Hydrogen generator

Abstract

Provided is a hydrogen generator that can be miniaturized.　The present invention comprises: a water-permeable member that carries a photocatalyst; and a pair of gas barrier members that sandwich the water-permeable member.

Description

Hydrogen generator

[0001] This invention relates to a hydrogen generation device, and more particularly to a device that decomposes water using a photocatalyst.

[0002] A method for generating hydrogen by decomposing water using a photocatalyst is known. For example, Patent Document 1 discloses a technique for decomposing water by irradiating an aqueous dispersion in which photocatalytic particles are dispersed in water with light.

[0003] Japanese Patent Publication No. 2013-180245

[0004] In the method described in Patent Document 1, it is not easy to deliver light to the interior of the aqueous dispersion due to light scattering within the dispersion. Therefore, a stirring device is required to agitate the aqueous dispersion. As a result, the hydrogen generation device tends to be large.

[0005] The present invention aims to provide a hydrogen generation device that can be miniaturized.

[0006] A hydrogen generation apparatus according to one embodiment of the present invention comprises the following configuration: a water-permeable member supporting a photocatalyst, and a pair of gas barrier members sandwiching the water-permeable member.

[0007] We can provide a hydrogen generation device that can be miniaturized.

[0008] Plan view of a hydrogen generation apparatus according to one embodiment. Cross-sectional view of a hydrogen generation apparatus according to one embodiment. Schematic diagram of a hydrogen generation system according to one embodiment.

[0009] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more of the features described in the embodiments may be combined in any way. Furthermore, identical or similar configurations will be given the same reference numeral, and redundant descriptions will be omitted.

[0010] A hydrogen generation device according to one embodiment of the present invention comprises a water-permeable member and a gas barrier member. Figures 1 and 2 show an example of the configuration of a hydrogen generation device 100 according to one embodiment of the present invention. Figure 1 is a plan view of the hydrogen generation device 100. Figure 2 is a cross-sectional view taken along line A-A in Figure 1. The hydrogen generation device 100 shown in Figures 1 and 2 has a pair of gas barrier members 111 and 112 and a water-permeable member 120.

[0011] (Gas Barrier Members) Gas barrier members 111 and 112 sandwich a water permeable member 120. Gas barrier members 111 and 112 have gas barrier properties. That is, gas barrier members 111 and 112 have the characteristic of suppressing the permeation of gas from the outside to the water permeable member 120.

[0012] The shape of the gas barrier member 111 is not particularly limited. In one embodiment, the hydrogen generator 100 has a plate-like or sheet-like shape. Therefore, the gas barrier member 111 can also have a plate-like or sheet-like shape. In one embodiment, the gas barrier member 111 is a sheet-like member. The planar shape of the hydrogen generator 100 is also not particularly limited. The planar shape of the hydrogen generator 100 can be rectangular, circular, elliptical, or other shapes.

[0013] In one embodiment, the thickness of the gas barrier member 111 is 5 μm or more and 10 cm or less, preferably 10 μm or more and 1 cm or less. By making the gas barrier member 111 thinner, the hydrogen generator 100 can be miniaturized. Also, by making the gas barrier member 111 thicker, the strength of the hydrogen generator 100 can be increased. In one embodiment, the hydrogen generator 100 is a flexible device that can be bent. In this case, the thickness of the gas barrier member 111 is preferably 10 μm or more and 5 mm or less, more preferably 15 μm or more and 1 mm or less, and more preferably 30 μm or more and 100 μm or less. By making the gas barrier member 111 thinner, the hydrogen generator 100 becomes easier to bend. The gas barrier member 111 may also be a gas barrier film. The gas barrier film is, for example, a sheet-like member having a thickness of 1 mm or less.

[0014] The gas barrier member 111 has gas barrier properties. In one embodiment, the oxygen permeability of the gas barrier member 111 is 1 cm ３ / (m ２ It is less than 0.5 cm (day atm), preferably 0.5 cm ３ / (m ２ (day·atm) or less, more preferably 0.05 cm ３ / (m ２ The oxygen permeability is less than or equal to (day atm). The inventors of this application have found that the hydrogen production efficiency is improved by lowering the oxygen permeability of the gas barrier member 111. Although the reason is not clear, the inventors of this application believe that the gas barrier member 111 having low oxygen permeability suppresses side reactions caused by oxygen entering the interior from the air. In this specification, oxygen permeability is measured in accordance with JIS K 7126-1:2006.

[0015] The material of the gas barrier member 111 is not particularly limited as long as it is translucent. For example, the material of the gas barrier member 111 may be glass or resin. Alternatively, the gas barrier member 111 may be a gas barrier film such as a thin-film glass or resin film. Furthermore, the gas barrier member 111 may be a translucent inorganic thin film.

[0016] The type of glass that constitutes the gas barrier member 111 is not particularly limited. Examples of glass include soda-lime glass, quartz glass, and aluminosilicate glass.

[0017] Examples of inorganic thin films used as gas barrier members 111 include inorganic compound thin films and metal thin films. Inorganic compounds constituting the inorganic compound thin film include inorganic oxides such as silicon oxide, aluminum oxide, zinc oxide, or indium oxide; inorganic nitrides such as silicon nitride, aluminum nitride, or titanium nitride; and inorganic oxidized nitrides such as silicon oxidized nitride. Metals constituting the metal thin film include aluminum, magnesium, zinc, and tin. One of these raw materials may be used alone, or two or more raw materials may be used in combination.

[0018] Such inorganic thin films can be formed by, for example, PVD (physical deposition) such as vacuum deposition, sputtering, or ion plating; CVD (chemical deposition) methods such as thermal CVD, plasma CVD, or photo-CVD; or atomic layer deposition (ALD). For example, such inorganic thin films may be laminated on a water-permeable member 120.

[0019] Examples of resin films used as gas barrier members 111 include films made of gas barrier resins. Examples of gas barrier resins include polyvinyl alcohol or its partially saponified form, ethylene-vinyl alcohol copolymers, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, and polychlorotrifluoroethylene. These resins are poorly permeable to oxygen.

[0020] Another example of a resin film used as a gas barrier member 111 is a film having a substrate and a gas barrier layer. A resin film can be used as the substrate. Examples of resin components of the resin film include polyimide, polyamide, polyamide-imide, polyphenylene ether, polyether ketone, polyether ether ketone, polyolefin, polyester, polycarbonate, polysulfone, polyethersulfone, polyphenylene sulfide, polyarylate, acrylic resin, cycloolefin polymer, aromatic polymer, and polyurethane polymer. The thickness of the substrate is not particularly limited, but from the viewpoint of ease of handling, it is preferably 10 μm to 500 μm, more preferably 10 μm to 300 μm, and even more preferably 25 μm to 100 μm.

[0021] The gas barrier layer can impart gas barrier properties to the substrate. The material of the gas barrier layer is not particularly limited. Examples of gas barrier layers include inorganic compound thin films and the aforementioned inorganic thin films such as metal thin films. Two or more gas barrier layers may be provided on the substrate.

[0022] Furthermore, a silicon-containing polymer compound may be used to form a silicon-containing inorganic compound thin film. For example, a thin film of a silicon-containing polymer compound can be formed on a substrate. Specifically, a thin film of a silicon-containing polymer compound can be provided on a substrate by applying a coating liquid containing the silicon-containing polymer compound onto the substrate and drying the applied coating. Then, an inorganic compound thin film can be formed by performing a modification treatment on the thin film of the silicon-containing polymer compound.

[0023] Examples of the silicon-containing polymer compound include polysilazane-based compounds, polycarbosilane-based compounds, polysilane-based compounds, polyorganosiloxane-based compounds, poly(disilanylene phenylene)-based compounds, and poly(disilanylene ethynylene)-based compounds. A preferred example of the silicon-containing polymer compound is perhydropolysilazane. Examples of the modification treatment include ion implantation treatment, plasma treatment, ultraviolet irradiation treatment, and heat treatment. As a specific example, a silicon oxynitride thin film can be formed by performing argon ion implantation treatment on a perhydropolysilazane thin film.

[0024] From the viewpoint of gas barrier properties, the thickness of the gas barrier layer is preferably 1 nm or more and 2,000 nm or less, more preferably 3 nm or more and 1,000 nm or less, still more preferably 5 nm or more and 500 nm or less, and particularly preferably 40 nm or more and 200 nm or less.

[0025] The gas barrier member 112 can have the above configuration exemplified as the gas barrier member 111. In the embodiment shown in Figure 1, the gas barrier member 111 and the gas barrier member 112 are made of the same material and have the same shape. On the other hand, at least one of the material and shape may differ between the gas barrier member 111 and the gas barrier member 112. For example, one of the gas barrier member 111 and the gas barrier member 112 may be translucent while the other is opaque. In one embodiment, the gas barrier member 112 may be a light-reflective member. In such a configuration, it is expected that the light utilization efficiency will improve when light is irradiated from only one side of the hydrogen generation device 100 (the gas barrier member 111 side). For example, the gas barrier member 112 may be a metal foil such as aluminum foil.

[0026] (Water-permeable member) The water-permeable member 120 is a member that water can penetrate. In this embodiment, "water-permeable" means that water can penetrate into the interior of the water-permeable member 120 by bringing water into contact with a part of the water-permeable member 120 sandwiched between the gas barrier members 111 and 112. For example, water can penetrate into the interior of the water-permeable member 120 by capillary action.

[0027] The shape of the water-permeable member 120 is not particularly limited. In one embodiment, the hydrogen generator 100 has a plate-like or sheet-like shape. Therefore, the water-permeable member 120 can also have a plate-like shape. In one embodiment, the water-permeable member 120 is a sheet-like member. The planar shape of the water-permeable member 120 is also not particularly limited. The planar shape of the water-permeable member 120 can be rectangular, circular, elliptical, or other shapes.

[0028] In one embodiment, the thickness of the water-permeable member 120 is not less than 10 μm and not more than 10 cm, preferably not less than 20 μm and not more than 1 cm. By reducing the thickness of the water-permeable member 120, the hydrogen generator 100 can be reduced in size. In addition, by increasing the thickness of the water-permeable member 120, the hydrogen generation efficiency can be improved. In one embodiment, the hydrogen generator 100 is a bendable flexible device. In this case, the thickness of the water-permeable member 120 is preferably not less than 10 μm and not more than 5 mm, more preferably not less than 20 μm and not more than 1 mm, and still more preferably not less than 50 μm and not more than 500 μm. By reducing the thickness of the water-permeable member 120, the hydrogen generator 100 becomes easier to bend.

[0029] The material of the water-permeable member 120 is not particularly limited. For example, the water-permeable member 120 may be a fiber aggregate or a porous body. Further, the water-permeable member 120 may be a fiber sheet or a water-permeable membrane.

[0030] Examples of fibers include natural fibers, regenerated fibers, semi-synthetic fibers, synthetic fibers, and inorganic fibers. Examples of natural fibers include pulp, cotton, linen, silk, and wool. Examples of regenerated fibers include regenerated cellulose fibers including rayon and cupra. Examples of semi-synthetic fibers include acetate. Examples of synthetic fibers include polyvinyl alcohol-based resins and polyamide-based resins. Further, another example of synthetic fibers is hydrophilized synthetic resin. Examples of the hydrophilization treatment include plasma treatment, corona discharge treatment, and graft polymerization treatment. The synthetic resin to be subjected to the hydrophilization treatment is not particularly limited. Examples of the synthetic resin to be subjected to the hydrophilization treatment include polyolefin fibers, polyester fibers, polyamide resins, polysulfone resins, and fluororesins. Examples of inorganic fibers include glass fibers such as borosilicate glass fibers, and ceramic fibers. One of these fibers may be used alone. Alternatively, two or more types of fibers may be used in combination. From the viewpoint of improving water permeability, the fiber may be a hydrophilic fiber.

[0031] From the viewpoint of water permeability, the fibers are preferably polysaccharide fibers, glass fibers, or hydrophilically treated synthetic fibers. Polysaccharide fibers include natural fibers and regenerated fibers. Polysaccharide fibers may contain at least one of cellulose and hemicellulose. Polysaccharide fibers may be, for example, α-cellulose, β-cellulose, or γ-cellulose. In one embodiment, the polysaccharide fiber is a cellulose fiber. Cellulose fibers have a structure in which cellulose is linked in a chain via β1-4 bonds.

[0032] Examples of porous materials include hydrophilic porous films or sheets formed from synthetic resins, and porous films or sheets molded by filling such resins with organic or inorganic fillers. Examples of synthetic resins that can be subjected to hydrophilic treatment are as described above. Other examples of porous materials include porous bodies of hydrophilic resins, porous glass, and porous ceramics. From the viewpoint of increasing water permeability, porous materials can be hydrophilic.

[0033] A fiber sheet is a sheet containing fibers. A fiber sheet may also be a sheet made of fibers. Examples of fiber sheets include woven fabrics, nonwoven fabrics, and knitted fabrics.

[0034] A permeable membrane is a membrane through which water can pass. A permeable membrane can be, for example, a membrane filter or a porous membrane such as a porous ceramic membrane. Examples of membrane filters include cellulose-based membrane filters containing cellulose, cellulose acetate, or nitrocellulose, as well as hydrophilic treated resin membrane filters. In this case, examples of resins constituting the membrane filter include fluororesins such as polytetrafluoroethylene or polyvinylidene fluoride, and polyethersulfone. In one embodiment, the permeable membrane is a hydrophilic treated porous resin membrane. From the viewpoint of water permeability, the pore size (maximum diameter of pores) of the membrane filter is preferably 0.5 μm or more and 10 μm or less, and more preferably 1 μm or more and 5 μm or less.

[0035] In one embodiment, the water-permeable member 120 has water absorbency. In one embodiment, from the viewpoint of promoting the reaction between the photocatalyst and water, the weight of the water-permeable member 120 increases by 5% or more and 1000% or less due to water absorption, preferably increases by 10% or more and 800% or less, more preferably increases by 50% or more and 500% or less, and still more preferably increases by 100% or more and 300% or less. In the present specification, the weight increase due to water absorption is referred to as water absorption performance. Water absorption performance (%) is represented by 100×(weight after immersion in pure water−weight before immersion in pure water) / (weight before immersion in pure water). The weight before immersion in pure water is the weight of the sufficiently dried water-permeable member 120 under conditions of 25° C. and 50% humidity. Further, the weight after immersion in pure water is the weight immediately after immersing the water-permeable member 120 in pure water for 10 minutes and removing moisture adhering to the surface of the sheet.

[0036] The water-permeable member 120 carries a photocatalyst. The photocatalyst is a catalyst that promotes the decomposition of water under light irradiation, and the type thereof is not particularly limited. Further, the type of light is not particularly limited. For example, the light may be visible light or may be ultraviolet light. Examples of photocatalysts include TiO ２ , WO ３ , SrTiO ３ , La-doped NaTaO ３ , Zn-doped Ga ２ O ３ , and Al-doped SrTiO ３ , and the like. Such a photocatalyst may carry a cocatalyst. Examples of the cocatalyst include metals such as Pt and Cu, and NiO ｘ and RhCrO ｘ metal compounds such as the above. Further, as the photocatalyst, a Z-scheme catalyst in which a hydrogen-generating photocatalyst that generates hydrogen from water and an oxygen-generating photocatalyst that generates oxygen from water are joined can also be used. Examples of the hydrogen-generating photocatalyst include Rh-doped SrTiO ３ , Ir-doped SrTiO ３ , Cr-doped SrTiO ３ , Rh-doped perovskite-type SrTiO ３ , and BaTaO ２ N, and the like. Further, examples of the oxygen-generating photocatalyst include WO３ BiVO ４ , TiO ２ Ta ３ N ５ , and Bi ２ MoO ６ Examples include the above. Furthermore, the hydrogen-generating photocatalyst may support a hydrogen-generating co-catalyst such as Pt, Pd, Rh, or Ru. Similarly, the oxygen-generating photocatalyst may support an oxygen-generating co-catalyst such as Co, Mn, Fe, Ni, or Cr. One of these photocatalysts may be used alone. Alternatively, two or more photocatalysts may be used in combination.

[0037] In this embodiment, the fact that the water-permeable member 120 supports the photocatalyst means that the photocatalyst is present in the voids of the water-permeable member 120. At this time, water that permeates into the voids can come into contact with the photocatalyst. The photocatalyst present in the voids may be physically held by the material of the water-permeable member 120, or it may be chemically bonded to the material of the water-permeable member 120. For example, the photocatalyst may be physically held within the matrix of the material (e.g., fibers) of the water-permeable member 120. Alternatively, the photocatalyst may be attached to the material (e.g., fibers) of the water-permeable member 120 via hydrogen bonds or ionic bonds. Furthermore, the photocatalyst may be covalently bonded to the material (e.g., fibers) of the water-permeable member 120. In one embodiment, the water-permeable member 120 supports the photocatalyst such that the position of the photocatalyst relative to the water-permeable member 120 is fixed under the operating conditions of the hydrogen generation device. In the hydrogen generation device 100, water can diffuse into the water-permeable member 120 by permeation. In other words, it is not necessary for water to flow quickly through the water-permeable member 120. Nor is it necessary for water to pass through the water-permeable member 120. For this reason, the bond between the water-permeable member 120 and the photocatalyst does not need to be strong. Hydrophilic fibers or porous materials, such as polysaccharide fibers, glass fibers, or hydrophilized porous resins, have hydrophilic groups on their surface. For this reason, they are suitable for supporting photocatalysts.

[0038] (Overall Configuration) As shown in Figures 1 and 2, the hydrogen generator 100 in one embodiment has a flat plate or sheet shape. In the embodiment shown in Figure 1, a portion of the outer circumference of a pair of gas barrier members 111 and 112 is sealed to define at least two openings. In Figure 1, the gas barrier member 111 and the gas barrier member 112 are sealed to each other at a sealing portion 115. The sealing portion 115 also defines openings 101 and 102.

[0039] In the following description, water enters the hydrogen generator 100 through the opening 101. That is, the water enters the space between the gas barrier member 111 and the gas barrier member 112 at the opening 101. The water that enters the hydrogen generator 100 moves along the water-permeable member 120 sandwiched between the gas barrier member 111 and the gas barrier member 112. For example, by capillary action, the water can move through the water-permeable member 120 toward the opening 102. This allows contact between the water and the photocatalyst supported by the water-permeable member 120 to occur. However, it is not necessary for the water to permeate the entire water-permeable member 120. The hydrogen and oxygen produced by the decomposition of water by the photocatalyst can be removed from the hydrogen generator 100 through the opening 102. Alternatively, water may enter the hydrogen generator 100 from the opening 102.

[0040] As shown in Figure 2, a portion of the outer circumference of the pair of gas barrier members 111 and 112 may be bonded to each other by adhesive 130. In this example, gas barrier member 111 and gas barrier member 112 are bonded together by adhesive 130 applied to the sealing portion 115. On the other hand, adhesive 130 is not applied to the openings 101 and 102. The type of adhesive is not particularly limited. Examples of adhesives include adhesives containing acrylic polymers, epoxy polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, vinyl acetate / vinyl chloride copolymers, modified polyolefins, epoxy polymers, fluorine polymers, or rubber polymers as base polymers.

[0041] On the other hand, a portion of the outer circumference of the pair of gas barrier members 111 and 112 may be fused to each other. For example, the pair of gas barrier members 111 and 112 can be heat-sealed in the sealing portion 115.

[0042] The water-permeable member 120 is fixed to the gas barrier members 111 and 112 by being sandwiched between them. In Figure 1, the shape of the water-permeable member 120 is shown by a dashed line. The water-permeable member 120 does not need to be bonded to the gas barrier members 111 or 112 using an adhesive or the like. On the other hand, the water-permeable member 120 may be bonded to the gas barrier members 111 or 112 using an adhesive or the like.

[0043] In one embodiment, a portion of the water-permeable member 120 is provided in contact with the opening 101. In Figure 1, one end of the water-permeable member 120 is located at the opening 101. With this configuration, the penetration of water into the water-permeable member 120 is promoted. The water-permeable member 120 is also provided so as to extend from the opening 101 between a pair of gas barrier members 111 and 112. However, one end of the water-permeable member 120 may be separated from the opening 101. In this case, water can reach the water-permeable member 120 from the opening 101 by capillary action or by external force, passing between the gas barrier members 111 and 112.

[0044] In the following description, the direction of water penetration is referred to as the length direction (L). The direction perpendicular to the direction of water penetration is referred to as the width direction (W). In the example shown in Figure 1, the hydrogen generator 100 has a rectangular shape. The pair of gas barrier members 111 and 112 also each have a rectangular shape. Furthermore, the water permeable member 120 also has a rectangular shape. The dimensions of the hydrogen generator 100 are length L × width W. The dimensions of the pair of gas barrier members 111 and 112 are also length L × width W. The two opposing sides of the pair of gas barrier members 111 and 112 are sealed at the sealing portion 115.

[0045] The size of the hydrogen generator 100 is not particularly limited. For example, from the viewpoint of miniaturizing the hydrogen generator 100 and improving hydrogen generation efficiency, the length L of the hydrogen generator 100 is preferably 1 cm to 10 m, more preferably 2 cm to 5 m, and even more preferably 5 cm to 2 m. From a similar viewpoint, the width W of the hydrogen generator 100 is preferably 1 cm to 10 m, more preferably 2 cm to 5 m, and even more preferably 5 cm to 2 m. The length may be longer or shorter than the width.

[0046] Each of the pair of gas barrier members 111 and 112 can be the same size as the hydrogen generator 100.

[0047] In the example shown in Figure 1, the width of the water permeable member 120 is shorter than that of the gas barrier member 111. The outer surface of the water permeable member 120 in the width direction is sealed by the sealing portion 115. From the viewpoint of miniaturizing the hydrogen generator 100 and improving hydrogen generation efficiency, the width of the water permeable member 120 is preferably 0.5 cm to 9.9 m, more preferably 1.5 cm to 4.9 m, and even more preferably 3 cm to 1.8 m. Furthermore, from the viewpoint of ensuring reliable sealing and improving hydrogen generation efficiency, the width of the sealing portion 115 is preferably 0.2 mm to 10 cm, more preferably 1 cm to 5 cm.

[0048] Furthermore, the length of the water-permeable member 120 may be the same as that of the gas barrier member 111. However, the length of the water-permeable member 120 may be shorter than that of the gas barrier member 111. For example, one end of the water-permeable member 120 may be separated from the opening 102. Also, as described above, one end of the water-permeable member 120 may be separated from the opening 101. Moreover, the length of the water-permeable member 120 may be longer than that of the gas barrier member 111. In this case, a part of the water-permeable member 120 extends outside the space between the pair of gas barrier members 111 and 112.

[0049] From the viewpoint of improving hydrogen generation efficiency and miniaturizing the hydrogen generation device 100, the area of ​​the water permeable member 120 is preferably 1 cm². ２ Over 100m２ The following is more preferable: 5 cm ２ 1 meter or more ２ The following applies:

[0050] Note that the configurations shown in Figures 1 and 2 are merely examples. For example, the hydrogen generator 100 may have only one opening. Such a hydrogen generator 100 can be manufactured, for example, by sealing a portion of the outer circumference of a pair of gas barrier members 111 and 112 to define a single opening. In this case, water can be allowed to permeate the water-permeable member 120 through the opening beforehand, and then hydrogen can be extracted from the opening by irradiating the hydrogen generator 100 with light. Alternatively, the entire outer circumference of the pair of gas barrier members 111 and 112 may be sealed. In this case, water can be allowed to permeate the water-permeable member 120 beforehand before sealing. Then, hydrogen can be extracted from the hydrogen generator 100 by releasing the seal when necessary.

[0051] (Method of using the hydrogen generator) The hydrogen generator according to one embodiment of the present invention is used to produce hydrogen by decomposing water. The hydrogen generator can also produce oxygen along with hydrogen. Water is supplied to the hydrogen generator in order to decompose water using a photocatalyst. Light (including sunlight) is also irradiated onto the hydrogen generator.

[0052] Figure 3 is a schematic diagram of a hydrogen generation system according to one embodiment. The hydrogen generation system 10 includes a hydrogen generation device 100, a water supply unit 200, and a light source 300.

[0053] As shown in Figure 3, the opening 101 of the hydrogen generator 100 can be connected to the water supply unit 200. As shown in Figure 3, the water supply unit 200 may be a container holding water. In this case, the opening 101 can be immersed in the water contained in the water supply unit 200. The hydrogen generator 100 can also be fixed vertically so that its length coincides with the vertical direction. In this case, the water supplied from the water supply unit 200 passes through the opening 101 and permeates into the water-permeable member 120 toward the opening 102.

[0054] However, the configuration of the water supply unit 200 is not particularly limited. The water supply unit 200 may be a device that pressurizes water into the hydrogen generator 100, such as a pump. Furthermore, it is not necessary to supply water from the water supply unit 200 at all times. In other words, the connection between the hydrogen generator 100 and the water supply unit 200 may be disconnected while light is being irradiated from the light source 300.

[0055] Furthermore, the arrangement of the hydrogen generator 100 during use is not particularly limited. For example, the hydrogen generator 100 may be fixed laterally so that its length coincides with the horizontal direction. Alternatively, the hydrogen generator 100 may be used in a bent state.

[0056] The light source 300 irradiates light toward the hydrogen generation device 100. The irradiated light reaches the water permeable member 120 via the gas barrier member 111 or the gas barrier member 112. The light source 300 can irradiate light with a wavelength and intensity suitable for the water splitting reaction by the photocatalyst supported on the water permeable member 120.

[0057] In the example shown in Figure 3, in one embodiment, the hydrogen and oxygen produced by the decomposition of water spontaneously move upward and exit the hydrogen generator 100 through the opening 102. However, the method of recovering the hydrogen and oxygen is not particularly limited. For example, the hydrogen and oxygen may be pushed towards the opening 102 by applying pressure to the surface of the hydrogen generator 100 using a pressing member such as a roller.

[0058] The hydrogen generation system 10 may have a gas collection unit connected to the opening 102. The gas collection unit may be a container or piping. The gas collection unit can store the gas that has escaped from the opening 102. The hydrogen generation system 10 may also have a separation device communicating with the opening 102 via the gas collection unit. The separation device can separate the hydrogen that has escaped from the opening 102 from oxygen, or increase the hydrogen concentration in the gas. The separation device may further store the gas containing the separated hydrogen or concentrated hydrogen.

[0059] Thus, in the hydrogen generation apparatus according to this embodiment, the irradiated light can easily reach the photocatalyst supported by the water-permeable member through at least one of the pair of gas barrier members. Therefore, the utilization efficiency of the photocatalyst can be improved. Furthermore, in the hydrogen generation apparatus according to this embodiment, it is easy to deliver light to the photocatalyst without using additional units such as a stirring unit. Therefore, the hydrogen generation apparatus can be miniaturized. In particular, by using a sheet-like member as the water-permeable member, it becomes even easier for light to reach the photocatalyst, thereby improving the utilization efficiency of the photocatalyst. Furthermore, the hydrogen generation apparatus according to this embodiment is easily made lighter and thinner. Also, the hydrogen generation apparatus according to this embodiment is easily transportable. Therefore, the hydrogen generation apparatus according to this embodiment can be easily installed in various locations, including curved surfaces, walls, and high places. Also, the hydrogen generation apparatus according to this embodiment can have high maintainability.

[0060] (Method for Manufacturing a Hydrogen Generator) The method for manufacturing the hydrogen generator 100 is not particularly limited. For example, the hydrogen generator 100 can be manufactured by sandwiching a water-permeable member 120 between a pair of gas barrier members 111 and 112. When manufacturing the hydrogen generator 100, the space between the gas barrier member 111 and the gas barrier member 112 can be sealed to provide a sealing portion 115.

[0061] An example of a manufacturing method for the hydrogen generation device 100 is described below. First, a laminate is created by stacking a gas barrier member 111, a water permeable member 120, and a gas barrier member 112 in that order. For example, the water permeable member 120 can be placed on the gas barrier member 111 such that a part of the outer circumference of the gas barrier member 111 is exposed. Adhesive 130 can also be applied to the exposed part of the outer circumference of the gas barrier member 111. Furthermore, the gas barrier member 112 can be placed so as to cover the water permeable member 120. In this way, a laminate can be created. Then, the hydrogen generation device 100 can be manufactured by laminating this laminate. Examples of lamination methods include hot lamination, cold lamination, vacuum lamination, and heat sealing.

[0062] [Example 1] (Fabrication of Gas Barrier Member) A gas barrier member was fabricated by applying a gas barrier coating to a PET film. Specifically, perhydropolysilazane (manufactured by AZ Electronic Materials) was applied to a PET film (thickness 50 μm) by spin coating and heated at 120°C for 2 minutes to form a perhydropolysilazane layer (thickness 150 nm). Subsequently, the surface of the perhydropolysilazane layer was modified by implanting argon (Ar) using a plasma ion implanter under the following conditions. In this way, a gas barrier member with gas barrier properties was fabricated, consisting of a silicon nitride oxide layer (thickness 20 nm) and a silicon oxide layer (thickness 130 nm). The gas barrier performance of the gas barrier member was OTR (oxygen permeability) 5 × 10⁻⁶ －２ cm ３ / (m ２ It was a day ATM.

[0063] (Plasma Ion Implantation System) ・RF Power Supply: Model No. "RF56000", manufactured by JEOL Ltd. ・High-Voltage Pulse Power Supply: "PV-3-HSHV-0835", manufactured by Kurita Manufacturing Co., Ltd. (Plasma Ion Implantation Conditions) ・Plasma Generating Gas: Ar ・Gas Flow Rate: 100 sccm ・Duty Ratio: 0.5% ・Repetition Frequency: 1,000 Hz ・Applied Voltage: -10 kV ・RF Power Supply: Frequency 13.56 MHz, Applied Power 1,000 W ・Chamber Pressure: 0.2 Pa ・Pulse Width: 5 μsec ・Processing Time (Ion Implantation Time): 200 seconds

[0064] (Preparation of water-permeable member supporting photocatalyst) In this example, filter paper made of α-cellulose fibers was used as the water-permeable member. First, a photocatalytic dispersion was prepared by dispersing photocatalytic particles (composition: platinum-supported strontium titanate) in water. Then, the photocatalytic dispersion was filtered by suction using filter paper (made of α-cellulose fibers, ADVANTEC FILTER PAPER 5A, thickness 220 μm). The filter paper after suction filtration was cut into 5 cm x 10 cm pieces and used as a water-permeable member supporting the photocatalyst.

[0065] (Fabrication of Hydrogen Generator) By cutting the fabricated gas barrier member, two rectangular film-shaped gas barrier members (10 cm x 10 cm), each larger than the water-permeable member, were obtained. The water-permeable member was sandwiched between the two gas barrier members in the arrangement shown in Figure 1. Then, the ends of two opposing sides of the two gas barrier members were sealed by vacuum lamination using a hot-melt sealing material. In this way, a hydrogen generator was fabricated.

[0066] (Measurement of water absorption performance) A dry water-permeable material was immersed in pure water for 10 minutes, then removed, and the moisture adhering to the surface was removed. The weight of the water-permeable material was measured before and after immersion in pure water. The water absorption performance (%) is expressed as 100 × (weight after immersion in pure water - weight before immersion in pure water) / (weight before immersion in pure water). The evaluation results are shown in Table 1.

[0067] (Evaluation of water splitting performance) As shown in Figure 3, the hydrogen generator was fixed vertically inside a container holding pure water, with one unsealed end of the gas barrier member facing downwards and the other unsealed end facing upwards. The unsealed end was submerged in the pure water. The other unsealed end and most of the hydrogen generator were in the air. Light was then shone from one side of the hydrogen generator (using a solar simulator HAL-320 manufactured by Asahi Spectroscopy, with an illuminance of 1000 W / m²). ２ The sample was irradiated with (10 minutes). Then, the presence or absence of bubbles in the hydrogen generator was observed. The evaluation results are shown in Table 1. In Table 1, ○ indicates that bubbles were observed, and × indicates that bubbles were not observed.

[0068] [Examples 2-4 and Comparative Examples 1-2] Hydrogen generation devices were similarly constructed using the following materials instead of PET film or α-cellulose fiber filter paper with a gas barrier coating. The water absorption and water splitting performance were also evaluated similarly. • Example 2: As a gas barrier member, a glass film with gas barrier properties (thickness 700 μm, gas barrier performance OTR 1×10) was used. －3 cm ３ / (m ２ - A filter with a temperature of 10°C (day atm) or less was used. - Example 3: A glass fiber filter (ADVANTEC GLASS FIBER FILTER PAPER GA55, thickness 210 μm) was used instead of filter paper. - Example 4: A hydrophilic PTFE filter (ADVANTEC MEMBRANE FILTER H100A090C, thickness 35 μm) was used instead of filter paper. - Comparative Example 1: A PTFE filter (ADVANTEC MEMBRANE FILTER T300A090C, thickness 75 μm) was used instead of filter paper. - Comparative Example 2: A PET film without a gas barrier coating (thickness 50 μm, gas barrier performance OTR 10 cm) was used instead of a gas barrier member. ３ / (m ２ I used (day ATM).

[0069]

[0070] As shown in Table 1, when light was irradiated onto the hydrogen generation apparatus according to Examples 1 to 4, it was confirmed that bubbles were generated on the water-permeable member supporting the photocatalyst, thus confirming that hydrogen was being generated.

[0071] On the other hand, when a PTFE filter was used as the water-permeable material, as in Comparative Example 1, no bubble formation was observed. This is thought to be because the PTFE filter is hydrophobic, preventing water penetration by capillary action, and therefore preventing contact between the catalyst and water. It should be noted that the glass fiber used in Example 3 and the hydrophilic PTFE filter (hydrophilic coated PTFE filter) used in Example 4 are considered to have lower hydrophilicity than α-cellulose fiber. Nevertheless, it was confirmed that hydrogen is generated by using a water-permeable material with a water absorption capacity of 5% or more, preferably 10% or more.

[0072] Furthermore, as in Comparative Example 2, even when PET, which does not have a gas barrier coating and therefore does not have sufficient gas barrier properties, was used instead of the gas barrier member, no bubble formation was observed. This result demonstrates the importance of gas barrier members that possess gas barrier properties.

[0073] The invention is not limited to the embodiments described above, and various modifications and changes are possible within the scope of the gist of the invention.

[0074] This application claims priority based on Japanese Patent Application No. 2025-052354, filed on 26 March 2025, and all of its contents are incorporated herein by reference.

Claims

1. A hydrogen generation device comprising: a water-permeable member supporting a photocatalyst; and a pair of gas barrier members sandwiching the water-permeable member.

2. The hydrogen generating apparatus according to claim 1, wherein the water-permeable member is a fiber sheet or a water-permeable membrane.

3. The hydrogen generating apparatus according to claim 1, wherein the water-permeable member is a fiber sheet containing polysaccharide fibers or glass fibers, or a porous resin membrane that has been treated to be hydrophilic.

4. The hydrogen generating apparatus according to claim 1, wherein the weight of the water-permeable member increases by 10% or more due to water absorption.

5. The hydrogen generation apparatus according to claim 1, wherein the gas barrier member is a resin film having a gas barrier layer or a thin film glass.

6. The oxygen permeability of the gas barrier member is 1 cm ３ / (m ２ The hydrogen generating apparatus according to claim 1, wherein the temperature is less than 1 / day atm.

7. The hydrogen generation apparatus according to claim 1, wherein the water permeable member is a sheet-like member, the pair of gas barrier members is a pair of gas barrier films, and a portion of the outer periphery of the pair of gas barrier films is sealed to define at least two openings.

8. The hydrogen generation apparatus according to claim 7, wherein the portion of the outer periphery of the pair of gas barrier films is bonded to each other or fused to each other by an adhesive.

9. The hydrogen generating apparatus according to claim 7, wherein a portion of the water permeable member is provided in contact with one of the openings.

10. The hydrogen generation apparatus according to claim 7, wherein each of the pair of gas barrier films has a rectangular shape, and two opposing sides of the pair of gas barrier sheets are sealed.

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