Flexible gas diffusion electrode

Abstract

To provide a flexible gas diffusion electrode that has flexibility and less plastic deformation compared with conventional ones.SOLUTION: A flexible gas diffusion electrode comprises: a core material part with a planar shape having multiple open holes; a gas diffusion substrate having a coating layer that covers the periphery of the core material part; and a catalyst layer having multiple catalyst particles adhered to a first principal surface of the gas diffusion substrate. The coating layer has a yield stress larger than that of the core material part, and an elastic modulus smaller than that of the core material part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a flexible gas diffusion electrode that is primarily used as an electrode in an electrolysis device. [Background technology]

[0002] In recent years, electrolysis devices that electrolyze carbon dioxide to produce carbon compounds have been developed in an effort to realize a carbon-neutral society (for example, Patent Document 1). For example, the electrolysis device described in Patent Document 1 uses a gas diffusion electrode as a cathode electrode, and is capable of reducing carbon dioxide at the cathode electrode through an electrochemical reaction to produce a reduction product containing a carbon compound. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-140042 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when carbon compounds are produced industrially using electrolytic devices, it is necessary to increase the size of the gas diffusion electrodes. However, the gas diffusion electrode of Patent Document 1 has a problem in that it cannot be made large because carbon paper or carbon cloth is used as the gas diffusion layer. That is, if the gas diffusion electrode of Patent Document 1 is made large as it is, the gas diffusion layer may bend due to gravity when the gas diffusion electrode is installed in an electrolysis device. In the gas diffusion layer of Patent Document 1, when such bending or the like occurs, the yield stress is insufficient, so the gas diffusion layer bends beyond the yield stress, undergoes plastic deformation, and breaks irreversibly. Once a break occurs in the gas diffusion layer, a locally weakened portion is created, which may cause the bent portion to break during operation.

[0005] Therefore, an object of the present invention is to provide a flexible gas diffusion electrode that is flexible and less susceptible to plastic deformation than conventional gas diffusion electrodes. [Means for solving the problem]

[0006] One aspect of the present invention for solving the above-mentioned problems is a flexible gas diffusion electrode comprising a gas diffusion substrate having a core portion having a plurality of through holes and extending in a planar shape, a coating layer covering the periphery of the core portion, and a catalyst layer having a plurality of catalyst particles supported on a first main surface of the gas diffusion substrate, wherein the coating layer has a yield stress greater than that of the core portion and a modulus of elasticity less than that of the core portion.

[0007] The term "yield stress" used here refers to the stress at which the plasticity of a material begins.

[0008] According to this aspect, the core portion is reinforced by the coating layer having a large yield stress, so that the core portion is less susceptible to plastic deformation than conventional ones. According to this aspect, since the core portion has a higher elastic modulus than the covering layer, the shape can be maintained even if bending or the like occurs.

[0009] In a preferred aspect, the coating layer contains conductive particles.

[0010] According to this aspect, a conductive path can be ensured that connects the gas diffusion substrate side to the catalyst particles of the catalyst layer via the coating layer.

[0011] In a preferred aspect, when the gas diffusion substrate is viewed in cross section, a 1 μm gap is formed between the gas diffusion substrate and the catalyst layer. 2 In the region, 95% or more of the catalyst particles constituting the catalyst layer are directly adhered or fused to the gas diffusion substrate or adjacent catalyst particles.

[0012] According to this aspect, the catalyst particles in the catalyst layer are directly fixed or fused to each other without the intervention of a binder or the like, so that the interfacial resistance in the catalyst layer can be reduced.

[0013] In a preferred aspect, the catalyst particles are copper particles.

[0014] According to this aspect, for example, when used in the reduction of carbon dioxide, carbon dioxide can be reduced to a C2 compound.

[0015] In a preferred aspect, the core portion is formed by weaving a plurality of fibers.

[0016] This aspect makes it difficult for the shape to be distorted.

[0017] In a preferred aspect, the coating layer has a first coating portion covering the first main surface side of the core material portion and a second coating portion covering the second main surface side of the core material portion, and the second coating portion covers most of the second main surface of the core material portion.

[0018] In this context, "majority" means more than 50% of the total.

[0019] According to this aspect, since both sides of the core portion are covered with the coating layer, the core portion is less likely to undergo plastic deformation.

[0020] One aspect of the present invention is a flexible gas diffusion electrode comprising a gas diffusion substrate having a core portion having a plurality of through holes and extending in a planar shape, a coating layer covering the periphery of the core portion, and a catalyst layer having a plurality of catalyst particles supported on a first main surface of the gas diffusion substrate, the flexible gas diffusion electrode having a higher yield stress than one in which the core portion is made of carbon paper.

[0021] According to this aspect, the material has flexibility and is less susceptible to plastic deformation than conventional materials. [Effects of the Invention]

[0022] According to the present invention, the material has flexibility and is less susceptible to plastic deformation than conventional materials. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a diagram illustrating the principle of operation of an electrolysis device according to a first embodiment of the present invention. [Figure 2] FIG. 4 is a diagram showing the principle of operation of an electrolysis device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present invention will be described in detail.

[0025] The electrolysis device 1 of the first embodiment of the present invention mainly produces an oxide gas such as oxygen at the anode electrode section 21 shown in FIG. 1 , and produces a carbon compound gas from a material gas containing a carbon element such as carbon dioxide at the cathode electrode section 22. As shown in FIG. 1 , the electrolysis device 1 includes an electrolysis unit 2, an electrolyte solution supply unit 3, an anode-side recovery unit 4, an anode-side flow path 5, a material gas supply unit 6, a cathode-side recovery unit 7, a cathode-side flow path 8, and a power supply unit 9.

[0026] <Electrolytic section 2> As shown in FIG. 1, the electrolysis unit 2 includes an anode electrode unit 21, a cathode electrode unit 22, and an ion exchange unit .

[0027] (anode electrode part 21) The anode electrode section 21 is a section that oxidizes the electrolytic solution 10 passing through the anode-side flow path 5 during electrolysis to generate oxide gas. The anode electrode section 21 is provided between the ion exchange section 23 and the anode side flow path 5, and a portion of the anode electrode section 21 is exposed to the anode side flow path 5. The anode electrode part 21 is not particularly limited as long as it is conductive and allows the electrolyte 10 to move in the thickness direction toward the ion exchange part 23 side, and for example, a platinum mesh or the like can be used.

[0028] (Cathode electrode part 22) The cathode electrode part 22 is paired with the anode electrode part 21, and is a part that reduces the material gas passing through the cathode-side flow path 8 during electrolysis to generate a reduced gas. The cathode electrode section 22 of this embodiment is capable of reducing carbon dioxide contained in the source gas to generate a carbon compound gas as a reducing gas.

[0029] The cathode electrode section 22 is a gas diffusion electrode that allows gas to pass from the cathode-side flow path 8 side to the ion exchange section 23 side, and is a flexible electrode that is flexible and elastically deformable. The cathode electrode part 22 includes a gas diffusion substrate 30 and a catalyst layer 31, as shown in FIG.

[0030] The gas diffusion substrate 30 is a gas diffusion layer that allows gas to pass through in the thickness direction but does not allow the electrolyte solution 10 to pass through. The area of ​​the gas diffusion substrate 30 is 400 cm 2 More than 10000cm 2 It is preferable that: The gas diffusion substrate 30 includes a core portion 40 and a coating layer 41, as shown in FIG.

[0031] The core portion 40 has a planar shape and has a plurality of through holes that penetrate in the thickness direction. The core part 40 is a fabric-like body formed by weaving a plurality of fibers, and the through-holes are formed by the weave of the fibers. Specifically, the core part 40 is a carbon cloth woven from a plurality of carbon fibers, and is electrically conductive and elastically deformable. The weave of the fibers in the core portion 40 is not particularly limited, and may be, for example, plain weave, twill weave, satin weave, or the like.

[0032] The average thickness of the core portion 40 is preferably 100 μm or more and 500 μm or less. The term "average thickness" used here refers to the arithmetic mean of thicknesses at three random points in an electron microscope photograph. The same applies hereinafter.

[0033] The covering layer 41 is a layer that covers the periphery of the core portion 40, and has a first covering portion 51 and a second covering portion 52 as shown in FIG.

[0034] The first covering portion 51 is a layer that covers the first main surface 55 (the surface on the ion exchange portion 23 side) of the core portion 40, and has a smaller elastic modulus than the core portion 40 and a larger yield stress than the core portion 40. The first covering portion 51 is preferably less likely to bend or break than the core portion 40 . The first covering portion 51 preferably covers most of the first main surface 55 of the core portion 40, more preferably covers 80% or more, and even more preferably covers 95% or more. The first covering portion 51 of the present embodiment covers the entire first main surface 55 of the core portion 40 and hides the first main surface 55 of the core portion 40. In other words, the first main surface 55 of the core portion 40 is covered by the first covering portion 51 and is therefore not visible. The average thickness of the first covering portion 51 is preferably 100 μm or more and 500 μm or less.

[0035] The second covering portion 52 is a layer that covers the second main surface 56 (surface on the cathode-side flow path 8 side) of the core portion 40, and has a lower elastic modulus than the core portion 40 and a higher yield stress than the core portion 40. The second covering portion 52 is preferably less likely to bend or break than the core portion 40 . The second covering portion 52 preferably covers most of the second main surface 56 of the core portion 40, more preferably covers 80% or more, and even more preferably covers 95% or more. The second covering portion 52 of the present embodiment covers the entire second main surface 56 of the core portion 40 and hides the second main surface 56 of the core portion 40. In other words, the second main surface 56 of the core portion 40 is covered by the second covering portion 52 and is therefore not visible. The average thickness of the second covering portion 52 is preferably 100 μm or more and 500 μm or less.

[0036] As shown in FIG. 1, the first covering portion 51 includes conductive particles 60 and a reinforcing resin 61, and the second covering portion 52 includes conductive particles 70 and a reinforcing resin 71.

[0037] The conductive particles 60, 70 are not particularly limited as long as they are conductive, and for example, carbon particles such as carbon black can be used.

[0038] The reinforcing resins 61 and 71 have a higher yield stress than the core portion 40 and reinforce the yield stress of the gas diffusion substrate 30 . The reinforcing resins 61, 71 are not particularly limited as long as they have a higher yield stress than the core portion 40, and for example, polytetrafluoroethylene (PTFE) particles or the like can be used. The reinforcing resins 61 and 71 are water-repellent resins that have water-repellent properties. In this embodiment, the core portion 40 is also partially impregnated with the reinforcing resins 61 and 71 .

[0039] The catalyst layer 31 is a layer made up of a plurality of catalyst particles 80, and is configured such that the catalyst particles 80 are supported by the first covering portion 51. The catalyst particles 80 are not particularly limited as long as they function as a catalyst, and may be made of gold, silver, copper, platinum, palladium, nickel, cobalt, iron, manganese, titanium, cadmium, zinc, indium, gallium, lead, tin, or the like. The catalyst particles 80 of this embodiment are copper particles, and are capable of reducing carbon dioxide contained in the source gas to generate C2 compounds.

[0040] The catalyst layer 31 of this embodiment is formed in a layer shape with adjacent catalyst particles 80, 80 fixed together, and is composed of only the catalyst particles 80 without including a binder. The cathode electrode part 22 is formed by arranging the gas diffusion substrate 30 and the catalyst layer 31 over a width of 1 μm when the gas diffusion substrate 30 is viewed in cross section. 2 Of the catalyst particles 80 constituting the catalyst layer 31 in this region, it is preferable that 95% or more of the catalyst particles 80 are directly fixed to the gas diffusion substrate 30 or adjacent catalyst particles 80 . The average particle size of the catalyst particles 80 is smaller than the average particle size of the conductive particles 60, 70, and is preferably 10 nm or more and 100 nm or less, and more preferably 30 nm or more and 50 nm or less. The term "average particle size" used here refers to the average particle size of 20 randomly selected particles in an electron microscope photograph. The same applies hereinafter.

[0041] (ion exchange section 23) The ion exchange unit 23 is a separator interposed between the anode electrode unit 21 and the cathode electrode unit 22, as shown in FIG. The ion exchange section 23 is a film that allows only specific ions (carriers) to move in the thickness direction and restricts the movement of the remaining ions and electrons. The ion exchange section 23 of this embodiment is a cation exchange membrane, which restricts or disables the movement of anions and electrons and allows the movement of only cations.

[0042] The ion exchange section 23 also functions as a blocking film that blocks gas flow in the thickness direction. The ion exchange section 23 is not particularly limited as long as it is capable of ion exchange and does not cause crossover of hydrogen or oxygen, and for example, a polymer membrane such as a membrane of a perfluoroalkylsulfonic acid-based polymer can be used.

[0043] <Electrolyte supply section 3> The electrolytic solution supply unit 3 is a part that supplies an electrolytic solution 10 to the anode side flow path 5, as shown in FIG.

[0044] <Anode side recovery section 4> The anode-side recovery section 4 is a section that recovers the electrolyte solution 10 and the oxide gas generated in the anode electrode section 21 from the anode-side flow path 5 .

[0045] <Anode side flow path 5> The anode-side flow path 5 is a flow path that connects the electrolyte supply unit 3 and the anode-side recovery unit 4, and the anode electrode unit 21 forms the inner wall at the middle part in the direction of the electrolyte 10 flow.

[0046] <Material gas supply unit 6> The source gas supply unit 6 is a part that supplies the source gas toward the cathode side flow path 8.

[0047] <Cathode-side recovery section 7> The cathode-side recovery section 7 is a section that recovers the material gas and the reducing gas generated in the cathode electrode section 22 from the cathode-side flow path 8.

[0048] <Cathode side flow path 8> The cathode-side flow path 8 is a flow path that connects the source gas supply unit 6 and the cathode-side recovery unit 7, and the cathode electrode unit 22 forms the inner wall at the middle part in the gas flow direction.

[0049] <Power supply device 9> The power supply device 9 is a power supply device that supplies power to the electrolysis unit 2, and is a voltage application device that applies a voltage between the anode electrode unit 21 and the cathode electrode unit 22. The power supply device 9 is not particularly limited as long as it can apply a voltage between the anode electrode section 21 and the cathode electrode section 22 . The power supply device 9 may be a commercial power supply device, a power generation device using renewable energy such as a solar cell, or a power storage device such as a secondary battery.

[0050] (electrolyte 10) During electrolysis, the electrolytic solution 10 is oxidized by the anode electrode part 21, and oxide gases such as oxygen are generated. The electrolyte 10 is not particularly limited as long as it can be oxidized by the anode electrode part 21, and for example, water can be used.

[0051] (material gas) During electrolysis, the material gas is reduced by the cathode electrode portion 22 to generate a reduced gas. The source gas is not particularly limited as long as it can be reduced by the cathode electrode section 22, but for example, a carbon compound gas containing carbon element such as carbon dioxide can be used.

[0052] Next, a gas generating operation for generating an oxide gas and a carbon compound gas using the electrolysis device 1 of this embodiment will be described.

[0053] In the gas generating operation of this embodiment, first, the electrolytic solution 10 is supplied from the electrolytic solution supply unit 3 to the anode side flow path 5, and the anode side flow path 5 is filled with the electrolytic solution 10 (filling step).

[0054] Next, while supplying the electrolytic solution 10 from the electrolytic solution supply unit 3 to the anode side flow path 5 and flowing the material gas from the material gas supply unit 6 to the cathode side flow path 8, a voltage is applied between the anode electrode unit 21 and the cathode electrode unit 22 by the power supply unit 9 (application process).

[0055] At this time, the electrolytic solution 10 is oxidized on the anode electrode unit 21 to generate an oxide gas, which flows into the anode-side flow path 5 and is collected together with the electrolytic solution 10 in the anode-side recovery unit 4. Meanwhile, on the cathode electrode unit 22, the material gas is reduced to generate a carbon compound gas, which flows into the cathode-side flow path 8 and is collected together with the unreacted material gas in the cathode-side recovery unit 7.

[0056] Then, the recovered oxide gas and the electrolytic solution 10 are separated in the anode-side recovery unit 4 or another separation device, and the unreacted material gas and the carbon compound gas are separated in the cathode-side recovery unit 7 or another separation device (separation step).

[0057] According to the cathode electrode part 22 of this embodiment, the core part 40 is reinforced by the coating layer 41 having a large yield stress, and therefore is less susceptible to plastic deformation than when the core part 40 is formed alone. According to the cathode electrode part 22 of this embodiment, the core part 40 has a higher elastic modulus than the coating layer 41, and therefore the shape can be maintained even if bending or the like occurs.

[0058] According to the cathode electrode portion 22 of this embodiment, the first coating portion 51 of the coating layer 41 contains conductive particles 60, so that a conductive path can be secured that connects from the gas diffusion substrate 30 side to the catalyst particles 80 of the catalyst layer 31 via the first coating portion 51 of the coating layer 41.

[0059] According to the cathode electrode part 22 of this embodiment, the catalyst particles 80 of the catalyst layer 31 are directly fixed to each other without the intervention of a binder or the like, so that the interface resistance in the catalyst layer 31 can be reduced.

[0060] According to the cathode electrode part 22 of this embodiment, the catalyst particles 80 are copper particles, and therefore, when used to reduce a source gas containing carbon dioxide, the carbon dioxide can be reduced to a C2 compound.

[0061] According to the cathode electrode part 22 of this embodiment, the core part 40 is made of a plurality of woven fibers, and therefore is less likely to lose its shape.

[0062] According to the cathode electrode part 22 of this embodiment, both sides of the core part 40 are covered with the coating layer 41, and therefore, the core part 40 is less likely to undergo plastic deformation.

[0063] Next, an electrolysis device 101 according to a second embodiment of the present invention will be described. Note that the same components as those in the electrolysis device 1 according to the first embodiment will be denoted by the same reference numerals and will not be described again. The same applies hereinafter.

[0064] As shown in FIG. 2 , the electrolysis device 101 of the second embodiment includes an anode electrode unit 121, a cathode electrode unit 22, an ion exchange unit 23, an electrolyte solution supply unit 3, an electrolyte solution recovery unit 104, an anode side flow path 5, a material gas supply unit 6, a cathode side recovery unit 7, a cathode side flow path 8, a power supply unit 9, a second material gas supply unit 106, an anode side recovery unit 107, and a second anode side flow path 108.

[0065] <Anode electrode part 121> The anode electrode section 121 is a section that oxidizes the second source gas passing through the second anode-side flow path 108 during electrolysis to generate an oxide gas. The anode electrode section 121 is provided between the anode side flow path 5 and the second anode side flow path 108, with one main surface (the main surface on the ion exchange section 23 side) exposed to the anode side flow path 5 and the other main surface (the main surface opposite to the ion exchange section 23) exposed to the second anode side flow path 108. The anode electrode section 121 is a gas diffusion electrode that allows gas to pass from the second anode flow path 108 side to the anode flow path 5 side, and is a flexible electrode that is flexible and elastically deformable.

[0066] 2, the anode electrode part 121 includes a gas diffusion substrate 30 and a catalyst layer 131. That is, the anode electrode part 121 differs from the cathode electrode part 22 in the catalyst layer 131.

[0067] As shown in FIG. 2, the catalyst layer 131 is a layer in which a plurality of catalyst particles 180 are supported on carrier particles 181. The catalyst particles 180 are not particularly limited as long as they function as a catalyst, and may be made of gold, silver, copper, platinum, palladium, nickel, cobalt, iron, manganese, titanium, cadmium, zinc, indium, gallium, lead, tin, or the like. The catalyst particles 180 of this embodiment are platinum particles, and are capable of oxidizing the second material gas to generate an oxidizing gas.

[0068] The carrier particles 181 are water-repellent particles that have water repellency, and are fixing particles that fix the catalyst particles 180 to the gas diffusion substrate 30 . The carrier particles 181 are not particularly limited as long as they can be fixed to the gas diffusion substrate 30, and for example, polytetrafluoroethylene (PTFE) particles can be used. The carrier particles 181 of this embodiment are resin particles made of the same resin as the reinforcing resins 61 and 71, and have elasticity and a higher yield stress than the core portion 40. The average particle size of the carrier particles 181 is larger than the average particle size of the catalyst particles 180, and is preferably 0.1 μm or more and 0.0.5 μm or less.

[0069] <Second material gas supply unit 106> The second source gas supply unit 106 is a part that supplies the second source gas toward the second anode side flow path 108.

[0070] <Anode side recovery section 107> The anode-side recovery section 107 is a section that recovers the second source gas and the oxide gas generated in the anode electrode section 121 from the second anode-side flow path .

[0071] <Second anode side flow path 108> The second anode-side flow path 108 is a flow path that connects the second source gas supply unit 106 and the anode-side recovery unit 107, and the anode electrode unit 121 forms the inner wall at the middle part in the gas flow direction.

[0072] (Second material gas) During electrolysis, the second material gas is oxidized by the anode electrode part 121 to generate an oxide gas. The second material gas is not particularly limited as long as it can be reduced by the anode electrode part 121, and for example, water vapor can be used.

[0073] Next, a gas generating operation for generating an oxide gas and a carbon compound gas using the electrolysis device 101 of this embodiment will be described.

[0074] In the gas generating operation of the second embodiment, the application step is different from the gas generating operation of the first embodiment.

[0075] In the application process of the gas generation operation of the second embodiment, while supplying the electrolytic solution 10 from the electrolytic solution supply unit 3 to the anode side flow path 5, a material gas is flowed from the material gas supply unit 6 to the cathode side flow path 8, and further while flowing a second material gas from the second material gas supply unit 106 to the second anode side flow path 108, a voltage is applied between the anode electrode unit 121 and the cathode electrode unit 22 by the power supply unit 9.

[0076] At this time, the second material gas is oxidized on the anode electrode unit 121 to generate an oxide gas, and the generated oxide gas flows into the second anode-side flow path 108 and is recovered together with the unreacted second material gas in the anode-side recovery unit 107. Meanwhile, on the cathode electrode unit 22, the material gas is reduced to generate a carbon compound gas, and the generated carbon compound gas flows into the cathode-side flow path 8 and is recovered together with the unreacted material gas in the cathode-side recovery unit 7.

[0077] In the above-described embodiment, the catalyst layer 31 is formed by the catalyst particles 80 being fixed to one another, but the present invention is not limited to this. The catalyst layer 31 may also be formed by the catalyst particles 80 being fused to one another.

[0078] In the above embodiment, the covering portions 51 and 52 are provided on both main surfaces 55 and 56 of the core portion 40, respectively, but the present invention is not limited to this. The covering portions 51 and 52 may be provided on only one main surface of the core portion 40.

[0079] In the above-described embodiment, the core portion 40 is woven from a plurality of fibers, but the present invention is not limited to this. The core portion 40 may also be knitted from a plurality of fibers.

[0080] In the above-described embodiment, the coating layer 41 is a conductor having conductivity due to the conductive particles 60, 70, but the present invention is not limited to this. The coating layer 41 may be an insulator without the conductive particles 60, 70. In this case, a voltage is applied directly to the catalyst layer 31 from the power supply device 9.

[0081] In the above-described embodiment, the core portion 40 is a conductor having electrical conductivity, but the present invention is not limited to this. The core portion 40 may be an insulator having no electrical conductivity. In this case, a voltage is applied from the power supply device 9 to the coating layer 41 or the catalyst layer 31.

[0082] In the above-described embodiments, each component can be freely substituted or added between the respective embodiments as long as it falls within the technical scope of the present invention. [Explanation of symbols]

[0083] 22 Cathode electrode part (flexible gas diffusion electrode) 30 Gas diffusion substrate 31,131 Catalyst layer 40 Core part 41 Covering layer 51 First covering part 52 Second coating section 55 First main surface 56 Second main surface 60,70 Conductive particles 80,181 catalytic particles 121 Anode electrode part (flexible gas diffusion electrode)

Claims

1. a gas diffusion substrate having a core portion having a plurality of through holes and extending in a planar shape, a coating layer covering the periphery of the core portion, and a catalyst layer having a plurality of catalyst particles supported on a first main surface of the gas diffusion substrate; The flexible gas diffusion electrode, wherein the covering layer has a higher yield stress than the core portion and a lower elastic modulus than the core portion.

2. 10. The flexible gas diffusion electrode of claim 1, wherein the coating layer comprises conductive particles.

3. When the gas diffusion substrate is viewed in cross section, a gap of 1 μm spanning the gas diffusion substrate and the catalyst layer is formed. ２ 3. The flexible gas diffusion electrode according to claim 1, wherein 95% or more of the catalyst particles constituting the catalyst layer in the region are directly adhered or fused to the gas diffusion substrate or adjacent catalyst particles.

4. 3. The flexible gas diffusion electrode according to claim 1, wherein the catalyst particles are copper particles.

5. 3. The flexible gas diffusion electrode according to claim 1, wherein the core portion is made of a plurality of woven fibers.

6. the coating layer has a first coating portion covering a first main surface side of the core portion and a second coating portion covering a second main surface side of the core portion, 6. The flexible gas diffusion electrode according to claim 5, wherein the second covering portion covers most of the second main surface of the core portion.

7. a gas diffusion substrate having a core portion having a plurality of through holes and extending in a planar shape, a coating layer covering the periphery of the core portion, and a catalyst layer having a plurality of catalyst particles supported on a first main surface of the gas diffusion substrate; A flexible gas diffusion electrode having a core material portion with a higher yield stress than that of a core material portion made of carbon paper.

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