Substrate, electrode, membrane electrode assembly, electrochemical cell, stack, electrolytic device, and method for manufacturing the substrate

Abstract

The embodiment provides a substrate with excellent durability. [Solution] The substrate of the embodiment includes metal fibers and / or metal particles coated with a coating layer. The coating layer includes a first material which is one or more selected from the group consisting of Pt, Au, Pd, Ru, and Ni.

Description

[Technical Field]

[0001] Embodiments of the present invention relate to a substrate, an electrode, a membrane electrode assembly, an electrochemical cell, a stack, an electrolytic device, and a method for manufacturing the substrate. [Background technology]

[0002] In recent years, electrochemical cells have been actively researched. Among electrochemical cells, polymer electrolyte membrane electrolysis cells (PEMECs) are expected to be used for hydrogen production in large-scale energy storage systems. To ensure sufficient durability and electrolytic properties, platinum (Pt) nanoparticle catalysts are generally used for the cathode of PEMECs, and precious metal catalysts such as iridium (Ir) nanoparticle catalysts are generally used for the anode. Methods for obtaining hydrogen from ammonia are also being investigated. In addition, they can be used as anodes in electrolytic devices that electrolyze carbon dioxide to produce organic substances such as methanol and ethylene, as well as carbon monoxide. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2019-167620 [Overview of the project] [Problems that the invention aims to solve]

[0004] The embodiment provides a substrate with excellent durability. [Means for solving the problem]

[0005] The substrate of the embodiment includes metal fibers and / or metal particles coated with a coating layer. The coating layer includes a first material which is one or more selected from the group consisting of Pt, Au, Pd, Ru, and Ni. [Brief explanation of the drawing]

[0006] [Figure 1] Schematic diagram of the base material of the embodiment. [Figure 2] Flowchart of the manufacturing method of the base material of the embodiment. [Figure 3] Partial schematic diagram of the base material of the embodiment. [Figure 4] Schematic diagram related to the manufacturing method of the base material of the embodiment. [Figure 5] Schematic diagram related to the manufacturing method of the base material of the embodiment. [Figure 6] Partial schematic diagram of the base material of the embodiment. [Figure 7] Schematic diagram related to the manufacturing method of the base material of the embodiment. [Figure 8] Schematic diagram related to the manufacturing method of the base material of the embodiment. [Figure 9] Schematic diagram related to the manufacturing method of the base material of the embodiment. [Figure 10] Partial schematic diagram of the base material of the embodiment. [Figure 11] Schematic diagram related to the manufacturing method of the base material of the embodiment. [Figure 12] Schematic diagram related to the manufacturing method of the base material of the embodiment. [Figure 13] Partial schematic diagram of the base material of the embodiment. [Figure 14] Schematic diagram related to the manufacturing method of the base material of the embodiment. [Figure 15] Schematic diagram of the electrode of the embodiment. [Figure 16] Partial schematic diagram of the electrode of the embodiment. [Figure 17] Schematic diagram of the membrane electrode assembly of the embodiment. [Figure 18] Partial schematic diagram of the membrane electrode assembly of the embodiment. [Figure 19] Analysis spot of the embodiment. [Figure 20] Schematic diagram of the electrochemical cell of the embodiment. [Figure 21] Schematic diagram of the stack of the embodiment. [Figure 22] Conceptual diagram of the electrolyzer of the embodiment. [Figure 23] Table of examples.

Mode for Carrying Out the Invention

[0007] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same members are denoted by the same reference numerals, and the description of the members once described will be omitted as appropriate.

[0008] The physical property values in the specification are values at a temperature of 25 [°C] and a pressure of 1 [atom]. The thickness of each member is the average value of the distances in the stacking direction.

[0009] (First Embodiment) The first embodiment relates to a substrate. FIG. 1 shows a schematic cross-sectional view of the substrate 1 of the embodiment. The substrate 1 shown in FIG. 1 includes a first material 1A and a second material 1B.

[0010] The substrate 1 includes the first material 1A. The substrate 1 preferably optionally includes the second material 1B. The first material 1A and the second material 1B are preferably not mixed and are present in separate regions. The region where the first material 1A is present and the region where the second material 1B is present are preferably separated. It is acceptable that a very small part (0 [wt%] or more and 3 [wt%] or less of the first material 1A contained in the substrate 1) of the first material 1A is included in the region where the second material 1B is present. Also, it is acceptable that a very small part (0 [wt%] or more and 3 [wt%] or less of the second material 1B contained in the substrate 1) of the second material 1B is included in the region where the first material 1A is present.

[0011] The substrate 1 is used as a support for a catalyst for electrolysis. The electrolysis reaction produces hydrogen from, for example, water or ammonia. The electrolysis reaction produces carbon monoxide from, for example, carbon dioxide. The electrolysis reaction produces ammonia from nitrogen.

[0012] The substrate 1 is a conductive porous body. Considering the movement of substances, the porosity of the substrate 1 is preferably 20 [%] or more and 95 [%] or less, and more preferably 40 [%] or more and 90 [%] or less.

[0013] The base material 1 mainly consists of the first material 1A or the first material 1A and the second material 1B. The total amount of the first material 1A and the second material 1B is preferably 90 [wt%] or more and 100 [wt%] or less of the base material 1, more preferably 95 [wt%] or more and 100 [wt%] or less, and even more preferably 98 [wt%] or more and 100 [wt%] or less. The base material 1 is preferably substantially composed of the first material 1A and the second material 1B.

[0014] The first material 1A includes metal fibers and / or metal particles coated with a coating layer. Preferably, the first material 1A is metal fibers and / or metal particles coated with a coating layer. The metal fibers and / or metal particles are coated with the metal of the coating layer. Preferably, the coating layer is one or more selected from the group consisting of Pt, Au, Pd, Ru, and Ni.

[0015] The first material 1A preferably contains one or more selected from the group consisting of metal fibers coated with Pt, metal fibers coated with Au, metal particles coated with Pt, and metal particles coated with Au, and more preferably contains one or more selected from the group consisting of metal fibers coated with Pt, metal fibers coated with Au, metal particles coated with Pt, and metal particles coated with Au.

[0016] The first material is not composed of aggregates of metal fibers and / or metal particles covered with a coating layer, but rather preferably consists of aggregates of metal fibers and / or metal particles covered with a coating layer.

[0017] The metal fibers and metal particles of the first material 1A may be coated with two types of metal. For example, metal fibers coated with Ni (Ni-P) may be further coated with Pd or Au. Forms in which metal fibers coated with Ni (Ni-P) are further coated with Pd or Au are also included in metal fibers coated with Pt and metal fibers coated with Au.

[0018] A method for coating the metal fibers and metal particles of the first material 1A is, for example, electroless plating.

[0019] The fiber diameter of the metal fibers in the first material 1A is preferably 1 [μm] or more and 500 [μm] or less, and more preferably 1 [μm] or more and 100 [μm] or less, considering reactivity and power supply properties. The average fiber diameter of the metal fibers in the first material 1A is preferably [μm] or more and 500 [μm] or less, and more preferably 1 [μm] or more and 100 [μm] or less, considering reactivity and power supply properties.

[0020] The primary particle size (diameter) of the metal particles of the first material 1A is preferably 1 [μm] or more and 500 [μm] or less, and more preferably 1 [μm] or more and 100 [μm] or less, considering reactivity and power supply properties. The average primary particle size (average diameter) of the metal particles of the first material 1A is preferably 1 [μm] or more and 500 [μm] or less, and more preferably 1 [μm] or more and 100 [μm] or less, considering reactivity and power supply properties.

[0021] The metal fibers of the first material 1A preferably contain one or more metals selected from the group consisting of titanium, aluminum, tantalum, niobium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony, more preferably contain titanium, and even more preferably be titanium.

[0022] The metal particles of the first material 1A preferably contain one or more metals selected from the group consisting of titanium, aluminum, tantalum, niobium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony, more preferably contain titanium, and even more preferably be titanium.

[0023] The first material 1A, which uses metal fibers, may be, for example, a felt made of metal fibers, and the felt may be plated.

[0024] It is preferable that the first materials 1A are in direct contact with each other. It is preferable that a coating layer covering metal fibers and / or metal particles exists between the first materials 1A in the portion that is in direct contact. In the portion that the first materials 1A are in direct contact with each other, it is preferable that the metal fibers and / or metal particles are connected via a coating layer made of one or more selected from the group consisting of Pt, Au, Pd, Ru, and Ni, or Pt and / or Au, and that the metal fibers and / or metal particles are not in direct contact with each other in the portion that the first materials 1A are in direct contact with each other.

[0025] The thickness of the coating layer covering the metal fibers and / or metal particles of the first material 1A is preferably 50 nm or more and 2000 nm or less, and more preferably 100 nm or more and 500 nm or less.

[0026] The thickness of one or more materials selected from the group consisting of Pt, Au, Pd, Ru, and Ni that coat the metal fibers and / or metal particles of the first material 1A is preferably 50 nm or more and 2000 nm or less, and more preferably 100 nm or more and 500 nm or less.

[0027] Preferably, 90% to 100% of the surface of the metal fibers and / or metal particles of the first material 1A is covered with a coating layer. Preferably, 95% to 100% of the surface of the metal fibers and / or metal particles of the first material 1A is covered with a coating layer. Preferably, 99% to 100% of the surface of the metal fibers and / or metal particles of the first material 1A is covered with a coating layer. Preferably, the entire surface of the metal fibers and / or metal particles of the first material 1A is covered with a coating layer. Preferably, the majority of the surface of the metal fibers and / or metal particles of the first material 1A is not in direct contact with the metal fibers and / or metal particles, but is covered with a coating layer.

[0028] The second material 1B includes metal fibers and / or metal particles that are not coated with a coating layer. It is preferable that the second material 1B consists of metal fibers and / or metal particles that are not coated with a coating layer. It is not coated with the coating layer that coats the metal fibers and / or metal particles of the first material 1A. It is preferable that the second material 1B consists of uncoated metal fibers and / or uncoated metal particles.

[0029] The fiber diameter of the metal fibers in the second material 1B is preferably 1 μm or more and 500 μm or less, and more preferably 1 μm or more and 50 μm or less considering reactivity and power supply properties. The average fiber diameter of the metal fibers in the second material 1B is preferably 1 μm or more and 500 μm or less, and more preferably 1 μm or more and 50 μm or less considering reactivity and power supply properties.

[0030] The primary particle size (diameter) of the metal particles in the second material 1B is preferably 0.1 [μm] or more and 500 [μm] or less, and more preferably 0.5 [μm] or more and 50 [μm] or less, considering reactivity and power supply properties. The average primary particle size (average diameter) of the metal particles in the second material 1B is preferably 0.5 [μm] or more and 500 [μm] or less, and more preferably 0.5 [μm] or more and 50 [μm] or less, considering reactivity and power supply properties.

[0031] The metal fibers of the second material 1B preferably contain one or more metals selected from the group consisting of titanium, aluminum, tantalum, niobium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony, more preferably contain titanium, and even more preferably be titanium.

[0032] The metal particles of the second material 1B preferably contain one or more metals selected from the group consisting of titanium, aluminum, tantalum, niobium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony, more preferably contain titanium, and even more preferably be titanium.

[0033] The second material 1B, which uses metal fibers, may also be unplated felt made of metal fibers.

[0034] The first material 1A is preferably exposed to the first surface A, which is one of the main surfaces of the substrate 1. A catalyst layer is provided on the first material 1A on the side of the first surface A.

[0035] When the base material 1 includes a first material 1A and a second material 1B, it is preferable that the first material 1A is exposed on the first surface A, which is one of the main surfaces of the base material 1, and not exposed on the second surface B, which is the main surface on the opposite side of the first surface A.

[0036] When the base material 1 includes a first material 1A and a second material 1B, it is preferable that the first material 1A is exposed on the first surface A, which is one of the main surfaces of the base material 1, and not exposed on the second surface B, which is the main surface on the opposite side of the first surface A, and that the second material 1B is exposed on the second surface B.

[0037] It is preferable that the first material 1A exists in layers within the base material 1. It is preferable that the first material 1A is exposed on the first surface A side of the base material 1 and exists in layers. It is preferable that the first material 1A, which exists in layers, is exposed on the first surface A side and not exposed on the second surface B side. It is preferable that the first material 1A, which exists in layers, spreads in the planar direction of the first surface A.

[0038] The thickness of the layered first material 1A is preferably 0.01 [μm] or more and 10 [μm] or less, more preferably 0.1 [μm] or more and 1 [μm] or less, and even more preferably 0.1 [μm] or more and 0.5 [μm] or less.

[0039] It is preferable that the second material 1B exists in a layered manner within the base material 1. It is preferable that the second material 1B is exposed on the second surface B side within the base material 1 and exists in a layered manner. It is preferable that the layered second material 1B is exposed on the second surface B side and not exposed on the first surface A side. It is preferable that the layered second material 1B spreads in the planar direction of the second surface B.

[0040] The thickness of the layered second material 1B is preferably 0.001 [μm] or more and 2 [μm] or less, more preferably 0.001 [μm] or more and 1 [μm] or less, and even more preferably 0.01 [μm] or more and 0.6 [μm] or less.

[0041] The thickness of the layered second material 1B is preferably 0.01% to 30% of the thickness of the base material 1, more preferably 0.01% to 10%, and even more preferably 0.02% to 5%.

[0042] It is preferable that the first material 1A and the second material 1B, which are layered within the substrate 1, are in direct contact. It is preferable that the interface between the layered first material 1A and the layered second material 1B extends in the plane direction of the first surface A. It is preferable that the layered first material 1A and the layered second material 1B are not randomly mixed and have a flat interface or an uneven interface.

[0043] It is preferable that the first material 1A, which is present in layers, and the second material 1B, which is also present in layers, are in contact with each other via a coating layer provided by the first material 1A.

[0044] In the base material 1, each metal fiber and / or metal particle is coated with the aforementioned coating layer, so that the electrolyte membrane of the membrane electrode assembly using the base material 1 comes into contact with the first material 1A, preventing the metal fibers and / or metal particles from coming into direct contact with the electrolyte membrane. This has been shown to suppress the elution of the metal fibers and / or metal particles of the second material 1B, which are not in contact with the first material 1A and the electrolyte membrane, during electrolysis. The base material 1 of the embodiment has high durability, and the durability of the component using the base material 1 is also improved. Degradation of the metal fibers in the base material 1 is suppressed, and degradation of the electrode using the base material 1 is suppressed. By suppressing the degradation of the base material 1, degradation of the electrode paired with the electrode using the base material 1 in the membrane electrode assembly can also be suppressed. By using the base material 1, the rise in electrolysis voltage can be suppressed. Since the first material 1A is more expensive than the second material 1B, the first material 1A can be selectively used in parts where the elution of metal fibers and / or metal particles can be effectively suppressed, which is also useful from a cost standpoint.

[0045] As shown in the flowchart of Figure 2, the method for manufacturing the base material 1 of the embodiment includes the steps of: arranging a first material 1A, which is metal fibers and / or metal particles coated with a coating layer, in layers (S01); arranging a second material 1B, which is metal fibers and / or metal particles not coated with a coating layer, in layers (S02); and hot-pressing the first material 1A and the second material 1B arranged in layers (S03). When hot-pressing, it is more preferable to hot-press in a vacuum state where the pressure is reduced to below atmospheric pressure in order to suppress oxidation of the fiber surface.

[0046] The steps of arranging a first material 1A, which is metal fibers and / or metal particles coated with a coating layer, in layers (S01) and arranging a second material 1B, which is metal fibers and / or metal particles not coated with a coating layer, in layers (S02) may be performed in either order.

[0047] If the first step (S01) of arranging the first material 1A, which is metal fibers and / or metal particles covered with a coating layer, in layers is performed first, the second material 1B may be arranged in layers on the first material 1A arranged in layers and then the hot pressing step (S03) may be performed, or the first material 1A arranged in layers may be subjected to a hot pressing treatment (pre-hot pressing treatment) before the second material 1B is arranged in layers, and then the second material 1B, which is metal fibers and / or metal particles not covered with a coating layer, may be arranged in layers (S02), and then the hot pressing step (S03) may be performed again.

[0048] If the step of arranging the second material 1B, which is metal fibers and / or metal particles not covered by a coating layer, in layers (S02) is performed first, the first material 1A may be arranged in layers on the second material 1B arranged in layers and the hot pressing step (S03) may be performed, or the second material 1B arranged in layers may be subjected to a hot pressing treatment (pre-hot pressing treatment) before the first material 1A is arranged in layers, and then the step of arranging the first material 1A, which is metal fibers and / or metal particles not covered by a coating layer, in layers (S01) may be performed, and then the hot pressing step (S03) may be performed again.

[0049] The first material 1A and the second material 1B may be heat-pressed separately (pre-heat-pressed), and then the heat-pressed first material 1A and the heat-pressed second material 1B may be heat-pressed together to join them.

[0050] The temperature of the hot pressing process (S03) and the pre-hot pressing treatment (in-plane temperature of the press machine) is preferably 100°C or more and 3000°C or less, and more preferably 500°C or more and 1500°C or less.

[0051] The pressure for the hot pressing process (S03) and the pre-hot pressing treatment is 50 kg / cm². 2 ] or more 3000[kg / cm 2 It is preferable that it be less than or equal to 200 [kg / cm³]. 2 ] or more 1000[kg / cm 2It is more preferable that the following conditions apply.

[0052] The time for the hot pressing process (S03) and the pre-hot pressing treatment is preferably 0.1 hours or more and 50 hours or less, and more preferably 1 hour or more and 10 hours or less.

[0053] The following section provides a more detailed explanation of Substrate 1, referring to its schematic diagram. The following examples can be partially combined with other examples. Some explanations of common elements across the following examples will be omitted.

[0054] Figure 3 shows a specific schematic diagram of the base material 1. The schematic diagram in Figure 3 is a schematic cross-section of the base material 1 along the thickness direction (direction from the first surface A to the second surface B). The base material 1 in Figure 3 includes a first material 1A composed of metal fibers D covered with a coating layer C, and a second material 1B containing metal fibers E.

[0055] The substrate 1 shown in the schematic diagram of Figure 3 includes a first material 1A and a second material 1B that are arranged in layers. The layers of the first material 1A are connected to each other via a coating layer C. The first material 1A and the second material 1B are directly connected by the coating layer C of the first material 1A and the metal fibers E of the second material 1B. In the schematic diagram of Figure 3, the metal fibers D of the first material 1A and the metal fibers E of the second material 1B are the same thickness, but the fiber diameters of the metal fibers D of the first material 1A and the metal fibers 1E of the second material 1B may be different, and their average fiber diameters may be the same or different.

[0056] Furthermore, the metal fiber D contained in the first material 1A is preferably a fiber of one type of metal or one type of alloy, and the metal fiber E contained in the second material 1B is preferably a fiber of one type of metal or one type of alloy. The metal fiber D contained in the first material 1A and the metal fiber E contained in the second material 1B may be composed of the same material or may be composed of different materials.

[0057] Next, we will explain the manufacturing method of the base material 1 shown in the schematic diagram of Figure 3 with a specific example. First, as shown in the schematic diagram of the manufacturing method of the base material 1 in Figure 4, for example, felt made of titanium fibers and plated with Pt is arranged in layers on the lower press plate X as the first material 1A. When using a mold, felt made of titanium fibers and plated with Pt is arranged in layers at the bottom of the mold. Then, as shown in the schematic diagram of the manufacturing method of the base material 1 in Figure 5, multiple layers of unplated titanium fibers are arranged in layers on top of the felt of the first material 1A which is arranged in layers. Next, the layered members sandwiched between the heated upper press plate and the press plates on both sides of the lower press plate X are hot-pressed to obtain the base material 1.

[0058] Figure 6 shows a specific schematic diagram of the substrate 1. The schematic diagram in Figure 6 is a schematic cross-section of the substrate 1 along the thickness direction. The substrate 1 in Figure 6 contains a first material 1A composed of metal particles F coated with a coating layer C, and a second material 1B containing metal particles G.

[0059] The substrate 1 shown in the schematic diagram of Figure 6 includes a layered first material 1A and a layered second material 1B. The layered first material 1A is connected to each other via a coating layer C. The layered first material 1A and the layered second material 1B are directly connected by the coating layer C of the first material 1A and the metal particles G of the second material 1B. In the schematic diagram of Figure 6, the particle size of the metal particles F of the first material 1A and the particle size of the metal particles G of the second material 1B are the same, but the particle size of the metal particles F of the first material 1A and the particle size of the metal particles G of the second material 1B may be different, and their respective average particle sizes may be the same or different.

[0060] Furthermore, the metal particles F contained in the first material 1A are preferably particles of one type of metal or one type of alloy, and the metal particles G contained in the second material 1B are preferably fibers of one type of metal or one type of alloy. The metal particles F contained in the first material 1A and the metal particles G contained in the second material 1B may be composed of the same material or may be composed of different materials.

[0061] Next, we will explain the manufacturing method of the base material 1 shown in the schematic diagram of Figure 6 with a specific example. First, as shown in the schematic diagram of the manufacturing method of the base material 1 in Figure 7, for example, Au-plated titanium particles are arranged in layers on the lower press plate X as the first material 1A. If a mold is used, the Au-plated titanium particles are arranged in layers at the bottom of the mold. Then, as shown in the schematic diagram of the manufacturing method of the base material 1 in Figure 8, before arranging the second material 1B in layers, the layered Au-plated titanium particles are sandwiched between the heated upper press plate Y and the press plates on both sides of the lower press plate X and subjected to hot pressing (pre-hot pressing treatment). Then, separately from the first material 1A, unplated metal particles G of the second material 1B are arranged in layers on the lower press plate and subjected to hot pressing (pre-hot pressing). Then, the hot-pressed layered first material 1A and the hot-pressed layered second material 1B are placed on top of each other as shown in the schematic diagram of Figure 9, and the base material 1 is obtained by hot pressing while sandwiched between the heated upper press plate Y and the press plates on both sides of the lower press plate X.

[0062] Figure 10 shows a specific schematic diagram of the base material 1. The schematic diagram in Figure 10 is a schematic diagram of a cross-section along the thickness direction of the base material 1. The base material 1 in Figure 10 includes a first material 1A composed of metal fibers D and metal particles F coated with a coating layer C, and a second material 1B containing metal fibers E. In Figure 10, the metal fibers D and metal particles F coated with a coating layer C of the first material 1A are mixed, but the metal fibers D and metal particles F coated with a coating layer C are each separate layered bodies, and either the metal fibers D and metal particles F coated with a coating layer C of the layered body are located on the first surface A side.

[0063] The substrate 1 shown in the schematic diagram of Figure 10 includes a first material 1A and a second material 1B that are arranged in layers. The layers of the first material 1A are connected to each other via a coating layer C. The first material 1A and the second material 1B are directly connected by the coating layer C of the metal fibers D and the coating layer C of the metal particles F of the first material 1A and the metal fibers E of the second material 1B. The metal fibers E of the second material 1B are made up of materials with different fiber diameters, with the fiber diameter being thicker on the first surface A side and thinner on the second surface B side.

[0064] Next, we will explain the manufacturing method of the base material 1 shown in the schematic diagram of Figure 10 with a specific example. First, as shown in the schematic diagram of the manufacturing method of the base material 1 in Figure 11, for example, as the first material 1A, Pt-plated metal fibers D and Ni-Au-plated titanium particles (F plated with C) are arranged in layers on a lower press plate. When using a mold, the Pt-plated metal fibers D and Ni-Au-plated titanium particles are arranged in layers at the bottom of the mold. Then, as shown in the schematic diagram of the manufacturing method of the base material 1 in Figure 12, unplated titanium fibers are arranged in layers on top of the layered body in which the first material 1A is arranged in layers. The first material 1A and the second material 1B are combined and hot-pressed to obtain the base material 1.

[0065] Figure 10 shows a specific schematic diagram of the base material 1. The schematic diagram in Figure 10 is a schematic diagram of a cross-section along the thickness direction of the base material 1. The base material 1 in Figure 10 includes a first material 1A composed of metal fibers D and metal particles F coated with a coating layer C, and a second material 1B containing metal fibers E. In Figure 10, the metal fibers D and metal particles F coated with a coating layer C of the first material 1A are mixed, but the metal fibers D and metal particles F coated with a coating layer C are each separate layered bodies, and either the metal fibers D and metal particles F coated with a coating layer C of the layered body are located on the first surface A side.

[0066] Figure 13 shows a specific schematic diagram of the base material 1. The schematic diagram in Figure 10 is a schematic cross-section of the base material 1 along the thickness direction. The base material 1 in Figure 13 includes metal fibers D covered with a coating layer C.

[0067] Next, we will explain the manufacturing method of the base material 1 shown in the schematic diagram of Figure 13 with a specific example. First, as shown in the schematic diagram of the manufacturing method of the base material 1 in Figure 14, for example, Pt-plated metal fibers D are arranged in layers on a lower press plate as the first material 1A. If a mold is used, the Pt-plated metal fibers D are arranged in layers at the bottom of the mold. Then, the first material 1A is hot-pressed to obtain the base material 1.

[0068] (Second Embodiment) The second embodiment relates to an electrode. Figure 15 shows a schematic diagram of the electrode of the embodiment. The electrode 100 shown in the schematic diagram of Figure 15 has a substrate 1 and a catalyst layer 2.

[0069] The electrode 100 of the embodiment can be used, for example, as an anode for water electrolysis. If the catalyst layer 2 further contains a catalyst for a fuel cell, the electrode 100 of the embodiment can also be used as an oxygen electrode for a fuel cell. The electrode 100 of the embodiment can also be used as an anode for electrolytic production of ammonia. The electrode of the embodiment can be used as an anode for an electrolytic device for ammonia synthesis. In the following description, the first embodiment and other embodiments will be explained using water electrolysis as an example, but in addition to water electrolysis, the electrode 100 of the embodiment can be used as an anode for a membrane electrode assembly used in electrolysis for ammonia synthesis, for example, in which ultrapure water is supplied to the anode, the water is decomposed at the anode to produce protons and oxygen, the protons that have been generated pass through the electrolyte membrane, and nitrogen supplied to the cathode combines with the protons and electrons to produce ammonia. The electrode 100 of the embodiment can also be used as a cathode to electrolyze ammonia and produce hydrogen. The electrode of the embodiment can be used as a cathode for a hydrogen generator. In the following description of the second embodiment and other embodiments, water electrolysis will be used as an example. However, the electrode 100 of this embodiment can be used as the cathode of a membrane electrode assembly used in electrolysis for ammonia decomposition, for example, in which ammonia is supplied to the cathode, the ammonia is decomposed at the cathode to generate protons and nitrogen, the generated protons pass through the electrolyte membrane, and at the anode the protons and electrons combine to produce hydrogen.

[0070] A catalyst layer 2 is provided on the first surface A side of the substrate 1. The catalyst layer 2 is provided on the first material 1A of the substrate 1. The catalyst layer 2 is provided on the surface of the first material 1A on the first surface A side of the substrate 1. The catalyst layer 2 is provided on the surface of the coating layer C that covers the metal fibers and / or metal particles of the first material 1A on the first surface A side of the substrate 1.

[0071] The catalyst layer 2 preferably contains one or more elements selected from the group consisting of Ir, Ru, Pt, Pd, Ni, Co, Mn, Fe, Cu, V, Au, Cr, Sr, Y, Ag, Sn, W, Zn, Nb, Ta, Zr, Ti, Mo, and Hf. The catalyst layer 2 preferably contains an oxide containing one or more elements selected from the group consisting of Ir, Ru, Pt, Pd, Ni, Co, Mn, Fe, Cu, V, Au, Cr, Sr, Y, Ag, Sn, W, Zn, Nb, Ta, Zr, Ti, Mo, and Hf.

[0072] The catalyst layer 2 preferably contains one or more noble metals selected from the group consisting of Ir, Ru, Pt, and Pd. The catalyst layer 2 preferably contains one or more elements selected from the group consisting of Ni, Co, Mn, and Fe, and more preferably contains Ni.

[0073] The thickness of the catalyst layer 2 is preferably, for example, 100 nm or more and 2000 nm or less.

[0074] The catalyst layer 2 is preferably a porous material. The porosity of the catalyst layer 2 is preferably 10% or more and 90% or less, and more preferably 30% or more and 70% or less.

[0075] The amount of precious metal in catalyst layer 2 is 0.02 [mg / cm³]. 2 ] or more 1.0[mg / cm 2 Preferably less than or equal to 0.05 [mg / cm³]. 2 ] or more 0.5[mg / cm 2 The following is true. This sum of masses can be measured by ICP-MS.

[0076] The catalyst layer 2 preferably has a structure in which sheet layers 2A and gap layers 2B are alternately stacked. The stacked structure of the catalyst layer 2 is shown in the schematic cross-sectional view of the catalyst layer 2 in Figure 16. The sheet layers 2A and gap layers 2B are stacked in substantially parallel order. The gap layers 2B are mostly hollow, but in some parts, sheet layers 2A protrude and connect to them. The sheet layers 2A are connected by columnar bodies 2C present in the gap layers 2B, and the stacked structure is maintained.

[0077] Sheet layer 2A is a layer in which unsupported catalyst particles, such as metal oxides, are arranged in a sheet-like aggregate. There are some voids within sheet layer 2A. Sheet layer 2A is a dense layer containing a large number of catalyst particles.

[0078] The gap layer 2B is a region sandwiched between the sheet layers 2A and contains catalyst particles, which are unsupported metal oxide particles. Unlike the sheet layers 2A, the gap layer 2B does not have a regular structure of catalyst particles. The gap layer 2B is a region with a low density of catalyst particles.

[0079] The average thickness of each layer of sheet layer 2A is preferably 6 nm or more and 50 nm or less. The average thickness of each layer of gap layer 2B is preferably 6 nm or more and 50 nm or less. The average thickness of each layer of sheet layer 2A is preferably greater than the average thickness of each layer of gap layer 2B.

[0080] Next, an example of a method for fabricating electrode 100 is shown. Sheet layer precursors, which are substantially precursors of sheet layer 2A, and gap layer precursors, which are substantially precursors of gap layer 2B, are alternately sputtered onto substrate 1. At this time, the sheet layer precursors and gap layer precursors are formed in an oxidizing atmosphere. The laminate, in which the sheet layer precursors and gap layer precursors are alternately stacked, is treated with a solution that selectively dissolves the gap layer 2B precursor. The solution used for dissolution is, for example, sulfuric acid. After the solution treatment, the electrode 100 is optionally obtained by heat treatment in an oxidizing atmosphere.

[0081] The electrode 100 of this embodiment has a catalyst layer 2 provided on the surface of a highly durable substrate 1. The electrode 100 of this embodiment has high durability and high electrolytic properties as an electrolytic electrode.

[0082] (Third embodiment) The third embodiment relates to a membrane electrode assembly (MEA). Figure 17 shows a schematic diagram of the membrane electrode assembly 200 of the embodiment. The membrane electrode assembly 200 has a first electrode 11, a second electrode 12, and an electrolyte membrane 13. Preferably, the first electrode 11 is an anode electrode and the second electrode 12 is a cathode electrode. Preferably, the electrode 100 of the first embodiment is used for the first electrode 11 or the second electrode 12. The membrane electrode assembly 200 of the embodiment is a membrane electrode assembly for electrolysis. Preferably, the membrane electrode assembly 200 is used in an electrochemical cell or stack that performs hydrogen generation or oxygen generation.

[0083] The first electrode 11 has a first substrate 11B and a first catalyst layer 11A. The first catalyst layer 11A is provided on the first substrate 11B. Preferably, the first catalyst layer 11A is in direct contact with the electrolyte membrane 13. When electrode 100 is used as the first electrode 11, the first catalyst layer 11A is catalyst layer 2, and the first substrate 11B is substrate 1.

[0084] The second electrode 12 has a second substrate 12B and a second catalyst layer 12A. The second catalyst layer 12A is provided on the second substrate 12B. The second catalyst layer 12A is provided on the electrolyte membrane 13 side. It is preferable that the second catalyst layer 12A is in direct contact with the electrolyte membrane 13.

[0085] As the second substrate 12B, it is preferable to use a porous and highly conductive material. The second substrate 12B is a porous member through which gas and liquid pass. The second substrate 12B is, for example, carbon paper or a metal mesh. As the metal mesh, a porous substrate of valve metal is preferable. As the porous substrate of valve metal, a porous substrate containing one or more metals selected from the group consisting of titanium, aluminum, tantalum, niobium, hafnium, zirconium, zinc, tungsten, bismuth and antimony or a porous substrate of one metal selected from the group consisting of titanium, aluminum, tantalum, niobium, hafnium, zirconium, zinc, tungsten, bismuth and antimony is preferable. The second substrate 12B has a carbon layer (MPL layer) containing carbon fine particles and a water-repellent resin (fluororesin such as PTFE or Nafion). The carbon layer is provided, for example, between the carbon paper and the second catalyst layer 12A.

[0086] The second catalyst layer 12A has a catalyst metal. The second catalyst layer 12A is preferably composed of particles of a catalyst metal and the catalyst metal is not supported on a carrier. The second catalyst layer 12A is preferably a porous catalyst layer. The catalyst metal is not particularly limited, and for example, it contains one or more selected from the group consisting of Pt, Rh, Os, Ir, Pd and Au. It is preferable to contain one or more selected from the group consisting of such catalyst materials. The catalyst metal is preferably a metal, an alloy or a metal oxide. The second catalyst layer 12A is preferably particles of a catalyst material provided on the second substrate 12B. The second catalyst layer 12A preferably has a plurality of catalyst units in which sheet-like catalyst layers and gap layers are alternately laminated, for example.

[0087] The amount of metal per unit area of the second catalyst layer 12A is preferably 0.02 [mg / cm 2 or more and 1.0 [mg / cm 2 or less, more preferably 0.05 [mg / cm 2 or more and 0.5 [mg / cm 2 or less. The sum of this mass can be measured by ICP-MS.

[0088] The porosity of the second catalyst layer 12A is preferably 10% or more and 90% or less, and more preferably 30% or more and 70% or less.

[0089] The electrolyte membrane 13 is preferably a proton-conducting membrane. The electrolyte membrane 13 is preferably a fluorinated polymer or an aromatic hydrocarbon polymer having one or more groups selected from the group consisting of sulfonic acid groups, sulfonimide groups, and sulfate groups. The electrolyte membrane 13 is preferably a fluorinated polymer having sulfonic acid groups. Examples of fluorinated polymers having sulfonic acid groups include Nafion (trademark, manufactured by DuPont), Flemion (trademark, manufactured by Asahi Kasei Corporation), Celemion (trademark, manufactured by Asahi Kasei Corporation), Aquivion (trademark, manufactured by Solvay Specialty Polymers), or Aciplex (trademark, manufactured by Asahi Glass Co., Ltd.). In addition, various conductive membranes such as anion exchange membranes and porous membranes may be used instead of the proton-conducting membrane.

[0090] The thickness of the electrolyte membrane 13 can be appropriately determined considering the membrane's permeability characteristics and durability. From the viewpoint of strength, solubility, and MEA output characteristics, the thickness of the electrolyte membrane 13 is preferably 10 [μm] to 500 [μm], more preferably 40 [μm] to 300 [μm], and even more preferably 80 [μm] to 200 [μm].

[0091] The electrolyte membrane 13 is provided on the first surface A side of the substrate 1. Preferably, the electrolyte membrane 13 is embedded in the gaps of the first material 1A of the first electrode 11 (electrode 100), and more preferably, it is embedded in the gaps of the layered first material 1A of the first electrode 11. Preferably, the electrolyte membrane 13 is embedded in the gaps of the first substrate 11B on which the first catalyst layer 11A is provided, and more preferably, it is embedded in the gaps of the layered first substrate 11B on which the first catalyst layer 11A is provided. The maximum depth to which the electrolyte membrane 13 is embedded in the gaps of the first material 1A is preferably less than or equal to the thickness of the layered first material 1A, more preferably 1% to 100% of the thickness of the layered first material 1A, and even more preferably 1% to 50% considering that the electrolyte membrane 13 moves during long-term operation.

[0092] Preferably, the electrolyte membrane 13 is in direct contact with the first catalyst layer 11A provided on the coating layer C. The electrolyte membrane 13 may also be in direct contact with the surface of the first material 1A where the first catalyst layer 11A is not provided.

[0093] The electrolyte membrane 13 preferably includes a noble metal region on the first electrode 11 side. The noble metal region contains noble metal particles. The noble metal region is preferably located on the surface of the electrolyte membrane 13. The noble metal region is preferably composed of a single region, but may be composed of multiple separate regions.

[0094] The precious metal particles are preferably one or more precious metal particles selected from the group consisting of Pt, Re, Rh, Ir, Pd, and Ru. The precious metal particles may also include alloy particles containing one or more precious metals selected from the group consisting of Pt, Re, Rh, Ir, Pd, and Ru. The precious metal particles are preferably one precious metal particle selected from the group consisting of Pt, Re, Rh, Ir, Pd, and Ru. Pt particles are preferred for the precious metal particles. Re particles are preferred for the precious metal particles. Rh particles are preferred for the precious metal particles. Ir particles are preferred for the precious metal particles. Pd particles are preferred for the precious metal particles. Ru particles are preferred for the precious metal particles.

[0095] The precious metal particles generate on the cathode side and oxidize the hydrogen passing through the electrolyte membrane 13. The precious metal particles can suppress hydrogen leakage. Because the precious metal particles are present on the anode side, they are less likely to oxidize the hydrogen emitted from the cathode side. The region where the precious metal particles are present may also exist in the electrolyte membrane 13 on the second electrode 12 (cathode) side.

[0096] The average circumscribed diameter of the precious metal particles is preferably 0.5 nm or more and 50 nm or less, more preferably 1 nm or more and 10 nm or less, and even more preferably 1 nm or more and 5 nm or less.

[0097] Figure 18 shows a partial cross-sectional view of the membrane electrode assembly 200. Figure 18 illustrates a configuration in which electrode 100 is used as the first electrode 11. Some of the catalyst layer 2 (located higher up; the red area in the figure below) does not need to be in direct contact with the electrolyte membrane 13. Because the catalyst layer is ion conductive, ions can flow through the catalyst layer 2 that is not in direct contact with the electrolyte membrane 13, and move away from the contact point with the electrolyte membrane 13, thus contributing to the reaction.

[0098] The areas where the first material 1A is provided and its ratio can be determined by observing the cross-sections of multiple analysis spots. The configuration in which the first material 1A of the substrate 1 and the electrolyte membrane 13 are in contact can also be evaluated by observing similar analysis spots. As shown in Figure 19, if the length D1 and width D2 (D1≧D2) of the electrode 100 of the substrate 1, electrode 100, or membrane electrode assembly 200 are defined as follows: Imaginary lines are drawn inward from two opposing sides of the electrode 100 at a distance of D3 (=D1 / 10), imaginary lines are drawn inward from two opposing sides of the electrode 100 at a distance of D4 (=D2 / 10), imaginary lines are drawn parallel to the width direction passing through the center of the electrode 100, and imaginary lines are drawn parallel to the length direction passing through the center of the electrode 100. The regions centered at the nine intersection points of these imaginary lines are defined as analysis spots A1 to A9. Each spot is square in shape and at least 1 mm in diameter. 2It has the region shown. The cross-section observed by SEM is in the cross-sectional direction of Figure 17 and is parallel to the width direction. The thickness of each gap layer 2B for analysis spots A1 to A9 is determined at 50 nm intervals in the width direction of the SEM image. The ratio of catalyst layer 2 present in a specific location is the average value for each spot. The ratio of catalyst layer 2 present in a specific location can be determined from the volume and ratio of catalyst layer 2. In addition, the composition of substrate 1 and catalyst layer 2 is determined by analysis using SEM-EDX.

[0099] By using an electrode 100 made of a highly durable substrate 1 as the electrode of the membrane electrode assembly 200, the durability of the membrane electrode assembly 200 is improved.

[0100] (Fourth Embodiment) The fourth embodiment relates to an electrochemical cell. Figure 20 shows a cross-sectional view of the electrochemical cell 300 of the fourth embodiment. The electrochemical cell 300 will be described below using water electrolysis as an example, but hydrogen can also be generated by decomposing ammonia or other substances in addition to water.

[0101] As shown in Figure 20, the electrochemical cell 300 of Embodiment 2 includes a first electrode (anode) 11, a second electrode (card) 12, an electrolyte membrane 13, a gasket 21, a gasket 22, a separator 23, and a separator 24. The sealing material for the first electrode 11 may be used as gasket 21. The sealing material for the second electrode 12 may be used as gasket 22.

[0102] It is preferable to use a membrane electrode assembly 200 in which a first electrode (anode) 11, a second electrode (card) 12, and an electrolyte membrane 13 are joined together. The anode power supply may be provided separately from the separator 23. The cathode power supply may be provided separately from the separator 24.

[0103] In the electrochemical cell 300 shown in Figure 20, a power supply (not shown) is connected to separators 23 and 24, and a reaction occurs at the first electrode 11 and the second electrode 12. For example, water is supplied to the first electrode 11, where the water is decomposed into protons, oxygen, and electrons. The electrode support and power supply are porous materials, and these porous materials function as flow channels. The generated water and unreacted water are discharged, and the protons and electrons are used in the cathode reaction. In the cathode reaction, protons and electrons react to produce hydrogen. Either or both of the generated hydrogen and oxygen can be used as fuel for a fuel cell, for example.

[0104] (Fifth embodiment) The fifth embodiment relates to a stack. Figure 21 is a schematic cross-sectional view showing the stack 400 of the fifth embodiment. The stack 400 of the fifth embodiment shown in Figure 21 consists of multiple MEA200s or electrochemical cells 300s connected in series. Clamping plates 31 and 32 are attached to both ends of the MEAs or electrochemical cells.

[0105] Since the amount of hydrogen produced by an electrochemical cell 300 consisting of a single MEA200 is small, a large amount of hydrogen can be obtained by configuring a stack 400 consisting of multiple MEA200s or multiple electrochemical cells 300s connected in series.

[0106] (Sixth Embodiment) The sixth embodiment relates to an electrolytic apparatus. Figure 22 shows a conceptual diagram of the electrolytic apparatus of the sixth embodiment. The electrolytic apparatus 500 uses an electrochemical cell 300 or a stack 400. The electrolytic apparatus in Figure 22 is for water electrolysis. An electrolytic apparatus for water electrolysis will be described. For example, when generating hydrogen from ammonia, it is preferable to use a different configuration apparatus using electrode 100. The electrodes of the embodiment can also be used in electrolytic apparatuses that electrolyze carbon dioxide to produce organic substances such as methanol and ethylene, or carbon monoxide.

[0107] As shown in Figure 21, a stack of single cells for water electrolysis is used as a stack 400, which is constructed by stacking single cells in series. A power supply 41 is attached to the stack 400, and a voltage is applied between the anode and cathode. A gas-liquid separator 42 and a mixing tank 43 are connected to the anode side of the stack 400 to separate the generated gas from unreacted water. Water is supplied to the mixing tank 43 by a pump 46 from an ion-exchange water production device 44, and then mixed in the mixing tank 43 through a check valve 47 from the gas-liquid separator 42 before being circulated to the anode. The oxygen generated at the anode passes through the gas-liquid separator 42 to obtain oxygen gas. On the cathode side, a hydrogen purification device 49 is connected in conjunction with the gas-liquid separator 48 to obtain high-purity hydrogen. Impurities are discharged through a path with a valve 50 connected to the hydrogen purification device 49. To stably control the operating temperature, the stack and mixing tank can be heated, and the current density during thermal decomposition can be controlled.

[0108] The present invention will be described more specifically below based on examples, but the present invention is not limited to the following examples.

[0109] (Examples) (Example 1) A nonwoven fabric of titanium metal fibers having a first material 1A plated with Pt is used as the base material 1, and a catalyst layer 2 is formed on the base material 1. The catalyst layer 2 has a structure in which 40 sheet layers and 40 gap layers are alternately stacked. Sheet layer precursors containing Ir oxide and gap layer precursors containing Ni oxide are alternately formed by sputtering in an oxidizing atmosphere. The loading density of the precious metal is 0.05 mg / cm³. 2 This is done. Then, the majority of the gap layer precursor is selectively dissolved with sulfuric acid to obtain the electrode 100 of the embodiment. The obtained electrode is used as the anode.

[0110] An electrode is obtained by using carbon paper as a substrate and forming a porous catalyst layer containing Pt on the substrate. The obtained electrode is used as a cathode. The loading density of the precious metal is 0.4 [mg / cm³]. 2 ]

[0111] A Nafion membrane is sandwiched between the obtained anode and cathode as an electrolyte membrane and pressed together to obtain a membrane electrode assembly 200. The obtained membrane electrode assembly is placed between two flow-channel separators, and the membrane electrode assembly 200 sealed with a gasket is fixed to obtain an electrochemical cell. 5[V] is applied between the anode and cathode of the obtained electrochemical cell, and an accelerated dissolution test of titanium from substrate 1 is performed. Before the accelerated dissolution test, and after approximately 150 hours, 200 hours, and 300 hours, water electrolysis is performed to evaluate the cell voltage.

[0112] A cell voltage of 2.00[V] or higher is evaluated as C, a cell voltage of less than 2.00[V] but 1.90[V] or lower is evaluated as B, and a cell voltage of less than 1.90[V] but 1.60[V] or lower is evaluated as A.

[0113] (Comparative Example 1) A film electrode assembly 200 was fabricated in the same manner as in Example 1, except that a nonwoven fabric of titanium fibers without the first material 1A plated with Pt was used as the base material 1, and the cell voltage was evaluated.

[0114] The evaluation results for Example 1 and Comparative Example 1 are shown in the table in Figure 23. Both Example 1 and Comparative Example 1 received an A rating and had low cell voltages before the accelerated dissolution test. However, in Comparative Example 1, the cell voltage increased to a C rating after approximately 150 hours from the start of the accelerated dissolution test. On the other hand, Example 1 still received a B rating even after approximately 300 hours from the start of the accelerated dissolution test, indicating that the increase in cell voltage and the degradation of the membrane electrode assembly 200 were less in Example 1 than in Comparative Example 1.

[0115] In the specification, some elements are represented only by their element symbols.

[0116] The following is a technical proposal for an embodiment. Technical proposal 1 It comprises metal fibers and / or metal particles coated with a coating layer, The coating layer comprises a substrate containing a first material selected from the group consisting of Pt, Au, Pd, Ru, and Ni. Technical proposal 2 The substrate according to Technical Proposal 1, wherein the first materials are in direct contact with each other, and the coating layer of the first material is present between the first materials in the portion that is in direct contact. Technical proposal 3 The substrate according to Technical Proposal 1 or 2, comprising a second material which is metal fibers and / or metal particles not coated with the coating layer. Technical proposal 4 The first material is a substrate according to any one of the technical proposals 1 to 3, which is exposed on the first surface side, which is one of the main surfaces of the substrate. Technical proposal 5 The substrate comprises a second material which is metal fibers and / or metal particles not coated with the coating layer. The first material is the substrate according to Technical Proposal 4, which is not exposed on the second surface side, which is the main surface opposite to the first surface. Technical proposal 6 The first material is exposed on the first surface side, which is one of the main surfaces of the substrate, The second material is the substrate according to Technical Proposal 3, which is exposed on the second surface side, which is the main surface opposite to the first surface. Technical proposal 7 The first material is present in layers on the first surface side, which is one of the main surfaces of the substrate. The second material is present in layers on the second surface side, which is the main surface opposite to the first surface. The substrate according to technical proposal 3 or 6, wherein the first material and the second material, which are present in layers, are in contact with each other via the coating layer. Technical proposal 8 The substrate according to Technical Proposal 7, wherein the thickness of the first material present in the layer is 0.01 [μm] or more and 10 [μm] or less. Technical proposal 9 The aforementioned metal fiber is titanium fiber. The aforementioned metal particles are titanium particles, as described in any one of Technical Proposals 1 to 8. Technical proposal 10 A substrate described in any one of Technical Proposals 1 to 9, The substrate has a catalyst layer provided on it, The catalyst layer is an electrode provided on the first material of the substrate. Technical proposal 11 The electrode described in Technical Proposal 10, The electrode is provided with an electrolyte membrane that is in direct contact with the catalyst layer, The first material is present in layers on the first surface side, which is one of the main surfaces of the substrate. The electrolyte membrane is provided on the first surface side, The electrolyte membrane is inserted into the gap of the first material, A membrane electrode assembly in which the maximum depth to which the electrolyte membrane penetrates the gaps of the first material is less than or equal to the thickness of the layered first material. Technical proposal 12 An electrochemical cell having a membrane electrode assembly as described in Technical Proposal 11. Technical proposal 13 A stack having an electrochemical cell as described in Technical Proposal 12. Technical proposal 14 An electrolytic device having the stack described in Technical Proposal 13. Technical proposal 15 A step of arranging a first material containing metal fibers and / or metal particles coated with a coating layer in layers, A step of arranging a second material, which includes metal fibers and / or metal particles not covered by the coating layer, in layers; A step of heat-pressing the first material and the second material, which are arranged in layers, A method for manufacturing a substrate having

[0117] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. Although PEMEC was given as a water electrolysis cell, the present invention can be similarly applied to other electrolysis cells. These novel embodiments described above can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0118] 1: Base material 1A: Metal fiber 1B: Metal particles 2: Catalyst layer 2A: Sheet layer 2B: Gap layer 2C: columnar body 11: 1st electrode 11A: 1st catalyst layer 11B: 1st base material 12:Second electrode 12A: 2nd catalyst layer 12B: 2nd base material 13: Electrolyte membrane 21: Gasket 22: Gasket 23: Separator 24: Separator 31: Clamping plate 32: Clamping plate 41:Power supply 42: Gas-liquid separation device 43: Mixing tank 44: Ion-exchanged water production device 46: Pump 47: Check valve 48: Gas-liquid separation device 49: Hydrogen purification equipment 50: Valve 100: Electrode 200: Membrane electrode assembly 300: Electrochemical cell 400: Stack 500: Water electrolysis system

Claims

1. It comprises metal fibers and / or metal particles coated with a coating layer, The coating layer is a substrate comprising a first material selected from the group consisting of Pt, Au, Pd, Ru, and Ni.

2. The substrate according to claim 1, wherein the first materials are in direct contact with each other, and the coating layer of the first material is present between the first materials in the portion that is in direct contact.

3. The substrate according to claim 1, wherein the substrate comprises a second material which is metal fibers and / or metal particles not coated with the coating layer.

4. The substrate according to claim 1, wherein the first material is exposed on the first surface side, which is one of the main surfaces of the substrate.

5. The substrate comprises a second material which is metal fibers and / or metal particles not coated with the coating layer. The substrate according to claim 4, wherein the first material is not exposed on the second surface side, which is the main surface opposite to the first surface.

6. The first material is exposed on the first surface side, which is one of the main surfaces of the substrate, The substrate according to claim 3, wherein the second material is exposed on the second surface side, which is the main surface opposite to the first surface.

7. The first material is present in layers on the first surface side, which is one of the main surfaces of the substrate. The second material is present in layers on the second surface side, which is the main surface opposite to the first surface. The substrate according to claim 3, wherein the first material and the second material, which are present in layers, are in contact with each other via the coating layer.

8. The substrate according to claim 7, wherein the thickness of the first material present in the layer is 0.01 [μm] or more and 10 [μm] or less.

9. The aforementioned metal fiber is titanium fiber. The substrate according to claim 1, wherein the metal particles are titanium particles.

10. A substrate according to any one of claims 1 to 9, The substrate has a catalyst layer provided on it, The catalyst layer is an electrode provided on the first material of the substrate.

11. The electrode described in claim 10, The electrode is provided with an electrolyte membrane that is in direct contact with the catalyst layer, The first material is present in layers on the first surface side, which is one of the main surfaces of the substrate. The electrolyte membrane is provided on the first surface side, The electrolyte membrane is inserted into the gap of the first material, A membrane electrode assembly in which the maximum depth to which the electrolyte membrane penetrates the gaps of the first material is less than or equal to the thickness of the layered first material.

12. An electrochemical cell having the membrane electrode assembly described in claim 11.

13. A stack having the electrochemical cell according to claim 12.

14. An electrolytic apparatus having the stack described in claim 13.

15. A step of arranging a first material containing metal fibers and / or metal particles coated with a coating layer in layers, A step of arranging a second material, which includes metal fibers and / or metal particles not covered by the coating layer, in layers; A step of heat-pressing the first material and the second material, which are arranged in layers, A method for manufacturing a substrate having

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