Catalyst coating membrane structure unit for producing hydrogen by electrolyzing water, membrane electrode structure and application

Abstract

The utility model relates to the field of hydrogen production by water electrolysis through a proton exchange membrane, in particular to a catalyst coating membrane structure unit for hydrogen production by water electrolysis, a membrane electrode structure and application, which comprises a proton exchange membrane, a cathode catalyst layer and an anode catalyst layer, the cathode catalyst layer and the anode catalyst layer are arranged on two sides of the proton exchange membrane, and the anode catalyst layer is arranged on the proton exchange membrane. A hydrogen blocking structure is arranged between the anode catalyst layer and the proton exchange membrane, the hydrogen blocking structure is composed of a high oxygen permeation layer and a hydrogen catalyst layer which are connected, and the hydrogen catalyst layer is arranged on one side close to the cathode catalyst layer. The utility model has the following advantages: (1) through the hydrogen blocking structure, under the condition of not increasing electrolysis energy consumption, the hydrogen permeability is reduced, and the performance of the membrane electrode is improved; and (2) the high oxygen permeation layer is adopted in the hydrogen blocking structure, so that the efficiency that the anode side oxygen reaches the hydrogen catalyst layer is greatly improved while the hydrogen is further blocked, the hydrogen elimination efficiency is improved, and the overall performance and the safety of the membrane electrode are further improved.

Description

Technical Field

[0001] This utility model relates to the field of proton exchange membrane electrolysis for hydrogen production, and more specifically, to a catalyst-coated membrane structure unit, membrane electrode structure, and application for hydrogen production by water electrolysis. Background Technology

[0002] Hydrogen energy is considered the best energy carrier due to its cleanliness, high efficiency, pollution-free nature, wide application, zero carbon dioxide emissions, and the ability to be stored and transported. Currently, the most practical and cleanest method for converting renewable clean energy into hydrogen is water electrolysis. Proton exchange membrane electrolysis (PEMWE) technology and devices are currently a key development focus. PEM electrolysis technology utilizes proton exchange membranes to efficiently decompose water, producing hydrogen and oxygen. It boasts advantages such as high current density, fast response, and compact structure, making it suitable for integration with renewable energy sources.

[0003] In proton exchange membrane water electrolysis, the membrane electrode assembly is the core component of the water electrolysis device. It mainly consists of the proton exchange membrane in the middle, the anion and cation catalyst layers on both sides of the proton exchange membrane in close contact with the proton exchange membrane, and the gas diffusion layer on the outside of the catalyst layer. The catalyst layer on one side of the proton exchange membrane is the anode catalyst layer, and the one on the other side is the cathode catalyst layer. When the water electrolysis device is working, water undergoes an oxygen evolution reaction under the catalysis of the anode catalyst (OER), producing and releasing oxygen, while releasing electrons and protons (1); protons migrate from the anode to the cathode through the proton exchange membrane and undergo a hydrogen evolution reaction under the catalysis of the cathode catalyst, releasing hydrogen gas (2).

[0004] Anode: 2H₂O = O₂ + 4H₂O + + 4e - (1)

[0005] Cathode: 4H + + 4e - =2H2(2)

[0006] Proton exchange membranes (PEMs) play a crucial role in PEM water electrolysis devices. Commonly used PEM materials are perfluorosulfonic acid resin membranes, such as Nafion 115 and Nafion 117 membranes. These membrane materials possess high proton conductivity and chemical stability, effectively isolating gases and conducting protons. Thanks to the low gas permeability and high mechanical strength of the PEM, PEMWE electrolyzers can directly produce high-pressure hydrogen. High-pressure PEMWE electrolyzers can be directly supplied to hydrogen-demanding systems such as gas pipelines (70 bar), synthetic ammonia (300 bar), gas cylinder storage tanks (500 bar), and hydrogen fuel cell vehicles (700 bar) without the need for mechanical compression, significantly reducing system construction costs and operating energy consumption.

[0007] However, in actual operation, PEMWE electrolyzers for producing high-pressure hydrogen face the problem of hydrogen gas at the cathode (hydrogen production side) undergoing reverse osmosis through the membrane to the anode (oxygen production side). Studies have shown that when the hydrogen-oxygen pressure difference in the PEMWE electrolyzer is 5 MPa, the hydrogen content in the anode oxygen will reach 5% under steady-state conditions, which is within the explosive limit of hydrogen in pure oxygen (4%-94%), jeopardizing the safe operation of the system. When the cathode pressure is much higher than the anode pressure, water will move from the high-pressure side to the low-pressure side within the membrane, and dissolved hydrogen gas will be transferred to the oxygen production side via convection, leading to an increase in the hydrogen content in the oxygen.

[0008] To reduce hydrogen permeation, commonly used proton exchange membranes for water electrolysis to produce hydrogen are relatively thick, such as Chemours' Nafion 117 (7 mil thick, 1 mil equals 25.4 micrometers) or Nafion 115 (5 mil thick). However, this method has a problem: during water electrolysis to produce hydrogen, the thicker the proton exchange membrane, the higher its resistance, and the higher the energy consumption, which is detrimental to improving the overall performance and efficiency of the electrolyzer. Utility Model Content

[0009] This invention aims to overcome at least one defect (deficiency) of the prior art and provides a catalyst-coated membrane structure unit, membrane electrode structure and application for hydrogen production by water electrolysis, used to reduce the permeability of hydrogen from the cathode side to the anode side.

[0010] One objective of this invention is to provide a catalyst-coated membrane structure unit for hydrogen production via water electrolysis, comprising a proton exchange membrane, a cathode catalytic layer, and an anode catalytic layer. The cathode catalytic layer and the anode catalytic layer are coated on both sides of the proton exchange membrane. A hydrogen-blocking structure is provided between the anode catalytic layer and the proton exchange membrane. The hydrogen-blocking structure consists of a connected high-oxygen-permeable layer and a hydrogen catalytic layer, with the hydrogen catalytic layer located on the side near the cathode catalytic layer.

[0011] In this technical solution, the hydrogen barrier structure is used to reduce the permeability of hydrogen from the cathode to the anode; the hydrogen catalytic layer is used to catalytically eliminate hydrogen that has permeated through the proton exchange membrane from the cathode, and hydrogen and oxygen react on this layer. This layer comprises a perfluorosulfonic acid resin, a catalyst, and a conductive support. The perfluorosulfonic acid resin is preferably a highly oxygen-permeable resin, and the catalyst can be one or more of Pt, Pt / Co, Pt / Pd, and Pt / Ni, with a precious metal loading of ≤0.1 mg / cm³. 2 When hydrogen permeates through the proton exchange membrane from the cathode side, it first reaches the hydrogen-oxygen reaction catalytic layer. Under the catalysis of the catalyst on this layer, the oxygen permeating from the anode side and the hydrogen permeating from the cathode react to produce water, thereby eliminating the hydrogen.

[0012] The high oxygen permeability layer can be made of different kinds of high oxygen permeability materials, as long as it can achieve an oxygen permeability higher than that of traditional perfluorosulfonic acid resin membranes. The traditional perfluorosulfonic acid resin membrane is Nafion membrane.

[0013] If a high-oxygen-permeable layer is made of traditional Nafion material, it only prevents hydrogen from further permeating to the anode, and at the same time, it also blocks oxygen from the anode side from reaching the hydrogen catalytic layer to some extent, thus affecting the hydrogen catalytic efficiency. In this solution, the membrane layer is made highly oxygen-permeable, which further blocks hydrogen while greatly improving the efficiency of oxygen from the anode side reaching the hydrogen catalytic layer, thereby improving the hydrogen removal efficiency and the hydrogen permeation effect.

[0014] Furthermore, the high oxygen permeability layer is a high oxygen permeability perfluorosulfonic acid polymer layer.

[0015] Furthermore, the thickness of the highly oxygen-permeable layer is 0.01 μm to 25 μm.

[0016] Furthermore, the thickness of the hydrogen catalyst layer is 0.01 μm to 5 μm.

[0017] Furthermore, the thickness of the proton exchange membrane is 0.01 μm to 50 μm.

[0018] Furthermore, the hydrogen barrier structure also includes a porous support structure.

[0019] Furthermore, the high oxygen permeability layer and the hydrogen catalytic layer have the same area.

[0020] Furthermore, two interconnected hydrogen-blocking structures are provided between the anode catalyst layer and the proton exchange membrane, and the hydrogen oxidation layers of the two hydrogen-blocking structures are both located on one side near the cathode catalyst layer.

[0021] Another objective of this invention is to provide a membrane electrode structure, comprising an anode gas diffusion layer, a cathode gas diffusion layer, and a catalyst-coated membrane structure unit of any one of the above, wherein the anode gas diffusion layer, the catalyst-coated membrane unit, and the cathode gas diffusion layer are sequentially stacked and connected.

[0022] Another objective of this invention is to provide an application of the above-mentioned membrane electrode structure in a proton exchange membrane water electrolysis hydrogen production device.

[0023] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0024] (1) This utility model prevents hydrogen from permeating from the cathode into the anode through a hydrogen barrier structure and eliminates hydrogen. At the same time, this solution does not require increasing the thickness of the proton exchange membrane. Therefore, this solution reduces the permeation rate of hydrogen to the anode and improves the performance of the membrane electrode without the need for electrolysis energy consumption. It also eliminates the safety hazards caused by the mixing of hydrogen and oxygen and provides the safety of the membrane electrode.

[0025] (2) The hydrogen barrier structure of this utility model adopts a high oxygen permeability layer. While the layer further blocks hydrogen, it greatly improves the efficiency of oxygen reaching the hydrogen catalytic layer on the anode side, thereby improving the hydrogen elimination efficiency.

[0026] (3) The catalyst coating membrane structure unit of this utility model has a simple structure, good processability, and is suitable for mass production. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the catalyst coating film structure unit of this utility model.

[0028] Figure reference numerals: 1. Anode catalyst layer; 2. Proton exchange membrane; 3. Cathode catalyst layer; 4. Hydrogen barrier structure; 42. Hydrogen catalyst layer; 41. High oxygen permeability layer. Detailed Implementation

[0029] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this invention. To better illustrate the following embodiments, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0030] Example 1

[0031] like Figure 1 As shown, this embodiment provides a catalyst-coated membrane structure unit for hydrogen production by water electrolysis, including a proton exchange membrane 2, a cathode catalyst layer 3, and an anode catalyst layer 1. The cathode catalyst layer 3 and the anode catalyst layer 1 are coated on both sides of the proton exchange membrane 2. A hydrogen barrier structure 4 is provided between the anode catalyst layer 1 and the proton exchange membrane 2. The hydrogen barrier structure 4 is composed of a connected high oxygen permeability layer 41 and a hydrogen catalyst layer 42. The hydrogen catalyst layer 42 is located on the side near the cathode catalyst layer 3.

[0032] The material of the proton exchange membrane 2 is perfluorosulfonic acid resin, which can be long-chain or short-chain resins of different EWs produced by companies such as Chemours, 3M, Dongyue, AGC, and Solvay.

[0033] The hydrogen catalytic layer 42 is used for the catalytic elimination of hydrogen that has permeated from the cathode through the proton exchange membrane 2. This layer comprises a perfluorosulfonic acid resin, a catalyst, and a conductive support. The catalyst, used to catalyze the reaction of hydrogen and oxygen, can be one or more of Pt, Pt / Co, Pt / Pd, and Pt / Ni. The noble metal loading of this layer is ≤0.1 mg / cm³. 2 Perfluorosulfonic acid resin is responsible for proton conduction. Preferably, it is a highly oxygen-permeable resin. The use of a highly oxygen-permeable resin facilitates oxygen conduction in this layer, further improving the catalytic efficiency of the hydrogen-oxygen reaction. When hydrogen permeates from the cathode side through the proton exchange membrane 2, it first reaches the hydrogen catalytic layer 42. Under the catalysis of the catalyst on this layer, oxygen permeating from the anode side and hydrogen permeating from the cathode side react to produce water, thereby eliminating hydrogen.

[0034] The high oxygen permeability layer 41 can be made of different high oxygen permeability materials, as long as its oxygen permeability is higher than that of traditional perfluorosulfonic acid resin membranes. A traditional perfluorosulfonic acid resin membrane is, for example, a Nafion membrane. Preferably, the high oxygen permeability layer 41 is a high oxygen permeability perfluorosulfonic acid polymer layer.

[0035] For example, the material of the high oxygen permeability layer 41 is a high oxygen permeability perfluorosulfonic acid polymer, and its structural formula can be:

[0036]

[0037] Where M represents other comonomers. A high oxygen permeability resin product with the above structure is, for example, AGC's IC512.

[0038] For example, the material of the high oxygen permeability layer 41 is a high oxygen permeability perfluorosulfonic acid polymer, and its structural formula can be:

[0039]

[0040] This highly oxygen-permeable perfluorosulfonic acid polymer is a HOPIs, which has an oxygen permeability 2-5 times higher than Nafion. Its synthesis method can be found in the following literature:

[0041] Macauley N , Lousenberg RD , Spinetta M ,et al.Highly DurableFluorinated High Oxygen Permeability Ionomers for Proton Exchange MembraneFuel Cells[J].Advanced Energy Materials, 2022, 12.DOI:10.1002 / aenm.202201063

[0042] If the high oxygen permeability layer 41 is made of traditional Nafion material, it only prevents hydrogen from further permeating into the anode, and at the same time, it will also block oxygen from the anode side from reaching the hydrogen catalytic layer 42 to some extent, affecting the hydrogen catalytic efficiency. In this solution, the membrane layer is set to be highly oxygen permeable, which not only further blocks hydrogen but also greatly improves the efficiency of oxygen from the anode side reaching the hydrogen catalytic layer 42, thereby improving the hydrogen elimination efficiency.

[0043] For example, the catalyst-coated membrane structure unit can be prepared by first coating a hydrogen catalytic layer 42 onto a proton exchange membrane, followed by coating a high oxygen permeability layer 41, or coating both layers simultaneously to form a combination of a proton exchange membrane and a hydrogen barrier structure 4. Then, an anode catalytic layer 1 and a cathode catalytic layer 3 are coated or transferred onto this combination. In actual production, membrane electrode manufacturers can directly purchase the combination from membrane manufacturing companies and then carry out subsequent production operations; alternatively, they can prepare the combination themselves.

[0044] Furthermore, the thickness of the high oxygen permeability layer 41 is 0.01 μm to 25 μm, for example, 10 μm, 15 μm, or 20 μm. The thickness of the hydrogen catalyst layer 42 is 0.01 μm to 5 μm, for example, 1 μm, 3 μm, or 4 μm. The thickness of the proton exchange membrane 2 is 0.01 μm to 50 μm, for example, 10 μm, 20 μm, or 40 μm.

[0045] Furthermore, the high oxygen permeability layer 41 and the hydrogen catalytic layer 42 have the same area. The hydrogen barrier structure 4 also includes a porous support structure. This porous support structure can be an e-PTFE sheet, a porous PPS sheet, a PEEK sheet, or a PSU sheet, etc.

[0046] Furthermore, one, two, or three interconnected hydrogen barrier structures 4 may be provided between the anode catalyst layer 1 and the proton exchange membrane 2, and the hydrogen oxidation layer of each hydrogen barrier structure 4 is provided on one side near the cathode catalyst layer 3.

[0047] Example 2

[0048] This embodiment provides a membrane electrode structure, including an anode gas diffusion layer, a cathode gas diffusion layer, and a catalyst-coated membrane structure unit provided in Example 1, wherein the anode gas diffusion layer, the catalyst-coated membrane unit, and the cathode gas diffusion layer are sequentially stacked and connected.

[0049] Example 3

[0050] This embodiment provides a proton exchange membrane electrolysis water production device. The electrolysis water production device is provided with a number of membrane frames, and each membrane frame holds a membrane electrode structure provided in Embodiment 2. The number of membrane frames is the same as the number of membrane electrode structures.

[0051] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the technical solution of this utility model, and are not intended to limit the specific implementation of this utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A catalyst-coated membrane structure unit for hydrogen production by water electrolysis, comprising a proton exchange membrane, a cathode catalyst layer, and an anode catalyst layer, wherein the cathode catalyst layer and the anode catalyst layer are coated on both sides of the proton exchange membrane, characterized in that, A hydrogen barrier structure is provided between the anode catalyst layer and the proton exchange membrane. The hydrogen barrier structure is composed of a connected high oxygen permeability layer and a hydrogen catalyst layer. The hydrogen catalyst layer is located on one side near the cathode catalyst layer. The high oxygen permeability layer is a high oxygen permeability perfluorosulfonic acid polymer layer.

2. The catalyst-coated membrane structure unit for hydrogen production by water electrolysis according to claim 1, characterized in that, The thickness of the high oxygen permeability layer is 0.01μm~25μm.

3. The catalyst-coated membrane structure unit for hydrogen production by water electrolysis according to claim 1, characterized in that, The thickness of the hydrogen catalyst layer is 0.01 μm to 5 μm.

4. The catalyst-coated membrane structure unit for hydrogen production by water electrolysis according to claim 1, characterized in that, The thickness of the proton exchange membrane is 0.01 μm to 50 μm.

5. The catalyst-coated membrane structure unit for hydrogen production by water electrolysis according to claim 1, characterized in that, The hydrogen barrier structure also includes a porous support structure.

6. The catalyst-coated membrane structure unit for hydrogen production by water electrolysis according to any one of claims 1 to 5, characterized in that, The high oxygen permeability layer and the hydrogen catalytic layer have the same area.

7. The catalyst-coated membrane structure unit for hydrogen production by water electrolysis according to any one of claims 1 to 5, characterized in that, Two interconnected hydrogen-blocking structures are provided between the anode catalyst layer and the proton exchange membrane, and the hydrogen oxidation layers of the two hydrogen-blocking structures are both located on one side of the near-cathode catalyst layer.

8. A membrane electrode structure, characterized in that, The device includes an anode gas diffusion layer, a cathode gas diffusion layer, and a catalyst-coated membrane structure unit for hydrogen production by water electrolysis as described in any one of claims 1 to 7, wherein the anode gas diffusion layer, the catalyst-coated membrane unit, and the cathode gas diffusion layer are sequentially stacked and connected.

9. The application of the membrane electrode structure according to claim 8 in a proton exchange membrane water electrolysis hydrogen production device.

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