Water electrolysis hydrogen production membrane electrode and proton exchange membrane electrolytic cell

Abstract

The invention relates to a water electrolysis hydrogen production membrane electrode and a proton exchange membrane electrolytic cell, and belongs to the technical field of water electrolysis hydrogen production. The water electrolysis hydrogen production membrane electrode comprises a proton exchange membrane, and a hydrogen elimination layer, an anode catalyst layer and an anode diffusion layer which are sequentially stacked on the surface of one side of the proton exchange membrane, the surface roughness Ra of the surface of the side, facing the anode catalyst layer, of the anode diffusion layer, the thickness H1 of the anode catalyst layer and the thickness H2 of the hydrogen elimination layer meet the following conditions that Ra is larger than or equal to 0.25 H1 and smaller than or equal to 0.75 H1; 0.3 H1 + 0.25 H2 is greater than or equal to Ra. By cooperatively controlling the surface roughness Ra of the anode diffusion layer, the thickness H1 of the anode catalyst layer and the thickness H2 of the dehydrogenation layer, the interface contact can be effectively optimized, the catalytic activity can be improved, the mass transfer resistance can be reduced, and meanwhile, the durability of the membrane electrode can be improved.

Description

Technical Field

[0001] This application relates to the field of water electrolysis for hydrogen production technology, and particularly to a water electrolysis membrane electrode and a proton exchange membrane electrolyzer for hydrogen production. Background Technology

[0002] Proton exchange membrane electrolyzers (PEMWEs) possess advantages such as high efficiency, fast dynamic response, compact structure, and simple auxiliary systems, thus demonstrating enormous commercial potential in the field of hydrogen production through water electrolysis. In a PEMWE system, the membrane electrode assembly (MEA) is one of the core components. Typically, the MEA consists of a proton exchange membrane (PEM) and, sequentially stacked on one side of the PEM, a hydrogen removal layer, an anode catalyst layer (CL), and an anode diffusion layer (PTL). However, conventional stacking arrangements result in poor interfacial contact between the layers, low catalyst utilization, low mass transfer efficiency, and difficulty in effectively balancing the electrochemical performance and structural stability of the MEA. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this application provides a water electrolysis hydrogen production membrane electrode and a proton exchange membrane electrolyzer, which effectively improves the electrochemical performance of the proton exchange membrane electrolyzer while enhancing its structural stability. In a first aspect, embodiments of this application provide a water electrolysis hydrogen production membrane electrode, comprising a proton exchange membrane and a hydrogen removal layer, an anode catalyst layer, and an anode diffusion layer sequentially stacked on one side surface of the proton exchange membrane; wherein the surface roughness Ra of the anode diffusion layer facing the anode catalyst layer, the thickness H1 of the anode catalyst layer, and the thickness H2 of the hydrogen removal layer satisfy the following conditions: 0.25H1≤Ra≤0.75H1; 0.3H1+0.25H2≥Ra. In the above technical solution, the hydrogen elimination layer, the anode catalyst layer and the anode diffusion layer in the water electrolysis hydrogen production membrane electrode are stacked in sequence. The anode diffusion layer provides mechanical support for the anode catalyst layer and realizes the transfer of heat and electrons. The anode catalyst layer is responsible for catalyzing the oxygen evolution reaction (OER) and providing a proton transport channel. The hydrogen elimination layer is located between the anode catalyst layer and the proton exchange membrane. Its main function is to eliminate the trace amount of hydrogen that permeates into the anode and prevent hydrogen and oxygen from mixing to form an explosive gas.

[0004] In this application, by controlling the surface roughness Ra of the anode diffusion layer facing the anode catalyst layer and the thickness H1 of the anode catalyst layer to satisfy 0.25H1≤Ra≤0.75H1, a "micro-interlocking" can be formed at the contact interface between the anode diffusion layer and the anode catalyst layer. This avoids insufficient contact area due to excessively small surface roughness Ra, and also avoids direct piercing or cracking of the anode catalyst layer due to excessively large surface roughness Ra. This helps to retain more active sites and pores, thereby improving catalyst utilization, reducing mass transfer resistance, and improving durability.

[0005] Furthermore, by synergistically controlling the thickness H2 of the hydrogen elimination layer and the thickness H1 of the anode catalyst layer to satisfy 0.3H1 + 0.25H2 ≥ Ra, the thicknesses of the hydrogen elimination layer and the anode catalyst layer synergistically buffer the mechanical pressure of the anode diffusion layer, reducing the impact of the rough surface of the anode diffusion layer on the structures of the hydrogen elimination layer and the anode catalyst layer. The sum of the thickness coefficients of the hydrogen elimination layer and the anode catalyst layer is 0.55, with the anode catalyst layer accounting for 0.3, which is greater than the hydrogen elimination layer's thickness proportion of 0.25. As the core of the catalytic reaction, the anode catalyst layer is in direct contact with the anode diffusion layer, undertaking the oxygen evolution reaction, charge transport, and proton transport. It is more sensitive to fracturing; controlling 0.3H1 prioritizes reducing the risk of fracturing the anode catalyst layer. The hydrogen elimination layer, whose main function is to eliminate permeated hydrogen, is in indirect contact with the anode diffusion layer. By controlling 0.25H2, it can be prevented from being compressed and densified or cracked, thus avoiding obstruction of proton transport. This helps maintain the hydrogen elimination activity and proton transport channels of the hydrogen elimination layer, reducing the safety risk of side reactions caused by hydrogen permeation, and also avoids an increase in mass transfer resistance due to excessive thickness.

[0006] Therefore, by controlling the surface roughness Ra of the anode diffusion layer facing the anode catalyst layer, the thickness H1 of the anode catalyst layer, and the thickness H2 of the hydrogen removal layer to meet the above dual conditions, the interfacial contact can be effectively optimized, the catalytic activity can be improved, the mass transfer resistance can be reduced, and the reliability of the membrane electrode can be improved.

[0007] In some embodiments, the surface roughness Ra of the surface of the anode diffusion layer facing the anode catalyst layer is 2 μm to 6 μm, preferably 3 μm to 4 μm. In the above technical solution, when the surface roughness Ra is within a suitable range, combined with the dual conditions of 0.25H1≤Ra≤0.75H1 and 0.3H1+0.25H2≥Ra, a "micro-interlocking" can be formed at the interface between the anode diffusion layer and the anode catalyst layer. This can increase the interface contact area and reduce the impact on the structure of the hydrogen elimination layer and the anode catalyst layer, thereby helping to further improve the catalytic activity of the membrane electrode, reduce the mass transfer resistance, and further improve the reliability of the membrane electrode.

[0008] In some embodiments, the anode diffusion layer includes at least one of titanium fiber felt, titanium sintered felt, nickel fiber felt, or nickel sintered felt. In the above technical solutions, these materials serve as the anode diffusion layer. They possess abundant porous structures, controllable surface roughness, and excellent structural stability, which facilitates the formation of a tight interface with the anode catalyst layer. This also improves the interface contact area and structural stability, and makes them suitable for various electrolysis systems (such as acidic or alkaline, high-voltage or low-voltage, etc.).

[0009] In some embodiments, the thickness of the anodic diffusion layer is 0.3 mm to 0.6 mm.

[0010] In the above technical solution, the thickness of the anode diffusion layer is within a suitable range, giving it sufficient structural support strength. At the same time, it can synergistically increase the interfacial contact area, reduce mass transfer resistance, and is easy to match with the thickness of the hydrogen elimination layer and the anode catalyst layer, thereby improving structural stability.

[0011] In some embodiments, the thickness H1 of the anode catalyst layer is 6 μm to 12 μm, preferably 8 μm to 10 μm. In the above technical solution, the thickness of the anode catalyst layer is within the appropriate range, which is beneficial to provide sufficient active sites and suitable proton transport channels. Combined with the dual conditions of 0.25H1≤Ra≤0.75H1 and 0.3H1+0.25H2≥Ra, it is beneficial to form a stable "micro-interlocking" structure with the rough surface of the anode diffusion layer. While increasing the interfacial contact area, it reduces the risk of being punctured or cracked, thereby further improving the catalytic activity of the membrane electrode, reducing the mass transfer resistance, and further improving the reliability of the membrane electrode.

[0012] In some embodiments, the anode catalyst layer includes an oxygen evolution catalyst and a first ionomer, wherein the mass ratio of the first ionomer to the oxygen evolution catalyst is (0.3~0.5):1.

[0013] In the above technical solution, the oxygen evolution catalyst is used to catalyze the generation of oxygen, hydrogen ions, and electrons from water molecules, and the first ionomer is used to form a proton transport channel, while simultaneously binding the oxygen evolution catalyst to form a continuous structure. By controlling the mass ratio of the first ionomer to the oxygen evolution catalyst within the aforementioned suitable range, it is beneficial to provide sufficient oxygen evolution catalyst while constructing a continuous proton transport channel, thereby further reducing mass transfer resistance and improving the reliability of the membrane electrode.

[0014] In some embodiments, the oxygen evolution catalyst includes at least one of iridium oxide, ruthenium oxide, supported iridium oxide, or supported ruthenium oxide.

[0015] In the above technical solutions, these oxygen evolution catalysts have high catalytic activity and structural stability, and are suitable for the anode catalyst layer structure of this application, which can effectively improve catalyst utilization and reduce costs. In some embodiments, the first ionomer includes at least one of sulfonated polysulfone, sulfonated polyethersulfone, perfluorosulfonic acid resin, sulfonated polyether ether ketone, sulfonated polyphenylene sulfide, perfluorocarboxylic acid resin, or perfluorophosphate resin.

[0016] In the above technical solutions, these ionomers all have good proton conduction efficiency, adhesion properties and chemical stability, and can be adapted to various types of oxygen evolution catalysts. In some embodiments, the thickness H2 of the hydrogen-removing layer is 6 μm to 12 μm, preferably 8 μm to 10 μm. In the above technical solution, the thickness of the hydrogen removal layer is within a suitable range, which is conducive to fully capturing hydrogen gas that permeates from the cathode to the anode and preventing anode free radicals from eroding the proton exchange membrane. Combined with the dual conditions of 0.25H1≤Ra≤0.75H1 and 0.3H1+0.25H2≥Ra, the risk of being squeezed and densified or cracked can be reduced while satisfying the hydrogen removal activity, which is conducive to further reducing the mass transfer resistance and further improving the reliability of the membrane electrode.

[0017] In some embodiments, the hydrogen removal layer includes a hydrogen removal catalyst and a second ionomer, wherein the mass ratio of the second ionomer to the hydrogen removal catalyst is (4~7):1. In the above technical solution, the hydrogen removal catalyst reacts with the hydrogen permeating from the cathode to the anode, eliminating trace amounts of hydrogen permeating to the anode and preventing the formation of an explosive gas mixture from hydrogen and oxygen. The second ionomer forms a proton transport channel and simultaneously binds the hydrogen removal catalyst to form a continuous structure. By controlling the mass ratio of the second ionomer to the hydrogen removal catalyst within a suitable range, it is beneficial to construct a continuous proton transport channel, improve hydrogen removal activity while reducing transport resistance, and further improve the reliability of the membrane electrode. In some embodiments, the hydrogen removal catalyst includes at least one of a platinum black catalyst or a platinum carbon catalyst. In the above technical solutions, these hydrogen removal catalysts have high hydrogen removal activity and chemical stability. When combined with the second ionomer to form a hydrogen removal layer, they can effectively improve the hydrogen removal efficiency, thereby further improving the reliability of the membrane electrode. In some embodiments, the second ionomer includes at least one of sulfonated polysulfone, sulfonated polyethersulfone, perfluorosulfonic acid resin, sulfonated polyether ether ketone, sulfonated polyphenylene sulfide, perfluorocarboxylic acid resin, and perfluorophosphate resin. In the above technical solutions, these ionomers all have good proton conduction efficiency, bonding performance and chemical stability, and can be adapted to a variety of hydrogen removal catalysts.

[0018] Secondly, embodiments of this application provide a proton exchange membrane electrolyzer, including the water electrolysis hydrogen production membrane electrode provided in the first aspect of this application. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of a water electrolysis hydrogen production membrane electrode provided in an embodiment of this application.

[0021] Figure 2 The images show SEM images (a) and (b) at magnification of the anode catalyst layer of the water electrolysis hydrogen production membrane electrode provided in Comparative Example 3 of this application after electrochemical performance testing.

[0022] Explanation of reference numerals in the attached figures: 100 - Water electrolysis hydrogen production membrane electrode; 10 - Proton exchange membrane; 20 - Hydrogen removal layer; 30 - Anode catalyst layer; 40 - Anode diffusion layer; 50 - Cathode catalyst layer; 60 - Cathode diffusion layer. Detailed Implementation

[0023] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the water electrolysis hydrogen production membrane electrode and a proton exchange membrane electrolyzer using the water electrolysis hydrogen production membrane electrode. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0024] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0025] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0026] The membrane electrode assembly (MEA) is a key component of a proton exchange membrane electrolyzer (PEMWE), typically consisting of a proton exchange membrane and, sequentially stacked on one side of the proton exchange membrane, a hydrogen removal layer, an anode catalyst layer, and an anode diffusion layer. The anode diffusion layer provides mechanical support to the anode catalyst layer, enabling heat and electron transfer and facilitating the transport of multiphase media (electrons, gas-liquid mixtures). The anode catalyst layer, comprising an oxygen evolution catalyst and an ionomer, is the core component catalyzing the oxygen evolution reaction and also provides a proton transport channel. The hydrogen removal layer, also comprising a hydrogen removal catalyst and an ionomer, eliminates trace amounts of hydrogen permeating to the anode, preventing the formation of an explosive gas mixture from hydrogen and oxygen, and also provides a proton transport channel. Because each membrane layer has a certain thickness, conventional stacking results in poor interfacial contact between the layers, low catalyst utilization, low mass transfer efficiency, and difficulty in effectively balancing the electrochemical performance and structural stability of the membrane electrode assembly. Based on this, this application provides a water electrolysis hydrogen production membrane electrode, including a proton exchange membrane and a hydrogen removal layer, an anode catalyst layer, and an anode diffusion layer sequentially stacked on one side surface of the proton exchange membrane; wherein, the surface roughness Ra of the anode diffusion layer facing the anode catalyst layer, the thickness H1 of the anode catalyst layer, and the thickness H2 of the hydrogen removal layer satisfy the following conditions: 0.25H1≤Ra≤0.75H1; 0.3H1+0.25H2≥Ra. In this embodiment, "surface roughness" refers to the unevenness of a surface with small spacing and minute peaks and valleys. The surface roughness of this application is measured using the arithmetic mean deviation Ra of the profile specified in GB / T1031-2009. The surface roughness Ra of the surface of the anode diffusion layer facing the anode catalyst layer can be tested using conventional testing methods and equipment in the art. For example, the water electrolysis hydrogen production membrane electrode can be disassembled, the anode diffusion layer can be separated, and the surface roughness Ra can be obtained by using a contact roughness tester according to the testing standard of GB / T1031-2009, selecting at least 3 test points, taking the average value, and calculating the standard deviation.

[0027] In this embodiment, the thickness H1 of the anode catalyst layer and the thickness H2 of the hydrogen elimination layer are the average thickness values ​​of the entire anode catalyst layer or hydrogen elimination layer. These can be obtained using conventional testing methods and equipment, by taking multiple test points and calculating the average value. For example, the water electrolysis hydrogen production membrane electrode can be disassembled, the anode catalyst layer or hydrogen elimination layer can be separated, and a contact thickness gauge can be used to directly measure multiple points and obtain the average value. Alternatively, a cross-section of the water electrolysis hydrogen production membrane electrode can be obtained, a cross-sectional SEM image can be obtained using a scanning electron microscope (SEM), and multiple points can be selected to read the thickness and calculate the average value.

[0028] In this application, by controlling the surface roughness Ra of the anode diffusion layer facing the anode catalyst layer and the thickness H1 of the anode catalyst layer to satisfy 0.25H1≤Ra≤0.75H1, a “micro-interlocking” can be formed at the contact interface between the anode diffusion layer and the anode catalyst layer. This avoids insufficient contact area due to excessively small surface roughness Ra, and also avoids direct piercing or cracking of the anode catalyst layer due to excessively large surface roughness Ra. This helps to retain more active sites and pores, thereby improving catalyst utilization, reducing mass transfer resistance, and improving durability.

[0029] Furthermore, by synergistically controlling the thickness H2 of the hydrogen elimination layer and the thickness H1 of the anode catalyst layer to satisfy 0.3H1 + 0.25H2 ≥ Ra, the thicknesses of the hydrogen elimination layer and the anode catalyst layer synergistically buffer the mechanical pressure of the anode diffusion layer, reducing the impact of the rough surface of the anode diffusion layer on the structures of the hydrogen elimination layer and the anode catalyst layer. The sum of the thickness coefficients of the hydrogen elimination layer and the anode catalyst layer is 0.55, with the anode catalyst layer accounting for 0.3, which is greater than the hydrogen elimination layer's thickness proportion of 0.25. As the core of the catalytic reaction, the anode catalyst layer is in direct contact with the anode diffusion layer, undertaking the oxygen evolution reaction, charge transport, and proton transport. It is more sensitive to fracturing; controlling 0.3H1 prioritizes reducing the risk of fracturing the anode catalyst layer. The hydrogen elimination layer, whose main function is to eliminate permeated hydrogen, is in indirect contact with the anode diffusion layer. By controlling 0.25H2, it can be prevented from being compressed and densified or cracked, thus avoiding obstruction of proton transport. This helps maintain the hydrogen elimination activity and proton transport channels of the hydrogen elimination layer, reducing the safety risk of side reactions caused by hydrogen permeation, and also avoids an increase in mass transfer resistance due to excessive thickness.

[0030] Therefore, by controlling the surface roughness Ra of the anode diffusion layer facing the anode catalyst layer, the thickness H1 of the anode catalyst layer, and the thickness H2 of the hydrogen removal layer to meet the above dual conditions, the interfacial contact can be effectively optimized, the catalytic activity can be improved, the mass transfer resistance can be reduced, and the reliability of the membrane electrode can be improved.

[0031] The structure and performance of the water electrolysis hydrogen production membrane electrode of this application embodiment will be described in detail below with reference to the accompanying drawings.

[0032] Figure 1 Please refer to the schematic diagram of a water electrolysis hydrogen production membrane electrode provided in this application embodiment. Figure 1 The water electrolysis hydrogen production membrane electrode 100 includes a proton exchange membrane 10 and a hydrogen elimination layer 20, an anode catalyst layer 30 and an anode diffusion layer 40 sequentially stacked on one side surface of the proton exchange membrane 10.

[0033] The surface roughness Ra of the anode diffusion layer 40 facing the anode catalyst layer 30, the thickness H1 of the anode catalyst layer 30, and the thickness H2 of the hydrogen elimination layer 20 satisfy the following conditions: 0.25H1≤Ra≤0.75H1; 0.3H1+0.25H2≥Ra.

[0034] In some embodiments, the surface roughness Ra of the surface of the anode diffusion layer 40 facing the anode catalyst layer 30 is 2 μm to 6 μm, preferably 3 μm to 4 μm. When the surface roughness Ra is within a suitable range, combined with the dual conditions of 0.25H1≤Ra≤0.75H1 and 0.3H1+0.25H2≥Ra, a "micro-interlocking" can be formed at the interface between the anode diffusion layer and the anode catalyst layer. This increases the interface contact area and reduces the impact on the structure of the hydrogen removal layer and the anode catalyst layer, thereby further improving the catalytic activity of the membrane electrode, reducing mass transfer resistance, and enhancing the reliability of the membrane electrode.

[0035] As an example, the surface roughness Ra is any single value or a range between any two values ​​from 2 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, and 6 μm. In some embodiments, the anode diffusion layer 40 comprises at least one of titanium fiber felt, titanium sintered felt, nickel fiber felt, or nickel sintered felt. These materials, as anode diffusion layers, possess abundant porous structures, controllable surface roughness, and excellent structural stability, which facilitates the formation of a tight interfacial bond with the anode catalyst layer, while simultaneously improving the interfacial contact area and structural stability. Furthermore, they are suitable for various electrolysis systems (e.g., acidic, high-voltage, or low-voltage systems).

[0036] In some embodiments, the thickness of the anode diffusion layer 40 is 0.3 mm to 0.6 mm. The thickness of the anode diffusion layer 40 is within a suitable range to provide sufficient structural support strength, while synergistically increasing the interfacial contact area, reducing mass transfer resistance, and easily matching the thickness of the hydrogen elimination layer and the anode catalyst layer, thereby improving structural stability.

[0037] As an example, the thickness of the anode diffusion layer 40 is any one value or a range between any two values ​​of 0.3 mm, 0.4 mm, 0.5 mm, and 0.6 mm.

[0038] Understandably, the anode diffusion layer 40 can be purchased commercially, and the required surface roughness and thickness can be directly customized. Alternatively, raw materials can be purchased for mechanical processing or chemical treatment, such as etching, sandblasting, grinding, etc. This application does not make specific limitations in this regard.

[0039] In some embodiments, the thickness H1 of the anode catalyst layer 30 is 6 μm to 12 μm, preferably 8 μm to 10 μm. The thickness of the anode catalyst layer 30 within this suitable range is beneficial for providing sufficient active sites and suitable proton transport channels. Combined with the dual conditions of 0.25H1≤Ra≤0.75H1 and 0.3H1+0.25H2≥Ra, it facilitates the formation of a stable "micro-interlocking" structure with the rough surface of the anode diffusion layer. This increases the interfacial contact area while reducing the risk of puncture or cracking, thereby further improving the catalytic activity of the membrane electrode, reducing mass transfer resistance, and further enhancing the reliability of the membrane electrode.

[0040] As an example, the thickness H1 of the anode catalyst layer 30 is any one value or a range between any two values ​​of 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, and 12 μm.

[0041] In some embodiments, the anode catalyst layer 30 includes an oxygen evolution catalyst and a first ionomer, wherein the mass ratio of the first ionomer to the oxygen evolution catalyst is (0.3~0.5):1. The oxygen evolution catalyst is used to catalyze the generation of oxygen, hydrogen ions, and electrons from water molecules, while the first ionomer is used to form a proton transport channel and simultaneously bind the oxygen evolution catalyst to form a continuous structure. By controlling the mass ratio of the first ionomer to the oxygen evolution catalyst within the aforementioned suitable range, it is beneficial to provide sufficient oxygen evolution catalyst while constructing a continuous proton transport channel, thereby further reducing mass transfer resistance and improving the reliability of the membrane electrode.

[0042] As an example, the mass ratio of the first ionomer to the oxygen evolution catalyst is 0.3:1, 0.4:1, 0.5:1, etc.

[0043] Furthermore, the oxygen evolution catalyst includes at least one of iridium oxide, ruthenium oxide, iridium oxide supported on a support, or ruthenium oxide supported on a support. These oxygen evolution catalysts possess high catalytic activity and structural stability, and are well-suited to the anode catalyst layer 30 structure of this application, effectively improving catalyst utilization and reducing costs.

[0044] Further, the first ionomer includes at least one selected from sulfonated polysulfone, sulfonated polyethersulfone, perfluorosulfonic acid resin, sulfonated polyetheretherketone, sulfonated polyphenylene sulfide, perfluorocarboxylic acid resin, or perfluorophosphate resin. These ionomers all possess good proton conductivity, bonding properties, and chemical stability, and are compatible with various types of oxygen evolution catalysts. Preferably, the first ionomer includes a perfluorosulfonic acid resin.

[0045] In some embodiments, the thickness H2 of the hydrogen removal layer 20 is 6 μm to 12 μm, preferably 8 μm to 10 μm. When the thickness of the hydrogen removal layer 20 is within a suitable range, combined with the dual conditions of 0.25H1≤Ra≤0.75H1 and 0.3H1+0.25H2≥Ra, the risk of densification or cracking due to compression can be reduced while satisfying the hydrogen removal activity. This is beneficial for further reducing mass transfer resistance and further improving the structural stability of the membrane electrode.

[0046] As an example, the thickness H2 of the hydrogen removal layer 20 is any one value or a range between any two values ​​of 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, and 12μm.

[0047] In some embodiments, the hydrogen removal layer 20 includes a hydrogen removal catalyst and a second ionomer, with a mass ratio of the second ionomer to the hydrogen removal catalyst of (4~7):1. The hydrogen removal catalyst catalyzes the reaction of oxygen with hydrogen permeating from the cathode to the anode, eliminating trace amounts of hydrogen permeating to the anode and preventing the formation of an explosive gas mixture from hydrogen and oxygen. The second ionomer forms a proton transport channel and simultaneously binds the hydrogen removal catalyst to form a continuous structure. By controlling the mass ratio of the second ionomer to the hydrogen removal catalyst within a suitable range, it is beneficial to construct a continuous proton transport channel, improve hydrogen removal activity while reducing transport resistance, and further improve the reliability of the membrane electrode.

[0048] As an example, the mass ratio of the second ionomer to the hydrogen elimination catalyst is 4:1, 5:1, 6:1, 7:1, etc.

[0049] Furthermore, the hydrogen removal catalyst includes at least one of platinum black catalyst or platinum carbon catalyst. These hydrogen removal catalysts have high hydrogen removal activity and chemical stability, and when combined with the second ionomer to form a hydrogen removal layer, they can effectively improve the hydrogen removal efficiency and the structural stability of the membrane electrode.

[0050] Furthermore, the second ionomer includes at least one of sulfonated polysulfone, sulfonated polyethersulfone, perfluorosulfonic acid resin, sulfonated polyether ether ketone, sulfonated polyphenylene sulfide, perfluorocarboxylic acid resin, and perfluorophosphate resin. These ionomers all possess good proton conductivity, bonding properties, and chemical stability, and are compatible with various types of hydrogen removal catalysts.

[0051] Preferably, the first ionomer and the second ionomer are the same.

[0052] In some embodiments, the proton exchange membrane 10 may be any one of a perfluorosulfonic acid resin membrane, a modified perfluorosulfonic acid resin membrane, or a reinforced perfluorosulfonic acid resin membrane.

[0053] Furthermore, the thickness of the proton exchange membrane 10 is 50 μm to 90 μm, for example, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, etc.

[0054] Please see again Figure 1 On the other side of the proton exchange membrane 10, a cathode catalytic layer 50 and a cathode diffusion layer 60 are stacked in sequence.

[0055] In the embodiments of this application, the thickness, material, etc. of the cathode catalyst layer 50 and the cathode diffusion layer 60 can be set in accordance with conventional methods, and this application does not impose specific limitations.

[0056] For example, the cathode catalyst layer 50 may include a hydrogen evolution catalyst and a third ionomer, wherein the hydrogen evolution catalyst may include at least one of Pt / C, Pt-Fe / C, Pt-Co / C, Pt-Mn / C, Pt-Pd / C, and Pt-Au / C. The cathode diffusion layer 60 may be carbon paper with a microporous layer.

[0057] The working principle of the above-mentioned water electrolysis hydrogen production membrane electrode 100 includes: The anode diffusion layer 40 provides mechanical support for the anode catalyst layer 30, enabling heat and electron transfer. The anode catalyst layer 30 is responsible for catalyzing the oxygen evolution reaction and providing a proton transport channel. The hydrogen removal layer 20 is located between the anode catalyst layer 30 and the proton exchange membrane 10, and its main function is to eliminate trace amounts of hydrogen that permeate to the anode side, preventing the formation of an explosive gas mixture from hydrogen and oxygen. The cathode catalyst layer 50 is responsible for the hydrogen evolution reaction and provides a proton transport channel. The cathode diffusion layer 60 provides mechanical support for the cathode catalyst layer 50 and enables electron conduction and hydrogen collection.

[0058] When the water electrolysis hydrogen production membrane electrode 100 is working, the positive electrode of the external power supply transfers electrons to the anode catalyst layer 30. Water permeates to the active sites of the anode catalyst layer 30 and undergoes an oxidation reaction under the catalytic action of the oxygen evolution catalyst, generating oxygen, protons, and electrons (2H2O→O2↑+ 4H). + + 4e - The generated electrons are transported to the positive electrode of the external power supply through the anode diffusion layer 40. Protons, under the action of the first ionomer, pass through the hydrogen elimination layer 20 and the proton exchange membrane 10, and migrate directionally to the cathode layer. The negative electrode of the external power supply supplies electrons to the cathode catalyst layer 50. Protons migrating from the anode side combine with electrons at the active sites of the cathode catalyst layer 50 to undergo a reduction reaction, generating hydrogen gas (4H₂O). + + 4e - → 2H2↑), collected through the cathode diffusion layer 60. During this period, a small amount of hydrogen may permeate from the cathode side through the proton exchange membrane 10 into the anode side, where it can react with oxygen on the anode side to generate water under the action of the hydrogen removal catalyst in the hydrogen removal layer 20.

[0059] In this embodiment, the water electrolysis hydrogen production membrane electrode 100 can be prepared by conventional spraying or transfer combined with hot pressing, and this application does not make specific limitations on this.

[0060] As an example, the preparation method of the water electrolysis hydrogen production membrane electrode 100 may include the following steps: S1: Prepare a hydrogen removal layer slurry by mixing the hydrogen removal catalyst and the second ionomer in a certain mass ratio, spray the hydrogen removal layer slurry onto one side surface of the proton exchange membrane 10, and form a hydrogen removal layer 20 after drying.

[0061] S2: Prepare an anode catalyst layer slurry by mixing the oxygen evolution catalyst and the first ionomer in a certain mass ratio, spray the anode catalyst layer slurry onto the surface of the hydrogen elimination layer 20, and dry it to form the anode catalyst layer 30.

[0062] S3: Prepare a cathode catalyst layer slurry by mixing the hydrogen evolution catalyst and the third ionomer in a certain mass ratio. Spray the cathode catalyst layer slurry onto the other side of the proton exchange membrane 10. After drying, form a cathode catalyst layer 50 and obtain a catalyst coating proton membrane (CCM).

[0063] S4: The anode diffusion layer 40, the catalyst-coated proton membrane and the cathode diffusion layer 60 are hot-pressed together to obtain the water electrolysis hydrogen production membrane electrode 100.

[0064] In addition, this application embodiment also provides a proton exchange membrane electrolyzer, including the above-mentioned water electrolysis hydrogen production membrane electrode.

[0065] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0066] Example 1 This embodiment provides a water electrolysis hydrogen production membrane electrode, the preparation method of which includes the following steps: (1) Select a perfluorosulfonic acid resin proton exchange membrane with a thickness of 80 μm.

[0067] (2) Prepare a hydrogen removal layer slurry according to the ratio of platinum black catalyst: perfluorosulfonic acid resin: water alcohol solution (mass ratio of water and ethanol 1:3) = 1:4:50; spray the hydrogen removal layer slurry onto one side of the proton exchange membrane and dry it in an oven at 60°C to form a hydrogen removal layer with a thickness of 10 μm H2.

[0068] (3) Prepare an anode catalyst slurry according to the ratio of iridium dioxide catalyst: perfluorosulfonic acid resin: water alcohol solution (1:3 (mass ratio)) = 1:0.3:100; spray the anode catalyst slurry onto the surface of the hydrogen elimination layer, and then dry it in an oven at 60°C to form an anode catalyst layer with a thickness H1 of 8μm.

[0069] (4) Prepare a cathode catalytic slurry according to the following ratio: Pt / C catalyst (Pt loading is 60%): perfluorosulfonic acid resin: water alcohol solution (1:3 (mass ratio)) = 1:1:100; spray the cathode catalytic slurry onto the other side of the proton exchange membrane, and then dry it in an oven at 60°C to form a cathode catalytic layer with a thickness of 10 μm, thus obtaining the catalyst-coated proton exchange membrane (CCM).

[0070] (5) Select a titanium fiber felt with a thickness of 0.4 mm and a surface roughness Ra of 3 μm as the anode diffusion layer, and select a carbon paper GDL with a thickness of 0.3 mm as the cathode diffusion layer. Hot press the anode diffusion layer, CCM and cathode diffusion layer to obtain a water electrolysis hydrogen production membrane electrode.

[0071] Example 2 This embodiment provides a water electrolysis hydrogen production membrane electrode, the preparation method of which differs from that of Embodiment 1 in that: In step (2), the thickness H2 of the hydrogen removal layer is 12 μm.

[0072] In step (3), the thickness H1 of the anode catalyst layer is 12 μm.

[0073] In step (5), the surface roughness Ra of the anodic diffusion layer is 5 μm.

[0074] Example 3 This embodiment provides a water electrolysis hydrogen production membrane electrode, the preparation method of which differs from that of Embodiment 1 in that: In step (5), the thickness of the anode diffusion layer is 0.6 mm.

[0075] Example 4 This embodiment provides a water electrolysis hydrogen production membrane electrode, the preparation method of which differs from that of Embodiment 1 in that: In step (3), the thickness H1 of the anode catalyst layer is 10 μm.

[0076] Example 5 This embodiment provides a water electrolysis hydrogen production membrane electrode, the preparation method of which differs from that of Embodiment 1 in that: Step (3) includes: preparing an anode catalyst slurry according to the ratio of iridium dioxide catalyst: perfluorosulfonic acid resin: water alcohol solution (1:3 (mass ratio)) = 1:0.5:100; spraying the anode catalyst slurry onto the surface of the hydrogen elimination layer, and then drying it in an oven at 60°C to form an anode catalyst layer with a thickness H1 of 8 μm.

[0077] Example 6 This embodiment provides a water electrolysis hydrogen production membrane electrode, the preparation method of which differs from that of Embodiment 1 in that: In step (2), the thickness H2 of the hydrogen removal layer is 12 μm.

[0078] Example 7 This embodiment provides a water electrolysis hydrogen production membrane electrode, the preparation method of which differs from that of Embodiment 1 in that: In step (2), the thickness H2 of the hydrogen removal layer is 6 μm.

[0079] Example 8 This embodiment provides a water electrolysis hydrogen production membrane electrode, the preparation method of which differs from that of Embodiment 1 in that: In step (3), the thickness H1 of the anode catalyst layer is 6 μm.

[0080] Example 9 This embodiment provides a water electrolysis hydrogen production membrane electrode, the preparation method of which differs from that of Embodiment 1 in that: Step (2) includes: preparing a hydrogen removal layer slurry according to the ratio of platinum black catalyst: perfluorosulfonic acid resin: water alcohol solution (mass ratio of water and ethanol 1:3) = 1:7:50; spraying the hydrogen removal layer slurry onto one side surface of the proton exchange membrane, and drying it in an oven at a constant temperature of 60°C to form a hydrogen removal layer with a thickness of 10 μm H2.

[0081] Comparative Example 1 This comparative example provides a water electrolysis hydrogen production membrane electrode, the preparation method of which differs from that of Example 1 in that: In step (5), the surface roughness Ra of the anode diffusion layer is 5 μm.

[0082] Comparative Example 2 This comparative example provides a water electrolysis hydrogen production membrane electrode, the preparation method of which differs from that of Example 1 in that: In step (2), the thickness H2 of the hydrogen removal layer is 12 μm.

[0083] In step (3), the thickness H1 of the anode catalyst layer is 5 μm.

[0084] In step (5), the surface roughness Ra of the anode diffusion layer is 4 μm.

[0085] Comparative Example 3 This comparative example provides a water electrolysis hydrogen production membrane electrode, the preparation method of which differs from that of Example 1 in that: In step (2), the thickness H2 of the hydrogen removal layer is 5 μm.

[0086] In step (5), the surface roughness Ra of the anode diffusion layer is 7 μm.

[0087] Comparative Example 4 This comparative example provides a water electrolysis hydrogen production membrane electrode, the preparation method of which differs from that of Example 1 in that: In step (5), the surface roughness Ra of the anode diffusion layer is 1.5 μm.

[0088] The preparation process parameters of the water electrolysis hydrogen production membrane electrode in Examples 1 to 9 and Comparative Examples 1 to 4 are shown in Table 1.

[0089] Table 1. Partial fabrication process parameters of the water electrolysis hydrogen production membrane electrode.

[0090] Performance testing and results analysis The anode plate, the water electrolysis hydrogen production membrane electrode from the examples and comparative examples, and the cathode plate were laminated and sealed with 15N. The torque of m was used to assemble a proton exchange membrane electrolyzer, and performance tests were conducted. The test results are shown in Table 2. The specific test method is as follows: 1. Polarization curve Under anodic circulation of 80℃ deionized water, the current density scan starts from 0.01 A / cm². 2 Up to 4A / cm 2 Record the current density and voltage values ​​to obtain the polarization curves. The analytical values ​​of the polarization curves are shown in Table 2.

[0091] 2. Surface resistance HFR Using Gamry electrochemical testing equipment, connect to the electrolytic cell, select a frequency of 1000Hz~10000Hz, read the starting point resistance, and multiply it by the effective area of ​​the membrane electrode to obtain the sheet resistance HFR.

[0092] 3. Durability A square wave cyclic test was performed, with 1.45V held for 5 seconds and 2.00V held for 5 seconds, for 10,000 cycles. Afterwards, the polarization curve of the membrane electrode was measured at 3 A / cm. 2 Calculate voltage decay based on the voltage value at the specified location.

[0093] 4. Hydrogen in Oxygen Test Anode circulation of 80℃ deionized water at 3A / cm 2The system was run for 0.5 hours with a cathode back pressure of 1.6 MPa. Under stable conditions, the hydrogen content in the anode oxygen was recorded.

[0094] The PEM electrolyzer, after durability testing, was disassembled, and the membrane electrode was taken for scanning electron microscopy to observe the structural integrity of the anode catalyst layer and hydrogen elimination layer, and to determine whether cracking or detachment occurred.

[0095] Table 2 Analytical values ​​of polarization curves

[0096] As can be seen from Tables 1 and 2, compared with Comparative Examples 1-4, the water electrolysis hydrogen production membrane electrodes prepared in Examples 1-9 of this application have lower transport polarization losses, corresponding to lower battery voltages (less than 1.8V), and lower sheet resistance HFR (≤80 mΩ•cm). 2 The good contact and high activity indicate that the voltage decay is less than 15mV after 10,000 cycles and the hydrogen content in the oxygen is less than 1%, indicating that the membrane electrode has good durability and reliability.

[0097] A comparison of the performance test results of Example 1 and Comparative Examples 1-3 shows that, although the surface roughness Ra of the anode diffusion layer facing the anode catalyst layer, the thickness H1 of the anode catalyst layer, and the thickness H2 of the hydrogen elimination layer in Comparative Example 1 do not satisfy 0.3H1+0.25H2≥Ra; the condition 0.25H1≤Ra≤0.75H1 is not satisfied in Comparative Example 2; and both 0.25H1≤Ra≤0.75H1 and 0.3H1+0.25H2≥Ra are not satisfied in Comparative Example 3, the voltage decay of its membrane electrode increases significantly (≥25mV) after 10,000 cycles, and the hydrogen content in oxygen also increases significantly (≥2.8%). Figure 2 The images shown are SEM images (a) and (b) at magnification of the surface of the anode catalyst layer of the water electrolysis hydrogen production membrane electrode provided in Comparative Example 3 of this application after a durability test. It can be seen that cracks appeared in the anode catalyst layer, which corresponds to a decrease in the durability and reliability of the membrane electrode.

[0098] The performance test results of Example 1 and Comparative Example 4 show that the cell voltage and surface resistance of the membrane electrode in Comparative Example 4 are significantly increased, and the voltage decay is also increased after 10,000 cycles. This may be because the surface roughness Ra of the anode diffusion layer facing the anode catalyst layer is too small, resulting in poor interfacial contact and poor conductivity. The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A hydrogen generating membrane electrode for water electrolysis, characterized by, The water electrolysis hydrogen production membrane electrode comprises a proton exchange membrane, a hydrogen elimination layer, an anode catalytic layer and an anode diffusion layer which are sequentially arranged on one side surface of the proton exchange membrane; wherein the surface roughness Ra of the anode diffusion layer on the side surface facing the anode catalytic layer, the thickness H1 of the anode catalytic layer and the thickness H2 of the hydrogen elimination layer satisfy the following conditions: 0.25H1≤Ra≤0.75H1; 0.3H1+0.25H2≥Ra.

2. The hydrogen- producing membrane electrode of water electrolysis according to claim 1, characterized in that, The surface roughness Ra of the anode diffusion layer on the side surface facing the anode catalytic layer is 2 μm to 6 μm, preferably 3 μm to 4 μm.

3. The hydrogen- producing membrane electrode of water electrolysis according to claim 1 or 2, characterized in that, The anode diffusion layer comprises at least one of titanium fiber felt, titanium sintered felt, nickel fiber felt or nickel sintered felt. And / or, the thickness of the anode diffusion layer is 0.3 mm to 0.6 mm.

4. The hydrogen- producing membrane electrode of water electrolysis according to any one of claims 1 to 3, characterized in that, The thickness H1 of the anode catalytic layer is 6 μm to 12 μm, preferably 8 μm to 10 μm.

5. The hydrogen- producing membrane electrode of water electrolysis according to any one of claims 1 to 4, characterized in that, The anode catalytic layer comprises an oxygen evolution catalyst and a first ionomer, and the mass ratio of the first ionomer to the oxygen evolution catalyst is (0.3-0.5):

1.

6. The hydrogen- producing membrane electrode of water electrolysis according to claim 5, characterized by The oxygen evolution catalyst comprises at least one of an oxide of iridium, an oxide of ruthenium, a carrier-supported oxide of iridium or a carrier-supported oxide of ruthenium. And / or, the first ionomer comprises at least one of sulfonated polysulfone, sulfonated polyether sulfone, perfluorosulfonic acid resin, sulfonated polyether ether ketone, sulfonated polyphenylene sulfide, perfluorocarboxylic acid resin or perfluorophosphoric acid resin.

7. The hydrogen- producing membrane electrode of any one of claims 1 to 6, wherein The thickness H2 of the hydrogen elimination layer is 6 μm to 12 μm, preferably 8 μm to 10 μm.

8. The hydrogen- producing membrane electrode of any one of claims 1 to 7, wherein, The hydrogen elimination layer comprises a hydrogen elimination catalyst and a second ionomer, and the mass ratio of the second ionomer to the hydrogen elimination catalyst is (4-7):

1.

9. The hydrogen- producing membrane electrode of water electrolysis according to claim 8, characterized by The hydrogen elimination catalyst comprises at least one of platinum black catalyst or platinum carbon catalyst. And / or, the second ionomer comprises at least one of sulfonated polysulfone, sulfonated polyether sulfone, perfluorosulfonic acid resin, sulfonated polyether ether ketone, sulfonated polyphenylene sulfide, perfluorocarboxylic acid resin or perfluorophosphoric acid resin.

10. A proton exchange membrane electrolyzer characterized by, The water electrolysis hydrogen production membrane electrode comprises the water electrolysis hydrogen production membrane electrode according to any one of claims 1 to 9.

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