JP2005350293A - Hydrogen forming unit and hydrogen generating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen forming unit with which the generation efficiency of H<SB>2</SB>and O<SB>2</SB>can be enhanced, and the conversion efficiency of CO to CO<SB>2</SB>can be improved, so as to reduce the discharge amount of CO; and to provide a hydrogen generating device which has a simplified compact constitution and can be manufactured at a low cost. <P>SOLUTION: In the hydrogen forming unit, hollow cavity parts 6 through which CO and H<SB>2</SB>O are allowed to flow are formed. The hydrogen forming unit has at least a structure body 7 formed from a transparent material and photocatalyst parts 10 each arranged in each cavity part 6 of the structure body 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a technology for generating hydrogen gas, which is a fuel gas supplied to a fuel cell mounted on a moving body such as an automobile, and is, for example, a fuel reformer for reforming fuel such as methanol, ethanol, gasoline, etc. The present invention relates to a hydrogen generation unit and a hydrogen generator installed on the downstream side.

  In recent years, hydrogen has been used in large quantities as a raw material for petroleum refining and fuel for fuel cells. In particular, fuel cells use hydrogen and oxygen as fuel and are clean power generation methods that do not generate exhaust gas during power generation. Therefore, they are attracting attention from the viewpoint of environmental protection, and various hydrogen production technologies have been researched and developed. .

  For example, a cathode and an anode which are electrically connected to each other in a solution containing a predetermined aqueous solution are immersed in the solution, and a p-type semiconductor of a solar cell having a p-type semiconductor and a pn junction of an n-type semiconductor as the anode A hydrogen generation apparatus is disclosed in which a photocatalyst layer that excites electron and hole pairs by light irradiation is formed on the surface of the layer (see Patent Document 1). According to the present hydrogen generator, hydrogen gas can be generated from the cathode surface by irradiating the anode with light energy.

  Also disclosed is a method of generating hydrogen by reacting Mg alloy powder and water (see Patent Document 2). For example, as an Mg alloy powder, an aggregate of Mg alloy particles comprising granular Mg and a plurality of catalytic metal fine particles (Ni fine particles, Fe fine particles, V fine particles, Ti fine particles, etc.) present on and inside the granular Mg. The thing which performed the hydrogenation process is used.

Further, for example, the complex metal hydride is heated in the presence of the lithium-containing composite oxide, and the complex metal hydride (LiAlH ₄ , NaAlH ₄ , LiBH ₄ , NaBH ₄ , KAlH ₄ , KBH ₄ , Mg (BH ₄ ) ₂ , Ca (BH ₄ ) ₂ , Ba (BH ₄ ) ₂ , Sr (BH ₄ ) _2, Fe (BH ₄ ) _2, etc.) have been disclosed to generate hydrogen (for example, (See Patent Document 3).

  Further, a method is disclosed in which a methanol reforming catalyst in which platinum and palladium are supported on a porous alumina film by hot water treatment and hydrogen is extracted from methanol using the methanol reforming catalyst (for example, Patent Document 4). reference).

  Furthermore, as a configuration in which a fuel reforming unit, a CO conversion unit, and a CO removal unit are connected, a method of generating hydrogen using a catalyst in each of these units is also disclosed (see, for example, Patent Document 5).

Also, hydrogen production that efficiently decomposes hydrocarbons, alcohols such as methanol and nitrogen-free hydrogen-containing compounds such as water under mild conditions using low-temperature plasma (non-equilibrium plasma) A method is also disclosed (for example, see Patent Document 6).
JP 2003-238104 A JP 2003-212501 A JP 2002-234701 A Japanese Patent Laid-Open No. 5-15778 JP 2001-180905 A JP 2002-338203 A

  However, the technology described in Patent Document 1 has poor hydrogen generation efficiency, and the technology described in Patent Document 2 also has a slow reaction rate for generating hydrogen, so that the amount of generated hydrogen is small and it is mounted on a moving body such as an automobile. It has been difficult to use as a method and apparatus for generating hydrogen gas to be supplied to a fuel cell.

  Further, in the hydrogen generation method described in Patent Document 3, since metal is generated as a residue, a device for recovering the metal or the like is separately required, and the hydrogen generation method is applied to a moving body that is required to be light and compact. It was difficult.

Furthermore, in the technique described in Patent Document 4, not only an expensive noble metal catalyst is used, but the temperature of the reaction field is set to 400 ° C. or higher in order to cause a catalytic action. In a fuel cell vehicle, it is disadvantageous in terms of energy efficiency to generate a high temperature of 400 ° C. or more, and a reactor containing a multi-stage catalyst is required to convert CO ₂ generated in large quantities into CO ₂ . .

Similarly to Patent Document 4, in the technique described in Patent Document 5, an expensive metal catalyst is used in each part, and from a CO conversion part and a CO removal part for converting CO generated in large quantities as an intermediate reaction into CO _2. There was a need for a reactor comprising a multi-stage catalyst.

Furthermore, in the technique described in Patent Document 6, the reaction selectivity and conversion efficiency when producing hydrogen are poor, and a large amount of energy is consumed. In addition, the conversion efficiency from CO to CO ₂ is poor, and a reaction device including a multi-stage catalyst is required to convert CO to CO _2, and a large and heavy reaction device is required separately. It was difficult to use it mounted on a moving body.

The present invention has been made to solve the above problems, that is, the hydrogen generation unit of the present invention forms a hollow cavity that allows CO and H ₂ O to flow inside, and is made of a transparent material. The gist is to include at least a structure to be configured and a photocatalyst portion disposed in the cavity of the structure.

The hydrogen generator of the present invention is composed of a transparent material, which includes a gas supply means for supplying a gas containing at least CO and H ₂ O, and a hollow cavity for flowing CO and H ₂ O therein. And at least a photocatalyst portion disposed in the cavity of the structure, the photocatalytic action oxidizes CO supplied from the gas supply means and decomposes H ₂ O supplied from the gas supply means. It is provided with a hydrogen generation unit that generates H ₂ , a light irradiation unit that irradiates light to the hydrogen generation unit, and a gas discharge unit that discharges a gas containing CO ₂ and H ₂ generated by the hydrogen generation unit. And

According to the hydrogen generation unit of the present invention, the photocatalyst portion is formed in the cavity, and the photocatalyst portion is evenly irradiated with light to promote water decomposition, so that the generation efficiency of H ₂ and O ₂ is increased, and CO to CO _The efficiency of conversion to ₂ can be improved and CO emissions can be reduced.

  According to the hydrogen generator of the present invention, not only can the apparatus configuration be simplified and compact, but also the degree of freedom in material selection can be increased, and the cost can be reduced.

  Hereinafter, a hydrogen generation unit and a hydrogen generation apparatus using the hydrogen generation unit according to embodiments of the present invention will be described with reference to the first embodiment and the second embodiment.

1st Embodiment (FIGS. 1-4)
In the first embodiment, an example in which the hydrogen generator according to the embodiment of the present invention is installed on the downstream side of the fuel reformer and CO reformed by the fuel reformer is used as a fuel is shown in FIG. A description will be given with reference to FIGS.

FIG. 1 is a schematic diagram showing a configuration of a hydrogen generator according to an embodiment of the present invention. In the hydrogen generator, H ₂ and CO ₂ are generated from CO and H ₂ O supplied from the outside. As shown in FIG. 1, the hydrogen generator 1 includes a gas supply means 2 that supplies a gas containing at least CO and H ₂ O, and CO that is supplied from the gas supply means 2 by photocatalysis and oxidizes the gas. A hydrogen generation unit 3 that decomposes H ₂ O supplied from the supply unit 2 to generate H ₂ , a light irradiation unit 4 that irradiates light to the hydrogen generation unit 3, CO ₂ generated by the hydrogen generation unit 3, and Gas discharge means 5 for discharging a gas containing H ₂ .

The gas supply means 2 includes, for example, a water supply pipe and a fuel gas supply pipe that supplies a fuel gas such as CO. The water supply pipe and the fuel gas supply pipe are connected to a reformer (not shown) installed on the upstream side of the hydrogen generator 1. CO is a gas exhausted from the reformer or the like, and H ₂ O is a gas supplied from the outside on the reformer or the downstream side of the reformer.

  The light irradiation means 4 preferably uses sunlight or an artificial light source. The artificial light source is preferably a light source that emits light in at least one wavelength region of the ultraviolet region, the visible region, and the infrared region. For example, a lamp or a laser can be used as the artificial light source. As an artificial light source lamp, a halogen lamp, a mercury lamp, a metal halide lamp, a xenon lamp, or an LED lamp can be used. As the laser that is an artificial light source, it is preferable to use a continuously oscillating laser light source such as a solid-state laser, a semiconductor laser, a metal laser, a rare gas halide / excimer laser, or a pulsed laser. In particular, it is preferable to use a semiconductor laser in order to increase quantum efficiency.

  Furthermore, when an artificial light source is actually installed, the artificial light source is embedded in a structure such as aluminum or iron that forms the skeleton of the hydrogen generator 1 that encloses the hydrogen generation unit 3 and is in contact with the hydrogen generation unit 3. Arranged. When the hydrogen generation unit 3 is embedded in the structure of the hydrogen generator 1, it is necessary to install a power source for an artificial light source outside the hydrogen generator 1. Further, when an artificial light source is disposed outside the hydrogen generator 1, the light that is connected to the structure of the hydrogen generator 1 through a waveguide through which light passes and the light that has passed through the waveguide is transmitted to the hydrogen generation unit 3. It is preferable that the waveguide is embedded in the structure so that light is emitted from a certain direction or from the whole.

  In addition, it is possible to effectively use the light radiated to the hydrogen generation unit 3 in the hydrogen generator 1. From the viewpoint of easy incorporation of the hydrogen generation unit 3 into the hydrogen generator 1, a semiconductor laser is used as the light irradiation means 2. It is preferable to use a surface emitting laser.

  The light from the semiconductor laser installed in the hydrogen generator 1 only needs to be able to irradiate the hydrogen generation unit 3 evenly. For this reason, when light can be irradiated to the whole hydrogen generation unit 3, light may be irradiated from a part of the surface direction inside the hydrogen generation unit 3. However, when light is irradiated from a part of the surface direction inside the hydrogen generation unit 3 and the light is not sufficiently irradiated, it is necessary to irradiate the hydrogen generation unit 3 from many directions.

The wavelength of light used in the light irradiation means 4 is preferably in the range of 100 nm ≦ light wavelength ≦ 1000 nm. The reason why the wavelength of light is defined in the above range is that when the wavelength of light is less than 100 nm, the energy consumed to generate CO ₂ and H ₂ from CO and H ₂ O becomes excessive and energy efficiency deteriorates. This is because if the wavelength exceeds 1000 nm, the light energy is small, the photocatalytic action does not function, and water cannot be decomposed.

The hydrogen generation unit 3 is an apparatus that oxidizes CO by photocatalysis and decomposes H ₂ O to generate H ₂ . An enlarged view of the hydrogen generation unit 3 is shown in FIG. As shown in FIG. 2, the hydrogen generation unit 3 includes a hollow body 6 in which CO and H ₂ O are flowed, and a structure 7 made of a transparent material. A photocatalyst portion (not shown) disposed in the hollow portion 6. In FIG. 2, the light irradiation means 4 includes a xenon lamp 8 and an optical fiber 9 connected to the xenon lamp 8. The light from the xenon lamp 8 is guided by the optical fiber 9 and irradiated to the hydrogen generation unit 3 through a waveguide (not shown) installed in the hydrogen generator 1.

The structure of the structure 7 in the hydrogen generation unit 3 is shown in FIGS. (a) is a cross-sectional view in the flow direction of CO and H ₂ O flowing in the cavity 6 formed in the structure 7, and (b) is a diagram of CO and CO flowing in the cavity 6 formed in the structure 7. it is a cross-sectional view in the flow direction and the vertical direction of H ₂ O. As shown in FIGS. 3 (a) and 3 (b), a plurality of cylindrical cavities 6 are formed at equal intervals in the structure 7 made of silica glass.

  The size of the cavity 6 in the hydrogen generating unit 3 is preferably in the range of 0.01 μm to 10 μm, for example, when the columnar cavity 6 is used. If the diameter of the cavity 6 is less than 0.01 μm, the cavity 6 may be clogged by impurities contained in the gas. Conversely, if the diameter of the cavity 6 exceeds 10 μm, the cavity per unit cross-sectional area This is because the number of 6 is insufficient, the amount of photocatalyst involved in the reaction is reduced, and the reaction is not promoted. In addition, it is desirable that the cavities 6 are densely arranged within a range in which the mechanical strength of the structure 7 can be maintained.

Furthermore, the structure of the photocatalyst part installed in the cavity part 6 shown in FIG. 2 is shown in FIG. As shown in FIG. 4, the photocatalyst unit 10 is made of a material in which metal fine particles 12 are supported on photocatalyst fine particles 11. The metal fine particles 12 function as a co-catalyst for the photocatalytic fine particles 11 and have a role of generating CO ₂ by adsorbing CO molecules and reacting with oxygen. The photocatalyst portion 10 is formed in the cavity portion 6. Specifically, in the cavity portion 6 of the structure 7, a thin film is formed on the inner wall of the cavity portion 6 from a material containing photocatalyst fine particles and metal fine particles. Alternatively, it is preferable that the catalyst particle material is inserted.

  In the present embodiment, the hollow cavity 6 shown in FIG. 2 is configured in a columnar shape, but is not limited to a columnar shape, and the hollow cavity 6 may be configured in a polygonal column.

  In the present embodiment, an example in which a reforming catalyst device is installed on the upstream side of the hydrogen generator 1 is described. However, the type of the reforming device is not limited, and a chemical plant device, an internal combustion engine, or the like is connected to a hydrogen generator. It can also be installed upstream of the generator 1. The reforming catalyst device is a device that generates hydrogen from fuel gas such as gasoline, methanol, ethanol or dimethyl ether, which mainly consists of hydrogen, oxygen and carbon, and water, and uses a metal catalyst that generates a large amount of CO as a byproduct. ing. In addition, a reforming catalyst device that generates hydrogen using plasma can be used. This reforming catalyst device has an electrode pair structure that generates at least one selected from arc discharge, glow discharge, barrier discharge, corona discharge, pulse streamer discharge, and creeping discharge, and a large amount of CO as a byproduct. It is a device that generates and emits CO.

  The constituent materials of the hydrogen generation unit 3 in the hydrogen generator 1 will be described.

  The structure 7 is preferably made of at least one transparent material selected from silica glass, titania, zinc oxide and alumina. In the present embodiment, silica glass is used as a constituent material of the structure 7, but silica glass is particularly preferable among the exemplified materials. The reason for this is that, as will be described later, a method for forming a hollow cavity 6 in the structure 7 has been established, mass production is becoming possible, and the wavelength of light that activates a usable photocatalyst. This is because it is almost transparent in the region (near ultraviolet region, visible region, far infrared region). That is, silica glass transmits almost 100% at a wavelength of 360 nm-2.25 μm, 85% at a wavelength of 340 nm, 70% at a wavelength of 320 nm, and 23% at 300 nm.

The photocatalyst fine particles are titania (TiO ₂ ), titania doped with nitrogen or sulfur, SrTiO ₃ , ZrO ₂ , Ta ₂ O ₅ , K ₄ Nb ₆ O ₁₇ , Na ₂ Ti ₆ O ₁₃ , K ₂ Ti ₆ O It is preferable to use fine particles formed of at least one material selected from ₁₃ and BaTi ₄ O ₉ .

  The metal fine particles are preferably 3d transition metal elements, metal oxides containing 4d transition metal elements, or Pt fine particles and Pt fine particles. This is due to the following reason. When light strikes, electrons are excited from the valence band in the photocatalyst fine particles to the conduction band. The excited electrons are moved to the metal fine particles, and water is reduced using the electrons to generate hydrogen. Therefore, it is particularly desirable to use fine particles made of Ni oxide, Ru oxide, and Pt element that easily emit electrons.

  The hydrogen generation unit 3 can be manufactured using a femtosecond laser technique and an etching technique or a material self-organization technique in order to form a cylindrical or polygonal hollow portion 6 in the structure 7.

[Method for producing hydrogen generation unit]
Hereinafter, the manufacturing method of the hydrogen generation unit 3 will be specifically described.

  First, in order to form the hollow cavities 6 arranged in an array in the silica glass structure 7, the femtosecond laser is used to form an interval of 5 μm on the silica glass surface and the light irradiation diameter is 2 μm. Repeat the irradiation.

Since the femtosecond laser can obtain a high energy density reaching 1 TW (10 ¹² W) / cm ² , high-density electrons can be excited in a short time when the material is irradiated with high energy density light. The energy of the excited electrons is converted to vibration energy of ions in the material within 1 nanosecond, but when the vibration energy density exceeds a predetermined threshold, the ions are detached from the material and the material is ablated, and the internal energy of the material is increased. A small hole is formed by ablation. Note that when the high energy density light is controlled during the formation of the holes, the structure of the atomic arrangement can be changed without destroying the material.

  In addition, in silica glass, there is a difference in the etching rate with respect to the hydrogen fluoride solution between the portion where the atomic arrangement has changed and the portion where the atomic arrangement does not change, and in particular, the portion where the atomic arrangement has changed is very easily etched. . For this reason, the cavity 6 is formed by etching a portion selectively irradiated with light using the difference in etching rate. By using this method, a transparent structure 7 in which hollow cavities 6 are finally formed in a large number of arrays is formed.

  Next, a method for forming a thin film as the photocatalyst portion 10 on the inner wall of the hollow portion 6 of the structure 7 will be described.

  For example, when the structure 7 is made of silica glass, a catalyst containing metal fine particles and photocatalyst fine particles is formed when a thin film is formed by pouring a liquid containing tetraethoxysilane on the inner wall of the cavity 6. A particulate material (for example, titania fine particle material with a Pt promoter) is poured into the cavity 6, and after the catalyst particle material is adhered, it is dried to form a thin film on the inner wall surface of the cavity 6. The thin film as the catalyst portion 10 may be formed by sputtering vapor deposition of a photocatalyst particle material and a metal fine particle material on the inner wall of the cavity portion 6.

  The thin film on the inner wall of the cavity 6 is not limited to the titania fine particle material with Pt promoter. For example, a titania nanotube with a Pt promoter having an inner diameter of 5 nm, an outer diameter of 8 nm, and a length of 100 nm is contained in the cavity 6. The hydrogen generation unit 3 can also be configured.

Titania (TiO ₂ ), which forms nanotubes, is an n-type semiconductor, and when excited with light having a wavelength equal to or greater than the band gap (forbidden band width) of the semiconductor, electron-hole pairs are generated inside the semiconductor. The When electrons and holes are extracted from the surface and reacted with water, a redox reaction proceeds to generate hydrogen and oxygen. Since the forbidden band of titania is 3 eV, the reaction occurs with light having a wavelength shorter than 415 nm.

In addition, titania does not exhibit its photocatalytic action effectively unless it is irradiated with light in the ultraviolet region. However, titania doped with nitrogen or sulfur has a photocatalytic action even in the blue region. For this reason, titania doped with nitrogen or sulfur is advantageous from the standpoint of energy efficiency as compared with a single titania. In particular, titania nanotubes having nano-level cavities have a large specific surface area and superior photocatalytic action as compared to spherical titania. When the titania nanotube is inserted into the cavity 6 to constitute the hydrogen generation unit 3, the conversion efficiency from CO to CO ₂ and the hydrogen generation efficiency are dramatically improved.

  Moreover, the said titania nanotube can be manufactured using the following manufacturing methods.

First, a solution in which a metal alkoxide such as titanium isopropoxide (Ti (OiC ₃ H ₇ ) ₄ ) and an alcohol such as isopropyl alcohol (IPA) are mixed is prepared, and after adding nitric acid to the prepared solution, Hydrolysis is performed by adding water, and TiO ₂ (crystal) is produced using a sol-gel method.

Next, the prepared TiO ₂ is put into a 10M KOH aqueous solution and subjected to alkali treatment at 100 ° C. for 15 hours. A TiO ₂ alkali aqueous solution is neutralized with a dilute hydrochloric acid (HCl) aqueous solution and pure water to form titania nanotubes. Titania nanotubes are put into alcohol mixed with Pt ultrafine particles, dried, and fired to obtain titania nanotubes containing Pt ultrafine particles.

  Hereinafter, the processing reaction of the hydrogen generator 1 installed on the downstream side of the fuel reformer will be described.

The reforming catalyst device installed upstream of the hydrogen generator 1 takes in methanol (CH ₃ OH) and water (H ₂ 0) that is about three times as much as methanol and mixes it with CH ₃ OH and H ₂ 0. The gas is heated with a heater to a high temperature of 350 ° C., and the reaction proceeds with a Cu—Zn catalyst to produce H ₂ . As a whole, the chemical reaction shown in Formula 1 is advanced to produce H ₂ .

CH ₃ OH + H ₂ 0 → CO ₂ + 3H ₂ (Formula 1)
More specifically, in the reforming catalyst device, CH ₃ OH and H ₂ 0 are introduced into a honeycomb structure having a Ni catalyst on _the surface via a water supply pipe and a fuel gas supply pipe. In the honeycomb structure, the reaction shown in Formula 1 proceeds to some extent, and CO ₂ and H ₂ are generated from CH ₃ OH and H ₂ 0. However, the reaction is stopped by the reaction shown in Formula 2, and CO and H ₂ are produced from CH ₃ OH, and the amount of CO generated becomes extremely high.

CH ₃ OH → CO + 2H ₂ (Formula 2)
For example, when the reforming catalyst device is used as a fuel supply source for a fuel cell, CO adversely affects the fuel cell electrode, so the selectivity of the reaction shown in Equation 3 is increased and the amount of CO generated is reduced. There is a need to.

CO + H ₂ O → CO ₂ + H ₂ (Formula 3)
Therefore, the hydrogen generating apparatus 1 installed in the downstream side after the reforming catalyst device, and CO exhausted from the reforming catalyst device, H ₂ captured either remain unreacted in the reforming catalyst device, or again from the outside O is introduced into the cavity 6 in the hydrogen generation unit 3. Then, the metal fine particles arranged in the cavity 6 adsorb CO and H ₂ O flowing in the cavity and then release H ₂ , and the photocatalyst fine particles release O ₂ . At this time, the CO adsorbed on the metal fine particles is oxidized by O ₂ released from the photocatalyst fine particles to become CO ₂ , and CO ₂ and H ₂ are generated by the reaction shown in Formula 3.

According to the present embodiment, CO is oxidized into CO ₂ in the hydrogen generator, and the CO concentration can be suppressed to about 0.05%. As a result, CO emissions can be greatly reduced.

Moreover, according to this embodiment, since the thin film which is the photocatalyst part 10 was formed in the cavity part 6 of the structure 7, it is possible to promote the decomposition of water by uniformly irradiating the photocatalyst particles in the photocatalyst part 10 with light. it can. This improves the quantum efficiency due to light is a production ratio of electrons and holes, increased generation efficiency of H ₂ and O ₂ by oxidation and reduction reactions, since that can be converted into CO by oxidizing O ₂ generated by the photocatalytic , CO to CO ₂ conversion efficiency can be increased. As a result, not only can the configuration of the apparatus be simplified and made compact, but there is no need to increase the temperature in the apparatus, the degree of freedom in material selection is increased, and cost can be reduced.

Second Embodiment (FIG. 5)
In the second embodiment, an example in which the hydrogen generator according to the embodiment of the present invention is installed on the downstream side of the plasma reforming apparatus using barrier discharge will be described with reference to FIG.

  FIG. 5 (a) is a schematic diagram showing a partial configuration of the hydrogen generator according to the embodiment of the present invention. As shown in FIG. 5A, a hydrogen generation unit 15 is installed in the frame 14 of the hydrogen generator 13, and an enlarged cross-sectional view of the frame 14 is shown in FIG. 5B. As shown in FIG. 5B, a GaN blue surface emitting laser 16 is embedded in the inner wall of the frame 14 as a light source of the light irradiation means 4.

In the plasma reformer, CH ₃ OH and H ₂ O are circulated between the electrodes via the water supply pipe and the fuel gas supply pipe, and a voltage is applied between the electrodes from the high frequency power source to discharge the electrodes. Generate plasma. Then, CH ₃ OH is decomposed and CO ₂ and H ₂ are generated from H ₂ O. At the same time, the amount of CO generated is extremely high.

The CO generated by the plasma reforming apparatus and the H ₂ O remaining unreacted or newly taken in from the plasma reforming apparatus are introduced into the hydrogen generation unit 15 to advance the CO shift reaction to generate hydrogen. Generate.
According to this embodiment, CO was oxidized and converted to CO ₂ in the hydrogen generator, so that the CO concentration could be suppressed to a low concentration of about 0.01%.

It is the schematic which shows the structure of the hydrogen generator which concerns on embodiment of this invention. It is a figure which shows the structure of the hydrogen production | generation unit shown in FIG. Is a cross-sectional view illustrating a structure of forming a hydrogen generation unit shown in FIG. 1, (a) is a sectional view in the direction of flow of CO and H ₂ O through a cavity portion of the structure, (b) has the structure body is a cross-sectional view in the flow direction and the vertical direction of CO and H ₂ O through a cavity portion of. It is a figure which shows the structure of the photocatalyst part formed in the cavity part shown in FIG. It is a figure which shows the structure of the hydrogen generator which concerns on 2nd Embodiment of this invention, (a) is the schematic which shows the structure of a part of hydrogen generator, (b) is the structure of a frame. It is sectional drawing expanded and shown.

Explanation of symbols

1 ... Hydrogen generator,
2 ... Gas supply means,
3 ... Hydrogen generation unit,
4 ... light irradiation means,
5 ... Gas discharge means,
6 ... Cavity,
7 ... Structure,
8 ... Xenon lamp,
9: optical fiber,
10 ... Photocatalyst part,
11 ... Photocatalyst fine particles,
12 ... metal fine particles,

Claims (8)

A hollow body that flows CO and H ₂ O inside is formed, and a structure composed of a transparent material,
A photocatalyst portion disposed in the cavity of the structure;
A hydrogen generation unit comprising at least   The hydrogen generation unit according to claim 1, wherein the hollow portion has a columnar or polygonal hollow shape.   3. The hydrogen generation unit according to claim 1, wherein the transparent material is at least one material selected from silica glass, titania, zinc oxide, and alumina. The photocatalyst portion is formed of a material carrying metal fine particles on the photocatalyst fine particles,
The hydrogen generation unit according to any one of claims 1 to 3, wherein the metal fine particles are 3d transition metal elements, metal oxides containing 4d transition metal elements, or Pt fine particles. The photocatalyst portion includes at least TiO ₂ , TiO ₂ doped with nitrogen or sulfur, SrTiO ₃ , ZrO ₂ , Ta ₂ O ₅ , K ₄ Nb ₆ O ₁₇ , Na ₂ Ti ₆ O ₁₃ , K ₂ Ti ₆ It is a thin film formed on the inner wall of the cavity from a material containing at least one kind of photocatalytic particles selected from O ₁₃ and BaTi ₄ O ₉ , or a titania nanotube formed in the cavity. The hydrogen generation unit according to any one of claims 1 to 4. Gas supply means for supplying a gas containing at least CO and H ₂ O;
A hollow-shaped cavity that allows CO and H ₂ O to flow therein is formed, and includes at least a structure formed of a transparent material and a photocatalyst disposed in the cavity of the structure. A hydrogen generation unit that oxidizes CO supplied from the gas supply means and decomposes H ₂ O supplied from the gas supply means to generate H ₂ ;
Light irradiation means for irradiating the hydrogen generation unit with light;
A gas discharge means for discharging a gas containing CO ₂ and H ₂ generated by the hydrogen generation unit;
A hydrogen generator characterized by comprising:   The hydrogen generator according to claim 6, wherein the light irradiation means is sunlight or an artificial light source. 8. The hydrogen generator according to claim 7, wherein the artificial light source is a lamp or a laser.

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