A membrane electrode for reducing hydrogen content in oxygen in a PEM water electrolyzer and a preparation method thereof

Abstract

The present invention relates to a membrane electrode for reducing the hydrogen content in oxygen of a PEM water electrolyzer and a preparation method thereof, by simply adding an organic silicone resin solution in the cathode catalyst slurry preparation process, changing the mass transfer and transfer from the catalyst layer to the porous transmission layer after hydrogen is generated in the test process, reducing the hydrogen flux of hydrogen permeating from the cathode to the anode, and thus reducing the hydrogen content in oxygen. The present invention has the advantages of low preparation cost, simple process and easy operation, and excellent performance.

Description

Technical Field

[0001] The invention relates to the technical field of polymer electrolyte membrane hydrogen production, in particular to a membrane electrode for reducing the hydrogen content in oxygen of a PEM water electrolyzer and a preparation method thereof. Background Art

[0002] Green hydrogen has great potential as a key element of energy transformation. In the past few decades, it has attracted more and more interest due to the advancement of hydrogen technology, such as fuel cells and electrolyzers for mobile and stationary applications. Compared with other technologies for hydrogen production, polymer electrolyte membrane water electrolyzer (PEMWE) has become the focus of global research due to its outstanding advantages such as high efficiency, fast reaction rate, green environmental protection, and simple operation.

[0003] The gas permeation of polymer electrolyte membranes (PEM) has been widely studied in recent years. In PEM water electrolysis, it is highly related to safety issues, efficiency losses and degradation. During the test process, the gas permeation of the membrane electrode is related to many factors, such as test temperature, current density, proton exchange membrane thickness, water flow and partial pressure. It has been confirmed in previous studies that the gas permeability of PEM membrane electrodes increases with the increase of temperature, current density and pressure. In actual application, the electrolyzer often involves high temperature, high current density and high cathode pressure operation. Therefore, reducing the gas permeability of the electrolyzer and thus reducing the hydrogen content in oxygen has great research significance.

[0004] There are usually several methods to reduce the hydrogen content in oxygen: (1) increase the cathode flux of hydrogen; this is achieved by changing the water circulation flow rate on the cathode side, the hydrophilicity of the porous transport layer (PTL) or the ionomer content; (2) block or weaken the permeation of hydrogen; this includes adding additional intermediate electrodes, modifying the membrane, developing non-fluorine membranes, adding platinum interlayers in the membrane or doping platinum in the anode catalyst; (3) reduce the hydrogen content in oxygen; this is mainly achieved by platinum plating on the anode side PTL or using a recombinant catalyst. Some of the above methods, such as modifying the proton exchange membrane, doping the catalyst with platinum or modifying the electrolysis system, undoubtedly have the disadvantages of high cost, complex process and performance impact. How to reduce costs while simplifying the process and taking into account the performance of the electrolyzer is a technical problem that needs to be solved urgently. Summary of the invention

[0005] To solve the above problems, the present invention provides a membrane electrode and a preparation method thereof for reducing the hydrogen content in oxygen of a PEM water electrolyzer, starting from the cathode catalyst slurry, and reducing the hydrogen content in oxygen of a proton exchange membrane electrolyzer. The present invention simply adds an organic silicone resin solution in the cathode catalyst slurry preparation process, changes the mass transfer and transfer from the catalyst layer to the porous transport layer (PTL) after hydrogen is generated during the test process, reduces the hydrogen flux of hydrogen permeating from the cathode to the anode, and thus reduces the hydrogen content in oxygen. The present invention has the advantages of low preparation cost, simple process and easy operation, and excellent performance.

[0006] The present invention provides a method for preparing a membrane electrode for reducing the hydrogen content in oxygen of a PEM water electrolyzer, which specifically comprises the following steps:

[0007] (1) Preparation of anode slurry

[0008] Take IrO2 catalyst and Nafion ionomer solution respectively and place them in beaker A, then add a certain amount of ultrapure water and anode slurry solvent into beaker A respectively, wherein the volume ratio of ultrapure water to anode slurry solvent is 1:(1-10), and then transfer beaker A to an ultrasonic cell crusher to ultrasonically disperse the slurry in beaker A, the ultrasonic frequency is 10-50kHz, and the ultrasonic time is 1-3h. After the ultrasonic treatment, the anode slurry is obtained.

[0009] Furthermore, the Nafion ionomer solutions in steps (1) and (2) include but are not limited to Nafion D521, Nafion D520, Nafion D2021, Nafion D2020, 3M725, and 3M800.

[0010] Furthermore, the anode slurry solvent in step (1) includes but is not limited to ethanol, isopropanol, 1-butanol, and ethylene glycol.

[0011] Furthermore, in step (1), the weight ratio of the IrO2 catalyst to the dry weight of the Nafion ionomer in the Nafion ionomer solution is (8-15):1.

[0012] Furthermore, the volume ratio of the ultrapure water to the anode slurry solvent in step (1) is 1:(1-10).

[0013] Furthermore, the concentration of the anode slurry in step (1) is 1 to 5 mg / mL.

[0014] (2) Preparation of cathode slurry

[0015] Take the cathode Pt / C catalyst and the first Nafion ionomer solution separately and place them in beaker B, then take a certain amount of silicone resin solution and add it to beaker B, then add a certain amount of ultrapure water and cathode slurry solvent to beaker B respectively, then transfer beaker B to an ultrasonic cell crusher to ultrasonically disperse the slurry in beaker B, the ultrasonic frequency is 10-50kHz, the ultrasonic time is 0.5-2h, then add the second Nafion ionomer solution to beaker B and continue to disperse for 0.5-1h, and finally obtain the cathode slurry.

[0016] Furthermore, the weight content of Pt in the Pt / C catalyst in step (2) is 20% to 60%.

[0017] Furthermore, the cathode slurry solvent in step (2) includes but is not limited to ethanol, isopropanol, 1-butanol, and ethylene glycol.

[0018] Furthermore, the weight ratio of the Pt / C catalyst in step (2) to the dry weight of Nafion in the first Nafion ionomer solution is (5-10):1.

[0019] Furthermore, the volume ratio of the ultrapure water to the cathode slurry solvent in step (2) is 1:(1-10).

[0020] Furthermore, the weight of the organic silicon resin solution in step (2) is 1 to 10% of the sum of the weights of the Pt / C catalyst and the first Nafion ionomer solution.

[0021] Furthermore, the organosilicon resin in the organosilicon resin solution in step (2) is polysiloxane, and its mass fraction is 30% to 80%.

[0022] Furthermore, the concentration of the cathode slurry in step (2) is 0.5 to 3 mg / mL.

[0023] (3) Membrane electrode preparation

[0024] The cathode slurry and the anode slurry are sprayed onto the proton exchange membrane respectively by ultrasonic spraying to prepare the membrane electrode.

[0025] Further, in step (3), the cut proton exchange membrane for water electrolysis is placed on an ultrasonic sprayer with a vacuum adsorption platform, the platform temperature is set to 60-90°C, the cathode slurry is added to the ultrasonic sprayer, the liquid flow rate is 10-50ul / s, and the cathode Pt loading is 0.1-0.6mg / cm 2; Transfer the cathode sprayed membrane electrode to the anode spraying platform, set the platform temperature to 60-90°C, add the anode slurry to the ultrasonic sprayer, the liquid flow rate is 10-50ul / s, and the anode Ir loading is 0.5-2mg / cm 2 , a membrane electrode is obtained, wherein the effective area of ​​the membrane electrode is 25 cm 2 .

[0026] Furthermore, the proton exchange membrane used in step (3) includes but is not limited to Nafion N117, Nafion N115, and Nafion N212.

[0027] The present invention also provides a membrane electrode for reducing the hydrogen content in oxygen of a PEM water electrolyzer obtained according to the preparation method.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention is different from the conventional method of reducing the hydrogen content in the oxygen of the PEM electrolyzer. It adopts a simple and low-cost method to directly improve the hydrophilicity of the cathode catalyst slurry and the saturation of hydrogen between ionomers during the hydrogen production process, reduce the hydrogen permeation flux, and then reduce the hydrogen content in the oxygen. In the process of membrane electrode preparation, the present invention further improves the hydrophilicity of the catalyst slurry by modifying the formula of the cathode catalyst slurry with low cost, adding a hydrophobic silicone resin solution, and adding ionomers in sequence through a two-step method, so that hydrogen can be discharged more quickly through the PTL during the hydrogen production process. The present invention avoids the use of high-cost methods such as platinum-doped anode catalysts, proton exchange membrane modification, and hydrogen production system modification, and provides a method or idea for reducing the hydrogen content in the oxygen of PEM electrolyzers. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of a test system for the hydrogen content in oxygen of a PEM electrolyzer, wherein 1 is a PEM electrolyzer, 2 is a water tank, 3 is a hydrogen-water separator, 4 is a special back pressure valve, 5 is a high-pressure hydrogen storage tank, 6 is an oxygen-water separator, and 7 is a hydrogen-in-oxygen test device;

[0031] Figure 2 The graphs are test diagrams of voltage values ​​corresponding to different current densities of the membrane electrodes prepared in Example 1 and Comparative Example 1 at 65°C;

[0032] Figure 3 At 2A / cm 2 Current density and hydrogen content in oxygen obtained by testing the membrane electrode prepared in Example 1 and Comparative Example 1 at 65°C and different cathode pressures;

[0033] Figure 4This is a graph of hydrogen content in oxygen obtained by testing the membrane electrode prepared in Example 1 and Comparative Example 1 at different current densities under 65° C. and isobaric conditions. DETAILED DESCRIPTION

[0034] In order to better understand the content of the present invention, the present invention will be further described below in conjunction with specific embodiments and drawings. The following embodiments are implemented based on the technology of the present invention, and detailed implementation methods and operating steps are given, but the protection scope of the present invention is not limited to the following embodiments.

[0035] The isopropanol used in Examples 1-3 and Comparative Example 1 was analytically pure with a content of 99.5%.

[0036] Embodiment 1:

[0037] (1) Preparation of anode slurry

[0038] 29.411 mg of IrO2 catalyst and 51.19 mg of Nafion D520 were taken and placed in beaker A, wherein the weight ratio of IrO2 catalyst to Nafion dry weight in Nafion D520 was 11:1, and then 1.24 mL of ultrapure water and 11.20 mL of isopropanol were added to beaker A, and then beaker A was transferred to an ultrasonic cell crusher to ultrasonically disperse the slurry in beaker A, the ultrasonic frequency was 30 kHz, the ultrasonic time was 2 h, and after the ultrasonication, an anode catalyst slurry was obtained, and its concentration was 2 mg / mL;

[0039] (2) Preparation of cathode slurry

[0040] 25 mg of cathode Pt / C catalyst and 62.5 mg of Nafion D520 were taken and placed in beaker B, wherein the mass fraction of Pt in the Pt / C catalyst was 50%, that is, the weight ratio of the Pt / C catalyst to the dry weight of Nafion in the above Nafion D520 was 8:1, and then 2.42 mg of a 60% silicone resin solution was taken and added to beaker B, wherein the silicone resin was polysiloxane, and 1.24 mL of ultrapure water and 11.19 mL of isopropanol were added to beaker B, and then beaker B was transferred to an ultrasonic cell crusher to ultrasonically disperse the slurry in beaker B, the ultrasonic frequency was 20 kHz, and the ultrasonic time was 1 h, and then 37.04 mg of Nafion D520 was added to beaker B and continued to disperse for 1 h, and finally a cathode catalyst slurry was obtained, and its concentration was 1 mg / mL;

[0041] (3) Preparation of membrane electrode

[0042] The membrane electrode was prepared by ultrasonic spraying. Specifically, the cut 5*5cm proton exchange membrane NafionN115 was placed on an ultrasonic sprayer with a vacuum adsorption platform. The platform temperature was set to 80°C. The cathode catalyst slurry was added to the ultrasonic sprayer with a liquid flow rate of 40ul / s and a cathode Pt loading of 0.5mg / cm 2 ; Transfer the cathode sprayed membrane electrode to the anode spraying platform, set the platform temperature to 80°C, add the anode catalyst slurry to the ultrasonic sprayer, the liquid flow rate is 20ul / s, and the anode Ir loading is 1mg / cm 2 , a membrane electrode is obtained, wherein the effective area of ​​the membrane electrode is 25 cm 2 .

[0043] Embodiment 2:

[0044] The preparation method in Example 1 was adopted, except that the cathode slurry was prepared differently in step (2). The rest was the same as in Example 1.

[0045] In this embodiment, step (2) is specifically as follows:

[0046] (2) Preparation of cathode slurry

[0047] Take 25 mg of cathode Pt / C catalyst and 62.5 mg of Nafion D520 respectively and place them in beaker B, wherein the mass fraction of Pt in the Pt / C catalyst is 50%, that is, the weight ratio of the Pt / C catalyst to the dry weight of Nafion in the above Nafion D520 is 8:1, then take 4.83 mg of a 60% mass fraction of silicone resin solution and add it to beaker B, the silicone resin is polysiloxane, and then add 1.24 mL of ultrapure water and 11.19 mL of isopropanol to beaker B respectively, and then transfer beaker B to an ultrasonic cell crusher to ultrasonically disperse the slurry in beaker B, the ultrasonic frequency is 20 kHz, and the ultrasonic time is 1 hour, then add 37.04 mg of Nafion D520 to beaker B and continue to disperse for 1 hour, and the final cathode catalyst slurry has a concentration of 1 mg / mL.

[0048] Embodiment 3:

[0049] (1) Preparation of anode slurry

[0050] 29.411 mg of IrO2 and 51.19 mg of Nafion D520 were taken and placed in beaker A, wherein the weight ratio of IrO2 catalyst to Nafion dry weight in Nafion D520 was 11:1, and then 1.24 mL of ultrapure water and 11.20 mL of isopropanol were added to beaker A, respectively, and then beaker A was transferred to an ultrasonic cell crusher to ultrasonically disperse the slurry in beaker A, the ultrasonic frequency was 30 kHz, the ultrasonic time was 3 h, and after the ultrasonication, an anode catalyst slurry was obtained, and its concentration was 2 mg / mL;

[0051] (2) Preparation of cathode slurry

[0052] Take 25 mg of cathode Pt / C catalyst and 62.5 mg of Nafion D520 respectively and place them in beaker B, wherein the mass fraction of Pt in the Pt / C catalyst is 50%, that is, the weight ratio of the Pt / C catalyst to the dry weight of Nafion in the above Nafion D520 is 8:1, then take 2.68 mg of a silicone resin solution with a mass fraction of 60% and add it to the above beaker B, the silicone resin is polysiloxane, and then add 1.24 mL of ultrapure water and 11.19 mL of isopropanol to beaker B respectively, and then transfer beaker B to an ultrasonic cell crusher to ultrasonically disperse the slurry in beaker B, the ultrasonic frequency is 20 kHz, and the ultrasonic time is 1.5 h, then add 37.04 mg of Nafion D520 to the above solution and continue to disperse for 1.5 h, and finally obtain a cathode catalyst slurry with a concentration of 1 mg / mL.

[0053] (3) Preparation of membrane electrode

[0054] The membrane electrode was prepared by ultrasonic spraying. Specifically, the cut 5*5cm proton exchange membrane NafionN115 was placed on an ultrasonic sprayer with a vacuum adsorption platform. The platform temperature was set to 80°C. The cathode catalyst slurry was added to the ultrasonic sprayer with a liquid flow rate of 40ul / s and a cathode Pt loading of 0.5mg / cm 2 ; Transfer the cathode sprayed membrane electrode to the anode spraying platform, set the platform temperature to 80°C, add the anode catalyst slurry to the ultrasonic sprayer, the liquid flow rate is 20ul / s, and the anode Ir loading is 1mg / cm 2 , a membrane electrode is obtained, wherein the effective area of ​​the membrane electrode is 25 cm 2 .

[0055] Comparative Example 1:

[0056] The preparation method in Example 1 was adopted, except that the cathode slurry was prepared differently in step (2). The rest was the same as in Example 1.

[0057] In this comparative example, step (2) is specifically as follows:

[0058] (2) Preparation of cathode slurry

[0059] Take 25 mg of cathode Pt / C catalyst and 99.54 mg of Nafion D520 respectively and place them in beaker B, wherein the mass fraction of Pt in the Pt / C catalyst is 50%, then add 1.24 mL of ultrapure water and 11.19 mL of isopropanol to beaker B respectively, and then transfer beaker B to an ultrasonic cell crusher to ultrasonically disperse the slurry in beaker B. The ultrasonic frequency is 20 kHz and the ultrasonic time is 2 h, and finally a cathode catalyst slurry is obtained with a concentration of 1 mg / mL.

[0060] Figure 1 The schematic diagram of the test system for the hydrogen content in oxygen of a PEM electrolyzer at normal pressure and differential pressure, wherein 1 is a PEM electrolyzer, which is composed of a membrane electrode, titanium felt, carbon paper, a current collecting plate, an insulating plate, and an end plate; 2 is a water tank, which provides ultrapure water for the reaction of the PEM electrolyzer; 3 is a hydrogen-water separator, in which the hydrogen generated by the reaction and a small amount of water passing through the proton exchange membrane enter the hydrogen-water separator together, and the separated water returns to the water tank through a pipeline; 4 is a special back pressure valve, which is used to adjust the size of the valve to test the hydrogen content in oxygen in the hydrogen-in-oxygen test equipment under different differential pressure conditions; 5 is a high-pressure hydrogen storage tank, which is used to collect the hydrogen generated by the reaction; 6 is an oxygen-water separator, in which the oxygen generated by the electrolyzer reaction and the water that has not completed the reaction pass through the oxygen-water separator, and the water is circulated back to the water tank through the pipeline, and the generated oxygen can be directly discharged from the pipeline; 7 is an oxygen-in-hydrogen test equipment, and the oxygen that has passed through the oxygen-water separator continues to be tested for content through the oxygen-in-hydrogen test equipment.

[0061] Use Figure 1 The PEM electrolyzer shown in the figure is used to test the polarization curve using an electrochemical workstation. Figure 2 These are the polarization curve performance test diagrams of the membrane electrodes prepared in Example 1 and Comparative Example 1 at 65°C.

[0062] Among them, comparative example 1 is at 1A / cm 2 , 2A / cm 2 、3A / cm 2 , 4A / cm 2 The voltage values ​​under current density are 1.662V, 1.829V, 1.994V, and 2.161V. In Example 1, the voltage under current density is 1A / cm 2 , 2A / cm 2 、3A / cm 2 , 4A / cm 2The voltage values ​​under the current density are 1.661V, 1.835V, 2.005V, and 2.174V. By comparison, it can be seen that Example 1 does not have a significant impact on the performance of the membrane electrode in the presence of a small amount of silicone resin solution. The performance of Example 1 is equivalent to that of Comparative Example 1 at a lower current density. Only at a high current density does the voltage performance slightly attenuate.

[0063] The hydrogen content in the pressure difference oxygen of the electrolyzer is tested by adjusting the pressure of the cathode pipeline back pressure valve. Figure 3 The membrane electrodes prepared in Example 1 and Comparative Example 1 were respectively 2 The hydrogen content in oxygen obtained by testing at current density and 65°C and different cathode pressures, wherein the hydrogen content in oxygen of Example 1 at 10 bar, 20 bar and 30 bar is 0.80%, 0.93% and 1.08% respectively, and the hydrogen content in oxygen of Comparative Example 1 at 10 bar, 20 bar and 30 bar is 1.11%, 1.32% and 1.53% respectively.

[0064] Figure 4 The graph is a graph of hydrogen content in oxygen obtained by testing the membrane electrode prepared in Example 1 and Comparative Example 1 at different current densities at 65°C and isobaric conditions. As the current density increases, the hydrogen permeation flux continues to increase, and the amount of hydrogen and oxygen produced continues to increase. The percentage of hydrogen permeating through the proton exchange membrane to the anode side shows a trend of first decreasing and then increasing with the increase of current density. In Example 1, at 0.1A / cm 2 , 1A / cm 2 , 2A / cm 2 、3A / cm 2 , 4A / cm 2 The hydrogen contents in oxygen under the conditions of 0.86%, 0.72%, 0.65%, 0.59% and 0.61% respectively, and the hydrogen contents in Comparative Example 1 under the conditions of 0.1A / cm 2 , 1A / cm 2 , 2A / cm 2 、3A / cm 2 , 4A / cm 2 The hydrogen contents in oxygen under the conditions were 1.07%, 1.00%, 0.91%, 0.81% and 0.84% ​​respectively.

[0065] In summary, the present invention utilizes simple cathode slurry improvements, changes the hydrophilicity of the cathode slurry, and weakens the permeation of hydrogen from the hydrogen production side to the oxygen production side, which can effectively reduce the hydrogen content in oxygen while taking into account the electrochemical performance of the electrolyzer. The present invention has high economic benefits such as low cost and simple operation, as well as performance benefits such as greatly reducing the hydrogen content in oxygen and having excellent hydrogen production capacity.

[0066] The above is only an embodiment of the present invention, and does not limit the present invention in any form. The present invention can also have other forms of embodiments according to the above structures and functions, which are not listed one by one. Therefore, any simple modification, equivalent change and modification made by any technician familiar with the profession to the above embodiment according to the technical essence of the present invention without departing from the scope of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a membrane electrode for reducing the hydrogen content in oxygen in a PEM water electrolyzer, characterized in that: The specific steps include: (1) Preparation of anode slurry IrO2 catalyst and Nafion ionomer solution are taken and placed in beaker A respectively, and then a certain amount of ultrapure water and anode slurry solvent are added to beaker A respectively, wherein the volume ratio of ultrapure water to anode slurry solvent is 1:(1-10), and then beaker A is transferred to an ultrasonic cell crusher for ultrasonic dispersion, the ultrasonic frequency is 10-50kHz, and the ultrasonic time is 1-3h. After the ultrasonic process is completed, the anode slurry is obtained; (2) Preparation of cathode slurry The cathode Pt / C catalyst and the first portion of the Nafion ionomer solution are respectively taken and placed in beaker B, and then a certain amount of the silicone resin solution is added to beaker B, and then a certain amount of ultrapure water and cathode slurry solvent are respectively added to beaker B, and then beaker B is transferred to an ultrasonic cell crusher for ultrasonic dispersion, the ultrasonic frequency is 10 to 50 kHz, and the ultrasonic time is 0.5 to 2 hours, and then the second portion of the Nafion ionomer solution is added to beaker B and continues to disperse for 0.5 to 1 hour, and finally a cathode slurry is obtained; (3) Membrane electrode preparation The cathode slurry and the anode slurry are sprayed onto the proton exchange membrane respectively by ultrasonic spraying to prepare the membrane electrode.

2. The method for preparing a membrane electrode for reducing the hydrogen content in oxygen in a PEM water electrolyzer according to claim 1, characterized in that: Step (3) is to place the cut proton exchange membrane for water electrolysis on an ultrasonic sprayer with a vacuum adsorption platform, set the platform temperature to 60-90°C, add the cathode slurry to the ultrasonic sprayer, the liquid flow rate is 10-50ul / s, and the cathode Pt loading is 0.1-0.6mg / cm 2 ; Transfer the cathode sprayed membrane electrode to the anode spraying platform, set the platform temperature to 60-90°C, add the anode slurry to the ultrasonic sprayer, the liquid flow rate is 10-50ul / s, and the anode Ir loading is 0.5-2mg / cm 2 , a membrane electrode is obtained, wherein the effective area of ​​the membrane electrode is 25 cm 2 .

3. The method for preparing a membrane electrode for reducing the hydrogen content in oxygen in a PEM water electrolyzer according to claim 1, characterized in that: The Nafion ionomer solutions in steps (1) and (2) include but are not limited to nafion D521, nafion D520, nafion D2021, nafion D2020, 3M725, and 3M800.

4. The method for preparing a membrane electrode for reducing the hydrogen content in oxygen in a PEM water electrolyzer according to claim 1, characterized in that: The anode slurry solvent in step (1) and the cathode slurry solvent in step (2) include but are not limited to ethanol, isopropanol, 1-butanol, and ethylene glycol.

5. The method for preparing a membrane electrode for reducing the hydrogen content in oxygen of a PEM water electrolyzer according to claim 1, characterized in that: The weight ratio of the IrO2 catalyst to the Nafion ionomer dry weight in step (1) is (8-15):

1.

6. The method for preparing a membrane electrode for reducing the hydrogen content in oxygen in a PEM water electrolyzer according to claim 1, characterized in that: The volume ratio of the ultrapure water to the anode slurry solvent in step (1) is 1:(1-10); the concentration of the anode slurry is 1-5 mg / mL.

7. The method for preparing a membrane electrode for reducing the hydrogen content in oxygen in a PEM water electrolyzer according to claim 1, characterized in that: The weight content of Pt in the Pt / C catalyst in step (2) is 20% to 60%; the weight ratio of the Pt / C catalyst to the dry weight of Nafion in the first Nafion ionomer solution is (5-10):1; the volume ratio of the ultrapure water to the cathode slurry solvent is 1:(1-10).

8. The method for preparing a membrane electrode for reducing the hydrogen content in oxygen in a PEM water electrolyzer according to claim 1, characterized in that: The weight of the organosilicon resin solution in step (2) is 1-10% of the sum of the weights of the Pt / C catalyst and the first Nafion ionomer solution; the organosilicon resin is polysiloxane, and its mass fraction is 30%-80%; the concentration of the cathode slurry is 0.5-3 mg / mL.

9. The method for preparing a membrane electrode for reducing the hydrogen content in oxygen in a PEM water electrolyzer according to claim 2, characterized in that: The proton exchange membrane used in step (3) includes but is not limited to Nafion N117, Nafion N115, and Nafion N212.

10. A membrane electrode for reducing the hydrogen content in oxygen in a PEM water electrolyzer obtained by the preparation method according to any one of claims 1 to 9.

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