JP2017210400A - Hydrogen production apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen production apparatus in which the decrease in hydrogen production reaction can be suppressed.SOLUTION: The hydrogen production apparatus includes a reaction section 3 which generates oxidation/reduction reaction upon receipt of sunlight energy, a water supply section 9 which supplies water to the reaction section 3, and a recovery section 11 which recovers hydrogen gas generated from the reaction section 3, and in which: a hydrogen occlusion member 5 is provided adjacent to the reaction section 3; the hydrogen occlusion member 5 is disposed with a space 15 between it and the reaction section 3; and the reaction section 3 is accommodated in a container 1 that can be depressurized.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a hydrogen production apparatus.

  In recent years, clean renewable energy that does not emit carbon dioxide in place of fossil fuel has attracted attention as a solution to problems such as global warming due to the increase in carbon dioxide accompanying consumption of fossil fuel.

  Solar energy, one of the renewable energies, does not have to worry about exhaustion. It can also contribute to the reduction of greenhouse gases. Under such circumstances, the form of seeking primary energy from sunlight and supporting secondary energy with hydrogen is one of the ideal clean energy systems, and its establishment is urgently needed.

  For example, as an example of applying a method of converting solar energy into chemical energy, a hydrogen production apparatus using a ceramic member as a reaction system carrier has been proposed (see, for example, Patent Document 1). This hydrogen production apparatus utilizes a reduction-oxidation reaction that occurs when a ceramic member is heated.

JP 2009-263165 A

  However, in the case of the invention disclosed in Patent Document 1, there is a problem that the generated hydrogen reduces the progress of the hydrogen generation reaction.

  Accordingly, an object of the present invention is to provide a hydrogen production apparatus capable of suppressing a decrease in hydrogen production reaction.

  The hydrogen production apparatus of the present invention includes a reaction unit that receives solar energy to cause an oxidation / reduction reaction, a water supply unit that supplies water to the reaction unit, and a recovery unit that recovers hydrogen generated from the reaction unit. And a hydrogen storage member is provided adjacent to the reaction section.

  According to the present invention, it is possible to suppress a decrease in the hydrogen production reaction.

It is sectional drawing which shows the state when operating the hydrogen production apparatus of this embodiment typically, (a) is the state which has produced | generated oxygen from the member for hydrogen production, (b) is for the hydrogen production In this state, hydrogen is generated from the member. The example of the light absorption member which comprises the reaction part of the hydrogen production apparatus of this embodiment is shown, (a) is a light absorption member, when (b) is a metal particle containing composite, (b) Is a metal film laminate. It is sectional drawing which shows typically the example of the member for hydrogen production applied to the reaction part of a hydrogen production apparatus. It is a perspective view which shows typically the external appearance structure of the reaction part. (A) is a flat plate type, (b) is a coaxial hollow cylindrical type, and (c) is a non-coaxial hollow cylindrical type. It is a cross-sectional schematic diagram which shows the structure of the reaction part which provided the metal film between the light absorption member and the member for hydrogen production.

  The hydrogen production apparatus of this embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view schematically showing a state when the hydrogen production apparatus of the present embodiment is operated, where (a) is a state where oxygen is generated from a hydrogen production member, and (b) In this state, hydrogen is generated from the hydrogen production member.

  The hydrogen production apparatus A of this embodiment has a configuration in which a reaction unit 3 and a hydrogen storage member 5 are installed in a container 1. Further, the container 1 is provided with a discharge port 7 for discharging oxygen from the reaction unit 1. In addition, a water supply unit 9 that supplies water to the reaction unit 3 and a recovery unit 11 that recovers hydrogen gas generated from the reaction unit 3 are attached to the container 1. Further, the upper surface plate 1a of the container 1 is provided with a window 1b for taking in sunlight. In this case, a transparent plate is installed in the window 1b.

  In addition, the hydrogen producing apparatus A is provided with a shielding plate 13 for the reaction unit 1 to receive or shield sunlight. The shielding plate 13 may be an opaque plate-like material, and plastic, metal, wood, or the like can be used as the material.

  The reaction part 3 is a part that receives solar energy (white arrow shown in FIG. 1A) to cause an oxidation / reduction reaction. The reaction unit 3 includes a light absorbing member 3a that converts sunlight into heat, and a hydrogen production member 3b that generates hydrogen when heated.

  According to the hydrogen production apparatus of the present embodiment, the hydrogen storage member 5 is provided so as to be adjacent to the reaction unit 3 where hydrogen is generated. It can be taken into the hydrogen storage member 5. Thereby, the fall of the speed | rate of the oxidation / reduction reaction in the reaction part 3 is suppressed, and the recovery rate of hydrogen can be raised.

  Hereinafter, features and effects of each member constituting the hydrogen production apparatus of the present embodiment will be described.

  FIG. 2 shows an example of a light-absorbing member constituting the reaction part of the hydrogen production apparatus according to the present embodiment. FIG. 2A shows a case where the light-absorbing member is a metal particle-containing composite, In this case, the light absorbing member is a metal film laminate.

  A light absorbing member 3a shown in FIG. 2 (a) is one in which a particulate material 3ab of either metal particles or ceramic particles is contained in a dense dielectric 3aa. Hereinafter, this may be referred to as a particulate matter-containing composite. As the metal particles, one kind of metal selected from the group consisting of tungsten, molybdenum, niobium, nickel, copper, silver, gold, platinum and palladium can be selected. Further, as the ceramic particles, a compound in which carbon (C) or nitrogen (N) or both carbon (C) and nitrogen (N) are bonded to a metal can be applied instead of the above-described metal. Examples of the compound include tantalum carbide (TaC), vanadium carbide (VC), titanium nitride (TiN), titanium carbide (TiC), titanium carbonitride (TiCN), niobium carbide (NbC), and niobium nitride (NbN). There may be mentioned at least one selected.

The average particle diameter of the particulate matter 3ab constituting the light absorbing member 3a is preferably, for example, 5 to 50 nm. On the other hand, the open porosity of the dielectric 3aa surrounding the particulate matter 3ab is preferably 5% or less. As a material for the dielectric 3aa, a low thermal expansion glass mainly composed of silicon oxide is preferable because of its high light transmission and excellent heat resistance. In addition, as dielectric 3aa, what consists of a component similar to the material of insulator 3bb which comprises the member 3b for hydrogen production mentioned later is also applicable.

  Further, as the light absorbing member 3a, a metal film laminate can be applied instead of the above-described dense dielectric 3aa containing the particulate matter 3ab. Hereinafter, this may be referred to as a metal-based film laminate. Examples of the metal-based film stack include a stack in which a tungsten film 3ac, an iron silicide (FeSi) film 3ad, and a silicon oxide film 3ae are formed in layers. In this case, the tungsten film 3ac and the iron silicide film 3ad formed on the lower layer side of the silicon oxide film 3ae play a role of absorbing light in a specific wavelength region. At the same time, the silicon oxide film 3ae, which is a dielectric, functions to suppress radiation from the lower tungsten film 3ac and the iron silicide film 3ad.

  Next, a reaction in which hydrogen is generated from the hydrogen production member 3b will be described. FIG. 3 is a cross-sectional view schematically showing an embodiment of a hydrogen production member applied to a reaction section of a hydrogen production apparatus. In this case, the hydrogen production member 3b is constituted by a ceramic composite in which fine ceramic particles 3ba are dispersed in a porous insulator 3bb.

  The insulator 3bb is formed of a material having a main component different from that of the ceramic particle 3ba. As a material for the insulator 3bb, silicon oxide, aluminum oxide, zinc oxide, an alkaline earth element oxide, a rare earth element oxide, and a composite oxide thereof are suitable materials. In this case, the insulator 3bb has a large number of open pores 3bc so that the open pores 3bc reach the internal ceramic particles 3ba from the outer surface 3Ba of the ceramic composite constituting the hydrogen production member 3b. It extends. In this case, the open porosity of the hydrogen production member 3b is preferably 10% or more. As the open porosity of the member 3b for hydrogen production, the value measured for the ceramic composite including the ceramic particles 3ba is used. This is because the ceramic particle 3ba is a dense body, and the porosity of the insulator 3bb corresponds to the porosity of the ceramic composite 3B as it is.

Ceramic particles 3ba are AXO _{3 ± δ} (where 0 ≦ δ ≦ 1, A: at least one of rare earth elements, alkaline earth elements, and alkali metal elements, X: at least one of transition metal elements and metalloid elements) 1 type, O: oxygen), at least one selected from the group of cerium oxide and zirconium oxide as a main component. In this case, the average particle diameter of the ceramic particles 3ba (denoted as D in FIG. 3) is preferably 5 to 200 nm. Here, the rare earth element is preferably at least one selected from lanthanide elements in the sixth period of the periodic table. The transition metal element is preferably at least one selected from the group consisting of Ti, V, Cr, Mn, Zr, Nb and Ta. The metalloid element is preferably at least one selected from the group consisting of B, Si, Ge, As, Se, Sb, Te, Po, and At. An example of a combination of plural types from the group of AXO _{3 ± δ} , cerium oxide, and zirconium oxide is a composite oxide in which part of zirconium oxide is substituted with cerium oxide.

  Here, the main component is, for example, an X-ray diffraction peak excluding an X-ray diffraction peak of a material corresponding to the insulator 3bb when a Rietveld analysis using X-ray diffraction is performed on the hydrogen production member 3b. The ratio which is 60 mass% or more in the ratio calculated | required in is said.

Next, the reaction process in the hydrogen production member 3b shown in FIG. 3 will be described. First, when the above-described hydrogen production member 3b is placed in a high-temperature environment, a defect reaction represented by the following formula (1) occurs in the ceramic particles 3ba constituting the hydrogen production member 3b.

  In this case, since the ceramic particles 3ba constituting the hydrogen production member 3b are fine particles, electrons generated in the ceramic particles 3ba due to the above-described defect reaction tend to stop on the surfaces of the ceramic particles 3ba. Thereby, the surface plasmon effect is enhanced in the ceramic particles 3ba. Thus, the hydrogen production member 3b itself can be changed to a high temperature state. As a result, the ceramic particle 3ba itself has a function of absorbing light.

  When the ceramic particles 3ba that cause such a reaction are present in the porous insulator 3bb, the ceramic particles 3ba have a reaction of releasing oxygen (hereinafter referred to as “Equation 2”) in a high temperature state as shown in the equation (2). , Sometimes referred to as oxygen release reaction). On the other hand, at a temperature lower than the temperature at which the oxygen releasing reaction occurs, a reaction for generating hydrogen (hereinafter sometimes referred to as a hydrogen generating reaction) as shown in formula (3) occurs.

  This is because, in the insulator 3bb constituting the hydrogen production member 3b, in addition to the surface plasmon effect appearing in the ceramic particles 3ba due to the above-described defect reaction, the reduction / oxidation reactions shown as Chemical Formula 2 and Chemical Formula 3 occur. Because.

  Further, from the viewpoint that the surface plasmon effect of the ceramic particles 3ba can be enhanced, the ratio of the ceramic particles 3ba contained in the ceramic composite 3B is preferably 20 to 80% by volume ratio. Further, it is preferable that 90% or more of the ceramic particles 3ba are dispersed and present as single particles in the insulator 3bb. That is, in this hydrogen production member 3b, it is preferable that the ceramic particles 3ba exist individually at a ratio of 90% or more by the number ratio through the material constituting the insulator 3bb.

  The ratio of the ceramic particles 3ba existing in the hydrogen production member 3b is obtained by using the electron microscope and an analyzer (EPMA) attached to the cross section of the ceramic composite 3B. For example, the member 3b for hydrogen production is polished to expose the ceramic particles 3ba, and a predetermined region where 30 to 100 ceramic particles 3ba existing in the cross section are specified is designated. Next, the area of this region and the total area of the ceramic particles 3ba existing in this region are obtained, and the total area of the ceramic particles 3ba with respect to the area of the region is obtained. The area ratio thus obtained is defined as a volume ratio. Whether or not the ceramic particles 3ba are present as single particles in the insulator 3bb is also determined by counting the number from the above observation.

  Next, the state when the hydrogen production apparatus A of this embodiment is operated will be described. In this hydrogen production apparatus A, as shown in FIG. 1A, when the shielding plate 13 is moved from the upper surface of the reaction unit 3, the reaction unit 3 receives light (sunlight). As a result, the hydrogen production member 3b installed in the reaction section 3 is in a high temperature state, and a reduction reaction occurs in the hydrogen production member 3b to generate oxygen.

  Next, as shown in FIG. 1B, when the reaction unit 3 is covered with a shielding plate 13, the reaction unit 3 is blocked from sunlight. At this time, when water is supplied to the reaction section 3 and the water is brought into contact with the hydrogen production member 3b, the hydrogen production member 3b is cooled from the state shown in FIG. This reduces the reduction reaction.

  Next, in the reaction part 3, an oxidation reaction occurs by reaction with water, and hydrogen gas is generated inside the hydrogen production member 3b. According to the hydrogen production apparatus A of the present embodiment, it is possible to efficiently absorb the heat from sunlight and increase the generation efficiency of hydrogen.

  In this hydrogen production apparatus A, a hydrogen storage member 5 is provided in the reaction unit 3 that generates hydrogen. In this case, as the hydrogen storage member 5, it is preferable to apply a hydrogen storage alloy exemplified below. If the hydrogen storage member 5 is made to adjoin the reaction part 3, the hydrogen gas discharged | emitted from the reaction part 3 can be once stored in the hydrogen storage member 5 which is solid. In this case, since the amount of hydrogen in the container 1 including the reaction unit 3 can be temporarily reduced, the hydrogen generation reaction represented by the above formula 3 can be continuously led to the right side. Thereby, the reaction rate of hydrogen can be increased. Moreover, since the produced hydrogen (gas) is absorbed by the solid hydrogen storage member 5, the volume of the produced hydrogen can be greatly reduced. Thereby, size reduction of the container 1 in which the reaction part 3 was accommodated, and the collection | recovery part 11 can be achieved.

  In the case of this hydrogen production apparatus A, the temperature of the hydrogen production member 3b when hydrogen is generated is at most 300 to 700 ° C. Since the temperature at which hydrogen is generated is such a relatively low temperature, the reaction of Chemical Formula 3 described above is easily affected by the hydrogen remaining in the reaction system. For this reason, it is necessary to prevent the generated hydrogen from affecting the reaction system in which hydrogen is generated in the vessel 1 as much as possible. That is, while hydrogen is being generated, it is necessary to avoid the hydrogen from continuing to exist in the hydrogen production member 3b as much as possible. Therefore, the hydrogen storage member 5 is preferably disposed adjacent to the hydrogen production member 3b.

  It should be noted that the hydrogen storage member 5 is provided with a space 15 so that a predetermined interval is provided between the hydrogen storage member 5 and the reaction unit 3 as shown in FIGS. It is good to arrange. When the space 15 is provided between the hydrogen storage member 5 and the reaction unit 3, hydrogen generated in the reaction unit 3 can be temporarily stored in the space 15, so that when hydrogen is stored in the hydrogen storage member 5. The speed of can be adjusted. In this way, the hydrogen production reaction shown in the above chemical formula 3 can be stably advanced.

The hydrogen storage alloy applicable to the hydrogen storage member 5 is an AB2 type alloy based on an alloy of transition elements such as titanium, manganese, zirconium and nickel. A AB5 type rare earth elements, niobium, transition elements having a catalytic effect on the zirconium (nickel, cobalt, aluminum, etc.) those based on an alloy containing _(such as LaNi _5, ReNi 5). In addition, Ti-Fe series, V series, Mg alloy, Pd series and Ca series alloys can be mentioned.

  Here, as shown in FIGS. 1 (a) and 1 (b), the reaction unit 3 is preferably accommodated in the container 1 in a decompressed state. Thereby, it can prevent that the heat | fever produced | generated by the light absorption member 3a moves to the external worlds other than the reaction part 3. FIG. Thereby, the heat supplied by the light absorbing member 3a can be stopped in the reaction part 3 and efficiently supplied to the hydrogen production member 3b.

  In addition, when the reaction unit 3 is decompressed, oxygen defects are easily formed on the hydrogen production member 3b side of the reaction unit 3, so that the reduction reaction of the hydrogen production member 3b proceeds and the hydrogen production member 3b The amount of the metal oxide having a non-stoichiometric composition to be generated can be further increased.

  In this case, the container 1 in which the reaction unit 3 and the hydrogen storage member 5 are arranged needs to be provided with an intake port for sucking gas from the container 1, but in the hydrogen production apparatus A of the present embodiment, the container It is preferable to provide two intake ports 17a and 17b in one. In this case, taking the schematic diagram shown in FIGS. 1A and 1B as an example, one of the two intake ports 17a and 17b (in this case, the intake port 17a) depressurizes the entire interior of the container 1. It will be used for. This is to prevent heat from moving from the periphery of the light absorbing member 3 a to the periphery of the container 1. The other intake port (in this case, the intake port 17b) is preferably passed through the light absorbing member 3a to reach the hydrogen production member 3b. This is for adjusting the pressure inside the member 3b for hydrogen production in the reaction part 3 installed in the container 1. For example, the pressure inside the hydrogen production member 3b is adjusted to a pressure higher than that around the light absorbing member 3a. In this way, when water vapor is supplied into the hydrogen production member 3b, the oxidation reaction easily proceeds inside the member 3b, and the amount of hydrogen produced can be further increased.

  FIG. 4 is a perspective view schematically showing the external structure of the reaction unit. (A) is a flat plate type, (b) is a coaxial hollow cylindrical type, and (c) is a non-coaxial hollow cylindrical type. That is, as the reaction unit 3 constituting the hydrogen production apparatus A of the present embodiment, a flat laminated structure shown in FIG. 3A and a coaxial hollow cylindrical tube laminated structure shown in FIG. Or a non-coaxial hollow cylindrical laminated structure shown in FIG. 4C is suitable.

  Here, regarding the hollow cylindrical tube type laminated structure, the coaxial type means that the central axis C1 of the cross section of the cylindrical hydrogen production member 33b and the central axis C2 of the cross section of the cylindrical light absorbing member 33a are at the same position. Says a structure. In other words, the structure is such that the central axis C1 of the hydrogen production member 33b disposed inside the reaction section 33 overlaps the central axis C0 when the outer periphery of the reaction section 33 (the outer periphery of the light absorbing member 33a) is the periphery. is there.

  On the other hand, the non-coaxial type is a structure (non-coaxial structure) in which the central axis C1 of the cross section of the cylindrical hydrogen production member 33b and the central axis C2 of the cross section of the cylindrical light absorbing member 33a do not overlap. say. In other words, the center axis C1 of the hydrogen production member 33b disposed inside the reaction unit 33 is at a position shifted from the center axis C0 when the outer periphery of the reaction unit 33 (the outer periphery of the light absorbing member 33a) is the periphery. .

  That is, in the non-coaxial type, for example, as shown in FIG. 4C, the thickness of the cross section of the light absorbing member 33a is different in a relationship of t1> t2. In this case, the cross section of the cylindrical hydrogen production member 33b may be similar to the cross section of the reaction section 33 including the light absorbing member 33a.

  In the case of a flat laminated structure, the light absorbing member 33a is sandwiched from above and below the flat hydrogen production member 33b. For this reason, thickness reduction of the hydrogen production apparatus A can be achieved. As a result, the weight can be reduced, so that it is suitable for installation on the roof of a house.

  The laminated structure of the hollow cylindrical tube type has a structure in which a cylindrical light absorbing member 33a surrounds a cylindrical hydrogen production member 33b. In the case of this structure, the surface area of the light absorbing member 33a can be increased by arranging a plurality of hollow cylindrical tube type reaction portions 33 so as to be arranged in parallel. Thereby, the reaction part 33 with a high light absorption rate can be completed.

  Regarding the hollow cylindrical tube type laminated structure, the non-coaxial type hollow cylindrical type laminated structure is better than the coaxial type hollow cylindrical tube type in that the light absorption rate can be increased. In the case of a non-coaxial type hollow cylindrical laminated structure, as shown in FIG. 4C, when the thicker cross section of the light absorbing member 33a is on the upper side irradiated with sunlight, the light absorbing member 33a. The volume ratio of can be increased, and the amount of light absorption can be increased.

  At this time, the cross-sectional shape of the cylindrical hydrogen production member 33b and the cross-sectional shape of the light absorption member 33a are similar, and the thick side of the hydrogen production member 33b and the cross-sectional thickness of the light absorption member 33a are similar to each other. When the thicker side is on the same side with the central axis C0 as the center, both the light absorption amount and the hydrogen generation amount can be increased simultaneously in the direction in which sunlight is irradiated.

  FIG. 5 is a schematic cross-sectional view showing a configuration of a reaction portion in which a metal film is provided between a light absorbing member and a hydrogen production member. FIG. 5 shows an example in which the particulate matter-containing composite shown in FIG. 2A is applied as the light absorbing member 3a. However, the light absorbing member 3a is not limited to this, and FIG. The metal film laminate shown in FIG.

  As shown in FIG. 5, as the reaction part 3, it is good to make the metal film 3c intervene between the light absorption member 3a and the member 3b for hydrogen production. When the metal film 3c is provided between the light absorbing member 3a and the hydrogen production member 3b, the light entering the light absorbing member 3a is reflected on the surface of the metal film 3c. As a result, the light that has entered the light absorbing member 3a is hardly transmitted to the hydrogen producing member 3b side, and the light is concentrated inside the light absorbing member 3a. Thus, the amount of heat generated by the light absorbing member 3a can be increased. The material of the metal film 3c may be any metal that has high light reflectivity. For example, tungsten, molybdenum, nickel, copper, silver, gold, platinum, palladium and the like are suitable.

  Hereinafter, a hydrogen production apparatus was produced according to the following specifications, and the amount of hydrogen produced was evaluated. First, a container, a discharge port, a water supply unit, a recovery unit, an intake port, and a shielding plate were manufactured using SUS-316 material and assembled so as to have the structure of FIG.

Next, a hydrogen production member was produced using a perovskite material containing La _0.8 Sr _0.2 MnO ₃ as a main component and substituted with 0.5 mol of Fe at the Mn site. Each perovskite material was synthesized by preparing a metal alkoxide and having the above composition, followed by spray pyrolysis. Next, the synthesized powder was put into water, and the state of sedimentation for each hour was confirmed and classification operation was performed to obtain a powder of perovskite material (ceramic particles) having an average particle size of 55 nm.

Next, glass powder (borosilicate glass) was mixed with the obtained powder of perovskite material to prepare a mixed powder. In this case, the composition of the mixed powder was such that the powder of the perovskite material was 70% by mass and the glass powder was 30% by mass. This is the ratio at which the ratio of the perovskite material in the hydrogen production member is 45% by volume.

  Next, 10% by mass of PVA (polyvinyl alcohol) as an organic binder is added to the obtained mixed powder to produce a molded body. After degreasing, the maximum temperature is 1400 ° C. and holding time in the atmosphere using an infrared image furnace. Heating was performed for about 1 second to obtain a ceramic composite to be a member for hydrogen production.

  The produced hydrogen production member was polished so as to have a size of 10 mm × 10 mm × 5 mm. Moreover, the cross section of the produced member for hydrogen production was analyzed using an electron microscope and an analyzer (EPMA) attached thereto. In this case, the ceramic particles constituting the hydrogen production member had almost no grain growth, and the average particle diameter was equivalent to the state before heating.

  For the light absorbing member, a particulate matter-containing composite in which about 30% by mass of tungsten particles having an average particle diameter of 40 nm were dispersed in silica glass was applied. The heating conditions were the same as those for the hydrogen production member.

  Next, gold (Au) was vapor-deposited as a metal film on one surface of the produced light absorbing member, and a hydrogen production member was superimposed on the surface and heated to produce a reaction part.

Next, LaNi ₅ was prepared as a hydrogen storage member, and as shown in FIG. 1, it was attached in the container with a space of about 2 mm from the reaction part.

  The amount of hydrogen (gas) produced was measured by installing a gas chromatograph device in the recovery section of the hydrogen production device. In this case, the hydrogen production apparatus measured the amount of production obtained through 10 cycles so that the reaction part was depressurized and received sunlight in a state of 1 SUN.

  Here, the amount of hydrogen produced was compared between the configuration of this example in which the hydrogen storage member was adjacent to the reaction part and the configuration of a comparative example in which no hydrogen storage member was installed in the container. The amount of hydrogen produced in the configuration of this example was 1.65 ml / g, but in the configuration of the comparative example in which no hydrogen storage member was installed, it was 1.1 ml / g. In this example, the decrease in the hydrogen production reaction was suppressed.

A ············· Hydrogen production device 1 ··························································· ... Light absorbing member 3aa ... Dielectric material 3ab ...... Particulate matter 3b, 33b ...... Hydrogen production member 3ba ...... Ceramic particles 3bb ... .... Insulator 3c ... ... Metal film 5 ... ... Hydrogen storage member 7 ... ... Discharge port 9 ... ··· Water supply unit 11 ······ Recovery unit 13 ··· Shield plate 15 ··· Spaces 17a and 17b · · · intake

Claims (14)

A reaction part that receives solar energy to cause an oxidation / reduction reaction;
A water supply unit for supplying water to the reaction unit;
And a recovery unit that recovers hydrogen generated from the reaction unit, and a hydrogen storage member is provided adjacent to the reaction unit.   The hydrogen production apparatus according to claim 1, wherein the hydrogen storage member is disposed with a space between the reaction portion and the hydrogen storage member.   The hydrogen production apparatus according to claim 1, wherein the reaction unit is housed in a container capable of being depressurized.   The hydrogen production apparatus according to claim 3, wherein the container is provided with two or more intake ports.   5. The hydrogen production apparatus according to claim 4, wherein one of the two intake ports serves to reduce the pressure in the entire container, and the other serves to reduce the pressure in the reaction unit.   The hydrogen production apparatus according to any one of claims 3 to 5, wherein the container is provided with a window for taking in sunlight.   7. The hydrogen production apparatus according to claim 1, wherein the reaction unit is a laminated structure of a flat hydrogen production member and a flat light absorption member.   7. The hydrogen production apparatus according to claim 1, wherein the reaction unit is a hollow cylindrical laminated structure in which a cylindrical light absorption member surrounds a cylindrical hydrogen production member. .   The hollow cylindrical laminated structure is a non-coaxial structure in which a central axis of a cross section of a cylindrical hydrogen production member does not overlap a central axis of a cross section of a cylindrical light absorbing member. 8. The hydrogen production apparatus according to 8. In the hydrogen production member, a plurality of ceramic particles having an average particle diameter of 5 to 200 nm are dispersed in a porous insulator having a composition different from that of the ceramic particles, and the ceramic particles are AXO _{3 ± δ} (where 0 ≦ δ ≦ 1, A: at least one of rare earth elements, alkaline earth elements, and alkali metal elements, X: at least one of transition metal elements and metalloid elements, O: oxygen 10) The hydrogen production apparatus according to any one of claims 1 to 9, wherein the hydrogen production apparatus comprises a ceramic composite mainly comprising at least one selected from the group consisting of cerium oxide and zirconium oxide.   11. The hydrogen production apparatus according to claim 10, wherein a ratio of the ceramic particles in the hydrogen production member is 20 to 80% by volume.   The hydrogen production apparatus according to claim 10 or 11, wherein 90% or more of the plurality of ceramic particles are present in isolation. 8. The light absorbing member is a metal particle-containing composite in which metal particles are dispersed in a dielectric, or a metal film laminate in which a metal film and a dielectric are stacked. The hydrogen production apparatus according to any one of 12.   The hydrogen production apparatus according to claim 7, wherein a metal film is provided between the hydrogen production member and the light absorption member.

Images