 were used, and Au was added to the surface in the same manner as Preparation Example C-7, except that triethanolamine was not added. Ta ₃ N ₅ (Au / Ta ₃ N ₅ ) particles on which is supported.

(Preparation Example C-15)
<Preparation of Au-supported N—TiO ₂ (Au / N—TiO ₂ ) Particles by Photodeposition Method>
Using 1 g of N-TiO ₂ particles obtained in Preparation Example A-1 instead of copper (I) oxide powder, the amount of water was changed to 90 g, the amount of methanol was changed to 90 g, and triethanolamine was not added. In the same manner as in Preparation Example C-8, N—TiO ₂ (Au / N—TiO ₂ ) particles having Au supported on the surface were obtained.

(Preparation Example C-16)
<Preparation of Au-supported Ta ₂ O ₅ (Au / Ta ₂ O ₅ ) particles by photodeposition method>
Instead of calcium iron oxide particles, 0.5 g of tantalum oxide (Ta ₂ O ₅ ) particles prepared as a precursor before nitrogen doping in Preparation Example A-2 were used, no triethanolamine was added, and the total wavelength of the mercury lamp The Ta ₂ O ₅ (Au / Ta ₂ O ₅ ) particles having Au supported on the surface were obtained in the same manner as in Preparation Example C-7 except that the above light was irradiated.

(Preparation Example D-1)
<Preparation of 1,3-propanedithiol-modified Au / N-TiO ₂ (PDT-Au / N-TiO ₂ ) particles>
0.2 g of Au / N-TiO ₂ particles obtained in Preparation Example C-15, 0.1 g of 1,3-propanedithiol and 20 ml of methanol were mixed and stirred at room temperature for 2 hours. The obtained dispersion was filtered, and the filter cake was washed with water, dried at 45 ° C. for 6 hours and at 90 ° C. for 12 hours, and Au / N—TiO ₂ whose surface was modified with 1,3-propanedithiol. It was obtained (PDT-Au / N-TiO 2) particles.

(Preparation Example D-2)
<Preparation of 1,3-propanedithiol-modified Au / ZnO (PDT-Au / ZnO) particles>
The surface is 1,3-propanedithiol in the same manner as in Preparation Example D-1, except that 0.2 g of Au / ZnO particles obtained in Preparation Example C-10 is used instead of Au / N—TiO ₂ particles. Modified Au / ZnO (PDT-Au / ZnO) particles were obtained.

(Preparation Example D-3)
<Preparation of 1,4-benzenedithiol-modified Au / WO ₃ (BDT-Au / WO ₃ ) particles>
Instead of Au / N—TiO ₂ particles, 0.2 g of Au / WO ₃ particles obtained in Preparation Example C-11, 0.2 g of 1,4-benzenedithiol instead of 1,3-propanedithiol, methanol Au / WO ₃ (BDT-Au / WO ₃ ) particles whose surface was modified with 1,4-benzenedithiol were obtained in the same manner as in Preparation Example D-1, except that 20 ml of ethanol was used instead of.

(Preparation Example D-4)
<Preparation of 1,4-benzenedithiol modified Au / BiVO ₄ (BDT-Au / BiVO ₄ ) particles>
The surface was modified with 1,4-benzenedithiol in the same manner as in Preparation Example D-3 except that 0.2 g of Au / BiVO ₄ particles obtained in Preparation Example C-13 was used instead of Au / WO ₃ particles. Au / BiVO ₄ (BDT-Au / BiVO ₄ ) particles were obtained.

(Preparation Example D-5)
<Preparation of 2-aminoethanethiol modified Au / TaON (AET-Au / TaON) particles>
Aside from using 0.2 g of Au / TaON particles obtained in Preparation Example C-12 instead of Au / N—TiO ₂ particles and using 0.2 g of 2-aminoethanethiol instead of 1,3-propanedithiol. In the same manner as in Preparation Example D-1, Au / TaON (AET-Au / TaON) particles whose surface was modified with 2-aminoethanethiol were obtained.

(Preparation Example D-6)
<Preparation of 2-Aminoethanethiol-modified Au / Ta ₃ N ₅ (AET-Au / Ta ₃ N ₅ ) Particles>
The surface was modified with 2-aminoethanethiol in the same manner as Preparation Example D-5, except that 0.2 g of Au / Ta ₃ N ₅ particles obtained in Preparation Example C-14 were used instead of Au / TaON particles. Au / Ta ₃ N ₅ (AET-Au / Ta ₃ N ₅ ) particles were obtained.

(Preparation Example D-7)
<Preparation of nano Au supported _MPSI-TiO 2 by particles supporting method (Au / MPSi-TiO ₂₎ particles>
₂ g of MPSi-TiO ₂ particles obtained in Preparation Example B-1 and 10 ml of Au nanocolloid solution prepared by laser ablation were mixed and stirred at room temperature for 2 hours. The obtained dispersion was filtered, and the filter cake was washed with water, and then dried overnight at 45 ° C. to obtain MPSi—TiO ₂ (Au / MPSi—TiO ₂ ) particles having Au nanoparticles supported on the surface. It was.

(Preparation Example D-8)
<Preparation of Nanoparticles supporting method according Au bearing _{MBA-N-TiO 2 (Au} / MBA-N-TiO 2) particles>
Au nanoparticles were supported on the surface in the same manner as in Preparation Example D-7, except that 0.2 g of MPSi-N-TiO ₂ particles obtained in Preparation Example B-10 were used instead of MPSi-TiO ₂ particles. and has _MBA-N-TiO 2 was obtained (Au / MBA-N-TiO 2) particles.

(Preparation Example D-9)
<Preparation of Pd-supported MBA-N-TiO ₂ (Pd / MBA-N-TiO ₂ ) Particles by Nanoparticle Support Method>
MBA-N-TiO ₂ (in which Pd nanoparticles are supported on the surface) in the same manner as in Preparation Example D-8 except that 10 ml of Pd nanocolloid solution prepared by laser ablation was used instead of Au nanocolloid solution. to obtain a _{pd / MBA-N-TiO 2} ) particles.

(Preparation Example D-10)
<Preparation of Au-supported MPSi-ZnO (Au / MPSi-ZnO) particles by nanoparticle support method>
MPSi in which Au nanoparticles are supported on the surface in the same manner as in Preparation Example D-7, except that 0.2 g of MPSi—ZnO particles obtained in Preparation Example B-11 was used instead of MPSi—TiO ₂ particles. -ZnO (Au / MPSi-ZnO) particles were obtained.

<Electron microscope observation>
The supporting state of the metal particles on the semiconductor particles was observed using a scanning electron microscope ("Ultra High Resolution Field Emission Scanning Electron Microscope S-5500" manufactured by Hitachi High-Technologies Corporation, acceleration voltage: 7 kV). FIG. 4 shows a reflected electron image photograph of the Au / N—Ta ₂ O ₅ particles obtained in Preparation Example C-1. The bright part in the figure is Au particles, and the dark part is N-Ta ₂ O ₅ particles.

As is clear from the results shown in FIG. 4, it was confirmed that Au particles were supported on the N—Ta ₂ O ₅ particles. The particle diameter of the _N-Ta 2 _{O 5} particles is 20 to 40 nm, particle size of Au particles was 15nm or less.

Example 1
MPSi—TiO ₂ particles obtained in Preparation Example B-1 (0.04 g), Au / N—Ta ₂ O ₅ particles obtained in Preparation Example C-1 (0.2 g), and methanol (20 ml) were mixed and mixed at room temperature for 2 hours. Stir. The obtained dispersion was filtered, and the filter cake was washed with water, and then dried at 45 ° C. for 12 hours to obtain semiconductor heteroparticles in which MPSi—TiO ₂ particles and Au / N—Ta ₂ O ₅ particles were combined. Obtained.

  In a test tube made of Pyrex (registered trademark) having a capacity of 8 ml, 8 mg of the composite semiconductor heteroparticles and 4 ml of water adjusted to the pH shown in Table 1 using sulfuric acid were added and mixed. A dispersion containing was prepared.

(Examples 2-3, Examples 5-15, Comparative Examples 1-6, Comparative Examples 8-11)
A test tube made of Pyrex (registered trademark) having a capacity of 8 ml was mixed with particles of the types and blending amounts shown in Table 1 and 4 ml of water adjusted to the pH shown in Table 1 using sulfuric acid, and mixed. A dispersion containing the particles was prepared.

Example 4
Using MPSi-TiO ₂ MMSi-TiO ₂ particles 0.06g obtained in Preparation Example B-2 in place of the particles, except for changing the amount of Au / _N-Ta 2 _{O 5} particles 0.18g Example In the same manner as in Example 1, semiconductor heteroparticles in which MMSi—TiO ₂ particles and Au / N—Ta ₂ O ₅ particles were combined were obtained. A dispersion containing semiconductor hetero particles was prepared in the same manner as in Example 1 except that 8 mg of the composite semiconductor hetero particles were used as the semiconductor hetero particles.

(Comparative Example 7)
In the same manner as in Example 1 except that 0.2 g of N-Ta ₂ O ₅ particles obtained in Preparation Example A-2 were used instead of Au / N—Ta ₂ O ₅ particles, MPSi-TiO ₂ particles and Semiconductor hetero particles in which N-Ta ₂ O ₅ particles were combined were obtained. A dispersion containing semiconductor hetero particles was prepared in the same manner as in Example 1 except that 8 mg of the composite semiconductor hetero particles were used as the semiconductor hetero particles.

(Example 16)
In the same manner as in Example 1 except that 0.2 g of Au / Ta ₂ O ₅ particles obtained in Preparation Example C-16 was used instead of Au / N—Ta ₂ O ₅ particles, MPSi—TiO ₂ particles and Semiconductor hetero particles in which Au / Ta ₂ O ₅ particles were combined were obtained. A dispersion containing semiconductor hetero particles was prepared in the same manner as in Example 1 except that 8 mg of the composite semiconductor hetero particles were used as the semiconductor hetero particles.

(Examples 17 to 39, Comparative Examples 12 to 40)
In a test tube made of Pyrex (registered trademark) having a capacity of 8 ml, particles of the types and blending amounts shown in Tables 2 to 5 and 4 ml of water adjusted to the pH shown in Tables 2 to 5 using sulfuric acid or sodium hydroxide, Were mixed to prepare a dispersion containing semiconductor hetero particles.

<Infrared spectroscopic analysis>
Using a Fourier transform infrared spectrometer (“VERTEX80” manufactured by Bruker Optics), the binding of organic molecules to the semiconductor particles was confirmed by the total reflection method (ATR method). FIG. 5 shows the FT-IR measured by the ATR method of the MPSi—TiO ₂ particles obtained in Preparation Example B-1, the semiconductor heteroparticles obtained in Example 1, and the semiconductor heteroparticles obtained in Comparative Example 7. The spectrum is shown.

As is clear from the results shown in FIG. 5, in the MPSi—TiO ₂ particles (Preparation Example B-1), an SH stretch band was confirmed at a wave number of 2560 cm ⁻¹ . Further, this SH stretch band was also confirmed in composite particles (Comparative Example 7) of MPSi—TiO ₂ particles and N—Ta ₂ O ₅ particles. On the other hand, in the composite particle (Example 1) of MPSi—TiO ₂ particles and Au / N—Ta ₂ O ₅ particles, no SH stretch band was observed at a wave number of 2560 cm ⁻¹ , and MPSi—TiO ₂ particles It was confirmed that the mercapto group of Au and the Au particles of Au / N—Ta ₂ O ₅ particles were bonded.

<Photocatalytic activity evaluation>
Argon gas was passed through the dispersions obtained in Examples and Comparative Examples for 15 minutes to saturate, and the test tube was sealed with a rubber stopper. The test tube is mounted on a merry-go-round rotating device, and a xenon lamp (USHIO INC., 500 W) is used as a light source while stirring the dispersion with a stirrer. A heat ray absorption filter (Asahi Glass Co., Ltd.) The photocatalytic reaction was performed by irradiating visible light that passed through “super cold”) for 24 hours. Thereafter, the gas component in the gas phase portion in the test tube was analyzed using gas chromatography. Tables 6 to 10 show the amount of hydrogen produced (24 hours).

As is clear from the results shown in Table 6, TiO ₂ particles having organic groups bonded to the surface and N—Ta ₂ O ₅ particles having Au particles supported on the surface are mixed or combined. It was confirmed that the photocatalytic function was expressed (Examples 1 to 12). In particular, these particles were found to exhibit a photocatalytic function regardless of the presence or absence of the composite treatment (Examples 1 and 2). Moreover, even if the coupling | bonding form of a semiconductor particle and an organic group is a covalent bond (Examples 1-4, Examples 8-12) or an ionic bond (Examples 5-7), a photocatalytic function is expressed. I found out that Furthermore, the method for supporting Au particles is not particularly limited, and it has been found that the photocatalytic function is exhibited in any of the photoprecipitation method, the impregnation support method, and the nanoparticle support method (Examples 2, 10, and 11).

On the other hand, TiO ₂ particles (Comparative Example 1), TiO ₂ particles to which organic groups are bonded (Comparative Example 2), organic group-modified TiO ₂ particles carrying Au particles (Comparative Example 3), and Au particles Even when each of the supported N—Ta ₂ O ₅ particles (Comparative Example 4) was used alone, the photocatalytic function was not expressed. In addition, when the organic group was not bonded to the TiO ₂ particles (Comparative Examples 5 and 6), the photocatalytic function was not exhibited regardless of whether the metal particles were supported on the N-Ta ₂ O ₅ particles. . Furthermore, even when the organic group was bonded to the TiO ₂ particles, the photocatalytic function was not exhibited when the metal particles were not supported on the N—Ta ₂ O ₅ particles (Comparative Example 7).

In addition, when N—Ta ₂ O ₅ particles in which Au particles and Pt particles are supported are mixed with TiO ₂ particles to which organic groups are bonded (Example 13), only Au particles are supported. It was found that the photocatalytic activity was very high as compared with the case of mixing N-Ta ₂ O ₅ particles (Example 3). This is presumably because the Pt particles function as a promoter. On the other hand, when N—Ta ₂ O ₅ particles carrying Au particles and Pt particles are used alone (Comparative Example 8) or mixed with TiO ₂ particles to which no organic group is bonded (Comparison) In Example 9), the photocatalytic function was not expressed.

Furthermore, even when Ag particles or Pd particles are supported on N-Ta ₂ O ₅ particles instead of Au particles (Examples 14 and 15), by mixing with TiO ₂ particles to which organic groups are bonded, It was confirmed that the photocatalytic function was expressed. On the other hand, when N—Ta ₂ O ₅ particles carrying Ag particles or Pd particles were used alone (Comparative Examples 10 and 11), the photocatalytic function was not expressed.

In Examples 3 and 13, when photocatalytic reaction was performed using heavy water (D ₂ O) as water, most of the generated hydrogen was deuterium (D ₂ ). From this, in the photocatalytic reaction in water using the semiconductor heteroparticle of the present invention, it was confirmed that water is an electron source and a hydrogen source.

As can be seen from the results shown in Table 7, in the semiconductor heterostructure particles of the present invention, as the first semiconductor particles, in addition to the TiO ₂ particles, N-TiO ₂ particles, ZnO particles, WO ₃ particles can be used In addition to the N—Ta ₂ O ₅ particles, it was confirmed that Ta ₂ O ₅ particles, CaFe ₂ O ₄ particles, Cu ₂ O particles, and Zn—Fe ₂ O ₃ particles can be used as the second semiconductor particles. (Examples 16 to 21).

  On the other hand, when the first semiconductor particles (Comparative Examples 12 and 14) to which organic groups are bonded and the second semiconductor particles (Comparative Examples 15, 18, and 19) carrying Au particles are used alone However, the photocatalytic function was not expressed. Further, even when the first semiconductor particles to which the organic group was bonded and the second semiconductor particles on which the metal particles were not supported were mixed, the photocatalytic function was not exhibited (Comparative Examples 13, 17, and 20). . Furthermore, even when the second semiconductor particles carrying Au particles were mixed with the first semiconductor particles to which no organic group was bonded, the photocatalytic function did not appear (Comparative Example 16).

As apparent from the results shown in Table 8, Au particles are supported on the surface of the first semiconductor particles such as TiO ₂ particles, and organic groups are formed on the surface of the N-Ta ₂ O ₅ particles as the second semiconductor particles. Even in the case of binding (Examples 22 to 26), it was confirmed that the photocatalytic function was developed as in Examples 1 to 21.

  On the other hand, when the first semiconductor particles carrying the Au particles (Comparative Examples 21, 26 and 28) and the second semiconductor particles having the organic group bonded thereto (Comparative Example 23) are used alone. The photocatalytic function was not expressed. Further, even when the first semiconductor particles carrying Au particles and the second semiconductor particles having no organic group bonded thereto, the photocatalytic function did not appear (Comparative Examples 22, 27, 29 to 29). 31). Furthermore, when metal particles were not supported on the first semiconductor particles, the photocatalytic function did not appear regardless of the presence or absence of organic group binding to the second semiconductor particles (Comparative Examples 24 and 25). .

  As is clear from the results shown in Table 9, the Au particles supported on the first semiconductor particles and the Au particles or Ag particles supported on the second semiconductor particles have a metal-bonded functional group. It was confirmed that the photocatalytic function was expressed by bonding through an organic group (Examples 27 to 34).

  On the other hand, when metal particles were not supported on the second semiconductor particles (Comparative Examples 32 and 34), the photocatalytic function was not exhibited even if an organic group having a metal-bonded functional group was present.

  As is apparent from the results shown in Table 10, the first organic group bonded to the first semiconductor particle and the second organic group bonded to the second semiconductor particle are converted into metal particles. It was confirmed that the photocatalytic function was expressed by binding via the C.

  On the other hand, when no metal particles were present (Comparative Examples 35, 37, 38, and 40), the photocatalytic function was not expressed. In addition, when the second organic group was not bonded to the second semiconductor particles (Comparative Examples 36 and 39), the photocatalytic function was not exhibited even if the metal particles were present.

  As described above, according to the present invention, it is possible to develop a photocatalytic function in a relatively wide pH range without using a solution-based electron mediator in a semiconductor heteroparticle having two types of semiconductor particles. Become. Moreover, the semiconductor heteroparticle of the present invention can be easily produced by subjecting the semiconductor particle to a simple modification such as bonding an organic group or supporting a metal particle.

  Therefore, the semiconductor heteroparticle of the present invention can be applied not only as a photocatalyst but also in a wide range of fields such as a light emitter and a sensor.

  1: organic group, 1a: first organic group, 1b: second organic group, 2a: first semiconductor particle, 2b: second semiconductor particle, 3: metal particle, 3a: first metal particle, 3b: second metal particles, 4: light.

Claims (11)

A first semiconductor particle, a second semiconductor particle, a metal particle, and an organic group;
The potential at the lower end of the conduction band of the first semiconductor particles is more negative than the potential at the upper end of the valence band of the second semiconductor particles;
The metal particles are bonded to one of the first and second semiconductor particles;
The organic group is bonded to the other semiconductor particle of the first and second semiconductor particles;
A semiconductor heteroparticle, wherein the organic group has a metal bond functional group, and the metal bond functional group is bonded to the metal particle.   2. The semiconductor heteroparticle according to claim 1, wherein the metal particle is supported on one of the first and second semiconductor particles. A first semiconductor particle, a second semiconductor particle, a first metal particle, a second metal particle, and an organic group;
The potential at the lower end of the conduction band of the first semiconductor particles is more negative than the potential at the upper end of the valence band of the second semiconductor particles;
The first and second metal particles are bonded to the first and second semiconductor particles, respectively;
The organic group has a first metal binding functional group and a second metal binding functional group, and the first and second metal binding functional groups bind to the first and second metal particles, respectively. The semiconductor heteroparticle characterized by the above-mentioned.   4. The semiconductor heteroparticle according to claim 3, wherein the first and second metal particles are supported on the first and second semiconductor particles, respectively. A first semiconductor particle, a second semiconductor particle, a first organic group, a second organic group, and a metal particle;
The potential at the lower end of the conduction band of the first semiconductor particles is more negative than the potential at the upper end of the valence band of the second semiconductor particles;
The first and second organic groups are bonded to the first and second semiconductor particles, respectively;
The first and second organic groups have first and second metal binding functional groups, respectively, and the metal particles are in the first metal binding functional group and the second metal binding functional group, respectively. A semiconductor heteroparticle characterized by being bonded. A first semiconductor particle, a second semiconductor particle, a metal particle, and an organic group, wherein the potential at the lower end of the conduction band of the first semiconductor particle is higher than the potential at the upper end of the valence band of the second semiconductor particle. A method for producing negative semiconductor heteroparticles, comprising:
Bonding metal particles to one of the first and second semiconductor particles;
The other semiconductor particle of the first and second semiconductor particles is mixed with an organic molecule having a metal bond functional group to prepare a semiconductor particle to which the organic group having a metal bond functional group is bonded. Process,
Mixing the semiconductor particles to which the metal particles are bonded and the semiconductor particles to which the organic groups having the metal bonding functional groups are bonded to bond the metal particles to the metal bonding functional groups; The manufacturing method of the semiconductor heteroparticle characterized by including.   7. The method for producing semiconductor hetero particles according to claim 6, wherein in the step of joining the metal particles, the metal particles are supported on one of the first and second semiconductor particles. 1st semiconductor particle, 2nd semiconductor particle, 1st metal particle, 2nd metal particle, and organic group are provided, and the electric potential of the conduction band lower end of said 1st semiconductor particle is said 2nd semiconductor A method for producing a semiconductor heteroparticle that is more negative than the potential at the top of the valence band of the particle,
Bonding the first metal particles to the first semiconductor particles;
Bonding the second metal particles to the second semiconductor particles;
One of the first and second semiconductor particles to which the metal particles are bonded is mixed with an organic molecule having a first metal-bonded functional group and a second metal-bonded functional group, The metal particles are bonded to one of the first and second metal-bonding functional groups, the metal particles are bonded, and the metal particles are bonded to the first and second metal-bonding functional groups. Preparing a semiconductor particle to which an organic group having the other metal-bonded functional group of the group is bonded;
The other semiconductor particle of the first and second semiconductor particles bonded to the metal particle is bonded to the organic group bonded to the metal particle and having the other metal-bonded functional group. A method of producing semiconductor heteroparticles, comprising: mixing a semiconductor particle, and bonding the metal particle bonded to the other semiconductor particle to the other metal-binding functional group. .   9. The method for producing semiconductor hetero particles according to claim 8, wherein in the step of bonding the first metal particles, the first metal particles are supported on the first semiconductor particles.   The method for producing semiconductor heteroparticles according to claim 8 or 9, wherein in the step of bonding the second metal particles, the second metal particles are supported on the second semiconductor particles. 1st semiconductor particle, 2nd semiconductor particle, 1st organic group, 2nd organic group, and metal particle are provided, and the electric potential of the conduction band lower end of said 1st semiconductor particle is said 2nd semiconductor A method for producing a semiconductor heteroparticle that is more negative than the potential at the top of the valence band of the particle,
Mixing first semiconductor particles and organic molecules having a first metal-binding functional group to prepare first semiconductor particles to which the first organic group having the metal-binding functional group is bonded; ,
Mixing second semiconductor particles and organic molecules having a second metal-bonded functional group to prepare second semiconductor particles to which the second organic group having the metal-bonded functional group is bonded; ,
Mixing the semiconductor particles and the metal particles to which one organic group of the first and second organic groups is bonded, and bonding the metal-bonded functional group in the organic group and the metal particles; Preparing a semiconductor particle to which the organic group is bonded and the metal particle is bonded to a metal bonding functional group in the organic group;
The semiconductor particle to which the other organic group of the first and second organic groups is bonded, the organic group is bonded, and the metal particle is bonded to the metal bonding functional group in the organic group. And a step of mixing the semiconductor particles to bond the metal-bonded functional group in the other organic group and the metal particles.