JP2007039298A - Hydrogen generator, hydrogen generation method and hydrogen generation system - Google Patents

Abstract

[PROBLEMS] To efficiently generate hydrogen from a hydrogen source containing a compound having hydrogen as a constituent element by using visible light responsive photocatalyst material radiated from a light source, or accumulate it as protons and electrons. A hydrogen generation apparatus capable of performing the above, a hydrogen generation method using the same, and a hydrogen generation system.
A proton generation unit, a proton conduction unit, a hydrogen generation unit, an electron storage unit, a proton storage unit, and a switch are provided. The proton conducting part is sandwiched between the proton generating part and the hydrogen generating part, and is further joined to the proton accumulating part. The proton generator and the hydrogen generator are connected to each other via an electron storage unit and a switch in this order. The proton generator includes a first electrically conductive material, a visible light responsive photocatalytic material, and a charge separation material, and the hydrogen generator includes a second electrically conductive material and a metal material.
[Selection figure] None

Description

The present invention relates to a hydrogen generator, a hydrogen generation method, and a hydrogen generation system, and more specifically, from a hydrogen source containing a compound having hydrogen (H) as a constituent element by using visible light irradiated from a light source. The present invention relates to a hydrogen generator capable of generating hydrogen (H ₂ ) or storing it as protons and electrons, a hydrogen generation method using the hydrogen generator, and a hydrogen generation system including the hydrogen generator.

In recent years, there are concerns about the problem of gas discharged from mobile objects and the depletion of fuel resources.
Therefore, in recent years, research and development of fuel cells using hydrogen (H ₂ ) and oxygen (O ₂ ) as fuels have been conducted.

The fuel cell generates power using hydrogen (H ₂ ) and oxygen (O ₂ ) as fuel. However, since hydrogen (H ₂ ) hardly exists in nature, an apparatus for generating hydrogen (H ₂ ) is required.
From such a background, hydrogen (H ₂ ) generation by water (H ₂ O) photocatalyst has been studied and attracted attention.

For example, a hydrogen generation apparatus has been proposed in which a cathode and an anode electrically connected to each other are provided in a container containing a predetermined aqueous solution (see Patent Document 1).
The anode of this device has a structure in which a photocatalytic layer for exciting electron and hole pairs by light irradiation is formed on the surface of a p-type semiconductor layer of a solar cell having a pn junction made of a p-type semiconductor and an n-type semiconductor. . By irradiating the anode with light energy, hydrogen gas can be generated from the cathode surface.

Such a hydrogen generation device aims to generate hydrogen with high efficiency only by sunlight by providing one element with two functions of hydrogen generation and a solar cell.
More specifically, the solar cell surface of a silicon (Si) or the like, deposition of the semiconductor thin film having a so-called photocatalytic function to excite the electrons and hole pairs by light irradiation such as titanium oxide (TiO _2), TiO 2 / A heterostructure such as Si is adopted.
Thus, long-wavelength sunlight transmitted through the semiconductor thin film (TiO ₂ or the like) is absorbed by the solar cell layer (Si or the like) to generate electron-hole pairs, and the hydrogen generation potential of the semiconductor film By adding the electromotive potential and lifting it, the hydrogen generation efficiency by sunlight is greatly increased.

  In addition, a hydrogen generation apparatus is proposed in which a first working electrode and a second working electrode of a platinum electrode are immersed in a reaction tank that stores water, and a DC voltage is applied by a DC power source interposed between the two working electrodes. (See Patent Document 2).

Specifically, in this hydrogen generator, the first working electrode has a transparent electrode provided with indium tin oxide (ITO) on the surface of the glass substrate, and a photocatalytic electrode film is provided on the electrode surface.
As the photocatalytic electrode film, a titanium dioxide thin film is employed, and a ruthenium complex as a visible light absorbing dye is supported on the film surface.
Further, the DC voltage is applied at a voltage value of less than 2 V so that the first working electrode side is positive and the second working electrode side is negative. Under this application condition, the light from the tungsten lamp is irradiated.
JP 2003-238104 A JP 2002-356301 A

However, the hydrogen generation apparatus described in Patent Document 1 has a problem that the apparatus is expensive because an expensive semiconductor thin film is used.
In addition, there is a problem that the amount of hydrogen generated varies greatly corresponding to the amount of light irradiated from sunlight, and hydrogen cannot be generated particularly when no light is applied.

  Furthermore, in the hydrogen generator described in Patent Document 2, the voltage is applied between the electrodes, so that the power consumption is large, the generation efficiency of hydrogen is poor with respect to the input energy, and the ruthenium complex is used. There was a problem of poor durability.

  Furthermore, the hydrogen generators described in Patent Documents 1 and 2 require a large hydrogen tank for storing hydrogen, and the system itself is large. Therefore, there is also a problem that it is not easy to mount the hydrogen generator on the moving body.

The present invention has been made in view of such problems of the prior art, and the object of the present invention is to use visible light responsive photocatalyst material with hydrogen ( A hydrogen generator and a hydrogen generator capable of efficiently generating hydrogen (H ₂ ) from a hydrogen source containing a compound having H) as a constituent element or storing them as protons (H ⁺ ) and electrons (e ⁻ ) An object of the present invention is to provide a hydrogen generation method and a hydrogen generation system using the hydrogen generation apparatus.

As a result of intensive studies to achieve the above object, the inventor brought a hydrogen source containing a compound having hydrogen (H) as a constituent element into contact with a visible light responsive photocatalytic material, and obtained visible light from a light source. irradiating the said visible light responsive photocatalyst material, a hydrogen source and a proton (H ⁺⁾ electrons ^- generate, resulting protons (H ⁺⁾ of the flow and electron (e) ^- control the flow of (e) Thus, the inventors have found that the above object can be achieved by controlling the generation amount of hydrogen (H ₂ ), and have completed the present invention.

That is, the hydrogen generator of the present invention is an apparatus that generates hydrogen (H ₂ ) from a hydrogen source containing a compound having hydrogen (H) as a constituent element, using visible light emitted from a light source.
Such a hydrogen generator includes a proton generation unit, a proton conduction unit, a hydrogen generation unit, an electron storage unit, a proton storage unit, and a switch, and the proton conduction unit includes the proton generation unit and the hydrogen generation unit. The proton conducting part is joined to the proton accumulating part, and the proton producing part and the hydrogen producing part are arranged from the proton producing part side to the electron accumulating part, the proton producing part, and The hydrogen generation unit is connected to the switch through which the hydrogen generation unit can be electrically connected in this order, and the proton generation unit includes a first electrically conductive material, a visible light responsive photocatalytic material, and a charge separation material, The hydrogen generator includes a second electrically conductive material and a metal material.

The hydrogen generation method of the present invention is a hydrogen generation method using the hydrogen generation apparatus of the present invention, comprising a hydrogen source containing a compound having hydrogen (H) as a constituent element and a visible light responsive photocatalytic material. The visible light responsive photocatalyst material is irradiated with visible light from a light source to generate protons (H ⁺ ) and electrons (e ⁻ ) from the hydrogen source, and the flow of protons (H ⁺ ) obtained and The flow of electrons (e ⁻ ) is controlled to control the generation amount of hydrogen (H ₂ ).

  Furthermore, the hydrogen generation system of the present invention is a hydrogen generation system using the hydrogen generator of the present invention, and includes the hydrogen generator and a compound having hydrogen (H) as a constituent element in the hydrogen generator. A hydrogen source supply means for supplying a hydrogen source and a control means for controlling a switch of the hydrogen generator, wherein the control means intermittently controls the switch.

According to the present invention, a hydrogen source containing a compound having hydrogen (H) as a constituent element is brought into contact with a visible light responsive photocatalyst material, the visible light responsive photocatalyst material is irradiated with visible light from a light source, (e ^-) protons ^{(H +)} and electrons from the hydrogen source to produce the resulting protons ^{(H +)} of the flow and electron (e ^-) to control the flow of the generation amount of hydrogen _{(H 2)} Because of control, etc., hydrogen (H ₂ ) is efficiently obtained from a hydrogen source containing a compound having hydrogen (H) as a constituent element using visible light responsive photocatalytic material using visible light emitted from a light source. To provide a hydrogen generator that can be generated or stored as protons (H ⁺ ) and electrons (e ⁻ ), a hydrogen generation method using the hydrogen generator, and a hydrogen generation system using the hydrogen generator. it can.

Hereinafter, the hydrogen generator of the present invention will be described in detail.
As described above, the hydrogen generator of the present invention is an apparatus that generates hydrogen (H ₂ ) from a hydrogen source containing a compound having hydrogen (H) as a constituent element, using visible light emitted from a light source. A proton generation unit, a proton conduction unit, a hydrogen generation unit, an electron storage unit, a proton storage unit, and a switch, and the proton conduction unit is sandwiched between the proton generation unit and the hydrogen generation unit. The proton conducting part is joined to the proton accumulating part, and the proton producing part and the hydrogen producing part are connected to the electron accumulating part, the proton producing part and the hydrogen producing part from the proton producing part side. Are connected via the switches in this order.

  And this proton production | generation part contains a 1st electric conduction material, visible light responsive photocatalyst material, and a charge separation material, and this hydrogen production | generation part contains a 2nd electric conduction material and a metal material.

By adopting such a configuration, the visible light responsive photocatalyst material is activated by the visible light irradiated from the light source, and the hydrogen source containing the compound having hydrogen (H) as a constituent element is used as the visible light responsive photocatalyst. When the switch is in the on state, hydrogen (H ₂ ) can be efficiently generated, and when the switch is in the off state, the electron (e ⁻ ) Proton (H ⁺ ) can be stored in the storage unit and in the proton storage unit.

Further, when the switch is turned on from the accumulated state, hydrogen (H ₂ ) can be generated even when light is not irradiated from the light source.

Furthermore, as described above, since it can be stored in the state of electrons (e ⁻ ) and protons (H ⁺ ) instead of hydrogen (H ₂ ), a hydrogen tank is not necessarily required when the system is constructed. Also, when a hydrogen tank is provided, the hydrogen tank can be reduced in size.

Further, the energy source utilized in obtaining the hydrogen (H ₂₎ from the hydrogen source is miniaturized than the conventional.
Specifically, it is not always necessary to apply an external power source to generate hydrogen (H ₂ ), and the hydrogen generator can be further downsized.
Furthermore, since it is not always necessary to use an expensive semiconductor thin film and it is not always necessary to use a ruthenium complex, it can be designed to be inexpensive and durable. It becomes easy to mount on a moving body.

In the present invention, a current detector may be provided between the proton generator and the electron storage unit.
Such a current detector can measure the amount of hydrogen (H ₂ ) generated when the switch is in an on state, and roughly in the electron storage section when the switch is in an off state. The amount of accumulated electrons can be estimated.
Based on such measurements or estimates, by executing the control of the hydrogen generating apparatus, can be generated more efficiently hydrogen (H _2).

Furthermore, in the present invention, a photodetector may be provided.
Here, the photodetector is a so-called optical sensor that detects visible light irradiated from a light source to a hydrogen generator, more preferably a proton generator, and more preferably visible light-responsive photocatalyst material. There is no particular limitation as long as the amount can be measured, and for example, a photodiode or the like can be used.
Then, based on measurements of such light detector, by executing the control of the hydrogen generating apparatus, can be generated more efficiently hydrogen (H _2).

Here, the hydrogen generator of the present invention will be described in more detail with reference to the drawings.
FIG. 1 is a schematic view showing an example of the hydrogen generator of the present invention. As shown in the figure, the hydrogen generator 1 includes a proton generation unit 10, a proton conduction unit 20, a hydrogen generation unit 30, an electron storage unit 40, a proton storage unit 50, a switch 60, and a current detector. 70 and a photodetector 80.
The proton conducting unit 20 is sandwiched between the proton generating unit 10 and the hydrogen generating unit 30 and further joined to the proton accumulating unit 50.
Further, the proton generator 10 and the hydrogen generator 30 are connected to the current detector 70, the electron storage unit 40, and the switch 60 that can electrically connect the proton generator 10 and the hydrogen generator 30 from the proton generator 10 side. And are connected by a wiring w.
FIG. 1 shows a case where the switch 60 is in an off state.

Then, the visible light responsive photocatalyst material (not shown) contained in the proton generator 10 is activated by the visible light irradiated from the light source by irradiating visible light from the light source as indicated by an arrow a. However, by supplying water (H ₂ O), which is an example of a hydrogen source, to the visible light-responsive photocatalytic material as shown by an arrow b, the electrons (e ⁻ ) (not shown) are generated in the proton generator 10. ), Proton (H ⁺ ) (not shown), and oxygen (O ₂ ) as indicated by an arrow c, and the obtained electrons (e ⁻ ) pass through the current detector 70 and pass through the electron storage unit 40. On the other hand, the obtained proton (H ⁺ ) passes through the proton conducting part 20 and is accumulated in the proton accumulating part 50.
Further, FIG. 1 does not show a case where the switch 60 is in an ON state, but in that case, hydrogen (H ₂ ) is generated from the hydrogen generation unit 30 as indicated by a dashed arrow d. Details will be described later.

In addition, in the present invention, the electron storage section provided is not particularly limited as long as it can store electrons (e ⁻ ), but the material and shape thereof are not particularly limited, but a polymer, metal or metal oxide, and any of these It is desirable that the electron storage material includes a combination of the above and an insulating material, and the electron storage material is covered with the insulating material.

The polymer as the electron storage material is not particularly limited, and examples thereof include polyaniline, polypyrrole, and polythiophene.
The metal that is an electron storage material is not particularly limited, and examples thereof include iron (Fe), manganese (Mn), and nickel (Ni).
Furthermore, the metal oxide that is an electron storage material is not particularly limited, and examples thereof include tungsten trioxide (WO ₃ ), nickel oxide (NiO), copper oxide (CuO), and the like. It is desirable to use WO ₃ from the viewpoints of properties and electron storage capacity.

  The insulating material is not particularly limited, but is preferably an insulating polymer such as polycarbonate or polyethylene terephthalate from the viewpoint of light weight, free design of shape, and transparency. Can be used.

FIG. 2 shows a schematic cross-sectional shape of an example of an electron storage unit provided in the hydrogen generator of the present invention. As shown in the figure, the electron storage section 40 has a structure in which WO ₃ which is an example of the electron storage material 42 is covered with an insulating polymer which is an example of an insulating material 44 such as polycarbonate.
The electron accumulating material 42 is electrically connected to a proton generator and a switch (not shown) through a wiring w.

Furthermore, in the present invention, the material and shape of the proton accumulating portion provided is not particularly limited as long as it can accumulate protons (H ⁺ ), but it is not limited to solid polymer, glass or metal oxide, and these It is desirable that the proton storage material according to any combination of the above and a proton efflux prevention material have a structure covered with the proton efflux prevention material.

The solid polymer that is the proton storage material is not particularly limited, and examples thereof include a proton conductive membrane such as Nafion (registered trademark, manufactured by DuPont).
Further, the glass that is a proton storage material is not particularly limited, and examples thereof include proton conductive glass such as phosphate glass.
Furthermore, the metal oxide that is a proton storage material is not particularly limited, and examples thereof include tungsten trioxide (WO ₃ ), nickel oxide (NiO), copper oxide (CuO), and the like. It is desirable to use WO ₃ from the viewpoints of properties and proton accumulation capacity.

  The proton efflux prevention material is not particularly limited, but from the viewpoint of being lightweight, freely designing the shape, and being transparent, for example, a proton efflux prevention polymer such as polycarbonate or polyethylene terephthalate is used. It can be used suitably.

Here, it is desirable that the electron storage unit and the proton storage unit provided have a capacitor structure from the viewpoint of increasing the amount of electrons (e ⁻ ) and protons (H ⁺ ) stored.
For example, the capacitor structure may be constructed by the structure of the hydrogen generator itself, or the capacitor structure may be constructed by arranging a plurality of hydrogen generators when constructing the hydrogen generation system.

Next, the electronic state and the flow of electrons (e ⁻ ) in the hydrogen generator of the present invention will be described.
FIG. 3 is an explanatory view schematically showing the electronic state and the flow of electrons (e ⁻ ) in the hydrogen generator of the present invention. As shown in the figure, the electrons (e ⁻ ) generated in the proton generator 10 move to the electron accumulator 40 and further move to the hydrogen generator 30, while not shown, the protons generated in the proton generator (H ⁺ ) moves to the proton conducting part and further moves to the hydrogen generating part.
Note that the electronic state in the illustrated electron storage unit 40 is a case where a metal oxide having semiconductor properties is used as the electron storage material constituting the electron storage unit.

Further, as described above, in order to make the flow of electrons (e ⁻ ) and protons (H ⁺ ), particularly the flow of electrons (e ⁻ ) smooth, and to generate hydrogen (H ₂ ) efficiently, proton generation The electronic states in the parts, the electron storage part, and the hydrogen generation part have the following relationships [1] to [4] when the energy levels between the components in each part are compared. desirable.

[1] (Upper end of valence band of visible light responsive photocatalytic material) <(Upper end of valence band of charge separation material)
[2] (Upper end of valence band of charge separation material) <(Lower end of conduction band of visible light responsive photocatalytic material) <(Lower end of conduction band of charge separation material)
[3] (Lower end of conduction band of charge separation material)> (Highest energy level of the electron occupying state of the electron storage portion)> (Fermi level of the metal material of the hydrogen generating portion)
[4] (Lower end of conduction band of visible light responsive photocatalytic material)> (Highest energy level of electron occupying state of electron accumulating part)> (Fermi level of metal material of hydrogen generating part)

When the above relationship is established, the electrons (e ⁻ ) flow roughly in the following two ways.
That is, electrons generated by the visible light responsive photocatalyst material (e ^-) electrons are generated by the visible light responsive photocatalyst material and when flowing from through a charge separation material on the first electrically conductive material (e ^-) is first May flow directly into electrically conductive material.

First, in the above-described case, the visible light responsive photocatalyst material is irradiated with visible light, so that holes (holes) generated in the visible light responsive photocatalyst material, further electrons (e ⁻ ) and protons (H ⁺ ) are generated. The mechanism by which hydrogen (H ₂ ) is generated by the flow will be described.

Each of the visible light responsive photocatalyst material and the charge separation material can be used alone or in combination.
At this time, in order to prevent recombination of electrons (e ⁻ ) and holes (holes) generated by light absorption in the visible light responsive photocatalytic material, the band gap between the visible light responsive photocatalytic material and the charge separation material is increased. It is desirable to adjust.
In other words, the potential at which electrons (e ⁻ ) are emitted in the visible light responsive photocatalytic material (the energy level of the conduction band) is the potential at which the electrons (e ⁻ ) enter holes (holes) in the charge separation material. The energy level of the conduction band of the charge separation material is higher than the energy level of the conduction band of the visible light responsive photocatalytic material, and the band gap of the charge separation material is visible light. It is desirable to be smaller than the band gap of the responsive photocatalytic material.

FIG. 4 is a graph showing an example of an absorption spectrum of a visible light responsive photocatalytic material and a charge separation material having a preferable relationship as described above.
As shown in FIG. 4, the charge separation material itself exhibits plasmon absorption.

FIG. 5 is an explanatory diagram showing an example of an electronic state and an electron flow in the proton generation unit including the visible light responsive photocatalyst material and the charge separation material having a preferable relationship as described above.
As shown in FIG. 5, in the proton generator, visible light responsive photocatalytic material is irradiated with visible light, the electrons (e ⁻ ) are excited, and excited electrons (e ⁻ ) and holes (holes) are generated.
At the same time, the charge separation material is irradiated with visible light, and the electrons (e ⁻ ) are excited to generate excited electrons (e ⁻ ) and holes (holes).

At this time, for example, when water (H ₂ O) (not shown) as an example of a hydrogen source comes into contact with the visible light responsive photocatalyst, the water (H ₂ O) receives a hole and oxygen (O ₂ ) is appear.
Further, the electrons (e ⁻ ) generated in the visible light responsive photocatalyst material enter the valence band of the charge separation material, whereby the holes (holes) disappear and the electrons (e ⁻ ) generated in the charge separation material. Moves to a first electrically conductive material (not shown). Furthermore, the electrons (e ⁻ ) moved to the first electrically conductive material move to an electron storage unit (not shown).
When the switch is on, the electrons (e ⁻ ) move to the hydrogen generator. On the other hand, when the switch is off, electrons (e ⁻ ) are accumulated in the electron accumulation unit.

Furthermore, protons (H ⁺ ) generated from water (H ₂ O) move to the proton conducting part.
Then, when the switch is on, this proton (H ⁺ ) moves to the hydrogen generator. On the other hand, when the switch is off, protons (H ⁺ ) are accumulated in the proton accumulation unit.

  As a result, the reaction shown in the following formula (1) occurs in the proton generator.

2H ₂ O → O ₂ + 4H ⁺ + 4e ⁻ (1)

In the hydrogen generator, the reaction shown in the following formula (2) occurs, and hydrogen (H ₂ ) is generated.

4H ⁺ + 4e ⁻ → 2H ₂ (2)

As a result, hydrogen (H ₂ ) can be generated by the hydrogen generator.

In the case described later, the contained charge separation material is not used, but it goes without saying that it is included in the scope of the present invention. Specifically, as described above, in the proton generator, visible light-responsive photocatalytic material is irradiated with visible light, electrons (e ⁻ ) are excited, and excited electrons (e ⁻ ) and holes (holes) are generated. Generate.
At this time, for example, when water (H ₂ O), which is an example of a hydrogen source, comes into contact with the visible light responsive photocatalyst, the water (H ₂ O) receives holes and generates oxygen (O ₂ ). .
Moreover, the electrons (e ⁻ ) generated in the visible light responsive photocatalytic material move to the first electrically conductive material. Thereafter, electrons (e ⁻ ) and protons (H ⁺ ) are accumulated according to the flow of electrons (e ⁻ ) and protons (H ⁺ ) in the same manner as described above, and hydrogen (H ₂ ) is generated from the hydrogen generator. To do.

Next, the structure of the proton generator will be described.
As long as the reaction of the above formula (1) proceeds, the proton generator can contain the three components of the first electrically conductive material, the visible light responsive photocatalytic material, and the charge separation material in various modes.

For example, as shown in FIG. 6, it can be composed of a single layer 11 in which a first electrically conductive material, a visible light responsive photocatalytic material, and a charge separation material are mixed and dispersed.
At this time, the three components can be uniformly dispersed. Further, a large amount of the first electrically conductive material can be included on the proton conductive portion side, and a large amount of visible light responsive photocatalytic material can be included on the surface layer side (layer in contact with the hydrogen source).

Further, as shown in FIG. 7, the first layer 12 and the second layer 13 can be sequentially stacked on the proton conducting portion.
In this case, it is preferable that the first layer 12 is made of the first electrically conductive material, and the second layer 13 is made by mixing and dispersing the visible light responsive photocatalytic material and the charge separation material.
Note that one end of the wiring (not shown) is preferably connected to a layer (first layer) in contact with the proton conducting portion.

  Furthermore, as shown in FIG. 8, the first to third layers (12 to 14) may be sequentially stacked on the proton conducting portion.

For example, all of the first to third layers (12 to 14) are composed of a first electrically conductive material, a visible light responsive photocatalytic material, and a charge separation material, and the main component of the first layer 12 is the first electrically conductive material. The main component of the second layer 13 can be a charge separation material, and the main component of the third layer 14 can be a visible light responsive photocatalytic material.
Note that the “main component” is a layer containing three or more components of the first electric conductive material, the visible light responsive photocatalytic material, and the charge separation material as long as it is 1/3 or more of the total content. If so, it means to occupy 1/2 or more of their total content.

  The first layer 12 is made of a first electroconductive material, a visible light responsive photocatalytic material, and a charge separation material, the main component is the first electroconductive material, and the second layer 13 is electrolyzed with the visible light responsive photocatalytic material. It is also possible to make it composed of a separation material, the main component is a charge separation material, the third layer 14 is composed of a visible light responsive photocatalyst material and a charge separation material, and the main component is a visible light responsive photocatalyst material. .

Further, the first layer 12 may be made of a first electrically conductive material, the second layer 13 may be made of a charge separation material, and the third layer 14 may be made of a visible light responsive photocatalytic material.
The charge separation material is placed between the visible light responsive photocatalytic material and the first electrically conductive material so that the visible light responsive photocatalytic material is in contact with the hydrogen source, and the first electrically conductive material is in contact with the proton conducting portion. It is desirable to arrange in such a manner from the viewpoint of hydrogen generation efficiency. From such a viewpoint, in particular, the first layer 12 is made of the first electrically conductive material, the second layer 13 is made of the charge separation material, and the third layer is made. Desirably, 14 comprises a visible light responsive photocatalytic material.

  Here, when manufacturing the single-layer proton generator, for example, a slurry in which the first electrically conductive material, the visible light-responsive photocatalyst material, and the charge separation material are mixed is dried to generate a single-layer proton generator. However, the present invention is not limited to this.

Further, when the proton generation part having the above two-layer structure is produced, it is not particularly limited. For example, the conductive carbon cloth is coated with a slurry of conductive carbon particles or a conductive carbon porous body and dried. Then, a first layer is formed by pressing, and a slurry containing a visible light-responsive photocatalytic material and a charge separation material is applied on the first layer, followed by drying to form a second layer. A generation unit can be obtained.
At this time, the visible light responsive photocatalytic material and the charge separation material can be applied uniformly or non-uniformly.

Furthermore, when producing the proton generation part having the three-layer structure, there is no particular limitation, but after applying each material, drying treatment, press treatment, and heat treatment may be appropriately performed as follows.
For example, a conductive carbon cloth or a conductive carbon porous material slurry is applied to a conductive carbon cloth, dried to form a first layer, a slurry containing a charge separation material is applied thereon, and a second layer is formed. A layer containing a visible light responsive photocatalyst material is applied thereon to form a third layer, and the whole is heated to obtain a proton generation part having a three-layer structure.

  Also, a conductive carbon cloth or conductive carbon porous material slurry is applied to the conductive carbon cloth, dried, pressed to form a first layer, and a slurry containing a charge separation material is applied thereon, A second layer is formed by drying, and a slurry containing a visible light responsive photocatalytic material is applied thereon, dried and heat-treated to form a third layer, and a proton generator having a three-layer structure is formed. Obtainable.

  Furthermore, the conductive carbon cloth is coated with a slurry of conductive carbon particles or a conductive carbon porous body, dried, pressed to form a first layer, and a slurry containing a charge separation material is coated thereon and dried. Then, a second layer is formed, and further, a slurry containing a visible light responsive photocatalytic material is applied thereon and dried to form a third layer, whereby a three-layer structure proton generator can be obtained. .

  In addition, although the said drying process is not specifically limited, For example, it can carry out at 120-200 degreeC and about 1 to 2 hours. Moreover, although the said press process is not specifically limited, For example, it can carry out at about 0.1-40 Mpa. Furthermore, although the said heat processing is not specifically limited, For example, it can carry out at 400-1200 degreeC and about 2 to 20 hours.

Next, the structure of the hydrogen generator will be described.
As long as the reaction of the above formula (2) proceeds, the hydrogen generator can contain two components of the second electrically conductive material and the metal material in various modes.

For example, as shown in FIG. 9, it can be configured from a single layer 31 in which a second electrically conductive material and a metal material are mixed and dispersed.
At this time, the two components can be uniformly dispersed. In addition, a large amount of the second electrically conductive material can be included on the proton conductive portion side, and a large amount of metal material can be included on the back layer side (layer in contact with hydrogen).

Further, as shown in FIG. 10, the first layer 32 and the second layer 33 may be sequentially stacked on the proton conducting portion.
For example, the main component of the first layer 32 can be a second electrically conductive material, and the main component of the second layer 33 can be a metal material.
Note that one end of the wiring (not shown) is preferably connected to a layer (first layer) in contact with the proton conducting portion.

Further, the first layer 32 may be made of a second electrically conductive material, and the second layer 33 may be made of a metal material.
From the viewpoint of hydrogen generation efficiency, it is desirable to dispose the metal material so as to be in contact with the proton conducting portion so that the second electrically conductive material is in contact with the proton conducting portion. Desirably, the second layer 33 is made of a second electrically conductive material, and the second layer 33 is made of a metal material.

  Here, when manufacturing the single-layer hydrogen generation unit, although not particularly limited, for example, by drying the slurry containing the metal material and the second electrical conductive material, the single-layer hydrogen generation unit Can be obtained.

  Further, when producing the two-layered hydrogen generation part, there is no particular limitation. For example, a conductive carbon cloth or a conductive carbon porous material slurry is applied to a conductive carbon cloth and dried. Then, a first layer is formed by pressing, a slurry containing metal fine particles is applied thereon, and dried to form a second layer, and the whole is heat-treated to obtain a two-layer structure hydrogen generator. be able to.

  Furthermore, a conductive carbon cloth or a conductive carbon porous material slurry is applied to a conductive carbon cloth, dried, pressed to form a first layer, and metal fine particles are applied thereon and dried. It is also possible to form a second layer to obtain a hydrogen generation part having a two-layer structure.

  On the other hand, the proton generator, the proton conductor, and the hydrogen generator can be joined by, for example, disposing a proton conductor between the proton generator and the hydrogen generator, and pressing with a press. it can. In this case, for example, it can be performed at about 0.1 to 40 MPa.

Next, components of the proton generator will be described.
As described above, in the present invention, the proton generation unit provided includes the first electrically conductive material, the visible light responsive photocatalyst material, and the charge separation material.

The visible light-responsive photocatalytic material has a function of generating protons (H ⁺ ) from a hydrogen source containing a compound having hydrogen (H) as a constituent element by irradiation with visible light, preferably as a hydrogen source generate water _(H 2 O) from the proton ^{(H +),} but as the oxygen _{(O 2)} is not particularly limited if Sonaere the ability to produce results, for example, five nitride three tantalum _(Ta 3 N ₅ ) Photocatalysts, tantalum oxynitride (TaON) photocatalysts, photocatalysts obtained by doping titanium oxide (TiO ₂ ) with chromium (Cr) and antimony (Sb), and the like.
Furthermore, what contains the compound as described in the following [1]-[6] individually or in mixture can be mentioned.

[1] Tritantalum pentanitride (Ta ₃ N ₅ )
[2] Strontium-titanium oxide (SrTiO ₃ ), silver-tantalum oxide (AgTaO ₃ ), silver-niobium oxide (AgNbO ₃ ), indium-tantalum oxide (InTaO ₄ ), indium-niobium oxide (InNbO ₄ ), metal oxides doped with bismuth-vanadium oxide (BiVO ₄ ), or nitrogen (N), sulfur (S), chromium (Cr) or antimony (Sb), and any combination thereof. [3] ZnS doped with zinc sulfide (ZnS), copper (Cu) and / or nickel (Ni)
[4] Gallium (Ga) oxide, indium (In) oxide, zinc (Zn) oxide, silver (Ag) oxide, sodium (Na) oxide [5] Ga sulfide, In sulfide, Zn sulfide , Ag sulfide, Na sulfide [6] Gallium oxide-indium oxide solid solution (Ga ₂ O ₃ —In ₂ O ₃ )

The visible light responsive photocatalytic material is preferably composed of fine particles having an average diameter of 0.01 to 50 μm.
This is effective because holes generated in the photocatalyst are more likely to react with a hydrogen source (for example, water).

Furthermore, the visible light responsive photocatalytic material includes platinum (Pt), nickel oxide (NiO), ruthenium oxide (Ru ₂ O), iridium oxide (IrO ₂ ), and a promoter associated with any combination thereof. It can be supported. In particular, Pt fine particles can serve as promoters for various photocatalysts.

Typical combinations of the photocatalyst and the cocatalyst include Pt for Ta ₃ N _{5 and} NiO for InTaO ₄ .
In addition, the usage-amount of the said photocatalyst and a co-catalyst can typically be used in the range of 1000: 1-10: 1 by molar ratio. For example, it has been found that the molar ratio of Ta ₃ N ₅ : Pt is currently preferably 100: 1 to 50: 1.

In addition, an ultraviolet light-responsive photocatalyst material can be used together with the visible light-responsive photocatalyst material. For example, titanium oxide (TiO ₂ ), alkali tantalate, alkaline earth tantalate, alkaline niobate, alkaline earth niobate, zinc niobate, and the like can be given.

The charge separation material is preferably a visible light responsive photocatalyst and a photocatalyst having the function of separating and moving electrons (e ⁻ ) and holes (holes) generated in the visible light responsive photocatalyst material. There is no particular limitation as long as it has a function of separating and moving electrons (e ⁻ ) and holes (holes) generated in the charge separation material itself. Examples of those having the functions described below include those containing one or both of fine particles exhibiting plasmon absorption and pigments.
The visible light responsive photocatalytic material at present is limited to a visible light wavelength range of 380 nm to 550 nm, and in particular, a charge separation material exhibiting plasmon absorption is preferable from the viewpoint that the wavelength range of visible light that can be absorbed can be expanded. Since the absorption wavelength of plasmon absorption varies depending on the constituent elements and the size of the fine particles, it can be appropriately selected as necessary.

Examples of the fullerene include C ₆₀ , C ₇₀ , C ₇₆ , C ₇₈ , C ₈₂ , C ₈₄ , C ₉₀ , C _{96, and the} like, and a metal atom is appropriately included in the fullerene. You can also

As the fine particles exhibiting plasmon absorption, for example, one or both of gold (Au) and silver (Ag) can be used.
These can be nano-sized rod-shaped, spherical one or both shapes. In particular, Au nanorods are effective.

  Moreover, as a pigment | dye which shows the said plasmon absorption, the thing concerning a porphyrin compound, its metal complex, a phthalocyanine compound or its metal complex, and these arbitrary combinations can be used, for example.

Further, as described above, a material that exhibits plasmon absorption is preferable as the charge separation material. However, since the above-described fullerene functions effectively as an acceptor of electrons (e ⁻ ), additional fullerene is added to the material that exhibits plasmon absorption. Is desirable.

The first electrical conductive material is not particularly limited as long as it exhibits good electrical conductivity. For example, the conductive carbon particles, the conductive carbon porous body, or the conductive carbon cloth, and any combination thereof can be used. Can be used.
Further, the conductive carbon particles and the conductive carbon porous body have an advantage that they are excellent in electrical conductivity, and are fine particles, so that various materials can be easily carried. Specific examples include carbon black and carbon nanotubes.
On the other hand, as the conductive carbon cloth, one made of a fibrous carbon fiber excellent in conductivity can be suitably used.
Furthermore, the same material as the first electrically conductive material can be used as the second electrically conductive material in the hydrogen generation section described later.
Needless to say, the first electrically conductive material and the second electrically conductive material may be the same or different.

Next, the components of the proton conducting part will be described.
As described above, in the present invention, the proton conducting portion provided is not particularly limited as long as it exhibits almost no electron conductivity and good proton conductivity. For example, either one of a polymer and an oxide is used. Or it is desirable that it is a proton conductive membrane containing both.
For example, it is desirable to use Nafion (registered trademark, manufactured by DuPont) having high proton conductivity. Other polymer proton conducting membranes and proton conducting glasses can also be used. For example, there is phosphate glass which is proton conductive glass.

Next, components of the hydrogen generator will be described.
As described above, in the present invention, the hydrogen generation unit provided includes the second electrically conductive material and the metal material.

As the metal material, for example, Pt, NiO, Ru ₂ O or IrO ₂ and any combination thereof can be used, and Pt is particularly desirable. Further, it is desirable that these shapes are fine particles or tubes.
As the second electrically conductive material, the same material as the first electrically conductive material can be used as described above.

In the present invention, as the light source, a solar light source, a light emitting diode, a semiconductor laser, a lamp capable of emitting visible light equivalent to these, and a combination thereof can be used as appropriate.
In particular, from the viewpoint of excellent energy conversion efficiency, it is desirable to use a light emitting diode that enables light emission in a very narrow visible region.
Moreover, as long as the sun is shining, the sunlight which is not depleted and can be used may be used directly, or may be collected and collected.
Further, visible light may be spectrally separated by a prism.

Furthermore, in the present invention, the hydrogen source containing the compound having hydrogen as a constituent element is not particularly limited. For example, alcohol such as methanol or ethanol can be used as appropriate, but water or a sacrificial reagent can be used. It is particularly desirable to use a containing aqueous solution.
By using water as a hydrogen source, there is an advantage that the problem of exhaust gas can be completely solved.

The sacrificial reagent contained in the sacrificial reagent-containing aqueous solution may be a hydroxide ion (OH ⁻ ), a sulfite ion (SO ₃ ²⁻ ), a sulfide ion (S ²⁻ ), or a silver ion (Ag ⁺ ) in water. And compounds capable of generating ions according to any combination thereof.
When such oxidizable substances are present in the solution, they react with the holes generated when the visible light-responsive photocatalytic material is in an excited state, so that the generated electrons (e ⁻ ) recombine with the holes. And the probability of hydrogen (H ₂ ) is likely to be generated.
Typically, alcohol, potassium sulfite, sodium sulfide, silver nitrate or the like can be used as a sacrificial reagent.

In the present invention, it is desirable that the hydrogen generator is disposed in a light-transmitting casing.
In the hydrogen generator of the present invention, in order to take out the generated hydrogen (H ₂ ) as it is, it is necessary that at least the atmosphere around the hydrogen generator is non-oxidizing, and the proton generator contains It is necessary that the visible light-responsive photocatalytic material can be irradiated with light.
In order to satisfy such requirements, for example, it is desirable to have a structure in which the hydrogen generator itself is disposed in a light-transmitting casing.

Next, the hydrogen generation method of the present invention will be described in detail.
As described above, the hydrogen generation method of the present invention is a hydrogen generation method using the hydrogen generation apparatus of the present invention, and includes a hydrogen source containing a compound having hydrogen (H) as a constituent element and a visible light responsive photocatalytic material. contacting the door, the visible light from the light source is irradiated to the visible light responsive photocatalyst material, a hydrogen source and a proton (H ⁺⁾ electronic (e ^-) to generate the resulting protons (H ⁺⁾ In this method, the amount of hydrogen (H ₂ ) generated is controlled by controlling the flow and the flow of electrons (e ⁻ ).
By such a method, a visible light responsive photocatalyst material is activated by visible light irradiated from a light source, and a hydrogen source containing a compound having hydrogen (H) as a constituent element is brought into contact with the visible light responsive photocatalyst material. Therefore, hydrogen (H ₂ ) can be generated efficiently, or electrons (e ⁻ ) and protons (H ⁺ ) can be accumulated, respectively.
Further, even when light is not irradiated from the light source from the accumulated state, more specifically, hydrogen (H ₂ ) can be generated according to the irradiation amount from the visible light source. .

Next, the hydrogen generation system of the present invention will be described in detail.
As described above, the hydrogen generation system of the present invention is a hydrogen generation system using the hydrogen generation apparatus of the present invention, and the hydrogen generation apparatus and a compound having hydrogen (H) as a constituent element in the hydrogen generation apparatus And a control means for controlling the switch of the hydrogen generator, and the control means controls the switch intermittently.
By adopting such a configuration, it is possible to construct a hydrogen generation system that is very compact and consumes less energy.
Moreover, it becomes easy to mount in mobile bodies, such as a motor vehicle, by setting it as such a compact hydrogen generation system.

As said hydrogen source supply means, a hydrogen source tank, a pressure control valve, a pressure gauge, piping, a cock, etc. can be combined suitably, for example.
The control means is not particularly limited as long as it can control the switch of the hydrogen generator. Specifically, an electronic control device including a 16-bit microcomputer or a conventionally known arithmetic unit is appropriately used. Can be used.

Further, the control means can input the detection data from the photodetector provided in the hydrogen generator and the detection data from the current detector, and further calculate the integrated data of these detection data. It may be.
Furthermore, the control means may store in advance reference data for the detection data from the photodetector, and may also limit the amount of electron storage reference data for the detection data from the current detector and the limit of the electron storage unit. The accumulated amount may be stored in advance. At that time, the control of the hydrogen generator can be appropriately executed based on the limit accumulation amount of the reference data.

The control means may be configured to control the hydrogen source supply means.
Specifically, the supply amount of the hydrogen source supplied by the hydrogen source supply unit may be controlled by the control unit, for example, for opening and closing of a cock provided.

FIG. 11 is a schematic view showing an example of the hydrogen generation system of the present invention.
As shown in the figure, the hydrogen generation system 100 includes a hydrogen generator 1, a hydrogen source supply unit 110, and a control unit 120.
The hydrogen source supply means 110 has a cock (not shown) that stores water, which is an example of a hydrogen source, and sends the water to the hydrogen generator 1, and supplies water to the hydrogen generator 1.
Control means 120 by a photodetector (not shown) visible light irradiation amount from the light source, the necessity of hydrogen (H ₂₎ further generates controls for switches hydrogen generator 1, the hydrogen (H ₂₎ When necessary, the switch is turned on to generate hydrogen (H ₂ ), and when hydrogen (H ₂ ) is not needed, the switch is turned off to provide electrons (e ⁻ ). And protons (H ⁺ ) are stored in the electron storage unit and proton storage unit of the hydrogen generator 1, respectively.

Further, in the present invention, when the control device provided intermittently controls the switch, the control device is based on the data from the photodetector of the hydrogen generator and the integrated calculation data from the current detector of the hydrogen generator. It is desirable to control the switch.
By adopting such a configuration, it is possible not only to construct a hydrogen generation system that is very compact and consumes less energy, but also to improve the efficiency of hydrogen generation.

Further, in the present invention, a hydrogen tank may be provided. In this case, the hydrogen tank provided can be miniaturized, and a hydrogen generation system that is very compact and consumes less energy can be constructed.
Furthermore, for example, when the amount of electrons and protons accumulated in the electron accumulating unit and proton accumulating unit is limited, hydrogen is generated from the electrons and protons and stored in a hydrogen tank to further improve the hydrogen generation efficiency. be able to.
The hydrogen tank to be used is not particularly limited as long as the obtained hydrogen can be pressurized and stored in the hydrogen tank as needed, and a conventionally known hydrogen tank can be used and pressurized. In this case, a conventionally known pump can be used.

Furthermore, in the present invention, a visible light source may be provided. As the visible light source, for example, a light emitting diode, a semiconductor laser, a lamp that can emit visible light equivalent to these, and a combination thereof can be used as appropriate.
For example, when a hydrogen generation system is installed in an automobile, a fuel cell is usually used as another energy device. For example, when a solar light source cannot be used, the electricity generated by the fuel cell using a light-emitting diode is effectively used. Thus, hydrogen can also be generated.
In addition, water recovery means may be provided, and in combination with the fuel cell, specifically, the water discharged from the fuel cell is recovered and reused as a hydrogen source, whereby the hydrogen source tank provided is reduced in size. Or a more compact hydrogen generation system can be constructed.

FIG. 12 is a flowchart showing an example of a control flow of the hydrogen generator of the present invention.
As shown in the figure, in STEP 1 (hereinafter abbreviated as “S1”), the control means determines whether or not hydrogen to be generated is necessary. If it is necessary (YES), the process proceeds to S2.
In S2, it is determined whether or not sunlight is sufficient by the photodetector and the control means. If it is sufficient (YES), the process proceeds to S3.
In S3, water which is a kind of hydrogen source is supplied by the hydrogen source supply means and the control means.
In S4, the control means turns on the switch.
In S5, the hydrogen generator is operated to generate hydrogen.

  If it is not sufficient (NO) in S2, the process proceeds to S4. In S4, when the switch is turned on, when protons and electrons are accumulated in the proton accumulation and electron accumulation units, respectively, the operation of the hydrogen generator can be performed and hydrogen is generated.

If it is not necessary (NO) in S1, the process proceeds to S6.
In S6, it is determined whether the sunlight is sufficient by the photodetector and the control means. If it is sufficient (YES), the process proceeds to S7.
In S7, the switch is turned off by the control means.
In S8, water which is a kind of hydrogen source is supplied by the hydrogen source supply means and the control means.
In S9, electrons and protons are stored in the electron storage unit and proton storage unit, respectively.
In S6, if it is not sufficient (NO), nothing is done.

  Hereinafter, the present invention will be described in more detail with reference to some examples.

Example 1
<Production of proton generator>
Ta ₃ N ₅ as a visible light responsive photocatalytic material, gold nanorods (major axis: 65 ± 16 nm, minor axis: 20 ± 6 nm) as fine particles exhibiting plasmon absorption as a charge separation material, and carbon fiber as a first electric conductive material And carbon black.
A slurry containing a first electrically conductive material is applied to a heat-resistant ceramic substrate and dried to obtain a first layer made of the first electrically conductive material. A slurry containing a charge separation material is applied thereon and dried. To obtain a second layer made of a charge separation material, and apply a slurry containing a visible light responsive photocatalyst material thereon, and then dry to obtain a third layer made of a visible light responsive photocatalyst, and peel them off from the substrate. Thus, a proton generation part having a three-layer structure was obtained.

<Preparation of hydrogen generator>
Pt fine particles were prepared as the metal material, and carbon fiber and carbon black were prepared as the second electrically conductive material.
A slurry containing a second electrically conductive material is applied to a heat-resistant ceramic substrate and dried to obtain a first layer made of the second electrically conductive material. A slurry containing a metal material is applied thereon and dried. A second layer made of a metal material was obtained, and these were peeled off from the substrate to obtain a two-layer structure hydrogen generator.

<Production of electron storage unit>
WO ₃ was prepared as an electron storage material, and polycarbonate was prepared as an insulating polymer. The electron storage material was covered with an insulating polymer to obtain an electron storage portion.

<Production of proton accumulation part>
A plastic membrane made of Nafion (registered trademark, manufactured by DuPont) as a proton storage material and polycarbonate as a proton outflow prevention material was prepared. The proton storage material was covered with a plastic membrane to obtain a proton storage part.

<Construction of hydrogen generator>
The proton generation unit, the hydrogen generation unit, the electron storage unit, the proton storage unit, the proton conduction unit, a Nafion film, the wiring as a copper wire, the photodetector as a photodiode, a switch, a current detector, a light-transmitting casing A colorless and transparent glass container was prepared.
The proton conducting unit 20 was held between the proton generating unit 10 and the hydrogen generating unit 30, and these were put in a mold, pressed, and pressure bonded. Further, the proton conducting unit 20 and the proton accumulating unit 40 are joined, the first layer 12 of the proton generating unit 10 and a current detector (not shown) are connected by wiring (not shown), and the current detection is performed. The storage unit and the electron storage unit (not shown) are connected by wiring (not shown), the electron storage unit and the switch (not shown) are connected by wiring, and the switch and the hydrogen generation unit 30 are further connected. The first layer 32 was connected by wiring and housed in a light-transmitting casing 90 as shown in FIG. 13 to construct the hydrogen generator of this example.
FIG. 13 is a schematic configuration diagram of the hydrogen generator according to the first embodiment. Although not shown, the current detector, the electron storage unit, and the switch are housed in the light transmissive casing 90. Although not shown, the photodetector is also arranged so that the visible light irradiation amount in the proton generator 10 can be measured.

(Example 2)
<Production of proton generator>
A slurry containing a first electrically conductive material, a charge separation material and a visible light responsive photocatalyst material is applied to a heat resistant ceramic substrate, and dried to dry the first electrically conductive material, the charge separation material and the visible light responsive photocatalyst material. A monolayer having a uniform distribution was obtained, and this was peeled from the substrate to obtain a proton generation part having a single layer structure.

<Preparation of hydrogen generator>
A slurry containing a second electrically conductive material and a metal material is applied to a heat resistant ceramic substrate, and dried to obtain a single layer of uniform distribution composed of the second electrically conductive material and the metal material. A hydrogen generation part having a single layer structure was obtained.

<Construction of hydrogen generator>
The same configuration as in Example 1 except that a single-layer proton generator is used instead of the three-layer proton generator, and a single-layer hydrogen generator is used instead of the two-layer hydrogen generator. The hydrogen generator of this example was constructed.

(Example 3)
<Production of proton generator>
Fullerene (C ₆₀ ) was added to gold nanorods (major axis: 65 ± 16 nm, minor axis: 20 ± 6 nm), which are fine particles exhibiting plasmon absorption prepared as a charge separation material, to produce a fullerene-containing charge separation material.
Except for using the fullerene-containing charge separation material, the same operation as in the production of the proton generator of Example 1 was repeated to obtain a proton generator.

<Construction of hydrogen generator>
A hydrogen generator of this example was constructed by adopting the same configuration as in Example 1 except that a proton generator having a three-layer structure manufactured using the fullerene-containing charge separation material was used.

Example 4
<Production of proton accumulation part>
Except for using proton conductive glass as the proton storage material, the same operation as in the production of the proton storage section in Example 1 was repeated to obtain a proton storage section.

<Construction of hydrogen generator>
A hydrogen generator of this example was constructed by adopting the same configuration as that of Example 1 except that the proton accumulating part produced using the proton conductive glass was used.

(Example 5)
<Production of proton generator>
Except for using zinc porphyrin as the charge separation material, the same operation as in the production of the proton generator in Example 1 was repeated to obtain a proton generator.

<Construction of hydrogen generator>
A hydrogen generator of this example was constructed by adopting the same configuration as in Example 1 except that the proton generator produced using the zinc porphyrin was used.

(Example 6)
<Production of electron storage unit>
Except for using iron (Fe) as the electron storage material, the same operation as in the production of the electron storage unit in Example 1 was repeated to obtain an electron storage unit.

<Construction of hydrogen generator>
A hydrogen generator of this example was constructed by adopting the same configuration as in Example 1 except that the electron accumulating part produced using Fe was used.

[Performance evaluation 1]
Using the hydrogen generators of the above examples (see FIG. 1), water was circulated through a flow path formed in the housing, and sunlight was used as a light source for performance evaluation.
(Evaluation conditions)
・ Light source: Solar light source ・ Hydrogen source: Water ・ Accumulation time: 1 hour

As a result of the performance evaluation, the hydrogen generator of Example 1 was able to generate hydrogen even when it was not irradiated with sunlight.
In Example 2, the amount of hydrogen generated per unit time was smaller than that in Example 1.
Furthermore, in Example 3, the amount of hydrogen generated per unit time was larger than that in Example 1.
Further, in Example 4, the amount of hydrogen generated per unit time was equivalent to that in Example 1.
Furthermore, in Examples 5 and 6, the amount of hydrogen generated per unit time was equivalent to that in Example 1.

(Example 7)
FIG. 14 is a schematic diagram showing an example of an automobile hydrogen generation system.
As shown in the figure, an automobile hydrogen generation system was constructed using the hydrogen generation apparatus constructed in Example 1.

Specifically, in the automobile hydrogen generation system 200, the hydrogen generator 1 is mounted on the roof 210 of the automobile.
As a hydrogen source supply means for supplying a hydrogen source containing a compound having hydrogen as a constituent element, a cock (not shown) for flowing water that has entered the hydrogen source tank 220 attached to the roof 210 into the hydrogen generator 1. ) And a pipe (not shown) connecting the hydrogen source tank 220 and the hydrogen generator 1. A pump (not shown) was provided in the middle of the pipe.
A 16-bit microcomputer or the like was used as a control means for controlling the switch and the like of the hydrogen generator 1 and was built inside the vehicle body.
In the automobile hydrogen generation system 200, the obtained hydrogen is returned to the hydrogen tank (not shown).

Although the present invention has been described in detail with some preferred embodiments, the present invention is not limited to these embodiments, and various modifications are possible within the scope of the gist of the present invention.
For example, it can be incorporated in a paint film or window glass painted on the outer plate of the vehicle.

It is the schematic which shows an example of the hydrogen generator of this invention. It is explanatory drawing which shows schematic cross-sectional shape of an example of an electronic storage part. It is explanatory drawing which shows typically the electronic state and the flow of an electron (e < ^- >) in the hydrogen generator of this invention. It is a graph which shows an example of the absorption spectrum of a visible light responsive photocatalyst material and a charge separation material. It is explanatory drawing which shows an example of the electronic state and electron flow in the proton production | generation part containing a visible light responsive photocatalyst material and a charge separation material. It is the schematic which shows an example of the structure of a proton production | generation part. It is the schematic which shows the other example of the structure of a proton production | generation part. It is the schematic which shows the further another example of the structure of a proton production | generation part. It is the schematic which shows an example of the structure of a hydrogen production | generation part. It is the schematic which shows the other example of the structure of a hydrogen production | generation part. It is the schematic which shows an example of the hydrogen generation system of this invention. It is a flowchart which shows an example of the control flow of the hydrogen generator of this invention. 1 is a schematic configuration diagram of a hydrogen generator of Example 1. FIG. It is the schematic which shows an example of the hydrogen generation system for motor vehicles.

Explanation of symbols

1 nanorods hydrogen generator 10 protons generating unit 11 monolayers 12 first layer 13 gold second layer 13a 14 third layer 14a Ta ₃ N ₅
DESCRIPTION OF SYMBOLS 20 Proton conduction part 30 Hydrogen production | generation part 31 Single layer 32 1st layer 33 2nd layer 40 Electron storage part 42 Electron storage material 44 Insulating material 50 Proton storage part 52 Proton storage material 54 Proton outflow prevention material 60 Switch 70 Current detector 80 Photodetector 90 Light transmissive casing 100 Hydrogen generation system 110 Hydrogen source supply means 120 Control means 200 Automotive hydrogen generation system 210 Roof 220 Hydrogen source tank

Claims (26)

An apparatus for generating hydrogen from a hydrogen source containing a compound having hydrogen as a constituent element using visible light emitted from a light source,
A proton generation unit, a proton conduction unit, a hydrogen generation unit, an electron storage unit, a proton storage unit, and a switch;
The proton conducting part is sandwiched between the proton generating part and the hydrogen generating part,
The proton conducting part is joined to the proton accumulating part,
The proton generation unit and the hydrogen generation unit are connected in this order from the proton generation unit side to the electron storage unit and the switch that can electrically connect the proton generation unit and the hydrogen generation unit. Connected,
The proton generator includes a first electrically conductive material, a visible light responsive photocatalytic material, and a charge separation material,
The hydrogen generator includes the second electrically conductive material and a metal material.   The hydrogen generator according to claim 1, further comprising a current detector between the proton generator and the electron storage unit.   The hydrogen generator according to claim 1, further comprising a photodetector. The electron accumulating portion comprises at least one electron accumulating material selected from the group consisting of polymers, metals and metal oxides, and an insulating material;
The hydrogen generating apparatus according to claim 1, wherein the electron storage material has a structure covered with the insulating material.   The hydrogen generator according to claim 4, wherein the metal oxide is tungsten trioxide. The proton accumulating portion comprises at least one proton accumulating material selected from the group consisting of a solid polymer, glass and a metal oxide, and a proton outflow prevention material;
The hydrogen generation apparatus according to claim 1, wherein the proton storage material has a structure covered with the proton outflow prevention material.   The hydrogen generator according to claim 6, wherein the solid polymer is a proton conducting membrane.   The hydrogen generator according to claim 6 or 7, wherein the glass is proton conductive glass.   The hydrogen generator according to any one of claims 6 to 8, wherein the metal oxide is tungsten trioxide.   The said visible light responsive photocatalyst material has a function which produces | generates a proton from the hydrogen source containing the compound which has hydrogen as a structural element by irradiation of visible light, The claim | item 1 characterized by the above-mentioned. The hydrogen generator described in 1.   2. The charge separation material has a function of separating and moving electrons and holes generated in the visible light responsive photocatalyst material or the visible light responsive photocatalyst material and the charge separation material itself. 10. The hydrogen generator according to any one of items 10 to 10.   The hydrogen generation apparatus according to any one of claims 1 to 11, wherein the charge separation material contains fine particles and / or a pigment exhibiting plasmon absorption.   13. The hydrogen generator according to claim 12, wherein the fine particles exhibiting plasmon absorption are gold and / or silver, and are nano-sized rod-shaped and / or spherical.   13. The hydrogen generator according to claim 12, wherein the dye exhibiting plasmon absorption is at least one selected from the group consisting of a porphyrin compound, a metal complex thereof, a phthalocyanine compound, and a metal complex thereof.   The hydrogen generator according to claim 1, wherein the charge separation material contains fullerene.   The first electric conductive material and / or the second electric conductive material is at least one selected from the group consisting of conductive carbon particles, a conductive carbon porous body, and a conductive carbon cloth. The hydrogen generator according to any one of claims 1 to 15.   The hydrogen generator according to claim 1, wherein the proton conducting part is a proton conducting membrane containing a polymer and / or an oxide.   The hydrogen generation apparatus according to claim 1, wherein the metal material is platinum.   19. The light source according to claim 1, wherein the light source is at least one selected from the group consisting of a solar light source, a light-emitting diode, a semiconductor laser, and a lamp capable of emitting visible light equivalent thereto. The hydrogen generator according to any one item.   The hydrogen generation apparatus according to any one of claims 1 to 19, wherein the hydrogen source containing a compound having hydrogen as a constituent element is water or an aqueous solution containing a sacrificial reagent.   21. The hydrogen generator according to any one of claims 1 to 20, wherein the hydrogen generator is disposed in a light-transmitting casing. A hydrogen generation method using the hydrogen generator according to any one of claims 1 to 21,
A hydrogen source containing a compound having hydrogen as a constituent element is brought into contact with a visible light responsive photocatalytic material, and the visible light responsive photocatalytic material is irradiated with visible light from a light source to generate protons and electrons from the hydrogen source. A hydrogen generation method characterized by controlling the amount of generated hydrogen by controlling the flow of protons and the flow of electrons obtained. A hydrogen generation system using the hydrogen generator according to any one of claims 1 to 21,
A hydrogen source supply means for supplying a hydrogen source containing a compound having hydrogen as a constituent element to the hydrogen generator, and a control means for controlling a switch of the hydrogen generator,
The hydrogen generation system, wherein the control means intermittently controls the switch.   When the control device intermittently controls the switch, the switch is controlled based on data from the photodetector of the hydrogen generator and integrated calculation data from the current detector of the hydrogen generator. The hydrogen generation system according to claim 23.   The hydrogen generation system according to claim 23, further comprising a hydrogen tank.   A visible light source is provided, and the light source is at least one selected from the group consisting of a light emitting diode, a semiconductor laser, and a lamp capable of emitting visible light equivalent thereto. The hydrogen generation system according to any one of the items.

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