Hydrogen gas production device and hydrogen gas production method

Abstract

Provided is a device capable of producing high purity hydrogen gas. Provided is a method capable of producing high purity hydrogen gas.　This hydrogen gas production device comprises a cathode, an anode disposed facing one side of the cathode, and a solid electrolyte member disposed between the cathode and the anode, the hydrogen gas production device being provided with a hydrogen gas recovery passage disposed on the other side of the cathode.

Description

Hydrogen gas production device and method for producing hydrogen gas

[0001] The present disclosure relates to a hydrogen gas production device and a method for producing hydrogen gas.

[0002] The use of hydrogen gas as a clean energy source has been studied. Known methods for producing hydrogen gas include, for example, electrolyzing pure water using electrodes and a polymer electrolyte membrane (PEM). In methods for producing hydrogen gas by electrolyzing pure water using electrodes and a PEM, water vapor is typically mixed into the produced hydrogen gas. This is because the PEM has very high water vapor permeability, and water vapor also migrates with hydrogen ions as they migrate from the anode side to the cathode side during electrolysis.

[0003] As an example of a hydrogen generation device that generates hydrogen using electrodes and a PEM, a hydrogen generation device capable of generating hydrogen from which water vapor has been removed is described in Patent Document 1. The hydrogen generation device described in Patent Document 1 includes a water electrolysis cell that has an anode section with a positive electrode, a cathode section with a negative electrode, and a solid electrolyte membrane that separates the anode section and the cathode section, and that electrolyzes water to generate oxygen gas in the anode section and hydrogen gas in the cathode section, and a hydrogen separation tank that is connected to the cathode section and introduces hydrogen gas from the cathode section and water into the tank for gas-liquid separation under pressure so that the hydrogen gas generated in the cathode section can be extracted under pressure. Patent Document 1 also describes that the hydrogen gas stored in the hydrogen separation tanks 4, 40 is transported and supplied to the locations where the hydrogen gas is used via hydrogen gas supply piping 21, 21′, that the hydrogen gas supply piping 21, 21′ is provided with hydrogen gas dehumidification means 23, 23′ for dehumidifying the hydrogen gas, that the hydrogen gas dehumidification means 23, 23′ dehumidifies the hydrogen gas by circulating hydrogen gas inside the hollow fiber membrane and circulating dry air outside the hollow fiber membrane, and that if it is desired to obtain hydrogen gas of higher purity (for example, 6N (99.9999) or higher), it is preferable to provide a purifier made of molecular sieves such as zeolite or activated alumina downstream of the hydrogen gas dehumidification means 23, 23′ or in place of the hydrogen gas dehumidification means.

[0004] Japanese Patent Application Laid-Open No. 2006-124772

[0005] The hydrogen generation device described in Patent Document 1 can generate hydrogen from which water vapor has been removed. However, since alcohol and ammonia dissolve in the PEM and permeate the PEM, if alcohol or ammonia is mixed into pure water, the hydrogen that is generated by permeating the PEM may contain the alcohol or ammonia as an impurity.

[0006] The object of the present disclosure is to provide an apparatus capable of producing high-purity hydrogen gas. Another object of the present disclosure is to provide a method for producing high-purity hydrogen gas.

[0007] The present disclosure includes the following: [1] A hydrogen gas production device having a cathode, an anode disposed opposite one side of the cathode, and a solid electrolyte member disposed between the cathode and the anode, wherein a hydrogen gas recovery passage is disposed on the other side of the cathode. [2] The hydrogen gas production device according to [1], wherein the cathode is tubular in shape with a longitudinal direction. [3] The hydrogen gas production device according to [2], wherein the tubular cathode is closed on one side in the longitudinal direction and open on the other side in the longitudinal direction. [4] The hydrogen gas production device according to [2] or [3], wherein a support member is disposed inside the tubular cathode. [5] The hydrogen gas production device according to any one of [1] to [4], wherein the cathode is permeable to hydrogen ions. [6] The hydrogen gas production device according to [5], wherein the cathode is permeable to hydrogen ions but not to hydrogen molecules. [7] The hydrogen gas production device according to [5] or [6], wherein the cathode contains at least one selected from the group consisting of titanium, vanadium, manganese, nickel, copper, zirconium, niobium, palladium, silver, tantalum, platinum, and gold. [8] The hydrogen gas production device according to any one of [1] to [7], wherein the anode contains at least one selected from the group consisting of carbon, platinum, and gold. [9] The hydrogen gas production device according to any one of [1] to [8], wherein the solid electrolyte member contains a perfluorocarbon.

[10] A method for producing hydrogen gas, comprising: immersing a hydrogen gas production device having a cathode, an anode disposed opposite one side of the cathode, a solid electrolyte member disposed between the cathode and the anode, and a hydrogen gas recovery channel disposed on the other side of the cathode, in a raw material liquid; applying current to the cathode and the anode; and recovering hydrogen gas from the hydrogen gas recovery channel.

[11] The production method according to

[10] , wherein the cathode has a cylindrical shape with a longitudinal direction.

[12] The manufacturing method according to

[11] , wherein the cylindrical cathode is closed on one side in the longitudinal direction and open on the other side in the longitudinal direction.

[13] The manufacturing method according to any one of

[10] to

[12] , wherein the cathode is permeable to hydrogen ions.

[14] The manufacturing method according to

[13] , wherein the cathode is permeable to hydrogen ions but not to hydrogen molecules.

[15] The manufacturing method according to any one of

[10] to

[14] , wherein the temperature of the raw material liquid is controlled to 60° C. to 95° C.

[16] The hydrogen gas production device according to any one of [1] to [9], wherein the shape of the solid electrolyte member is strip-shaped.

[17] The hydrogen gas production device according to any one of [1] to [9] and

[16] , wherein the shape of the anode is linear or strip-shaped.

[0008] The hydrogen gas production device of the present disclosure includes a cathode disposed opposite an anode, and a hydrogen gas recovery passage disposed on the side of the cathode opposite the anode, through which hydrogen gas is recovered. By using this hydrogen gas production device, high-purity hydrogen gas can be produced.

[0009] Fig. 1 is a cross-sectional view showing an embodiment of a hydrogen gas production apparatus. Fig. 2 is a schematic diagram showing another embodiment of a hydrogen gas production apparatus. Fig. 3 is a side view showing another embodiment of a hydrogen gas production apparatus. Fig. 4 is a side view showing another embodiment of a hydrogen gas production apparatus. Fig. 5 is a perspective view showing another embodiment of a hydrogen gas production apparatus. Fig. 6 is a graph showing the relationship between the temperature of the raw material liquid and the current when current is passed through the electrodes, the flow rate of hydrogen gas generated, or the efficiency of hydrogen gas generation.

[0010] The present disclosure will be described in more detail below based on embodiments, but the present disclosure is not limited to the following embodiments, and it is of course possible to implement the present disclosure with modifications within the scope that is compatible with the intent described above and below, and all of these modifications are included in the technical scope of the present disclosure.

[0011] An embodiment of the hydrogen gas production device is a hydrogen gas production device having a cathode, an anode arranged opposite to one side of the cathode, and a solid electrolyte member arranged between the cathode and the anode, and the gist is that a hydrogen gas recovery passage is arranged on the other side of the cathode.

[0012] An embodiment of a hydrogen gas production apparatus will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of a hydrogen gas production apparatus 100. The hydrogen gas production apparatus 100 has a cathode 1. An anode 2 is disposed opposite one side of the cathode 1. A solid electrolyte member 3 is disposed between the cathode 1 and the anode 2. A solid electrolyte is a solid that allows ions to pass through. A hydrogen gas recovery passage 4 is disposed on the other side of the cathode 1. By immersing the hydrogen gas production apparatus 100 in a raw material liquid and applying current between the cathode 1 and the anode 2, hydrogen gas can be recovered and produced through the hydrogen gas recovery passage 4. That is, by immersing the hydrogen gas production apparatus 100 in the raw material liquid and applying current between the cathode 1 and the anode 2, oxygen gas is generated from the anode 2 side, and the ionized hydrogen ions migrate within the solid electrolyte member 3 and reach the surface of the cathode 1. It is believed that the hydrogen ions that reach the surface of the cathode 1 are adsorbed and occluded by the cathode 1 and then diffuse within the cathode 1. The diffused hydrogen ions move to the other side of the cathode 1 (i.e., the side of the cathode 1 opposite to the side facing the anode 2), and recombine with each other to form hydrogen gas on the surface of the other side of the cathode 1. The generated hydrogen gas can be recovered through a hydrogen gas recovery passage 4 arranged on the other side of the cathode 1.

[0013] The anode 2 may be made of any known material, and preferably contains at least one material selected from the group consisting of carbon, platinum, and gold, and more preferably is made of at least one material selected from the group consisting of carbon, platinum, and gold.

[0014] The shape of the anode 2 is not particularly limited, and examples thereof include a flat shape, a curved shape, a cylindrical shape, a linear shape, and a strip shape.

[0015] The anode 2 may be elastic. This allows the anode 2 to absorb the swelling of the solid electrolyte member 3 even if the solid electrolyte member 3 swells, thereby maintaining an optimal contact state between the cathode 1 and the solid electrolyte member 3, and between the solid electrolyte member 3 and the anode 2. As a result, the hydrogen gas recovery efficiency can be improved.

[0016] When the anode 2 is cylindrical, the cross-sectional shape perpendicular to the longitudinal direction is not particularly limited and may be, for example, circular, triangular, square, rectangular, polygonal, elliptical, oval, or a combination thereof, with circular or elliptical being preferred, and circular being more preferred. When the anode 2 is cylindrical and the cross-sectional shape perpendicular to the longitudinal direction is triangular, square, rectangular, or polygonal, at least one corner may be rounded.

[0017] When the anode 2 is linear, the cross-sectional shape perpendicular to the longitudinal direction is not particularly limited and may be, for example, a circle, a triangle, a square, a rectangle, a polygon, an ellipse, an oval, or a combination thereof, with a circle, a triangle, a square, a rectangle, or an ellipse being preferred, and a circle, a square, or a rectangle being more preferred. When the anode 2 is linear and the cross-sectional shape perpendicular to the longitudinal direction is a triangle, a square, a rectangle, or a polygon, at least one corner may be rounded.

[0018] When the anode 2 is strip-shaped, the cross-sectional shape perpendicular to the longitudinal direction may be, for example, rectangular, and at least one corner of the rectangle may be rounded. When the anode 2 is strip-shaped, the width of the anode 2 may be, for example, 1.3 mm to 4 mm, 1.5 mm to 3.5 mm, or 1.8 mm to 3 mm. When the anode 2 is strip-shaped, the thickness of the anode 2 may be, for example, 0.5 mm to 2 mm, 0.8 mm to 1.8 mm, or 1 mm to 1.5 mm.

[0019] The anode 2 may be non-porous or perforated, and if perforated, may be porous. Alternatively, the anode 2 may be solid.

[0020] The oxygen gas generated from the anode 2 side (i.e., the oxygen gas generated between the anode 2 and the solid electrolyte member 3) can be recovered and utilized as needed. The recovered oxygen gas may be purified as needed.

[0021] The solid electrolyte member 3 may be a solid that is permeable to ions, particularly hydrogen ions (protons), and may be made of a known material.

[0022] Examples of materials for the solid electrolyte member 3 include polymer electrolytes, and more specifically, fluorine-based polymer electrolytes and aromatic hydrocarbon-based polymer electrolytes.

[0023] Examples of the fluorine-based polymer electrolyte include a fully fluorinated sulfonic acid polymer, a fully fluorinated phosphonic acid polymer, and a fully fluorinated carboxylic acid polymer. The fluorine-based polymer electrolyte preferably contains a perfluorocarbon. Specific examples of the fluorine-based polymer electrolyte include Nafion (registered trademark) manufactured by DuPont Corporation, Aciplex (registered trademark) manufactured by Asahi Kasei Chemicals Corporation, Flemion (registered trademark) manufactured by Asahi Glass Co., Ltd., and Dowex (registered trademark) manufactured by The Dow Chemical Company.

[0024] The aromatic hydrocarbon-based polymer electrolyte is an electrolyte containing an aromatic hydrocarbon-based polymer having an ionic group. The aromatic hydrocarbon-based polymer is a polymer consisting of a hydrocarbon skeleton having an aromatic ring in the main chain, and specifically includes a polymer having a structure selected from polysulfone, polyethersulfone, polyetherketone, polyetherphosphine phosphate, polyetherimide, polyphenylene oxide, polyphenylene sulfide, polyphenylene sulfide sulfone, polyparaphenylene, polyarylene ether-based polymer, polyarylene-based polymer, polyarylene ketone, polyarylene phosphine phosphate, polybenzoxazole, polybenzothiazole, polybenzimidazole, polyamide, polyimide, and polyimide sulfone in the main chain together with an aromatic ring. Polysulfone, polyethersulfone, polyetherketone, etc. are general terms for structures having sulfone bonds, ether bonds, or ketone bonds in their molecular chains, and include polyetherketoneketone, polyetheretherketone, polyetheretherketoneketone, polyetherketoneetherketoneketone, polyetherketonesulfone, etc. The hydrocarbon skeleton may have multiple structures selected from these structures. Among these, polyetherketone is preferred.

[0025] A mixture of two or more of these polymers may be used as the polymer electrolyte, for example, a mixture of an aromatic hydrocarbon-based polymer having an ionic group and an aromatic hydrocarbon-based polymer not having an ionic group may be used.

[0026] The shape of the solid electrolyte member 3 is not particularly limited, and examples thereof include a flat shape, a curved shape, a cylindrical shape, a linear shape, a string shape, a net shape, and a strip shape.

[0027] When the solid electrolyte member 3 has a flat or curved shape, the solid electrolyte member 3 may be in the form of a plate, a membrane, or a film.

[0028] When the solid electrolyte member 3 has a linear shape, the cross-sectional shape perpendicular to the longitudinal direction is not particularly limited and may be, for example, a circle, a triangle, a square, a rectangle, a polygon, an ellipse, an oval, or a combination thereof, with a circle, a triangle, a square, a rectangle, or an ellipse being preferred, and a circle, a square, or a rectangle being more preferred. When the solid electrolyte member 3 has a linear shape and the cross-sectional shape perpendicular to the longitudinal direction is a triangle, a square, a rectangle, or a polygon, at least one corner may be rounded.

[0029] When the solid electrolyte member 3 has a strip-like shape, the cross-sectional shape in a direction perpendicular to the longitudinal direction may be rectangular, and at least one corner of the rectangle may be rounded. When the solid electrolyte member 3 has a strip-like shape, the width of the solid electrolyte member 3 may be, for example, 1.3 mm to 4 mm, 1.5 mm to 3.5 mm, or 1.8 mm to 3 mm. When the solid electrolyte member 3 has a strip-like shape, the thickness of the solid electrolyte member 3 may be, for example, 0.5 mm to 5 mm, 0.8 mm to 4 mm, or 1 mm to 3 mm.

[0030] The surface of the solid electrolyte member 3 may be uneven, and the unevenness may be protrusions or grooves. By providing the unevenness on the cathode 1 side of the solid electrolyte member 3, hydrogen gas generated on the surface of the cathode 1 facing the solid electrolyte member 3 can be easily discharged, preventing hydrogen gas from accumulating on the surface of the cathode 1 facing the solid electrolyte member 3, which would cause electrolysis to become unstable or stop. As a result, the recovery efficiency of hydrogen gas can be improved. By providing the unevenness on the anode 2 side of the solid electrolyte member 3, oxygen gas generated on the surface of the anode 2 facing the solid electrolyte member 3 can be easily discharged, preventing oxygen gas from accumulating on the surface of the anode 2 facing the solid electrolyte member 3, which would cause electrolysis to become unstable or stop. As a result, the recovery efficiency of hydrogen gas can be improved. The solid electrolyte member 3 may be uneven on both the cathode 1 side and the anode 2 side.

[0031] The solid electrolyte member 3 may be non-porous or perforated. By making the solid electrolyte member 3 non-porous, the solid electrolyte member 3 acts as a diaphragm between the anode and cathode, and can prevent the hydrogen gas generated between the cathode 1 and the solid electrolyte member 3 and the oxygen gas generated between the anode 2 and the solid electrolyte member 3 from mixing. By making the solid electrolyte member 3 perforated, the hydrogen gas generated between the cathode 1 and the solid electrolyte member 3 can be removed, thereby ensuring the contact area between the cathode 1 and the solid electrolyte member 3 and increasing the efficiency of hydrogen gas generation. In addition, the pressure load on the cathode 1 due to the hydrogen gas generated between the cathode 1 and the solid electrolyte member 3 can be reduced. When the solid electrolyte member 3 is perforated, it may be porous, for example.

[0032] The material constituting the cathode 1 is preferably permeable to hydrogen ions. By using a material permeable to hydrogen ions as the cathode 1, the purity of the hydrogen gas recovered from the other side of the cathode 1 can be increased.

[0033] The material constituting the cathode 1 may be permeable to hydrogen ions but not permeable to hydrogen molecules. By using a material for the cathode 1 that is permeable to hydrogen ions but not permeable to hydrogen molecules, the purity of the hydrogen gas recovered from the other side of the cathode 1 can be further increased. "Not permeable to hydrogen molecules" means that hydrogen gas generated on the surface of one side of the cathode 1 (i.e., the side of the cathode 1 facing the anode 2) does not permeate the cathode 1 in the state of hydrogen molecules. For example, if hydrogen gas dissolves and diffuses in the cathode 1 in the state of hydrogen molecules, or if holes are formed through the cathode 1 in the thickness direction, the hydrogen gas will have permeated the cathode 1 in the state of hydrogen molecules.

[0034] Cathode 1 may be non-porous, solid, or solid. The bulk density of cathode 1 may be, for example, 97% or more, or 98% or more. The porosity of cathode 1 may be, for example, 3% by volume or less, or 2% by volume or less.

[0035] The cathode 1 may be made of a material permeable to hydrogen ions, and is preferably made of a material permeable to hydrogen ions but impermeable to hydrogen molecules. Examples of materials permeable to hydrogen ions but impermeable to hydrogen molecules include metals such as titanium, vanadium, manganese, nickel, copper, zirconium, niobium, palladium, silver, tantalum, platinum, and gold. The cathode 1 may contain at least one metal selected from these groups, or may be an alloy of two or more metals. Alternatively, the cathode 1 may be made of a metal a selected from these groups plated with a metal b selected from these groups that is different from the metal a. Alternatively, the cathode 1 may be made of an alloy a containing two or more metals selected from these groups plated with a metal selected from these groups, or an alloy b containing two or more metals selected from these groups that is different from the alloy a. The cathode 1 is preferably made of at least one metal selected from the group consisting of titanium, vanadium, manganese, nickel, copper, zirconium, niobium, palladium, silver, tantalum, platinum, and gold, and more preferably made of palladium or a palladium alloy.

[0036] The shape of the cathode 1 is not particularly limited, and examples thereof include a flat shape, a curved shape, and a cylindrical shape, with a cylindrical shape being preferred. When the cathode 1 has a cylindrical shape and the radially inner side of the cylindrical cathode 1 is formed as the hydrogen gas recovery passage 4, the generated hydrogen gas can be easily recovered.

[0037] When the cathode 1 is cylindrical, the cross-sectional shape in the direction perpendicular to the longitudinal direction is not particularly limited and may be, for example, circular, triangular, square, rectangular, polygonal, elliptical, oval, etc., with circular or elliptical being preferred, and circular being more preferred. When the cathode 1 is cylindrical and the cross-sectional shape in the direction perpendicular to the longitudinal direction is triangular, square, rectangular, or polygonal, at least one corner may be rounded.

[0038] As described above, the shape of the solid electrolyte member 3 is not particularly limited, and may be, for example, planar, curved, cylindrical, linear, string-like, or mesh-like. Even if the cathode 1 is cylindrical, the shape of the solid electrolyte member 3 is not particularly limited. That is, in the case of a hydrogen generation device that generates hydrogen using electrodes and a PEM as described in Patent Document 1, a solid electrolyte membrane disposed between the cathode and anode separates the cathode and anode, and the solid electrolyte membrane is required to have a function of allowing ions to pass through but not allowing gas to pass through. Separating the cathode and anode with the solid electrolyte membrane prevents the gases generated on the cathode side and the anode side from mixing, even when current is applied to the cathode and anode. Furthermore, separating the cathode and anode with the solid electrolyte membrane prevents the gas generated on the cathode side from leaking to the anode side when the gas is pressurized and extracted. To fulfill these functions, the solid electrolyte membrane must be strong enough to withstand the generated gas. Therefore, the solid electrolyte membrane is required to be non-porous, solid, and defect-free. In contrast, when the cathode 1 is cylindrical and hydrogen gas is recovered from the side of the cathode 1 opposite to the solid electrolyte member 3, the cathode 1 and the solid electrolyte member 3 need only be in contact with each other, and the shape of the solid electrolyte member 3 does not need to be planar (membrane-like). Therefore, the solid electrolyte member 3 may be perforated or may be string-like, mesh-like, or linear. Furthermore, the solid electrolyte member 3 can be used even if it has some defects. Furthermore, since the solid electrolyte member 3 does not need to withstand the pressure of gas generation on the cathode side, the thickness of the solid electrolyte member 3 can be thin.

[0039] When the cathode 1 is cylindrical, the solid electrolyte member 3 is preferably curved, linear, or strip-shaped, and more preferably strip-shaped. When the cathode 1 is cylindrical and the solid electrolyte member 3 is linear or strip-shaped, the solid electrolyte member 3 may be wound around the surface of the cathode 1 in a coil shape. By forming a linear or strip-shaped solid electrolyte member 3 covering the surface of the cathode 1 and providing a gap between the solid electrolyte members 3 covering the surface of the cathode 1, hydrogen gas generated on the surface of the cathode 1 facing the solid electrolyte member 3 can be discharged through the gap between the solid electrolyte members 3. This prevents hydrogen gas from accumulating on the surface of the cathode 1 facing the solid electrolyte member 3, which could cause electrolysis to become unstable or stop. As a result, the hydrogen gas recovery efficiency can be improved. When the solid electrolyte members 3 are strip-shaped, the gap between the solid electrolyte members 3 may be, for example, 0.1 mm to 1 mm or 0.3 mm to 0.5 mm.

[0040] When the cathode 1 has a cylindrical shape and the solid electrolyte member 3 has a linear or strip shape, the direction in which the solid electrolyte member 3 is wound around the cathode 1 is not particularly limited, and may be a right-handed spiral (Z-winding) or a left-handed spiral (S-winding).

[0041] When the cathode 1 is cylindrical, the anode 2 is preferably curved, linear, or strip-shaped, more preferably linear or strip-shaped, and even more preferably strip-shaped. When the cathode 1 is cylindrical and the anode 2 is linear or strip-shaped, the anode 2 may be wound in a coil shape around the surface of the solid electrolyte member 3 disposed on the surface of the cathode 1. When the anode 2 covering the surface of the solid electrolyte member 3 is linear or strip-shaped and gaps are provided between the anodes 2, oxygen gas generated on the surface of the anode 2 facing the solid electrolyte member 3 can be discharged through the gaps between the anodes 2. This prevents oxygen gas from accumulating on the surface of the anode 2 facing the solid electrolyte member 3, which can cause electrolysis to become unstable or stop. As a result, the hydrogen gas recovery efficiency can be improved. When the anode 2 is linear or strip-shaped and covers the surface of the solid electrolyte member 3, the gap between the anodes 2 may be, for example, 0.1 mm to 1 mm or 0.3 mm to 0.5 mm.

[0042] When the cathode 1 is cylindrical and the anode 2 is linear or strip-shaped, the direction in which the anode 2 is wound around the cathode 1 is not particularly limited, and may be a right-handed spiral (Z-winding) or a left-handed spiral (S-winding).

[0043] When the cathode 1 is cylindrical, the solid electrolyte member 3 is linear or strip-shaped, and the anode 2 is linear or strip-shaped, the solid electrolyte member 3 and the anode 2 may be wound around the cathode 1 in the same direction or in different directions, but are preferably wound in different directions. When the solid electrolyte member 3 and the anode 2 are wound around the cathode 1 in different directions, the gaps between the solid electrolyte members 3 and the gaps between the anodes 2 are less likely to overlap, making it easier to discharge hydrogen gas and oxygen gas.

[0044] Next, another embodiment of the hydrogen gas production device will be described, in which the cathode has a cylindrical shape with a longitudinal direction. The same reference numerals will be used to designate parts that overlap with other drawings to avoid redundant explanation (the same applies hereinafter).

[0045] FIG. 2 is a schematic diagram showing another embodiment of the hydrogen gas production device 100. The hydrogen gas production device 100 has a cathode 11 and an anode 21. The cathode 11 is cylindrical with a longitudinal direction and a circular cross section perpendicular to the longitudinal direction, and the anode 21 is cylindrical with a longitudinal direction and a circular cross section perpendicular to the longitudinal direction. A cylindrical anode 21 is disposed opposite one side of the cylindrical cathode 11. For ease of explanation, FIG. 2 shows a partial cut-out of the cylindrical anode 21 to allow the interior of the hydrogen gas production device 100 to be seen. A hydrogen gas recovery passage 4 is disposed on the other side of the cylindrical cathode 11. In FIG. 2, the hydrogen gas recovery passage 4 is disposed radially inside the cylindrical cathode 11. A cylindrical solid electrolyte member 3 is disposed between the cylindrical cathode 11 and the cylindrical anode 21.

[0046] 2 , the solid electrolyte member 3 is disposed radially outside the cylindrical cathode 11, and the cylindrical anode 21 is disposed radially outside the solid electrolyte member 3. The arrangement order of the cylindrical cathode 11, the cylindrical solid electrolyte member 3, and the cylindrical anode 21 is not limited to this, and the cylindrical solid electrolyte member 3 may be disposed radially outside the cylindrical anode 21, the cylindrical cathode 11 may be disposed radially outside the solid electrolyte member 3, and the hydrogen gas recovery passage 4 may be disposed radially outside the cylindrical cathode 11.

[0047] 2 , the cylindrical cathode 11 and the cylindrical anode 21 are arranged so that their axial centers coincide with each other. However, the arrangement positions of the cylindrical cathode 11 and the cylindrical anode 21 are not limited to this, and the axial centers of the cylindrical cathode 11 and the cylindrical anode 21 may be misaligned.

[0048] When the cathode 11 has a cylindrical shape having a longitudinal direction, both one end 11a and the other end 11b in the longitudinal direction of the cylindrical cathode 11 may be open, or one end 11a in the longitudinal direction may be open and the other end 11b closed. Preferably, one end 11a in the longitudinal direction is open and the other end 11b is closed. By having one end 11a in the longitudinal direction open and the other end 11b closed, hydrogen gas generated on the other side of the cylindrical cathode 11 can be collected in one direction. Furthermore, by having the other end 11b in the longitudinal direction closed, it is possible to suppress the effects of expansion of the cylindrical cathode 11 due to occlusion of hydrogen ions in the cylindrical cathode 11 or contraction of the cylindrical cathode 11 due to permeation of the hydrogen ions occluded in the cylindrical cathode 11 through the cylindrical cathode 11.

[0049] When the cathode 11 has a cylindrical shape having a longitudinal direction, the solid electrolyte member 3 is disposed radially outside the cathode 11, and the cylindrical anode 21 is disposed radially outside the solid electrolyte member 3, a support member may be disposed radially inside the cylindrical cathode 11. By disposing the support member, the support member serves as a reinforcing material for the cylindrical cathode 11, and deformation of the cylindrical cathode 11 can be prevented even when negative pressure is applied to the radially inside of the cylindrical cathode 11.

[0050] The shape of the support member is not particularly limited and may be, for example, a wire or a plate, and the plate may be strip-shaped. When the support member is in the shape of a wire, the cross-sectional shape perpendicular to the longitudinal direction is not particularly limited and may be, for example, a circle, a triangle, a square, a rectangle, a polygon, an ellipse, an oval, or the like. A circle, a square, a rectangle, or an ellipse is preferred, and a circle or a rectangle is more preferred. A straight wire may be disposed on the inner surface of the cylindrical cathode 11, or a curved wire may be disposed. Furthermore, when the wire disposed on the inner surface of the cylindrical cathode 11 is curved, the wire may be annular or coiled, and is preferably coiled.

[0051] Examples of materials that can be used to form the support member include steel (especially stainless steel), titanium, vanadium, manganese, nickel, copper, zirconium, niobium, palladium, silver, tantalum, platinum, and gold.

[0052] Next, another embodiment of the hydrogen gas production device will be described, which is another example of the configuration in which the cathode has a cylindrical shape having a longitudinal direction.

[0053] FIG. 3 is a side view showing another embodiment of the hydrogen gas production device 100. The hydrogen gas production device 100 has a cathode 11 and an anode 22. The cathode 11 is cylindrical with a longitudinal direction and a circular cross section perpendicular to the longitudinal direction, and the anode 22 is linear (coiled). A linear anode 22 is arranged in a coil shape facing one side of the cylindrical cathode 11. A hydrogen gas recovery passage 4 is arranged on the other side of the cylindrical cathode 11. In FIG. 3, the hydrogen gas recovery passage 4 is arranged radially inside the cylindrical cathode 11 with a longitudinal direction. A cylindrical solid electrolyte member 3 is arranged between the cylindrical cathode 11 and the linear (coiled) anode 22.

[0054] Next, another embodiment of the hydrogen gas production device will be described, which is another example of the configuration in which the cathode has a cylindrical shape having a longitudinal direction.

[0055] FIG. 4 is a side view showing another embodiment of the hydrogen gas production device 100. The hydrogen gas production device 100 has a cathode 11 and an anode 23. The cathode 11 is cylindrical with a longitudinal direction and a circular cross section perpendicular to the longitudinal direction. The anode 23 is strip-shaped and has a rectangular cross section perpendicular to the longitudinal direction. A strip-shaped anode 23 is disposed opposite one side of the cylindrical cathode 11. A hydrogen gas recovery passage 4 is disposed on the other side of the cylindrical cathode 11. In FIG. 4, the hydrogen gas recovery passage 4 is disposed radially inside the cylindrical cathode 11 having a longitudinal direction. A solid electrolyte member 31 is disposed between the cylindrical cathode 11 and the strip-shaped anode 23. The solid electrolyte member 31 is strip-shaped and has a rectangular cross section perpendicular to the longitudinal direction. The strip-shaped solid electrolyte member 31 is wound around the cylindrical cathode 11 in a right-handed spiral (Z-winding), and the strip-shaped anode 23 is wound around the cylindrical cathode 11 in a left-handed spiral (S-winding).

[0056] Next, another embodiment of the hydrogen gas production device will be described, which is another example of the configuration in which the cathode has a cylindrical shape having a longitudinal direction.

[0057] FIG. 5 is a perspective view showing another embodiment of a hydrogen gas production device 100. The hydrogen gas production device 100 shown in FIG. 5 includes a cathode 12 and a holding member 5. A solid electrolyte member and an anode are disposed radially outside the cathode 12, but the solid electrolyte member and the anode are not shown. The cathode 12 has a longitudinal cylindrical shape, and the cross section perpendicular to the longitudinal direction is circular. A hydrogen gas recovery passage is disposed radially inside the longitudinal cylindrical cathode 12. The cathode 12 has one end 12a and the other end 12b in the longitudinal direction. The cathode 12 is curved in a U-shape so that the one end 12a and the other end 12b are in contact with the same plane. The one end 12a and the other end 12b of the cathode 12 are fixed to one surface 5a of the holding member 5. The holding member 5 has a hole penetrating in the thickness direction of the holding member 5 from the one surface 5a to the other surface 5b at a position where one end 12a of the cathode 12 is fixed to the one surface 5a of the holding member 5. In addition, the holding member 5 has a hole penetrating in the thickness direction of the holding member 5 from the one surface 5a to the other surface 5b at a position where the other end 12b of the cathode 12 is fixed to the one surface 5a of the holding member 5. When current is applied between the cathode 12 and the anode, hydrogen ions that reach the surface of the cathode 12 are adsorbed and occluded by the cathode 12 and diffuse within the cathode 12. The diffused hydrogen ions move radially inward of the cathode 12, where they recombine to form hydrogen gas. This hydrogen gas passes through a hydrogen gas recovery passage disposed radially inward of the cathode 12, passes through the hole formed in the holding member 5, and can be recovered from the other surface 5b of the holding member 5.

[0058] As shown in FIG. 5 , one end 12a and the other end 12b of the cathode 12 may be fixed to one surface 5a of the holding member 5. Alternatively, for example, one end and the other end of the cathode 12 may be embedded in holes penetrating from the one surface 5a to the other surface 5b of the holding member 5, and the one end 12a and the other end 12b of the cathode 12 may reach the other surface 5b of the holding member 5. Alternatively, a part of the end of the cathode 12 may protrude from the other surface 5b of the holding member 5. The shape of the holding member 5 is not limited to the disk shape shown in FIG. 5 and may be, for example, cylindrical. The one end 12a and the other end 12b of the cathode 12 may be fixed to a side surface of the cylindrical holding member 5. Examples of a material for the holding member 5 include steel (particularly, stainless steel).

[0059] Next, an embodiment of a method for producing hydrogen gas will be described.

[0060] Hydrogen gas can be produced by using the above-described hydrogen gas production device. For example, hydrogen gas can be produced by immersing a hydrogen gas production device having a cathode 1, an anode 2 disposed opposite one side of the cathode 1, a solid electrolyte member 3 disposed between the cathode 1 and the anode 2, and a hydrogen gas recovery passage 4 disposed on the other side of the cathode 1, as shown in Fig. 1, in a raw material liquid, applying current to the cathode 1 and the anode 2, and recovering hydrogen gas from the hydrogen gas recovery passage 4.

[0061] As the raw material liquid, for example, water can be used, and pure water is preferred.

[0062] The temperature of the raw material liquid is not particularly limited, but is preferably controlled to, for example, 60°C to 100°C. By setting the temperature of the raw material liquid to 60°C or higher, the rate at which hydrogen ions permeate the cathode can be increased. The temperature of the raw material liquid is preferably 60°C or higher, more preferably 65°C or higher, and even more preferably 70°C or higher. The higher the temperature of the raw material liquid, the higher the rate at which hydrogen ions permeate the cathode. However, if the temperature of the raw material liquid is too high, the solid electrolyte member 3 may be damaged. Therefore, the temperature of the raw material liquid is preferably, for example, 100°C or lower, more preferably 95°C or lower, and even more preferably 90°C or lower. That is, the temperature of the raw material liquid may be 60°C to 100°C, 60°C to 95°C, 65°C to 90°C, or 70°C to 90°C.

[0063] The hydrogen gas recovered from the hydrogen gas recovery passage 4 does not contain moisture and can be used for the intended purpose without dehumidification, but if necessary, it may be purified, such as by dehumidification, before being used for the intended purpose.

[0064] This application claims the benefit of priority based on Japanese Patent Application No. 2024-154310 filed on September 6, 2024, and Japanese Patent Application No. 2025-134832 filed on August 13, 2025. The entire contents of the specifications of Japanese Patent Application No. 2024-154310 and Japanese Patent Application No. 2025-134832 are incorporated herein by reference.

[0065] Hereinafter, the present disclosure will be described in more detail with reference to examples. However, the present disclosure is not limited to the following examples, and it is of course possible to implement the present disclosure by making modifications within the scope that is compatible with the intent described above and below, and all such modifications are included in the technical scope of the present disclosure.

[0066] Hydrogen gas was produced using the hydrogen gas production apparatus shown in FIG.

[0067] (No. 1) The hydrogen gas production apparatus shown in FIG. 3 was immersed in a raw material liquid, and electricity was applied to the cylindrical cathode 11 and the linear (coiled) anode 22. Pure water was used as the raw material liquid. A container equipped with a heater was used as the container containing the raw material liquid. A silicon cord heater was used as the heater. The cylindrical cathode 11 was a hollow tube made of an alloy containing palladium, silver, and gold, with the balance consisting of inevitable impurities. The alloy containing palladium, silver, and gold, with the balance consisting of inevitable impurities, is permeable to hydrogen ions but not to hydrogen molecules. The coiled anode 22 was a solid platinum wire. A cylindrical solid electrolyte member 3 was disposed between the cylindrical cathode 11 and the coiled anode 22, and Nafion (registered trademark) manufactured by DuPont was used as the solid electrolyte member 3. The pressure on the radially outer side of the cylindrical cathode 11 (i.e., the side of the coiled anode 22) was 0.2 MPa. The temperature of the raw material solution was 120°C, and the current passed through the cylindrical cathode 11 and the coiled anode 22 was 0.785 A and the voltage was 5 V. When the current passed through the cylindrical cathode 11 and the coiled anode 22 was 0.785 A and the voltage was 5 V, the theoretical flow rate of hydrogen gas generated was 5.5 SCCM. The results of the current application are shown in Table 1 and FIG. 6 below. FIG. 6 is a graph showing the relationship between the temperature of the raw material solution and the current applied to the electrodes, the flow rate of hydrogen gas generated, or the hydrogen gas generation efficiency (= hydrogen gas generation flow rate / theoretical generation flow rate×100). In FIG. 6, the coarse dotted line with black circles plotted points indicates the relationship between the temperature of the raw material solution and the current passed through the electrodes (left axis), the solid line with black circles plotted points indicates the relationship between the temperature of the raw material solution and the flow rate of hydrogen gas generated (left axis), and the fine dotted line with black squares plotted points indicates the relationship between the temperature of the raw material solution and the hydrogen gas generation efficiency (right axis).

[0068] (No. 2) The same conditions as in No. 1 were used, except that the temperature of the raw material solution was 100°C and the current passed through the cylindrical cathode 11 and the coiled anode 22 was 0.61 A. When the current passed through the cylindrical cathode 11 and the coiled anode 22 was 0.61 A and the voltage was 5 V, the theoretical flow rate of hydrogen gas was 4.2 SCCM. The results of passing current are shown in Table 1 below and FIG. 6.

[0069] (No. 3) The same conditions as in No. 1 were used, except that the temperature of the raw material solution was 80° C. and the current passed through the cylindrical cathode 11 and the coiled anode 22 was 0.62 A. When the current passed through the cylindrical cathode 11 and the coiled anode 22 was 0.62 A and the voltage was 5 V, the theoretical flow rate of hydrogen gas was 4.3 SCCM. The results of passing current are shown in Table 1 below and FIG. 6.

[0070] (No. 4) The same conditions as in No. 1 were used, except that the temperature of the raw material solution was 60°C and the current passed through the cylindrical cathode 11 and the coiled anode 22 was 0.6 A. When the current passed through the cylindrical cathode 11 and the coiled anode 22 was 0.6 A and the voltage was 5 V, the theoretical flow rate of hydrogen gas was 4.2 SCCM. The results of passing current are shown in Table 1 below and FIG. 6.

[0071]

[0072] Next, the purity of the hydrogen gas obtained in Nos. 1 to 4 was measured using a dew point meter. The amount of impurities contained in the hydrogen gas was also measured using a gas chromatograph. Synthetic zeolite (MS-5A) or silica gel (Unibeads S) was used as the column packing material. As a result, the impurities contained in the hydrogen gas obtained in Nos. 1 to 4 were 1 ppm or less, and the impurities included water vapor, oxygen, and carbon dioxide.

[0073] The following can be concluded from Table 1, Figure 6, and the measurement results of hydrogen gas purity. By using a hydrogen gas production device that satisfies the requirements specified in this disclosure, high-purity hydrogen gas can be produced. It can be seen that the higher the temperature of the raw material liquid, the larger the current, the greater the flow rate of hydrogen gas generated, and the higher the efficiency of hydrogen gas generation. Hydrogen gas could be produced even when the temperature of the raw material liquid was controlled at 120°C, but the heat resistance of Nafion (registered trademark) used as the solid electrolyte member 3 was around 100°C, so the durability of the hydrogen gas production device was slightly deteriorated.

[0074] In this way, the use of the device and method disclosed herein makes it possible to produce high-purity hydrogen gas with higher production efficiency than conventional technologies, thereby reducing greenhouse gas emissions and contributing to some of the Sustainable Development Goals (SDGs).

[0075] REFERENCE SIGNS LIST 1 Cathode 2 Anode 3 Solid electrolyte member 4 Hydrogen gas recovery passage 11 Cylindrical cathode 12 U-shaped cathode 21 Cylindrical anode 22 Wire-shaped (coil-shaped) anode 23 Strip-shaped anode 31 Strip-shaped solid electrolyte member 100 Hydrogen gas production device

Claims

1. A hydrogen gas production device having a cathode, an anode disposed opposite one side of the cathode, and a solid electrolyte member disposed between the cathode and the anode, wherein a hydrogen gas recovery passage is disposed on the other side of the cathode.

2. The hydrogen gas production device according to claim 1, wherein the cathode has a cylindrical shape having a longitudinal direction.

3. The hydrogen gas production device according to claim 2, wherein the cylindrical cathode is closed on one side in the longitudinal direction and open on the other side in the longitudinal direction.

4. The hydrogen gas production device according to claim 2, wherein a support member is disposed inside the cylindrical cathode.

5. The hydrogen gas production device according to claim 1, wherein the cathode is permeable to hydrogen ions.

6. The hydrogen gas production device according to claim 5, wherein the cathode is permeable to hydrogen ions but not to hydrogen molecules.

7. The hydrogen gas production device according to claim 5, wherein the cathode contains at least one metal selected from the group consisting of titanium, vanadium, manganese, nickel, copper, zirconium, niobium, palladium, silver, tantalum, platinum, and gold.

8. The hydrogen gas production device according to claim 1, wherein the anode contains at least one material selected from the group consisting of carbon, platinum, and gold.

9. The hydrogen gas production device according to claim 1, wherein the solid electrolyte member contains a perfluorocarbon.

10. A method for producing hydrogen gas, comprising: immersing a hydrogen gas production device having a cathode, an anode disposed opposite one side of the cathode, a solid electrolyte member disposed between the cathode and the anode, and a hydrogen gas recovery passage disposed on the other side of the cathode, in a raw material liquid; applying current to the cathode and the anode; and recovering hydrogen gas from the hydrogen gas recovery passage.

11. The manufacturing method according to claim 10, wherein the cathode has a cylindrical shape having a longitudinal direction.

12. The manufacturing method according to claim 11, wherein the cylindrical cathode is closed on one side in the longitudinal direction and open on the other side in the longitudinal direction.

13. The method of claim 10, wherein the cathode is permeable to hydrogen ions.

14. The method of claim 13, wherein the cathode is permeable to hydrogen ions but not permeable to hydrogen molecules.

15. The method of manufacturing according to claim 10, wherein the temperature of the raw material liquid is controlled to 60°C to 95°C.

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