PEM hydrogen production membrane electrode based on batch spraying of nanoscale gradient slurry and preparation method of PEM hydrogen production membrane electrode

Abstract

The invention discloses a PEM hydrogen production membrane electrode based on batch spraying of nanoscale gradient slurry and a preparation method. The preparation method comprises the following steps: firstly, preparing three catalyst slurries with different nanoscale DLS particle sizes by accurately regulating and controlling process parameters of ice-bath ultrasound, ultrasonic disruption and high-pressure homogenization, namely a first IrOx slurry (5-10 nm), a second IrOx slurry (10-15 nm) and a third IrOx / TiO2 slurry (20-40 nm); and then sequentially spraying the three kinds of slurry on a film substrate in batches according to the sequence of particle sizes from small to large by adopting an ultrasonic spraying technology, and accurately controlling the iridium loading capacity of each layer. According to the invention, by constructing a nanoscale gradient catalyst layer structure from compact to loose, a three-phase reaction interface is effectively increased, and ohmic resistance and mass transfer resistance are reduced, so that the catalytic activity and oxygen evolution reaction efficiency of the membrane electrode are greatly improved while the use amount of noble metal is remarkably reduced.

Description

Technical Field

[0001] This invention relates to the field of proton exchange membrane (PEM) water electrolysis hydrogen production technology, and particularly to a high-performance, low-precious-metal-content PEM hydrogen production membrane electrode based on batch spraying of nanoscale gradient slurry and its preparation method. Background Technology

[0002] Proton exchange membrane (PEM) water electrolysis is a key technology for producing high-purity green hydrogen. However, its anodic oxygen evolution reaction (OER) kinetics are slow, requiring the use of large amounts of the precious metal iridium (Ir) as a catalyst, which greatly increases the cost of PEM electrolyzers and restricts their large-scale commercial application.

[0003] Currently, the anode catalyst layer is usually prepared by coating or spraying a single catalyst slurry. The catalyst layer structure prepared by this method is uniform, but it is difficult to simultaneously optimize the multiple mass transfer and conduction processes that are mutually restrictive within the catalyst layer, and the following bottlenecks exist: (1) In order to obtain high catalytic activity, the catalyst needs to be in full contact with the ionomer to form a large number of three-phase reaction interfaces, which often leads to a dense catalyst layer structure; while in order to ensure rapid mass transfer of oxygen and water, the catalyst layer needs to have loose and porous channels. A single-structure catalyst layer cannot take both into account. (2) Although the dense catalyst layer has sufficient contact, it may not be able to adhere well to the proton exchange membrane, resulting in a high proton conduction interface resistance. (3) Some catalysts are buried in regions that do not participate in the reaction and fail to form effective active sites.

[0004] Therefore, developing a PEM hydrogen production membrane electrode that can precisely control the microstructure of the catalyst layer and achieve functional gradient, thereby improving the overall performance while reducing the amount of precious metals used, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a PEM hydrogen production membrane electrode based on batch spraying of nanoscale gradient slurry and its preparation method. The method of this invention prepares three catalyst slurries with different nanoscale particle sizes and sequentially sprays them to construct a catalytic layer structure with a gradient from dense to porous pore size, thereby significantly reducing ohmic resistance and mass transfer resistance, improving the utilization rate of precious metals, and lowering the battery reaction voltage.

[0006] In a first aspect, the present invention provides a PEM hydrogen production membrane electrode based on batch spraying of nanoscale gradient slurry, which is achieved by the following technical solution.

[0007] A PEM hydrogen production membrane electrode based on batch spraying of nanoscale gradient slurry includes a membrane substrate. On one side of the membrane substrate, a layered structure with continuously increasing dynamic light scattering particle size is sequentially arranged from the inside to the outside to form a catalytic layer with a nanoscale gradient structure. On the other side of the membrane substrate, there is a hydrogen evolution catalytic layer.

[0008] Furthermore, an oxygen-evolving dense layer, an oxygen-evolving intermediate layer, and an oxygen-evolving porous layer are sequentially arranged from the inside to the outside on one side of the membrane substrate. The slurry of the oxygen evolution dense layer contains IrOx catalyst with a dynamic light scattering particle size of 5-10 nm. The oxygen evolution intermediate layer slurry contains IrOx catalyst with a dynamic light scattering particle size of 10-15 nm. The oxygen evolution porous layer slurry contains an IrOx / TiO2 composite catalyst with a dynamic light scattering particle size of 20-40 nm.

[0009] Secondly, the present invention provides a method for preparing a PEM hydrogen production membrane electrode based on batch spraying of nanoscale gradient slurry, which is achieved by the following technical solution.

[0010] A method for preparing a PEM hydrogen production membrane electrode based on batch spraying of a nanoscale gradient slurry includes the following steps: preparing nanoscale catalyst slurries with different dynamic light scattering particle sizes; sequentially spraying the slurry onto a membrane substrate using ultrasonic spraying technology according to the order of dynamic light scattering particle size from small to large, forming a catalyst layer with a nanoscale gradient structure; after preparing the gradient anode catalyst layer, preparing or attaching a cathode catalyst layer on the other side of the membrane substrate to obtain a complete membrane electrode.

[0011] Furthermore, the membrane substrate is a proton exchange membrane.

[0012] Specifically, a method for preparing a PEM hydrogen generation membrane electrode based on batch spraying of nanoscale gradient slurry includes the following steps: S1. Preparation of nanoscale gradient catalyst slurry: a. Preparation of oxygen evolution dense layer slurry: IrOx catalyst, ionomer, water, and organic solvent are mixed in a mass ratio of 1:(0.8~1.2):(8~12):(25~35); ultrasonic treatment is performed under ice bath conditions, followed by ultrasonic crushing treatment, and finally high-pressure homogenization treatment. The dynamic light scattering (DLS) particle size of the resulting slurry is precisely controlled within 5-10 nm. This slurry has excellent dispersibility and small particle size.

[0013] b. Preparation of oxygen evolution intermediate layer slurry: IrOx catalyst, ionomer, water and organic solvent are mixed in a mass ratio of 1:(0.8~1.2):(8~12):(25~35), ultrasonically treated under ice bath conditions, followed by ultrasonic crushing treatment, and finally high pressure homogenization treatment, so that the dynamic light scattering (DLS) particle size of the obtained slurry is precisely controlled within 10-15 nm. c. Preparation of oxygen-evolving porous layer slurry: IrOx / TiO2 composite catalyst, ionomer, water, and organic solvent are mixed in a mass ratio of 1: (0.8~1.2): (8~12): (25~35); ultrasonic treatment is performed under ice bath conditions, followed by ultrasonic crushing treatment, and finally high-pressure homogenization treatment is performed to precisely control the dynamic light scattering (DLS) particle size of the obtained slurry to 20-40 nm; S2. Batch sequential ultrasonic spraying: Using ultrasonic spraying equipment, oxygen-evolving porous layer slurry, oxygen-evolving intermediate layer slurry, and oxygen-evolving dense layer slurry were sequentially sprayed onto PTFE material in descending order of particle size. The iridium loading in the oxygen-evolving porous layer was controlled to be 0.1 mg / cm³. 2 The iridium loading in the oxygen evolution interlayer was 0.3 mg / cm³. 2 The iridium loading in the oxygen evolution dense layer was 0.2 mg / cm³. 2 ; S3. Membrane electrode assembly: After the gradient anode catalyst layer is prepared, the oxygen evolution catalyst layer on the PTFE membrane is transferred to the proton exchange membrane by hot pressing at 120-150℃ and 0.8-1.5 MPa. In the same way, the cathode catalyst layer is thermally transferred to the other side of the proton exchange membrane with the oxygen evolution catalyst layer to obtain a complete membrane electrode.

[0014] Furthermore, perfluorosulfonic acid was selected as the ionomer.

[0015] Furthermore, the organic solvent is selected from one or more of isopropanol, 2-butanol, 1,2-propanediol, and N,N-dimethylformamide.

[0016] Further, in steps S1a and S1b, chloroiridic acid is mixed with citric acid, formic acid, or oxalic acid in an aqueous solution at a molar ratio of 1:03~0.8, and kept at a constant temperature of 120~180℃ for 12~24h to obtain a black precipitate. After washing and drying, the black powder is ground and mixed with sodium nitrate at a mass ratio of 1:10~20, and calcined at a constant temperature of 300~550℃ in an air atmosphere at a heating rate of 2-10℃ / min for 0.5~3h. Then it is washed and dried to obtain IrOx.

[0017] Furthermore, in step S1a, the conditions for ice bath ultrasonic treatment are: power 300-500W, time 30-60min.

[0018] Furthermore, in step S1a, the ultrasonic crushing treatment conditions are: power 600-800W, working time 5s, interval 5s, total time 5-10min.

[0019] Furthermore, in step S1a, the high-pressure homogenization parameters are a pressure of 1000-1500 bar and a cycle of 5-10 times.

[0020] Furthermore, in step S1b, the conditions for ice bath ultrasonic treatment are: power 300-500W, time 20-40min.

[0021] Furthermore, in step S1b, the ultrasonic crushing treatment conditions are: power 600-800W, working time 5s, interval 5s, total time 3-8min.

[0022] Furthermore, in step S1b, the high-pressure homogenization parameters are 1000-1500 bar pressure, and 3-7 cycles.

[0023] Furthermore, in step S1c, the IrOx / TiO2 composite catalyst is prepared using the Adams method. The specific preparation method is as follows: chloroiridium acid, TiN, and sodium nitrate are mixed in water or isopropanol solution at a mass ratio of 0.4~0.8:1:10~20 and evaporated to dryness. Then, the dried powder is heated at 300-550℃ for 0.5~3h at a heating rate of 2-10℃ / min, cooled, washed, and dried to obtain IrOx / TiO2.

[0024] Furthermore, in step S1c, the conditions for ice bath ultrasonic treatment are: power 300-500W, time 10-30min.

[0025] Furthermore, in step S1c, the ultrasonic crushing conditions are: power 600-800W, working time 5s, interval 5s, total time 2-5min.

[0026] Furthermore, in step S1c, the high-pressure homogenization parameters are 1000-1500 bar pressure, and 2-5 cycles.

[0027] Furthermore, in step S2, after each layer of slurry is sprayed, it is dried and cured at 80-90℃ before the next layer of slurry is sprayed.

[0028] Furthermore, in step S3, the cathode catalyst layer is selected from Johnson Matthey's commercially available 40wt%Pt / C, 50wt%Pt / C, or 60wt%Pt / C.

[0029] Thirdly, the present invention provides a PEM water electrolyzer, which is achieved by the following technical solution.

[0030] A PEM water electrolyzer includes the aforementioned PEM hydrogen production membrane electrode based on batch spraying of nanoscale gradient slurry.

[0031] This application has the following beneficial effects.

[0032] (1) Nanoscale gradient structure: This invention innovatively achieves a continuous gradient transition of the catalyst layer from a nanoscale dense layer to a nanoscale porous layer through DLS particle size control. The dense bottom layer ensures high activity and low interfacial resistance, while the porous top layer ensures low mass transfer resistance, thus resolving the contradiction in the design of the catalyst layer structure.

[0033] (2) This invention significantly reduces the amount of precious metals used: the total iridium loading is reduced to 0.6 mg / cm³. 2 It is far lower than the industry standard of 1-2 mg / cm³. 2 This improved the level of technology and significantly reduced material costs.

[0034] (3) Overall performance improvement: The gradient structure of this invention optimizes the electron, proton and mass transfer process, so that the membrane electrode has a lower reaction voltage (higher activity), lower ohmic impedance and lower mass transfer polarization.

[0035] (4) Strong process controllability: This invention achieves controllable preparation of the catalyst layer nanostructure by accurately monitoring the slurry particle size through DLS and combining it with online weighing control of ultrasonic spraying. It has good repeatability and is suitable for large-scale production. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the nanoscale gradient catalytic layer structure of the present invention (in the figure: from bottom to top, the hydrogen evolution catalytic layer, the proton exchange membrane, the upper layer closely attached to the membrane is a dense and highly active bottom layer formed by DLS 5-10nm IrOx small particles, the middle layer is a transition layer formed by DLS 10-15nm IrOx particles, and the top layer is a loose and porous top layer formed by DLS 20-40nm IrOx / TiO2 particles). Figure 2 This is a comparison diagram of the polarization curves of Embodiment 1 of the present invention and Comparative Examples 1 to 4; Figure 3 This is Example 1 of the present invention (gradient slurry, total loading 0.6 mg / cm). 2 Comparative Example 3 (single IrOx slurry, loading 0.6 mg / cm³) 2 The electrochemical impedance spectroscopy test results are shown in the figure. Detailed Implementation

[0037] The present patent application will be further described below with reference to the embodiments. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the materials used in the preparation process in the following embodiments have not undergone further processing and have been commercially available.

[0038] The following embodiments of this application use Nafion D520 solution obtained from The Chemours Company; The Nafion 115 membrane used in the following embodiments of this application was purchased from The Chemours Company; The PTFE material used in the following embodiments of this application was purchased from Zhengyu New Materials (Hubei) Co., Ltd.

[0039] Preparation Example 1 IrO x The preparation method is as follows: 2.0 g of chloroiridium acid (H₂IrCl₆·xH₂O) was dissolved in 150 mL of deionized water. 50 mL of a 0.5 mol / L sodium citrate solution was slowly added while continuously stirring. The mixture was transferred to a 250 mL polytetrafluoroethylene-lined high-pressure reactor and reacted at 180 °C for 12 h. After the reaction, the mixture was allowed to cool naturally to room temperature. The resulting black precipitate was filtered and washed with deionized water until the filtrate tested negative for chloride ions using silver nitrate solution. The filter cake was dried overnight in a 90 °C forced-air drying oven. Finally, the powder was ground and mixed with 15 g of sodium nitrate, placed in a muffle furnace, and calcined at 350 °C in air at a heating rate of 8 °C / min for 2 h to obtain black IrOx catalyst powder.

[0040] Preparation Example 2 The preparation method of IrOx / TiO2 is as follows: 1.5 g of titanium nitride (TiN) powder was weighed as a precursor and dispersed in 200 mL of deionized water. 0.8 g of chloroiridium acid (H₂IrCl₆·xH₂O) and 8 g of sodium nitrate were dissolved in 50 mL of deionized water and then added dropwise to the TiN suspension under ultrasonic conditions. After the addition was complete, the mixed suspension was stirred and evaporated to dryness in an 80 °C water bath. The resulting solid powder was transferred to a quartz boat and placed in a tube furnace, where it was calcined at 400 °C in air for 1 h at a heating rate of 5 °C / min. During this process, TiN was oxidized to TiO₂, while the Ir precursor decomposed into IrOx and highly dispersed on the newly formed TiO₂ support, ultimately yielding an IrOx / TiO₂ composite catalyst.

[0041] Example 1 A method for preparing a PEM hydrogen generation membrane electrode based on batch spraying of nanoscale gradient slurry includes the following steps: S1. Slurry preparation: First slurry: Mix 1.0g IrOx powder, 1.0g Nafion solution, 10g deionized water, and 30g isopropanol. Sonicate in an ice bath (400W) for 45min, then process with a cell disruptor (700W, 5s working / 5s intermittent) for 8min, and homogenize in a high-pressure homogenizer (1200bar) for 8 cycles. The DLS particle size was measured to be 8±3nm.

[0042] Second slurry: Mix 1.0g IrOx powder, 1.0g Nafion solution, 10g deionized water, and 30g isopropanol. Sonicate in an ice bath (400W) for 30min, then process with a cell disruptor (700W, 5s working / 5s intermittent) for 5min, and homogenize in a high-pressure homogenizer (1200bar) for 5 cycles. The DLS particle size was measured to be 13±2nm.

[0043] Third slurry: Take 1.0g IrOx / TiO2 powder (Ir loading rate 40%), 1.0g Nafion solution, 10g deionized water, and 30g isopropanol and mix them. Sonicate in an ice bath (400W) for 20min, process with a cell disruptor (700W, 5s working / 5s intermittent) for 3min, and homogenize in a high-pressure homogenizer (1200bar) for 3 cycles. The particle size of DLS was measured to be 32±5nm.

[0044] S2. Graded spraying: Ultrasonic spraying on PFTE material.

[0045] First, the third slurry is sprayed on, and then dried and cured at 80℃, controlling the iridium metal loading of this layer to be 0.1 mg / cm³. 2 .

[0046] Then, a second slurry is sprayed on, and dried and cured at 80°C, with the iridium metal loading of this layer controlled at 0.3 mg / cm³. 2 .

[0047] Finally, the first slurry is sprayed on, and then dried and cured at 80°C. The iridium metal loading of this layer is controlled to be 0.2 mg / cm³ by weighing using a precision balance. 2 The total Ir loading for the three layers above is 0.6 mg / cm³. 2 .

[0048] Subsequently, the PTFE membrane coated with three layers of oxygen evolution catalyst was hot-pressed together with the Nafion 115 membrane at 135°C and 1MPa for 2 minutes to obtain the oxygen evolution MEA. S3. Fabrication of membrane electrode (MEA): On the cathode side, a 0.5 mg / cm² coating is first ultrasonically sprayed onto the PTFE material. 2Pt / C, then the PTFE membrane coated with hydrogen evolution catalyst was bonded to the other side of the Nafion 115 membrane with oxygen evolution catalyst layer, and together they were hot-pressed at 135°C and 1MPa for 2 minutes to obtain a complete membrane electrode.

[0049] Comparative Example 1 S1. Slurry preparation: Prepare the first and second slurries in the same manner as in Example 1. S2. Graded spraying: Ultrasonic spraying on PTFE material.

[0050] Spray the second slurry, dry at 80℃, and control the Ir weight gain to 0.35 mg / cm³. 2 .

[0051] Spray the first slurry, dry at 80℃, and control the Ir weight gain to 0.25 mg / cm³. 2 .

[0052] Total Ir loading was 0.6 mg / cm³. 2 .

[0053] S3. MEA preparation: Same as in Example 1.

[0054] Comparative Example 2 S1. Slurry preparation: Prepare the second and third slurries in the same manner as in Example 1. S2. Graded spraying: Ultrasonic spraying on PTFE material.

[0055] Spray the third slurry, dry at 80℃, and control the Ir weight gain to 0.2 mg / cm³. 2 .

[0056] Spray the second slurry, dry at 80℃, and control the Ir weight gain to 0.4 mg / cm³. 2 .

[0057] Total Ir loading was 0.6 mg / cm³. 2 .

[0058] S3. MEA preparation: Same as in Example 1.

[0059] Comparative Example 3 A single IrOx slurry (DLS average particle size 10~15nm) was used, with a total Ir loading of 0.6 mg / cm³. 2 The anode is prepared by spraying in one step, and the remaining steps are exactly the same.

[0060] Comparative Example 4 A single IrOx / TiO2 slurry (DLS average particle size 20~40nm) was used, with a total Ir loading of 0.6 mg / cm³. 2 The anode is prepared by spraying in one step, and the remaining steps are exactly the same.

[0061] Performance testing: Referencing T / CRES 0030—2025 Test Method for Proton Exchange Membrane Electrode in Water Electrolysis for Hydrogen Production, a 4cm section was tested at a water temperature of 60℃. 2 Single-cell performance.

[0062] The polarization curves show that at 1 A / cm 2 At the specified current density, the voltage in Example 1 was 1.7006V, the voltages in Comparative Examples 1 and 3 were approximately 1.7411V, the voltage in Comparative Example 2 was approximately 1.7841V, and the voltage in Comparative Example 4 was 1.8359V. The data demonstrate that the combination of only small-particle-size layers (Comparative Example 1) lacks gas channels, resulting in performance comparable to a traditional single IrOx layer (Comparative Example 3); the combination of only large-particle-size layers (Comparative Example 2) suffers from insufficient interfacial reaction, leading to a performance degradation; and the single IrOx / TiO2 layer (Comparative Example 4) exhibits the worst performance. Only by constructing a complete "dense-transition-porous" gradient structure through the specific nanoscale particle size combination and sequential spraying of this invention can the reaction interface and mass transfer channels be optimized simultaneously under low iridium loading, achieving a significant improvement in membrane electrode performance.

[0063] Electrochemical impedance spectroscopy tests showed that at 1 A / cm 2 At the current density, the impedance of Example 1 is 20 mΩ·cm. 2 The resistance is significantly lower than that of Comparative Example 3 (40 mΩ·cm). This data proves that the nanoscale gradient catalytic layer structure constructed in this invention can significantly optimize the charge transport process inside the membrane electrode and reduce the interfacial resistance and electrochemical reaction impedance by up to 50%.

[0064] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A PEM hydrogen production membrane electrode based on batch spraying of nanoscale gradient slurry, comprising a membrane substrate, characterized in that: A layered structure with continuously increasing dynamic light scattering particle size is sequentially arranged from the inside to the outside on one side of the membrane substrate to form a catalytic layer with a nanoscale gradient structure; a hydrogen evolution catalytic layer is formed on the other side of the membrane substrate.

2. The PEM hydrogen production membrane electrode based on batch spraying of nanoscale gradient slurry according to claim 1, characterized in that: An oxygen-evolving dense layer, an oxygen-evolving intermediate layer, and an oxygen-evolving porous layer are sequentially arranged from the inside to the outside on one side of the membrane substrate. The slurry of the oxygen evolution dense layer contains IrOx catalyst with a dynamic light scattering particle size of 5-10 nm. The oxygen evolution intermediate layer slurry contains IrOx catalyst with a dynamic light scattering particle size of 10-15 nm. The oxygen evolution porous layer slurry contains an IrOx / TiO2 composite catalyst with a dynamic light scattering particle size of 20-40 nm.

3. A method for preparing a PEM hydrogen production membrane electrode based on batch spraying of nanoscale gradient slurry as described in claim 1 or 2, characterized in that: Includes the following steps: Nanoscale catalyst slurries with different dynamic light scattering particle sizes were prepared. The slurries were then sequentially sprayed onto the membrane substrate using ultrasonic spraying technology in order of increasing dynamic light scattering particle size to form a catalyst layer with a nanoscale gradient structure. After the gradient anode catalyst layer was prepared, a cathode catalyst layer was prepared or attached to the other side of the membrane substrate to obtain a complete membrane electrode.

4. The method for preparing a PEM hydrogen production membrane electrode based on batch spraying of nanoscale gradient slurry according to claim 3, characterized in that: Includes the following steps: S1. Preparation of nanoscale gradient catalyst slurry: a. Preparation of oxygen evolution dense layer slurry: IrOx catalyst, ionomer, water, and organic solvent are mixed in a mass ratio of 1: (0.8~1.2): (8~12): (25~35); ultrasonic treatment is performed under ice bath conditions, followed by ultrasonic crushing treatment, and finally high pressure homogenization treatment is performed to precisely control the dynamic light scattering particle size of the obtained slurry within 5-10 nm; b. Preparation of oxygen evolution intermediate layer slurry: IrOx catalyst, ionomer, water and organic solvent are mixed in a mass ratio of 1: (0.8~1.2): (8~12): (25~35), ultrasonically treated under ice bath conditions, followed by ultrasonic crushing treatment, and finally high pressure homogenization treatment, so that the dynamic light scattering particle size of the obtained slurry is precisely controlled within 10-15 nm. c. Preparation of oxygen-evolving porous slurry: IrOx / TiO2 composite catalyst, ionomer, water, and organic solvent are mixed in a mass ratio of 1: (0.8~1.2): (8~12): (25~35); ultrasonic treatment is performed under ice bath conditions, followed by ultrasonic crushing treatment, and finally high-pressure homogenization treatment is performed to precisely control the dynamic light scattering particle size of the obtained slurry within 20-40 nm; S2. Batch sequential ultrasonic spraying: Using ultrasonic spraying equipment, oxygen-evolving porous layer slurry, oxygen-evolving intermediate layer slurry, and oxygen-evolving dense layer slurry were sequentially sprayed onto PTFE material in descending order of particle size. The iridium loading in the oxygen-evolving porous layer was controlled to be 0.1 mg / cm³. 2 The iridium loading in the oxygen evolution interlayer was 0.3 mg / cm³. 2 The iridium loading in the oxygen evolution dense layer was 0.2 mg / cm³. 2 ; S3. Membrane electrode assembly: After the gradient anode catalyst layer is prepared, the oxygen evolution catalyst layer on the PTFE membrane is transferred to the proton exchange membrane by hot pressing at 120-150℃ and 0.8-1.5 MPa. In the same way, the cathode catalyst layer is thermally transferred to the other side of the proton exchange membrane with the oxygen evolution catalyst layer to obtain a complete membrane electrode.

5. The method for preparing a PEM hydrogen production membrane electrode based on batch spraying of nanoscale gradient slurry according to claim 4, characterized in that: In step S1a, the conditions for ice bath ultrasonic treatment are: power 300-500W, time 30-60min; the conditions for ultrasonic crushing treatment are: power 600-800W, working time 5s, interval 5s, total time 5-10min; the parameters for high-pressure homogenization treatment are: pressure 1000-1500bar, cycle 5-10 times.

6. The method for preparing a PEM hydrogen production membrane electrode based on batch spraying of nanoscale gradient slurry according to claim 4, characterized in that: In step S1b, the conditions for ice bath ultrasonic treatment are: power 300-500W, time 20-40min; the conditions for ultrasonic crushing treatment are: power 600-800W, working for 5s and resting for 5s, total time 3-8min; the parameters for high-pressure homogenization treatment are: pressure 1000-1500bar, cycle 3-7 times.

7. The method for preparing a PEM hydrogen production membrane electrode based on batch spraying of nanoscale gradient slurry according to claim 4, characterized in that: In step S1c, the conditions for ice bath ultrasonic treatment are: power 300-500W, time 10-30min; the conditions for ultrasonic crushing treatment are: power 600-800W, working for 5s and resting for 5s, total time 2-5min; the parameters for high-pressure homogenization treatment are: pressure 1000-1500bar, cycle 2-5 times.

8. A PEM water electrolysis cell, characterized in that, Includes the PEM hydrogen production membrane electrode based on batch spraying of nanoscale gradient slurry as described in claim 1 or 2.

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