Preparation method of catalyst slurry for PEM electrolytic water hydrogen production and preparation method of membrane electrode thereof

Abstract

The present invention discloses a preparation method of a catalyst slurry for PEM electrolysis water hydrogen production and a preparation method of a membrane electrode. A proton-electron conductor, a binder, Pt / C powder with a platinum mass concentration of 20% to 60%, and a solvent are mixed and dispersed uniformly under ultrasonic waves to obtain a cathode catalyst slurry; a proton-electron conductor, a binder, iridium dioxide powder or an iridium dioxide / carbon black mixture, and a solvent are mixed and dispersed uniformly under ultrasonic waves to obtain an anode catalyst slurry. The introduced proton-electron conductor increases the sites for proton transport in the electrolysis water hydrogen production reaction, accelerates the transport of protons and electrons, and can improve the performance of the catalytic layer on the premise of reducing the amount of catalyst used in the catalytic layer. The present invention also uses a gas gun spraying, a spin coater spin coating or a glass rod scraping method to uniformly coat the catalyst slurry on the bottom membrane of the membrane electrode, and the process is simple and easy to operate.

Description

Technical Field

[0001] The present invention relates to the field of membrane electrode preparation, and particularly to a preparation method of a catalyst slurry for PEM water electrolysis hydrogen production and a preparation method of a membrane electrode thereof. Background Art

[0002] With the rapid development of social industrialization, the problem of energy crisis faced by mankind has become increasingly prominent. At present, most of the energy supply still comes from traditional fossil fuels, and the resulting environmental pollution problems have also become the focus of social attention. To solve the energy and environmental problems, researchers have turned their attention to emerging clean energies, such as solar energy, wind energy, tidal energy, and hydrogen energy. Among them, hydrogen energy (H2) has the advantages of high energy density, small molecular mass, and only water as the combustion product, and is considered to be an ideal carrier for future energy storage and supply. At present, the technologies for preparing elemental hydrogen mainly include fossil energy reforming hydrogen production, industrial by-product gas hydrogen production, and electrolytic water hydrogen production. Electrolytic water hydrogen production has the advantages of simple raw materials, no greenhouse gas emissions, high hydrogen production efficiency, and high product purity, and is considered to be the development direction of the future energy industry.

[0003] The electrolytic water hydrogen production technologies mainly include alkaline electrolyte (AWE) hydrogen production, proton exchange membrane (PEM) water electrolysis, solid polymer anion exchange membrane (AEM) water electrolysis, and solid oxide (SOE) water electrolysis. Among them, AWE is the earliest industrialized water electrolysis technology, with decades of application experience and is the most mature; the SOE water electrolysis technology is in the initial demonstration stage; the AEM water electrolysis research has just started. From a technical perspective, the PEM water electrolysis technology has a high current density, a small electrolytic cell volume, flexible operation, and is conducive to rapid load change, and has a good match with wind power and photovoltaic (the volatility and randomness of power generation are relatively large), and is considered to be the development trend in the next 5-10 years.

[0004] The membrane electrode is the most important reaction site in the PEM water electrolysis hydrogen production device and is the core component of the PEM water electrolysis cell. It directly affects the hydrogen production efficiency of the electrolytic cell and determines the safety and performance stability of the electrolysis reaction. According to whether a gas diffusion layer is used, the preparation process is divided into the GDE method and the CCM method. The former borrows a gas diffusion layer. After the catalyst is dried and formed, a gas diffusion layer electrode is obtained, and then it is hot-pressed on both sides of the proton exchange membrane to obtain a membrane electrode; the latter does not use a gas diffusion layer and directly uniformly coats the prepared catalyst on the surface of the proton exchange membrane to form a catalyst coating layer, and a membrane electrode is obtained after drying and forming. Among them, the membrane electrode prepared by the CCM method has a higher catalyst utilization rate and can establish a better ionomer / catalyst interface (triple-phase interface), so the CCM method has been more widely used at present.

[0005] The proton exchange membrane used in the CCM method must have relatively high proton conductivity and low electron conductivity; good anti-swelling performance; low gas permeability; and good chemical and mechanical stability in the operating environment of the PEM water electrolyzer. At present, Nafion series proton exchange membranes produced by DuPont Company in the United States are usually used. In the CCM method, the catalytic layer formed by the catalyst is the real place where the reaction occurs in the membrane electrode of the PEM water electrolyzer, that is, the electrochemical reaction occurs on the surface of the catalyst. Therefore, the composition of the catalyst slurry affects the hydrogen production efficiency of the electrolytic cell. In addition, the coating method of the catalyst slurry and the proton exchange membrane has always been a topic that scholars at home and abroad have competed to develop. Summary of the Invention

[0006] The purpose of the present invention is to provide a preparation method of a catalyst slurry for PEM electrolytic water hydrogen production, which is simple and easy to realize industrial production.

[0007] In order to achieve the above purpose, a preparation method of a catalyst slurry for PEM electrolytic water hydrogen production according to the present invention includes the following steps:

[0008] 1) Preparation of the cathode catalyst slurry: Mix a proton-electron conductor, a binder, Pt / C powder with a platinum mass concentration of 20% to 60%, and a solvent, and disperse them evenly under ultrasonic waves to obtain the cathode catalyst slurry;

[0009] 2) Preparation of the anode catalyst slurry: Mix a proton-electron conductor, a binder, iridium dioxide powder or an iridium dioxide / carbon black mixture, and a solvent, and disperse them evenly under ultrasonic waves to obtain the anode catalyst slurry.

[0010] According to the present invention, the proton-electron conductor is poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), that is, PEDOT-PSS.

[0011] According to the present invention, the binder is one of a Nafion solution with a mass concentration of 0.5% to 20%, a polybenzimidazole solution, a sulfonated polysulfone solution, a sulfonated polyether sulfone solution, a sulfonated polyether imide solution, a sulfonated polyether ether ketone solution, and a sulfonated polyarylether ketone solution.

[0012] According to the present invention, the solvent is a mixture of alcohol and deionized water.

[0013] Further, the alcohol is one or a mixture of two of ethanol, ethylene glycol, and isopropanol.

[0014] Further, the volume ratio of deionized water to alcohol in the mixture is 1:5 to 20.

[0015] According to the present invention, in step 1), the mass concentration of the proton-electron conductor in the Pt / C powder with a platinum mass concentration of 20% - 60% is 1 - 30% of the mass of the Pt / C powder.

[0016] According to the present invention, in step 1), the mass concentration of the binder in the Pt / C powder with a platinum mass concentration of 20% - 60% is 10 - 40% of the mass of the Pt / C powder.

[0017] According to the present invention, the conditions for ultrasonic dispersion in step 1) are an ice-water bath, and the time is 30 - 90 min.

[0018] According to the present invention, in step 2), the mass concentration of the proton-electron conductor in the iridium dioxide powder or the iridium dioxide / carbon black mixture is 1 - 30%.

[0019] According to the present invention, in step 2), the mass concentration of the binder in the iridium dioxide powder or the iridium dioxide / carbon black mixture is 10 - 40%.

[0020] According to the present invention, in step 2), the mass concentration of the iridium dioxide powder is 85% or 95%.

[0021] According to the present invention, in the iridium dioxide / carbon black mixture in step 2), the iridium dioxide powder accounts for 40 - 80% of the mass of the mixture.

[0022] According to the present invention, the conditions for ultrasonic dispersion in step 2) are an ice-water bath, and the time is 120 - 180 min.

[0023] Another object of the present invention is to provide a method for preparing a membrane electrode for PEM water electrolysis hydrogen production, comprising the following steps:

[0024] 1) Prepare a cathode catalyst slurry: Mix a proton-electron conductor, a binder, Pt / C powder with a platinum mass concentration of 20% - 40%, and a solvent, and disperse them evenly under ultrasonic waves to obtain a cathode catalyst slurry;

[0025] 2) Prepare an anode catalyst slurry: Mix a proton-electron conductor, a binder, iridium dioxide powder or an iridium dioxide / carbon black mixture, and a solvent, and disperse them evenly under ultrasonic waves to obtain an anode catalyst slurry;

[0026] 3) Pretreat a commercial Nafion membrane or a proton exchange membrane to obtain a bottom membrane of the membrane electrode;

[0027] 4) Fix the periphery of the bottom membrane obtained in step 3) on the surface of a flat support with a metal frame having a groove in the middle;

[0028] 5) Coat the cathode catalyst slurry prepared in step 1) on the surface of the bottom membrane prepared in step 4), then turn the bottom membrane to the other side, and fix the bottom membrane on the surface of a flat support with a metal frame. Coat the anode catalyst slurry prepared in step 2) on the other side of the bottom membrane, thus obtaining a membrane electrode for PEM electrolytic water hydrogen production.

[0029] According to the present invention, the commercial Nafion membrane in step 3) is Nafion115 or Nafion117.

[0030] According to the present invention, the proton exchange membrane in step 3) is one of polybenzimidazole, sulfonated polysulfone, sulfonated polyethersulfone, sulfonated polyetherimide, sulfonated polyetheretherketone and sulfonated polyaryletherketone.

[0031] According to the present invention, the pretreatment method of the Nafion membrane in step 3) is as follows: successively heat-treat the Nafion membrane with an aqueous solution of 2-5% H2O2 by mass concentration at 60-80 °C for 30-60 min, rinse with deionized water, then heat-treat with a 0.5-1 mol / L sulfuric acid aqueous solution at 60-80 °C for 30-60 min, rinse with deionized water, and heat-treat with deionized water at 60-80 °C for 30-60 min.

[0032] According to the present invention, the pretreatment method of the proton exchange membrane in step 3) is as follows: soak the membrane in an aqueous solution of 1-3 mol / L acid for 2-7 days.

[0033] Further, the acid is one of sulfuric acid, hydrochloric acid, formic acid, methanesulfonic acid and phosphoric acid.

[0034] According to the present invention, the flat support in step 4) is a glass plate or an aluminum sheet.

[0035] According to the present invention, the coating method in step 5) is air gun spraying, spin coating with a spin coater or scraping with a glass rod.

[0036] Further, the steps of air gun spraying are as follows: place the flat support prepared in step 4) on a hot stage, and evenly spray the cathode catalyst slurry prepared in step 1) on the surface of the bottom membrane with an air gun; then turn the other side of the bottom membrane upwards and place it in a metal frame, and fix it in the flat support, and evenly spray the anode catalyst slurry prepared in step 2) on the other side of the bottom membrane with an air gun.

[0037] Even further, the temperature of the hot stage is 30-80 °C.

[0038] Even further, the number of spraying times is 1-5 times.

[0039] Further, the steps of spin coating by the spin coater are as follows: Place the flat support obtained in step 4) on the adsorption table of the spin coater, lay a layer of the cathode catalyst slurry obtained in step 1) dropwise on the surface of the bottom film, turn on the spin coater, uniformly coat the cathode catalyst slurry on the surface of the bottom film, and then dry the bottom film; then place the other side of the bottom film facing up in the metal frame, fix it in the flat support, place it on the adsorption table of the spin coater, lay a layer of the anode catalyst slurry obtained in step 2) dropwise on the other side of the bottom film, turn on the spin coater, uniformly coat the anode catalyst slurry on the other side of the bottom film, and then dry the bottom film.

[0040] Furthermore, the conditions for spin coating are a rotation speed of 1000 - 3000 revolutions per minute, a time of 5 - 20 s, and the number of times is 1 - 3 times.

[0041] Furthermore, the drying temperature is 30 - 80 °C.

[0042] Further, the steps of scraping with a glass rod are as follows: Stick both sides of the bottom film obtained in step 3) to the flat support with transparent tape, evenly scrape the cathode catalyst slurry obtained in step 1) on the surface of the bottom film with a glass rod, and immediately place the bottom film in an oven for drying; then stick the other side of the bottom film facing up to the flat support with transparent tape, evenly scrape the anode catalyst slurry obtained in step 2) on the other side of the bottom film with a glass rod, and immediately place the bottom film in an oven for drying.

[0043] Furthermore, the drying temperature is 30 - 80 °C.

[0044] Compared with the prior art, the present invention has the following advantages:

[0045] 1) The present invention uses a proton - electron conductor as the main component of the catalyst slurry. The proton - electron conductor increases the sites for proton transfer in the electrolytic water hydrogen production reaction, accelerates the transfer of protons and electrons, and can improve the performance of the catalytic layer while reducing the amount of catalyst used in the catalytic layer.

[0046] 2) The present invention uses a hydrophilic solution as the binder between the membrane - electrode bottom film and the catalyst, which helps the bonding of the catalyst and the membrane - electrode bottom film, reduces the interfacial resistance, improves the conductivity of the catalyst, and thus greatly improves the performance of the membrane electrode.

[0047] 3) The present invention uses methods such as air gun spraying, spin coating by a spin coater, or scraping with a glass rod to uniformly coat the catalyst slurry on the bottom film of the membrane electrode, and the process is simple and easy to operate. Specific Embodiments

[0048] The present invention will be further described below in conjunction with embodiments.

[0049] Example 1

[0050] 1) Preparation of the bottom membrane of the membrane electrode: Place a Nafion115 membrane (10 cm × 10 cm) in an aqueous solution of 5% H2O2 at 60 °C for 60 min. After repeatedly rinsing the membrane with deionized water, treat the membrane in deionized water at 80 °C for 30 min; then treat it in an aqueous solution of 0.5 mol / L sulfuric acid at 80 °C for 30 min. After repeatedly rinsing the membrane with deionized water, treat the membrane in deionized water at 80 °C for 30 min again. Take it out and wait for the membrane to cool naturally to be used as the bottom membrane of the membrane electrode.

[0051] 2) Preparation of the cathode catalyst slurry: Weigh 50 mg of Pt / C powder with a platinum mass concentration of 20%, add 50 mL of deionized water and 250 mL of ethanol, stir and mix them into a solution, and ultrasonically disperse the solution in an ice-water bath for 20 min; then add 0.5 mg of PEDOT-PSS and 100 mg of a 5% Nafion solution to the solution, and ultrasonically disperse it in an ice-water bath for 10 min to obtain the cathode catalyst slurry.

[0052] 3) Preparation of the anode catalyst slurry: Weigh 100 mg of iridium dioxide powder with a mass concentration of 95%, add 100 mL of deionized water and 500 mL of ethylene glycol, stir and mix them into a solution, and ultrasonically disperse the solution in an ice-water bath for 60 min; then add 10 mg of PEDOT-PSS and 400 mg of a 5% Nafion solution to the solution, and ultrasonically disperse it in an ice-water bath for 60 min to obtain the anode catalyst slurry.

[0053] 4) Preparation of the membrane electrode: Place the bottom membrane obtained in step 1) in a metal frame with a groove in the middle and fix it on the surface of a glass plate; place the glass plate on a hot plate at 40 °C. Pour the cathode catalyst slurry obtained in step 2) into the air gun tank, and use the air gun to evenly spray the cathode catalyst slurry on the surface of the bottom membrane. Spray 3 times to finish spraying the cathode catalyst slurry; then turn the bottom membrane to the other side, place it in a metal frame with a groove in the middle, and fix it on the surface of the glass plate; pour the anode catalyst slurry obtained in step 3) into the air gun tank, and use the air gun to evenly spray the anode catalyst slurry on the other side of the bottom membrane. Spray 3 times to finish spraying the anode catalyst slurry. At this time, the membrane electrode for PEM water electrolysis hydrogen production is prepared.

[0054] Example 2

[0055] 1) Preparation of the bottom membrane of the membrane electrode: Place the Nafion 117 membrane (10 cm × 10 cm) in an aqueous solution of 3% H2O2 at 80 °C for 40 min. After repeatedly rinsing the membrane with deionized water, treat the membrane in deionized water at 60 °C for 30 min; then treat it in an aqueous solution of 1 mol / L sulfuric acid at 80 °C for 30 min. After repeatedly rinsing the membrane with deionized water, treat the membrane in deionized water at 80 °C for 30 min again. Take it out, and after the membrane cools naturally, use it as the bottom membrane of the membrane electrode;

[0056] 2) Preparation of the cathode catalyst slurry: Weigh 75 mg of Pt / C powder with a platinum mass concentration of 40%, 75 mL of deionized water and 750 mL of isopropanol, stir and mix them into a solution, and ultrasonically disperse the solution in an ice-water bath for 30 min; then add 7.5 mg of PEDOT-PSS and 750 mg of a 20% Nafion solution by mass concentration to the solution, and ultrasonically disperse it in an ice-water bath for 30 min again to obtain the cathode catalyst slurry;

[0057] 3) Preparation of the anode catalyst slurry: Weigh 80 mg of iridium dioxide powder with a mass concentration of 95%, 120 g of carbon black, 200 mL of deionized water and 1600 mL of ethanol, stir and mix them into a solution, and ultrasonically disperse the solution in an ice-water bath for 120 min; then add 60 mg of PEDOT-PSS and 200 mg of a 20% Nafion solution by mass concentration to the solution, and ultrasonically disperse it in an ice-water bath for 60 min again to obtain the anode catalyst slurry;

[0058] 4) Preparation of the membrane electrode: Place the bottom membrane prepared in step 1) in a metal frame with a groove in the middle, fix it on the surface of an aluminum sheet, and place it on the adsorption platform of a spin coater; spread a layer of the cathode catalyst slurry prepared in step 2) on the surface of the bottom membrane, turn on the spin coater (rotation speed: 3000 revolutions per minute, time: 5 s), and uniformly coat the cathode catalyst slurry on the surface of the bottom membrane. Then place the bottom membrane in an oven at 50 °C for 5 min; repeat the above steps 2 more times, that is, spread the cathode catalyst slurry on the surface of the bottom membrane, spin coat, and dry; then turn the other side of the bottom membrane upwards, place it in the metal frame, fix it on the surface of the aluminum sheet, place it on the adsorption platform of the spin coater, spread a layer of the anode catalyst slurry prepared in step 3) on the surface of the bottom membrane, turn on the spin coater (rotation speed: 2500 revolutions per minute, time: 10 s), uniformly coat the anode catalyst slurry on the other side of the bottom membrane, and then place the bottom membrane in an oven at 50 °C for 5 min; repeat the above steps 2 more times, that is, spread the anode catalyst slurry on the other side of the bottom membrane, spin coat, and dry, thus obtaining the membrane electrode for PEM water electrolysis hydrogen production.

[0059] Example 3

[0060] 1) Preparation of the bottom membrane of the membrane electrode: Immerse the polybenzimidazole membrane in a 3 mol / L sulfuric acid aqueous solution for 5 days; take it out and use it as the bottom membrane of the membrane electrode after the membrane is naturally dried.

[0061] 2) Preparation of the cathode catalyst slurry: Weigh 34 mg of Pt / C powder with a platinum mass concentration of 60%, 40 mL of deionized water and 800 mL of ethylene glycol, stir and mix them into a solution, and ultrasonically disperse the solution in an ice-water bath for 40 min; then add 6.8 mg of PEDOT-PSS and 2.72 g of a 0.5% polybenzimidazole / N,N-dimethylacetamide solution to the solution, and ultrasonically disperse it in an ice-water bath for 50 min to obtain the cathode catalyst slurry.

[0062] 3) Preparation of the anode catalyst slurry: Weigh 110 mg of iridium dioxide powder with a mass concentration of 85%, 100 mL of deionized water and 1000 mL of isopropanol, stir and mix them into a solution, and ultrasonically disperse the solution in an ice-water bath for 120 min; then add 5.5 mg of PEDOT-PSS and 6.6 g of a 0.5% polybenzimidazole / N,N-dimethylacetamide solution to the solution, and ultrasonically disperse it in an ice-water bath for 60 min to obtain the anode catalyst slurry.

[0063] 4) Preparation of the membrane electrode: Stick the bottom membrane obtained in step 1) on both sides to the glass plate with 3 layers of transparent tape, and evenly scrape and coat the cathode catalyst slurry obtained in step 2) on one side of the bottom membrane with a glass rod, and immediately place the bottom membrane in an oven at 60 °C for 5 min; then turn the other side of the bottom membrane up and stick it to the glass plate with 3 layers of transparent tape, and evenly scrape and coat the anode catalyst slurry obtained in step 3) on the other side of the bottom membrane with a glass rod, and immediately place the bottom membrane in an oven at 60 °C for 5 min to obtain the membrane electrode for PEM water electrolysis hydrogen production.

[0064] Example 4

[0065] 1) Preparation of the bottom membrane of the membrane electrode: Immerse the sulfonated polyether ether ketone membrane in a 2 mol / L phosphoric acid aqueous solution for 7 days; take it out and use it as the bottom membrane of the membrane electrode after the membrane is naturally dried.

[0066] 2) Preparation of the cathode catalyst slurry: Weigh 100 mg of Pt / C powder with a platinum mass concentration of 20%, 100 mL of deionized water and 700 mL of isopropanol, stir and mix them into a solution, and ultrasonically disperse the solution in an ice-water bath for 20 min; then add 10 mg of PEDOT-PSS and 4 g of a 1% sulfonated polyether ether ketone / N,N-dimethylacetamide solution to the solution, and ultrasonically disperse it in an ice-water bath for 60 min to obtain the cathode catalyst slurry.

[0067] 3) Preparation of anode catalyst slurry: Weigh 94 mg of iridium dioxide powder with a mass concentration of 85%, 20 mg of carbon black, 100 mL of deionized water and 500 mL of ethylene glycol, stir and mix them into a solution, and ultrasonically disperse this solution in an ice-water bath for 90 min; then add 30 mg of PEDOT-PSS and 1 g of a 1% sulfonated polyether ether ketone / N,N-dimethylacetamide solution to this solution, and ultrasonically disperse it in an ice-water bath for 90 min again to obtain the anode catalyst slurry;

[0068] 4) Preparation of membrane electrode: Place the bottom membrane prepared in step 1) in a metal frame with a groove in the middle and fix it on the surface of a glass plate; place this glass plate on a hot plate at 50 °C, pour the cathode catalyst slurry prepared in step 2) into the air gun tank, and use the air gun to evenly spray this cathode catalyst slurry on the surface of the bottom membrane. After spraying 3 times, the cathode catalyst slurry can be completely sprayed; then turn the bottom membrane to the other side, place it in a metal frame with a groove in the middle, and fix it on the surface of the glass plate; pour the anode catalyst slurry prepared in step 3) into the air gun tank, and use the air gun to evenly spray this anode catalyst slurry on the other side of the bottom membrane. After spraying 3 times, the anode catalyst slurry can be completely sprayed. At this time, the membrane electrode for PEM water electrolysis hydrogen production is prepared.

Claims

1. A method for preparing a catalyst slurry for PEM electrolytic water hydrogen production, characterized in that, It includes the following steps: 1) Prepare the cathode catalyst slurry: Mix a proton-electron conductor, a binder, Pt / C powder with a platinum mass concentration of 20% - 60%, and a solvent, and disperse them evenly under ultrasonic waves to obtain the cathode catalyst slurry; The proton-electron conductor is poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), i.e., PEDOT-PSS; 2) Prepare the anode catalyst slurry: Mix a proton-electron conductor, a binder, iridium dioxide powder or an iridium dioxide / carbon black mixture, and a solvent, and disperse them evenly under ultrasonic waves to obtain the anode catalyst slurry; The conditions for ultrasonic dispersion are an ice-water bath, and the time is 30 - 90 min; The solvent is a mixture of alcohol and deionized water; The alcohol is ethylene glycol; The binder is one of a sulfonated polysulfone solution, a sulfonated polyethersulfone solution, a sulfonated polyetherimide solution, a sulfonated polyetheretherketone solution, and a sulfonated polyaryletherketone solution; The sulfonated polysulfone solution, the sulfonated polyethersulfone solution, the sulfonated polyetherimide solution, the sulfonated polyetheretherketone solution, and the sulfonated polyaryletherketone solution are N,N-dimethylacetamide solutions of sulfonated polysulfone, sulfonated polyethersulfone, sulfonated polyetherimide, sulfonated polyetheretherketone, and sulfonated polyaryletherketone.

2. The preparation method according to claim 1, characterized in that, In step 1), the proton-electron conductor accounts for 1 - 30% of the mass of the Pt / C powder with a platinum mass concentration of 20% - 60%.

3. The preparation method according to claim 1, characterized in that, In step 2), the proton-electron conductor accounts for 1 - 30% of the mass of the iridium dioxide powder or the iridium dioxide / carbon black mixture.

4. The preparation method according to claim 1, characterized in that, In step 1), the binder accounts for 10 - 40% of the mass of the Pt / C powder with a platinum mass concentration of 20% - 60%.

5. The preparation method according to claim 1, characterized in that, In step 2), the binder accounts for 10 - 40% of the mass of the iridium dioxide powder or the iridium dioxide / carbon black mixture.

6. The preparation method according to claim 1, characterized in that, The volume ratio of deionized water to alcohol in the mixture is 1:5 - 20.

7. The preparation method according to claim 1, characterized in that, The conditions for ultrasonic dispersion in step 2) are an ice-water bath, and the time is 120 - 180 min.

8. The preparation method according to claim 1, characterized in that, In step 2), the mass concentration of the iridium dioxide powder is 85% or 95%.

9. The preparation method according to claim 1, characterized in that, In the iridium dioxide / carbon black mixture in step 2), the iridium dioxide powder accounts for 40 - 80% of the mass of the mixture.

10. A method for preparing a membrane electrode for PEM electrolytic water hydrogen production, characterized in that, It includes the following steps: 1) Prepare the cathode catalyst slurry: Mix a proton-electron conductor, a binder, Pt / C powder with a platinum content of 20% - 40%, and a solvent, and disperse them evenly under ultrasonic waves to obtain the cathode catalyst slurry; The proton-electron conductor is poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), i.e., PEDOT-PSS; 2) Prepare the anode catalyst slurry: Mix a proton-electron conductor, a binder, iridium dioxide powder or an iridium dioxide / carbon black mixture, and a solvent, and disperse them evenly under ultrasonic waves to obtain the anode catalyst slurry; The conditions for ultrasonic dispersion are an ice-water bath, and the time is 30 - 90 min; The solvent is a mixture of alcohol and deionized water; The alcohol is ethylene glycol; The binder is one of sulfonated polysulfone solution, sulfonated polyethersulfone solution, sulfonated polyetherimide solution, sulfonated polyetheretherketone solution and sulfonated polyaryletherketone solution; the sulfonated polysulfone solution, sulfonated polyethersulfone solution, sulfonated polyetherimide solution, sulfonated polyetheretherketone solution and sulfonated polyaryletherketone solution are N,N-dimethylacetamide solutions of sulfonated polysulfone, sulfonated polyethersulfone, sulfonated polyetherimide, sulfonated polyetheretherketone and sulfonated polyaryletherketone; 3) Pretreat the proton exchange membrane to obtain the bottom membrane of the membrane electrode; 4) Fix the four sides of the bottom membrane obtained in step 3) on the surface of a flat support with a metal frame having a groove in the middle; 5) Coat the cathode catalyst slurry obtained in step 1) on the surface of the bottom membrane obtained in step 4), then turn the bottom membrane to the other side, fix the bottom membrane on the surface of the flat support with a metal frame, and coat the anode catalyst slurry obtained in step 2) on the other side of the bottom membrane, thus obtaining the membrane electrode for PEM water electrolysis hydrogen production; The coating method is air gun spraying, spin coating by a spin coater or scraping with a glass rod.

11. The preparation method according to claim 10, wherein In step 3), the proton exchange membrane is one of polybenzimidazole, sulfonated polysulfone, sulfonated polyethersulfone, sulfonated polyetherimide, sulfonated polyetheretherketone and sulfonated polyaryletherketone.

12. The preparation method according to claim 10, wherein The pretreatment method of the proton exchange membrane in step 3) is: soak the membrane in an aqueous solution of 1-3 mol / L acid for 2-7 days.

13. The preparation method according to claim 12, wherein The acid is one of sulfuric acid, hydrochloric acid, formic acid, methanesulfonic acid and phosphoric acid.

14. The preparation method according to claim 10, wherein In step 4), the flat support is a glass plate or an aluminum sheet.

15. The preparation method according to claim 10, wherein The steps of air gun spraying are: place the flat support obtained in step 4) on a hot stage, and use an air gun to evenly spray the cathode catalyst slurry obtained in step 1) on the surface of the bottom membrane; then turn the other side of the bottom membrane upwards and place it in a metal frame and fix it in the flat support, and use an air gun to evenly spray the anode catalyst slurry obtained in step 2) on the other side of the bottom membrane; the steps of spin coating by a spin coater are: place the flat support obtained in step 4) on the adsorption stage of the spin coater, spread a layer of the cathode catalyst slurry obtained in step 1) on the surface of the bottom membrane, turn on the spin coater, evenly coat the cathode catalyst slurry on the surface of the bottom membrane, and then dry the bottom membrane; then turn the other side of the bottom membrane upwards and place it in a metal frame and fix it in the flat support, place it on the adsorption stage of the spin coater, spread a layer of the anode catalyst slurry obtained in step 2) on the other side of the bottom membrane, turn on the spin coater, evenly coat the anode catalyst slurry on the other side of the bottom membrane, and then dry the bottom membrane; the steps of scraping with a glass rod are: stick both sides of the bottom membrane obtained in step 3) to the flat support with transparent tape, use a glass rod to evenly scrape the cathode catalyst slurry obtained in step 1) on the surface of the bottom membrane, and immediately place the bottom membrane in an oven to dry; then turn the other side of the bottom membrane upwards and stick it to the flat support with transparent tape, use a glass rod to evenly scrape the anode catalyst slurry obtained in step 2) on the other side of the bottom membrane, and immediately place the bottom membrane in an oven to dry.

16. The preparation method according to claim 15, wherein The temperature of the hot stage is 30-80 °C.

17. The preparation method according to claim 15, wherein The number of spraying times is 1-5 times.

18. The preparation method according to claim 15, wherein The conditions of spin coating are a rotation speed of 1000-3000 revolutions per minute, a time of 5-20 s, and a number of times of 1-3 times.

19. The preparation method according to claim 15, wherein The drying temperature is 30 to 80 °C.