A method for preparing a membrane electrode for electrolysis of water

Abstract

The application discloses a preparation method of a membrane electrode for electrolysis of water, and comprises the following steps: S10, treating a proton exchange membrane with a surfactant solution to obtain a modified proton exchange membrane; S20, arranging an anode catalytic layer on one side of the modified proton exchange membrane and arranging a cathode catalytic layer on the other side to obtain a membrane electrode; and the surfactant solution comprises a cationic surfactant and a solvent. The carbon chain skeleton rigidity of the proton exchange membrane is enhanced through the modification treatment, so that the swelling deformation degree of the proton exchange membrane under the action of water or low alcohol in the catalytic slurry is reduced, and the load uniformity of the catalytic layer is improved. Meanwhile, the interaction between the proton exchange membrane and the catalytic layer is also enhanced through the modification treatment, and the catalytic layer is effectively prevented from cracking in the subsequent drying process. Therefore, the catalytic layer of the membrane electrode prepared by the preparation method is uniformly loaded and is not prone to cracking, and the quality is stable.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of hydrogen production by water electrolysis, in particular to a preparation method of a CCM membrane electrode for water electrolysis. BACKGROUND

[0002] Solid polymer electrolyte (SPE) water electrolysis technology is generally considered to be the most promising in current water electrolysis hydrogen production technologies, and has the advantages of high current density, high hydrogen purity, low equipment maintenance cost and fast start-up speed, can be effectively combined with renewable energy, and realizes green hydrogen production. In the SPE water electrolysis device, the membrane electrode plays an important role in catalyzing electrolysis reaction, promoting gas generation and discharging, and transmitting electrolyte ions, and the specific working performance and stability of the membrane electrode are closely related to the hydrogen production efficiency and service life of the SPE water electrolysis.

[0003] The structure of the membrane electrode in the SPE water electrolysis generally comprises three layers of a proton exchange membrane, an anode catalyst layer and a cathode catalyst layer. The common processes for realizing the compounding of the three-layer structure at present include a transfer printing method and a direct coating method. In the transfer printing method, catalyst slurry (including a binder, a dispersant and a catalyst) is coated on the surface of a transfer printing substrate and dried to form a catalyst layer, and then the catalyst layer is transferred to the surface of the proton exchange membrane through hot pressing. This method is relatively complex, and problems such as incomplete transfer printing exist. In the direct coating method, catalyst slurry (including a binder, a dispersant and a catalyst) is directly coated on the surface of the proton exchange membrane. This method is relatively simple, and the contact between the catalyst layer and the proton exchange membrane is more close. However, the catalyst layer on the membrane electrode prepared by the direct coating method is prone to problems such as uneven loading and cracking, which seriously affects the working performance and stability of the membrane electrode. SUMMARY

[0004] The main purpose of the application is to provide a preparation method of a membrane electrode for water electrolysis, which aims to solve the problems of uneven loading and cracking of the catalyst layer of the membrane electrode prepared by the existing preparation method.

[0005] To achieve the above-mentioned purpose, the application provides a preparation method of a membrane electrode for water electrolysis, which comprises the following steps:

[0006] S10, treating a proton exchange membrane with a surfactant solution to obtain a modified proton exchange membrane;

[0007] S20, arranging an anode catalyst layer on one side of the modified proton exchange membrane and arranging a cathode catalyst layer on the other side, and then performing hot pressing treatment to obtain a membrane electrode for water electrolysis;

[0008] The surfactant solution comprises a cationic surfactant and a solvent.

[0009] Optionally, the cationic surfactant includes at least one of an alkyl quaternary ammonium salt, an aryl quaternary ammonium salt and a pyridinium salt; and / or,

[0010] The solvent includes at least one of water, methanol, ethanol, isopropanol, n-propanol, n-butanol and isobutanol.

[0011] Optionally, the cationic surfactant includes at least one of dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, dodecyldimethylbenzylammonium chloride, hexadecyldimethylbenzylammonium chloride, octadecyldimethylbenzylammonium chloride, dodecylpyridinium chloride, and hexadecylpyridinium chloride.

[0012] Optionally, step S10 includes:

[0013] The proton exchange membrane is immersed in a surfactant solution to obtain a modified proton exchange membrane; wherein the surfactant loading on the modified proton exchange membrane is 0.5 to 5.0 mg cm -2 .

[0014] Optionally, the mass fraction of the surfactant solution is 0.5 to 5 wt %, and the immersion treatment time is 1 to 12 hours.

[0015] Optionally, step S20 includes:

[0016] Applying an anode catalyst slurry on one side of the modified proton exchange membrane and a cathode catalyst slurry on the other side, drying, and then performing a hot pressing process to obtain an anode catalyst layer and a cathode catalyst layer provided on both sides of the modified proton exchange membrane, and a membrane electrode for electrolysis of water;

[0017] Wherein, the anode catalyst slurry includes an anode catalyst, a binder and a dispersant,

[0018] The cathode catalyst slurry includes a cathode catalyst, a binder and a dispersant.

[0019] Optionally, in the anode catalyst slurry:

[0020] The anode catalyst comprises IrO2; and / or,

[0021] The binder includes a perfluorosulfonic acid resin solution; and / or,

[0022] The dispersant includes at least one of water, ethanol, isopropanol and n-propanol.

[0023] Optionally, in the cathode catalyst slurry:

[0024] The cathode catalyst comprises Pt / C; and / or,

[0025] The binder comprises a perfluorosulfonic acid resin solution; and / or,

[0026] The dispersant comprises at least one of water, ethanol, isopropanol and n-propanol.

[0027] Optionally, the anode catalyst loading on the anode catalytic layer is 0.5-5.0 mg·cm -2 ; and / or,

[0028] The cathode catalyst loading on the cathode catalytic layer is 0.5-5.0 mg·cm -2 .

[0029] Optionally, in the hot-pressing step, the hot-pressing temperature is 90-140℃, the hot-pressing pressure is 0.2-5.0 MPa, and the hot-pressing time is 1-10 min.

[0030] In the technical solution provided by the present application, the proton exchange membrane is modified by using a cationic surfactant. In this process, the hydrophobic alkyl part of the cationic surfactant interacts with the hydrophobic carbon chain in the proton exchange membrane, thereby embedding into the surface layer of the proton exchange membrane, enhancing the rigidity of the carbon chain skeleton of the proton exchange membrane. In this way, the degree of swelling and deformation of the proton exchange membrane under the action of the dispersant (water or lower alcohol) in the catalyst slurry is reduced, thereby improving the uniformity of the catalyst layer loading. At the same time, the hydrophilic positively charged group in the cationic surfactant on the surface of the modified proton exchange membrane can be combined with the negatively charged binder component in the catalyst layer by electrostatic attraction, thereby enhancing the interaction force between the proton exchange membrane and the catalyst layer, effectively preventing the catalyst layer from cracking during the subsequent drying process. Through this cationic surfactant modification method, the catalyst layer of the electrolytic water membrane electrode prepared has uniform loading and is not prone to cracking, thereby making the membrane electrode have good working performance and stability, high yield, and simple process. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other related drawings can also be obtained without creative labor.

[0032] Figure 1 SEM image of the electrolytic water membrane electrode prepared in Example 1 of the present application;

[0033] Figure 2 SEM image of the electrolytic water membrane electrode prepared in Comparative Example 1 of the present application;

[0034] Figure 3 Fig. 1 is a graph showing the performance test results of the membrane electrode for electrolysis of water prepared in Example 1, Comparative Example 1 and Comparative Example 2 of the present application.

[0035] The purposes, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0036] In order to make the purposes, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below. The specific conditions not mentioned in the embodiments are carried out according to the conventional conditions or the conditions suggested by the manufacturers. The reagents or instruments not mentioned by the manufacturers are all conventional products that can be purchased in the market.

[0037] In addition, the meaning of "and / or" appearing throughout the text includes three parallel solutions. Taking "A and / or B" as an example, it includes the A solution, or the B solution, or the solution of A and B being satisfied at the same time. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that a person skilled in the art can realize it. When the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the protection scope required by the present application. Based on the embodiments in the present application, all other embodiments obtained by a person skilled in the art without creative labor are within the protection scope of the present application.

[0038] The structure of the membrane electrode in SPE electrolysis water is usually composed of three layers of proton exchange membrane, anode catalyst layer and cathode catalyst layer. The common processes for realizing the compounding of the three-layer structure at present are transfer printing method and direct coating method. Among them, the transfer printing method is relatively complex, and there are also problems such as incomplete transfer printing; the direct coating method is to coat the catalyst slurry (including binder, solvent and catalyst) directly on the surface of the proton exchange membrane. This method is relatively simple in process, and the contact between the catalyst layer and the proton exchange membrane is more close. However, in the direct coating, the water or low alcohol components contained in the catalyst slurry will cause the swelling deformation of the proton exchange membrane, resulting in uneven coating of the catalyst slurry, and in the subsequent drying, due to the deformation and shrinkage of the proton exchange membrane, it is easy to cause the cracking of the catalyst layer, which seriously affects the working performance and stability of the membrane electrode.

[0039] To address the aforementioned issues with direct coating, researchers have proposed a method for preparing a catalyst slurry by adding a dispersion containing carbon nanotubes as an additive to the catalyst slurry. However, carbon nanotubes are unstable in the anode environment of SPE water electrolysis, and oxidation can destroy their structure, leading to collapse of the catalytic layer and reduced structural stability of the membrane electrode. Therefore, there is currently no effective solution to the problems of proton exchange membrane swelling and catalytic layer cracking that occur during direct coating of membrane electrodes used for SPE water electrolysis.

[0040] In view of this, the present invention proposes a method for preparing a membrane electrode for water electrolysis. In this embodiment, the method for preparing a membrane electrode for water electrolysis includes the following steps:

[0041] Step S10: treating the proton exchange membrane with a surfactant solution to obtain a modified proton exchange membrane; wherein the surfactant solution includes a cationic surfactant and a solvent.

[0042] For the concrete kind of cationic surfactant, the present invention does not limit, and in the present embodiment, described cationic surfactant comprises at least a in alkyl quaternary ammonium salt, aryl quaternary ammonium salt and pyridinium salt.The hydrophilic positively charged group in the cationic surfactant can be combined with the negatively charged binder component in the catalytic layer with charge attraction.Particularly, for quaternary ammonium salt, the hydrophilic positively charged group is exactly quaternary ammonium group, and for pyridinium salt, the hydrophilic positively charged group is exactly pyridinium group.

[0043] Furthermore, the alkyl quaternary ammonium salt includes at least one of dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, and octadecyltrimethylammonium chloride. In another embodiment, the aryl quaternary ammonium salt includes at least one of dodecyldimethylbenzylammonium chloride, hexadecyldimethylbenzylammonium chloride, and octadecyldimethylbenzylammonium chloride. In another embodiment, the pyridinium salt includes at least one of dodecylpyridinium chloride and hexadecylpyridinium chloride.

[0044] Wherein, the solvent includes at least one of water, methanol, ethanol, isopropanol, n-propanol, n-butanol and isobutanol.

[0045] In one embodiment, step S10 includes: immersing the proton exchange membrane in a surfactant solution to obtain a modified proton exchange membrane.

[0046] If the surfactant loading on the modified proton exchange membrane is too low, the treatment effect will be poor, the proton exchange membrane will still swell significantly, and the binding force with the catalytic layer will be insufficient; if the loading is too high, the hydrophobicity of the proton exchange membrane will be enhanced and the proton conductivity will be weakened. In this embodiment, the surfactant loading on the modified proton exchange membrane is 0.5-5.0 mg·cm -2 Under the above loading, the carbon chain skeleton of the modified proton exchange membrane can be made rigid and the binding effect between the modified proton exchange membrane and the catalyst layer can be strengthened without affecting the performance of the proton exchange membrane itself. Preferably, the loading of the surfactant on the modified proton exchange membrane is 1.0 to 3.0 mg cm -2 In this way, the catalytic layer quality of the membrane electrode for water electrolysis is the best.

[0047] The present invention does not limit the specific parameters of the proton exchange membrane modification process, as long as the surfactant loading on the modified proton exchange membrane is 0.5 to 5.0 mg cm -2 That is, in this embodiment, the mass fraction of the surfactant solution is 0.5-5wt%, and the immersion treatment time is 1-12 hours. The surfactant solution can be purchased or prepared by yourself. When preparing by yourself, the following steps are included: dissolving 0.5-5g of cationic surfactant in every 100mL of solvent, and then mixing.

[0048] Step S20: an anode catalyst layer is provided on one side of the modified proton exchange membrane, and a cathode catalyst layer is provided on the other side to obtain a membrane electrode for water electrolysis.

[0049] In a specific embodiment, step S20 includes: applying an anode catalyst slurry on one side of the modified proton exchange membrane and applying a cathode catalyst slurry on the other side, drying, and then hot pressing to form an anode catalyst layer and a cathode catalyst layer on both sides of the modified proton exchange membrane, respectively. The resulting composite structure consisting of the anode catalyst layer, the cathode catalyst layer and the modified proton exchange membrane is a membrane electrode for water electrolysis.

[0050] The anode catalyst slurry comprises an anode catalyst, a binder, and a dispersant. In one embodiment, the anode catalyst comprises IrO2; and / or the dispersant comprises at least one of water, ethanol, isopropanol, and n-propanol. In another embodiment, the binder comprises a perfluorosulfonic acid resin solution, whereby the negatively charged groups in the binder component are sulfonic acid groups.

[0051] Furthermore, in the anode catalyst slurry, the anode catalyst concentration is 2 to 20 mg·mL -1 The mass of the perfluorosulfonic acid resin in the perfluorosulfonic acid resin solution is 20 to 50% of the mass of the anode catalyst.

[0052] The cathode catalyst slurry includes a cathode catalyst, a binder, and a dispersant. In one embodiment, the cathode catalyst comprises Pt / C, specifically one of Pt / C with varying Pt mass fractions. In another embodiment, the binder comprises a perfluorosulfonic acid resin solution; and / or the dispersant comprises at least one of water, ethanol, isopropanol, and n-propanol. Similarly, the negatively charged groups in the binder component are sulfonic acid groups.

[0053] Furthermore, in the cathode catalyst slurry, the cathode catalyst concentration is 2 to 20 mg·mL -1 The mass of the perfluorosulfonic acid resin in the perfluorosulfonic acid resin solution is 20 to 50% of the mass of the cathode catalyst.

[0054] Preferably, the anode catalyst loading on the anode catalyst layer is 0.5 to 5.0 mg·cm -2 In this way, the catalytic performance of the anode catalyst layer is better. In order to improve the catalytic performance of the cathode catalyst layer, in this embodiment, the cathode catalyst loading on the cathode catalyst layer is 0.5 to 5.0 mg cm -2 .

[0055] In order to ensure a tight bond between the catalytic layer and the proton exchange membrane without damaging the structure of the proton exchange membrane, in this embodiment, in the hot pressing step, the hot pressing temperature is 90-140°C, the hot pressing pressure is 0.2-5.0 MPa, and the hot pressing time is 1-10 min.

[0056] Furthermore, the cathode catalyst slurry and the anode catalyst slurry may be applied by any one of blade coating, brush coating, spray coating, and screen printing. It should be noted that the cathode catalyst slurry and the anode catalyst slurry application steps may be performed by applying the cathode catalyst slurry first, applying the anode catalyst slurry first, or both simultaneously.

[0057] In the technical solution provided by the present invention, a cationic surfactant is used to modify the proton exchange membrane. During this process, the hydrophobic alkyl portion of the cationic surfactant interacts with the hydrophobic carbon chain in the proton exchange membrane, thereby being embedded in the surface layer of the proton exchange membrane and enhancing the rigidity of the carbon chain skeleton of the proton exchange membrane. In this way, the degree of swelling and deformation of the proton exchange membrane under the action of a dispersant (water or a lower alcohol) in a catalyst slurry is reduced, thereby improving the load uniformity of the catalytic layer; at the same time, the hydrophilic positively charged groups in the cationic surfactant on the surface of the modified proton exchange membrane can combine with the negatively charged sulfonic acid groups of the binder in the catalytic layer by charge attraction, thereby enhancing the interaction between the proton exchange membrane and the catalytic layer, and effectively preventing the membrane electrode from cracking the catalytic layer during the subsequent drying process.

[0058] The present invention utilizes a cationic surfactant modification method to achieve a uniform catalyst layer loading on the resulting membrane electrode for water electrolysis, making it less susceptible to cracking. This results in excellent performance and stability, consistent quality, and a high yield rate for the membrane electrode. Furthermore, the modification method employed in the present invention is simple, has low production costs, and does not use toxic or hazardous substances during the membrane electrode production process, thereby minimizing environmental pollution.

[0059] The technical solutions of the present invention are further described in detail below in conjunction with specific embodiments and drawings. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0060] Example 1

[0061] (1) Dissolve 1.0 g of hexadecyltrimethylammonium chloride in 100 mL of ethanol to obtain a surfactant solution with a concentration of 1.0 wt %;

[0062] (2) Cut a 50×50 mm Nafion TM 117 proton exchange membrane was immersed in surfactant solution for 8 h to obtain a surfactant loading of 2.2 mg cm -2 The modified proton exchange membrane;

[0063] (3) The anode catalyst IrO2 and 5 wt% perfluorosulfonic acid resin solution were uniformly dispersed in a dispersant with a volume ratio of water to ethanol of 1:2 to form an anode catalyst slurry, wherein the IrO2 content in the anode catalyst slurry was 10 mg·mL -1 , the mass of perfluorosulfonic acid resin is 30% of the mass of IrO2; the cathode catalyst 40wt% Pt / C and 5wt% perfluorosulfonic acid resin solution are uniformly dispersed in a dispersant with a volume ratio of water and ethanol of 1:2 to form a cathode catalyst slurry, wherein the content of 40wt% Pt / C in the cathode catalyst slurry is 10mg·mL -1 , the mass of perfluorosulfonic acid resin is 30% of the mass of 40wt% Pt / C;

[0064] (4) Applying the anode catalyst slurry on one side of the modified proton exchange membrane and the cathode catalyst slurry on the other side, drying naturally, and then hot pressing at 130° C. and 1.5 MPa for 2 min to obtain an anode catalyst layer and a cathode catalyst layer arranged on both sides of the modified proton exchange membrane, i.e., a membrane electrode for water electrolysis, wherein the IrO2 loading on the anode catalyst layer is 2.0 mg cm -2 The 40 wt% Pt / C loading on the cathode catalyst layer was 1.0 mg cm -2 .

[0065] Example 2

[0066] (1) Dissolve 0.5 g of hexadecylpyridinium chloride in 100 mL of n-propanol to obtain a surfactant solution with a concentration of 0.5 wt %;

[0067] (2) Cut a 50×50 mm Nafion TM 117 proton exchange membrane was immersed in surfactant solution for 6 h to obtain a surfactant loading of 1.0 mg cm -2 Modified proton exchange membrane;

[0068] (3) The anode catalyst IrO2 and 5 wt% perfluorosulfonic acid resin solution were uniformly dispersed in a dispersant with a volume ratio of water to ethanol of 1:2 to form an anode catalyst slurry, wherein the IrO2 content in the anode catalyst slurry was 8 mg·mL -1 , the mass of perfluorosulfonic acid resin is 20% of the mass of IrO2; the cathode catalyst 40wt% Pt / C and 5wt% perfluorosulfonic acid resin solution are uniformly dispersed in a dispersant with a volume ratio of water and ethanol of 1:2 to form a cathode catalyst slurry, wherein the content of 40wt% Pt / C in the cathode catalyst slurry is 6mg·mL -1 , the mass of perfluorosulfonic acid resin is 20% of the mass of 40wt% Pt / C;

[0069] (4) spraying the anode catalyst slurry on one side of the modified proton exchange membrane and spraying the cathode catalyst slurry on the other side, drying naturally, and then hot pressing at 140° C. and 1.0 MPa for 1 min to obtain an anode catalyst layer and a cathode catalyst layer arranged on both sides of the modified proton exchange membrane, i.e., a membrane electrode for water electrolysis, wherein the IrO2 loading on the anode catalyst layer is 1.5 mg cm -2 The 40 wt% Pt / C loading on the cathode catalyst layer was 1.0 mg cm -2 .

[0070] Example 3

[0071] (1) Dissolve 4.0 g of dodecyltrimethylammonium chloride in 100 mL of water to obtain a surfactant solution with a concentration of 4.0 wt %;

[0072] (2) Cut 80×80mm Nafion TM 117 proton exchange membrane was immersed in surfactant solution for 1 h to obtain a surfactant loading of 2.8 mg cm -2 Modified proton exchange membrane;

[0073] (3) The anode catalyst IrO2 and 5 wt% perfluorosulfonic acid resin solution were uniformly dispersed in a dispersant with a volume ratio of water and isopropyl alcohol of 1:1 to form an anode catalyst slurry, wherein the IrO2 content in the anode catalyst slurry was 15 mg·mL -1 , the mass of perfluorosulfonic acid resin is 40% of the mass of IrO2; the cathode catalyst 60wt% Pt / C and 5wt% perfluorosulfonic acid resin solution are uniformly dispersed in a dispersant with a volume ratio of water and isopropanol of 1:1 to form a cathode catalyst slurry, wherein the content of 60wt% Pt / C in the cathode catalyst slurry is 10mg·mL -1 , the mass of perfluorosulfonic acid resin is 40% of the mass of 60wt%Pt / C;

[0074] (4) The anode catalyst slurry was scraped onto one side of the modified proton exchange membrane, and the cathode catalyst slurry was scraped onto the other side, and the mixture was dried naturally. Then, the mixture was hot-pressed at 110° C. and 3.0 MPa for 5 min to obtain an anode catalyst layer and a cathode catalyst layer disposed on both sides of the modified proton exchange membrane, i.e., a membrane electrode for water electrolysis, wherein the IrO2 loading on the anode catalyst layer was 3.0 mg cm -2 The 60 wt% Pt / C loading on the cathode catalyst layer was 1.2 mg cm -2 .

[0075] Example 4

[0076] (1) Dissolve 5.0 g of dodecyldimethylbenzyl ammonium chloride in 100 mL of methanol to obtain a surfactant solution with a concentration of 5.0 wt %;

[0077] (2) Cut 80×80mm Nafion TM 117 proton exchange membrane was immersed in surfactant solution for 6 h to obtain a surfactant loading of 5.0 mg cm -2 Modified proton exchange membrane;

[0078] (3) The anode catalyst IrO2 and 5 wt% perfluorosulfonic acid resin solution were uniformly dispersed in a dispersant with a volume ratio of water and isopropyl alcohol of 1:1 to form an anode catalyst slurry, wherein the IrO2 content in the anode catalyst slurry was 5 mg·mL -1 , the mass of perfluorosulfonic acid resin is 50% of the mass of IrO2; the cathode catalyst 60wt% Pt / C and 5wt% perfluorosulfonic acid resin solution are uniformly dispersed in a dispersant with a volume ratio of water and isopropanol of 1:1 to form a cathode catalyst slurry, wherein the content of 60wt% Pt / C in the cathode catalyst slurry is 5mg·mL -1 , the mass of perfluorosulfonic acid resin is 50% of the mass of 60wt%Pt / C;

[0079] (4) The anode catalyst slurry is scraped on one side of the modified proton exchange membrane, and the cathode catalyst slurry is scraped on the other side, and the mixture is dried naturally. Then, hot pressing is performed at 90° C. and 5.0 MPa for 10 min to obtain an anode catalyst layer and a cathode catalyst layer arranged on both sides of the modified proton exchange membrane, i.e., a membrane electrode for water electrolysis, wherein the IrO2 loading on the anode catalyst layer is 5.0 mg cm -2 The 60 wt% Pt / C loading on the cathode catalyst layer was 2.5 mg cm -2 .

[0080] Example 5

[0081] (1) Dissolve 1.0 g of octadecyldimethylbenzyl ammonium chloride in 100 mL of isopropyl alcohol to obtain a surfactant solution with a concentration of 1.0 wt %;

[0082] (2) Cut a 50×50 mm Nafion TM 117 proton exchange membrane was immersed in surfactant solution for 1 h to obtain a surfactant loading of 0.5 mg cm -2 Modified proton exchange membrane;

[0083] (3) The anode catalyst IrO2 and 5 wt% perfluorosulfonic acid resin solution were uniformly dispersed in a dispersant with a volume ratio of water and isopropyl alcohol of 1:1 to form an anode catalyst slurry, wherein the IrO2 content in the anode catalyst slurry was 20 mg·mL -1 , the mass of perfluorosulfonic acid resin is 20% of the mass of IrO2; the cathode catalyst 60wt% Pt / C and 5wt% perfluorosulfonic acid resin solution are uniformly dispersed in a dispersant with a volume ratio of water and isopropanol of 1:1 to form a cathode catalyst slurry, wherein the content of 60wt% Pt / C in the cathode catalyst slurry is 20mg·mL -1 , the mass of perfluorosulfonic acid resin is 20% of the mass of 60wt%Pt / C;

[0084] (4) Applying the anode catalyst slurry on one side of the modified proton exchange membrane and the cathode catalyst slurry on the other side, drying naturally, and then hot pressing at 130° C. and 0.2 MPa for 7 min to obtain an anode catalyst layer and a cathode catalyst layer arranged on both sides of the modified proton exchange membrane, i.e., a membrane electrode for water electrolysis, wherein the IrO2 loading on the anode catalyst layer is 2.0 mg cm -2 The 60 wt% Pt / C loading on the cathode catalyst layer is 0.5 mg cm -2 .

[0085] Comparative Example 1

[0086] Except that the proton exchange membrane is not modified, the remaining steps are the same as those in Example 1, that is, steps (1) and (2) are removed, and the cathode catalyst layer and the anode catalyst layer are directly arranged on both sides of the proton exchange membrane.

[0087] Comparative Example 2

[0088] In addition to modifying step (1) to: dissolve 5.0 g of hexadecyltrimethylammonium chloride in 100 mL of ethanol to obtain a surfactant solution with a concentration of 5.0 wt %, and obtain a surfactant loading of 5.5 mg·cm after impregnation. -2 The modified proton exchange membrane is prepared, and the remaining steps are the same as those in Example 1.

[0089] (1) Structural characterization

[0090] The membrane electrodes for water electrolysis prepared in Example 1 and Comparative Example 1 were observed under a scanning electron microscope. Figure 1 (Example 1) and Figure 2 As shown in (Comparative Example 1), by Figure 1 and Figure 2 A comparison shows that the catalyst distribution on the anode and cathode catalyst layers of the membrane electrode surface prepared in Example 1 is more uniform, and no catalyst layer cracking occurs. However, the catalyst on the catalyst layer of the membrane electrode surface prepared in Comparative Example 1 is partially distributed in a clumping manner, with poor uniformity. This indicates that the present invention, by modifying the proton exchange membrane, makes the catalyst loading on the catalyst layer of the membrane electrode for water electrolysis more uniform, while avoiding the occurrence of cracking.

[0091] (2) Performance test

[0092] The membrane electrodes for water electrolysis prepared in Example 1, Comparative Example 1 and Comparative Example 2 were placed in the SPE water electrolysis test system for testing. The test conditions were set to a current density of 2 A·cm -2 , temperature 80℃, test membrane electrode area 20cm 2 , and the test results are as follows Figure 3 shown.

[0093] Depend on Figure 3 It can be seen that the initial voltage of the membrane electrode in Example 1 is 1.848 V, and the voltage change during the 40-hour stability test is only 1.4%, while the initial voltage of the membrane electrode in Comparative Example 1 is 1.867 V, and the voltage change during the 40-hour stability test is 12.5%, indicating that the proton exchange membrane modification treatment has a significant improvement effect on the stability of the membrane electrode; the initial voltage of the membrane electrode in Comparative Example 2 reaches 1.976 V, indicating that too much surfactant will have a negative impact on the working performance of the membrane electrode.

[0094] The membrane electrodes for water electrolysis prepared in Examples 2-5 of the present invention were subjected to the same tests as in Example 1, confirming that the catalytic layers of the obtained membrane electrodes were uniform, had few cracks, and had good working performance and stability.

[0095] In summary, the present invention modifies the proton exchange membrane to produce a uniform, nearly crack-free catalyst layer on the resulting membrane electrode, thereby enhancing its stability. Furthermore, by carefully designing the parameters during the modification process, negative impacts on the membrane electrode's performance are avoided. Consequently, the membrane electrode produced by the present invention exhibits excellent performance and stability.

[0096] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of the present invention.

Claims

1. A method for preparing a membrane electrode for water electrolysis, characterized in that: The following steps are involved: S10, immersing the proton exchange membrane in a surfactant solution to obtain a modified proton exchange membrane; wherein the surfactant loading on the modified proton exchange membrane is 0.5 to 5.0 mg cm -2 ; S20, coating an anode catalyst slurry on one side of the modified proton exchange membrane and coating a cathode catalyst slurry on the other side, drying, and then performing a hot pressing process to obtain an anode catalyst layer and a cathode catalyst layer disposed on both sides of the modified proton exchange membrane, i.e., a membrane electrode for water electrolysis; The anode catalyst slurry includes an anode catalyst, a binder and a dispersant, and the cathode catalyst slurry includes a cathode catalyst, a binder and a dispersant, wherein the binder includes a perfluorosulfonic acid resin solution as a binder; The surfactant solution includes a cationic surfactant and a solvent, wherein the cationic surfactant includes at least one of dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, dodecyldimethylbenzylammonium chloride, hexadecyldimethylbenzylammonium chloride, octadecyldimethylbenzylammonium chloride, dodecylpyridinium chloride, and hexadecylpyridinium chloride.

2. The method for preparing a membrane electrode for water electrolysis according to claim 1, wherein: The solvent includes at least one of water, methanol, ethanol, isopropanol, n-propanol, n-butanol and isobutanol.

3. The method for preparing a membrane electrode for water electrolysis according to claim 1, wherein The mass fraction of the surfactant solution is 0.5 to 5 wt %, and the immersion treatment time is 1 to 12 hours.

4. The method for preparing a membrane electrode for water electrolysis according to claim 1, wherein In the anode catalyst slurry: The anode catalyst comprises IrO2; and / or, The binder includes a perfluorosulfonic acid resin solution; and / or, The dispersant includes at least one of water, ethanol, isopropanol and n-propanol.

5. The method for preparing a membrane electrode for water electrolysis according to claim 1, wherein: In the cathode catalyst slurry: The cathode catalyst comprises Pt / C; and / or, The binder includes a perfluorosulfonic acid resin solution; and / or, The dispersant includes at least one of water, ethanol, isopropanol and n-propanol.

6. The method for preparing a membrane electrode for water electrolysis according to claim 1, wherein: The anode catalyst loading on the anode catalyst layer is 0.5 to 5.0 mg·cm -2 ; and / or, the cathode catalyst loading on the cathode catalyst layer is 0.5 to 5.0 mg cm -2 .

7. The method for preparing a membrane electrode for water electrolysis according to claim 1, wherein: In the hot pressing step, the hot pressing temperature is 90-140° C., the hot pressing pressure is 0.2-5.0 MPa, and the hot pressing time is 1-10 min.

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