A catalyst coating film that reduces hydrogen cross-linking and is resistant to high-voltage oxidation, and its preparation method.

Abstract

This invention belongs to the field of water electrolysis, specifically relating to a catalyst coating membrane that reduces hydrogen cross-linking and is resistant to high-voltage oxidation. It includes a proton exchange membrane substrate, an anode catalyst layer, and a cathode catalyst layer. A platinum-supported catalyst layer, using a perfluorosulfonic acid resin grafted with poly(3,4-ethylenedioxythiophene) as a carrier, is disposed between the anode catalyst layer and the proton exchange membrane. The platinum-supported catalyst layer is disposed on the anode side of the proton exchange membrane, the anode catalyst layer is disposed on the surface of the platinum-supported catalyst layer, and the cathode catalyst layer is disposed on the cathode side of the proton exchange membrane. These layers are physically bonded together to form an integrated catalyst coating membrane. This catalyst coating membrane can both physically isolate and protect the catalyst under high voltage, preventing oxidation, and maintain efficient proton and electron conduction on the catalyst surface. It effectively suppresses hydrogen cross-linking without reducing catalyst activity, thereby significantly improving the lifespan of the membrane electrode and the safety performance of the electrolyzer.

Description

Technical Field

[0001] This invention belongs to the field of water electrolysis technology, specifically relating to a catalyst coating membrane that reduces hydrogen cross-linking and is resistant to high-voltage oxidation, and its preparation method. Background Technology

[0002] With the global energy transition towards cleaner and lower-carbon energy, proton exchange membrane (PEM) electrolysis of water to produce green hydrogen using renewable energy power generation has become a highly promising energy storage and hydrogen production technology due to its advantages such as high current density, high hydrogen purity, and fast response speed. However, in the actual operation of PEM electrolyzers, due to the thin proton exchange membrane and the large pressure difference between its two sides (the cathode is usually high-pressure hydrogen), hydrogen generated at the cathode can easily penetrate the proton exchange membrane and permeate to the anode side, resulting in a "hydrogen cross-contamination" phenomenon. Hydrogen cross-contamination not only reduces the Faraday efficiency of the electrolyzer, but more seriously, the hydrogen permeating to the anode mixes with the oxygen generated at the anode. Once the local hydrogen concentration reaches the explosion limit, it will cause serious safety accidents. To mitigate the hydrogen cross-contamination problem, existing technologies typically add composite catalysts (such as platinum-based catalysts) with redox properties for hydrogen to the inside of the proton exchange membrane or the anode catalyst layer. These catalysts then re-reconstitute the permeated hydrogen and oxygen into water.

[0003] However, this conventional approach reveals the following insurmountable technical flaws in practical applications: the operating potential on the anode side of the PEM water electrolysis (oxygen evolution reaction, OER) is extremely high (typically above 1.5V to 2.0V). Under this harsh acidic environment of high voltage and strong oxidizing properties, conventional exposed platinum (Pt) and other hydrogen composite catalysts are easily oxidized to form platinum oxide, resulting in severe dissolution and aggregation. This causes the catalyst to rapidly lose its redox ability against permeated hydrogen, failing to achieve long-term hydrogen permeation resistance and significantly shortening the lifespan of the membrane electrode.

[0004] Therefore, how to effectively physically isolate the hydrogen-free original catalyst to prevent high-voltage oxidation while maintaining excellent proton and electron conduction efficiency and high catalyst activity is a technical problem that urgently needs to be solved in the field of PEM water electrolysis technology. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a catalyst coating film that reduces hydrogen cross-linking and is resistant to high-voltage oxidation, which can not only physically isolate and protect the catalyst under high voltage to prevent it from being oxidized, but also maintain the efficient conduction of protons and electrons on the catalyst surface. Without reducing the catalyst activity, it effectively suppresses hydrogen cross-linking, thereby significantly improving the life of the membrane electrode and the safety performance of the electrolyzer.

[0006] The technical solution adopted by the present invention to solve the above-mentioned problems is as follows: A catalyst coating membrane that reduces hydrogen cross-linking and is resistant to high-voltage oxidation includes a proton exchange membrane substrate, an anode catalyst layer, and a cathode catalyst layer. A platinum-supported catalyst layer, using a perfluorosulfonic acid resin grafted with poly(3,4-ethylenedioxythiophene) as a carrier, is disposed between the anode catalyst layer and the proton exchange membrane substrate. The platinum-supported catalyst layer and the cathode catalyst layer are respectively disposed on opposite sides of the proton exchange membrane. The anode catalyst layer is then composited onto the surface of the platinum-supported catalyst layer via a peeling transfer method. The layers are interconnected through ion conduction and physical bonding to form an integrated catalyst coating membrane.

[0007] The present invention also provides a method for preparing the above-mentioned catalyst coating membrane that reduces hydrogen cross-linking and is resistant to high-voltage oxidation. The main process is as follows: a PEDOT-PFSA dispersion is prepared by mixing perfluorosulfonic acid resin (PFSA) with monomer 3,4-ethylenedioxythiophene (EDOT) and oxidatively polymerizing the mixture. After dialysis to remove impurities and centrifugation, a PEDOT-PFSA composite (i.e., perfluorosulfonic acid resin grafted with poly(3,4-ethylenedioxythiophene)) is obtained. The PEDOT-PFSA composite is used as a support and mixed with a platinum source. After stirring, drying and reduction, a supported platinum catalyst is obtained. The supported platinum catalyst is formulated into a slurry and sprayed onto the anode side of a proton exchange membrane. Then, an iridium oxide catalyst and a platinum-carbon cathode catalyst are respectively composited onto the anode and cathode sides of the proton exchange membrane by exfoliation transfer method to obtain the catalyst coating membrane. Furthermore, the method for preparing the catalyst coating film that reduces hydrogen cross-linking and is resistant to high-voltage oxidation specifically includes the following steps: (3) The perfluorosulfonic acid resin (PFSA) solution was mixed with the monomer 3,4-ethylenedioxythiophene (EDOT), a certain amount of water was added and stirred until the solution was milky white, and then ferric chloride was added and stirred to obtain a dark blue dispersion. The dark blue dispersion was dialyzed to remove unreacted monomers and iron ions, and then centrifuged to obtain the grafted poly(3,4-ethylenedioxythiophene) perfluorosulfonic acid resin, namely the PEDOT-PFSA complex. (4) Dissolve soluble platinum salts such as platinum nitrate in water to form a transparent solution, add PEDOT-PFSA complex and then ultrasonically disperse it evenly. After removing the solvent by rotary evaporation and vacuum drying, grind it evenly and perform reduction heat treatment under a reducing atmosphere to obtain Pt / PFSA-PEDOT catalyst powder, i.e. platinum supported catalyst. (3) Pt / PFSA-PEDOT catalyst powder, ultrapure water and isopropanol are mixed to form a slurry (i.e. platinum supported catalyst slurry), and then sprayed onto the anode side of the proton exchange membrane to form a supported platinum catalyst layer on the anode side of the proton exchange membrane with a perfluorosulfonic acid resin grafted with poly(3,4-ethylenedioxythiophene) as the support. (4) The anode catalyst layer is transferred to the surface of the supported platinum catalyst layer by the stripping transfer method, and the cathode catalyst layer is transferred to the cathode side of the proton exchange membrane by the same stripping transfer method to obtain the catalyst coating film.

[0008] According to the above scheme, in step (1), the solid content of the PFSA solution is in the range of 5-15%, and the equivalent mass (EW) of PFSA is in the range of 500-1500.

[0009] According to the above scheme, in step (1), the mass ratio of EDOT to PFSA (based on the effective amount of PFSA in the PFSA solution) is controlled between (0.5-4):1.

[0010] According to the above scheme, in step (1), the mass ratio of EDOT to water is 1-3%; the mass ratio of ferric chloride to EDOT is 30%-40%.

[0011] According to the above scheme, in step (1), the molecular weight cutoff for dialysis is 600-1200 Da; the dialysis solution needs to be changed 3-5 times during the dialysis process, with an interval of 2-3 hours between each change.

[0012] According to the above scheme, in step (2), the mass ratio of PEDOT-PFSA complex to platinum nitrate is (0.5-5):1.67; the sum of PEDOT-PFSA and platinum nitrate accounts for 1-5% of the mass of water.

[0013] According to the above scheme, in step (2), the temperature of the reduction heat treatment is 125-175℃ and the time is 2-4h; the reduction atmosphere is a mixture of hydrogen and nitrogen, or a mixture of hydrogen and inert gas, wherein the mass fraction of hydrogen is 3-6%.

[0014] According to the above scheme, in step (3), the cathode catalyst layer and the anode catalyst layer are formed by coating the cathode catalyst slurry and the anode catalyst slurry onto the surface of the PTFE substrate, respectively. The anode catalyst slurry is prepared by iridium oxide, water, isopropanol and Nafion; the cathode catalyst slurry is a slurry of Pt / C catalyst.

[0015] Compared with the prior art, the beneficial effects of the present invention are: To address the shortcomings of existing PEM (Polymer Electrolysis Membrane) anode catalyst layers, such as the easy oxidation and dissolution of the hydroxide precursor catalyst (e.g., platinum) under high-pressure, strong oxidizing conditions, and the potential for traditional polymers to block proton or electron conduction channels, this invention proposes a platinum-supported catalyst layer using a perfluorosulfonic acid resin grafted with poly(3,4-ethylenedioxythiophene) as a carrier, introduced between the proton exchange membrane and the anode catalyst layer. This platinum-supported catalyst layer adheres closely to the proton exchange membrane surface, providing physical isolation and protection for the catalyst under high voltage, preventing oxidation, while maintaining efficient proton and electron conduction on the catalyst surface. It also effectively eliminates hydrogen permeating from the cathode, suppressing hydrogen cross-linking without reducing catalyst activity, thereby significantly improving the membrane electrode lifespan and the safety performance of the electrolyzer.

[0016] The catalyst coating membrane of this invention comprises a platinum-supported catalyst layer supported on a perfluorosulfonic acid resin grafted with poly(3,4-ethylenedioxythiophene). Its proton conductivity ensures good ion contact with the membrane, while its electronic conductivity provides an efficient electronic pathway between the platinum catalyst and the reaction interface. Therefore, the catalyst coating membrane of this invention not only provides a dual-conductivity network but also anchors and protects platinum particles, mitigating the oxidative dissolution of platinum at high anodic potentials. Furthermore, by loading Pt onto a PFSA-PEDOT support, the impact on proton conduction of the membrane electrode is reduced, and hydrogen in oxygen on the anodic side is effectively decreased. Attached Figure Description

[0017] Figure 1 This is a transmission electron microscope (TEM) image of the Pt / PEDOT-PFSA catalyst powder prepared in Example 1 of this invention.

[0018] Figure 2 This is a transmission electron microscope (TEM) image of the catalyst coating film prepared in Example 1 of the present invention, which reduces hydrogen cross-linking and is resistant to high-voltage oxidation. The anode is the anode, and Pt / PEDOOT-PFSA represents the platinum-supported catalyst layer with a perfluorosulfonic acid resin grafted with poly(3,4-ethylenedioxythiophene) as the support.

[0019] Figure 3 The durability curves are for the catalyst coating films prepared in Example 1 and Comparative Example 2 of this invention.

[0020] Figure 4 This is a schematic diagram of the working mechanism of the Pt / PEDOT-PFSA catalyst layer under electrochemical high pressure environment. The left and right sides show the structural states before and after the application of high pressure, respectively.

[0021] Figure 5 The graph shows the hydrogen content in oxygen when the catalyst coating films prepared in Examples 1, 2, 3, 4 and Comparative Example 1 of this invention are used for oxygen production by water electrolysis. Detailed Implementation

[0022] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the present invention is not limited to the following embodiments.

[0023] All transmission electron microscope scans in the embodiments were taken using a transmission electron microscope (TEM, IEM-2100F, Japan).

[0024] Example 1 A catalyst coating film that reduces hydrogen cross-linking and is resistant to high-voltage oxidation is prepared by the following steps: (1) A commercially available perfluorosulfonic acid (PFSA) resin solution (D520, 5 wt%, EW1000) was selected, and its solid content was increased to 10 wt% by rotary evaporation. 0.2 g of 3,4-ethylenedioxythiophene (EDOT) and 2 g of 10 wt% perfluorosulfonic acid resin solution were added to 15 ml of deionized water and stirred for 2 h. The solution turned milky white. Then, 0.13 g of FeCl3·6H2O was added as an oxidant and stirred for another 24 h at room temperature to obtain a dark blue dispersion. Subsequently, the dark blue dispersion was purified by dialysis using a dialysis bag with a molecular weight cutoff of 500 Da to remove unreacted monomers and iron ions. After dialysis, the mixture was centrifuged multiple times to obtain the PEDOT-PFSA complex.

[0025] (2) Mix 0.167g of platinum nitrate powder with 50ml of deionized water and stir for 10 minutes until the solution is light yellow and transparent without precipitation. Add 0.1g of PEDOT-PFSA complex and sonicate for 10 minutes until no powder floats on the surface. Stir the mixture of PEDOT-PFSA and platinum nitrate vigorously for 24 h, then rotary evaporate at 60 ℃ and dry at 60 ℃ for 12 h. Grind the dried solid and heat it to 150 ℃ in a 5% H2 / Ar atmosphere for 2 h. Cool to room temperature to obtain Pt / PFSA-PEDOT catalyst powder.

[0026] (3) 0.1g of Pt / PFSA-PEDOT catalyst powder, 3.3g of ultrapure water, and 6.6g of isopropanol were ultrasonically mixed until homogeneous. The resulting slurry was then prepared at a depth of 4×4 cm. 2 The effective area is sprayed onto the anode side of the proton exchange membrane N212 to form a platinum-supported catalyst layer; (4) An anode catalyst slurry was prepared from iridium oxide, water, isopropanol, and Nafion solution, wherein the mass ratio of Nafion solution to iridium oxide was 1:9, and the mass ratio of water to isopropanol was 1:2; the cathode slurry was a commercially available 50wt% Pt / C catalyst slurry; the anode and cathode catalyst slurries were prepared at 4×4cm... 2The effective area is coated on the surface of the PTFE substrate to form an anode catalyst layer and a cathode catalyst layer. Then, the catalyst is transferred to the surface of the above-mentioned platinum-supported catalyst layer and the cathode side of the proton exchange membrane N212 by a peeling transfer method, respectively, to obtain the catalyst coating membrane product that reduces hydrogen cross-linking and is resistant to high-voltage oxidation.

[0027] Depend on Figure 1 It is known that in the Pt / PEDOOT-PFSA catalyst powder, platinum particles are coated inside by PEDOT-PFSA resin; this coating structure can inhibit the oxidation or dissolution of platinum particles under high anodic potential conditions, thereby improving the electrochemical stability of the catalyst.

[0028] Figure 2 This demonstrates that the catalyst coating film prepared in this embodiment, which reduces hydrogen cross-linking and is resistant to high-voltage oxidation, forms an integrated membrane electrode structure through proton-electron conduction and physical bonding between its layers. Good interfacial bonding is key to ensuring efficient proton and electron transport and reducing contact resistance. Furthermore, the Pt / PFSA-PEDOT catalyst layer is observed to be densely attached to the proton exchange membrane surface. From the perspective of device microstructure, this invention proves that the preparation method can successfully construct a composite membrane electrode with a complete structure and good interfacial bonding.

[0029] Example 2 A catalyst coating film that reduces hydrogen cross-linking and is resistant to high-voltage oxidation is prepared by the following steps: (1) Prepare the PEDOT-PFSA complex according to step (1) of Example 1.

[0030] (2) Mix 0.167g of platinum nitrate powder and 50ml of deionized water and stir for 10 minutes until the solution is light yellow and transparent and there is no precipitate. Add 0.2g of PEDOT-PFSA complex and sonicate for 10 minutes until there is no powder floating on the surface of the liquid. Stir the mixture of PEDOT-PFSA and platinum nitrate vigorously for 24 h, then rotary evaporate at 60 ℃ and dry at 60 ℃ for 12 h. Grind the dried solid and heat it to 150 ℃ in a 5% H2 / Ar atmosphere and keep it at that temperature for 2 h. Cool it to room temperature to obtain Pt / PFSA-PEDOT catalyst powder.

[0031] (3) 0.1g of Pt / PFSA-PEDOT catalyst powder, 3.3g of ultrapure water, and 6.6g of isopropanol were ultrasonically mixed until homogeneous. The resulting slurry was then prepared at a depth of 4×4 cm. 2 The effective area is sprayed onto the anode side of the proton exchange membrane N212 to form a platinum-supported catalyst layer; (4) An anode catalyst slurry was prepared from iridium oxide, water, isopropanol, and Nafion solution, wherein the mass ratio of Nafion solution to iridium oxide was 1:9, and the mass ratio of water to isopropanol was 1:2; the cathode slurry was a commercially available 50wt% Pt / C catalyst slurry; the anode and cathode catalyst slurries were prepared at 4×4cm... 2 The effective area is coated on the surface of the PTFE substrate to form an anode catalyst layer and a cathode catalyst layer. Then, the catalyst is transferred to the surface of the above-mentioned platinum-supported catalyst layer and the cathode side of the proton exchange membrane N212 by a peeling transfer method, respectively, to obtain the catalyst coating membrane product that reduces hydrogen cross-linking and is resistant to high-voltage oxidation.

[0032] The difference between Example 2 and Example 1 is that 0.2g of PEDOT-PFSA powder was used to control the ratio of PFSA-PEDOT to platinum nitrate. In Example 1, the mass ratio of PEDOT-PFSA complex to platinum nitrate was 1:1.67, while in Example 2, the mass ratio was 2:1.67.

[0033] Example 3 A catalyst coating film that reduces hydrogen cross-linking and is resistant to high-voltage oxidation is prepared by the following steps: (1) Prepare the PEDOT-PFSA complex according to step (1) of Example 1.

[0034] (2) Mix 0.167g of platinum nitrate powder with 50ml of deionized water and stir for 10 minutes until the solution is light yellow and transparent without precipitation. Add 0.3g of PEDOT-PFSA complex and ultrasonically disperse for 10 minutes until no powder floats on the surface. Stir the mixture of PEDOT-PFSA and platinum nitrate vigorously for 24 h, then rotary evaporate at 60 ℃ and dry at 60 ℃ for 12 h. Grind the dried solid and heat it to 150 ℃ in a 5% H2 / Ar atmosphere for 2 h. Cool to room temperature to obtain Pt / PFSA-PEDOT catalyst powder.

[0035] (3) 0.1g of Pt / PFSA-PEDOT catalyst powder, 3.3g of ultrapure water, and 6.6g of isopropanol were ultrasonically mixed until homogeneous. The resulting slurry was then prepared at a depth of 4×4 cm. 2 The effective area is sprayed onto the anode side of the proton exchange membrane N212 to form a platinum-supported catalyst layer; (4) An anode catalyst slurry was prepared from iridium oxide, water, isopropanol, and Nafion solution, wherein the mass ratio of Nafion solution to iridium oxide was 1:9, and the mass ratio of water to isopropanol was 1:2; the cathode slurry was a commercially available 50wt% Pt / C catalyst slurry; the anode and cathode catalyst slurries were prepared at 4×4cm...2 The effective area is coated on the surface of the PTFE substrate to form an anode catalyst layer and a cathode catalyst layer. Then, the catalyst is transferred to the surface of the above-mentioned platinum-supported catalyst layer and the cathode side of the proton exchange membrane N212 by a peeling transfer method, respectively, to obtain the catalyst coating membrane product that reduces hydrogen cross-linking and is resistant to high-voltage oxidation.

[0036] The difference between Example 3 and Example 1 is that 0.3g of PEDOT-PFSA powder was used to control the ratio of PFSA-PEDOT to platinum nitrate. In Example 1, the mass ratio of PEDOT-PFSA complex to platinum nitrate was 1:1.67, while in Example 3, the mass ratio was 3:1.67.

[0037] Example 4 A catalyst coating film that reduces hydrogen cross-linking and is resistant to high-voltage oxidation is prepared by the following steps: (1) Prepare the PEDOT-PFSA complex according to step (1) of Example 1.

[0038] (2) Mix 0.167g of platinum nitrate powder and 50ml of deionized water and stir for 10 minutes until the solution is light yellow and transparent and there is no precipitate. Add 0.4g of PEDOT-PFSA complex and sonicate for 10 minutes until there is no powder floating on the surface of the liquid. Stir the mixture of PEDOT-PFSA and platinum nitrate vigorously for 24 h, then rotary evaporate at 60 ℃ and dry at 60 ℃ for 12 h. Grind the dried solid and heat it to 150 ℃ in a 5% H2 / Ar atmosphere and keep it at that temperature for 2 h. Cool it to room temperature to obtain Pt / PFSA-PEDOT catalyst powder.

[0039] (3) 0.1g of Pt / PFSA-PEDOT catalyst powder, 3.3g of ultrapure water, and 6.6g of isopropanol were ultrasonically mixed until homogeneous. The resulting slurry was then prepared at a depth of 4×4 cm. 2 The effective area is sprayed onto the anode side of the proton exchange membrane N212 to form a platinum-supported catalyst layer; (4) An anode catalyst slurry was prepared from iridium oxide, water, isopropanol, and Nafion solution, wherein the mass ratio of Nafion solution to iridium oxide was 1:9, and the mass ratio of water to isopropanol was 1:2; the cathode slurry was a commercially available 50wt% Pt / C catalyst slurry; the anode and cathode catalyst slurries were prepared at 4×4cm... 2 The effective area is coated on the surface of the PTFE substrate to form an anode catalyst layer and a cathode catalyst layer. Then, the catalyst is transferred to the surface of the above-mentioned platinum-supported catalyst layer and the cathode side of the proton exchange membrane N212 by a peeling transfer method, respectively, to obtain the catalyst coating membrane product that reduces hydrogen cross-linking and is resistant to high-voltage oxidation.

[0040] The difference between Example 4 and Example 1 is that 0.4g of PEDOT-PFSA was used to control the ratio of PFSA-PEDOT to platinum nitrate. In Example 1, the mass ratio of PEDOT-PFSA complex to platinum nitrate was 1:1.67, while in Example 4, the mass ratio was 4:1.67.

[0041] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that steps (1) to (3) are omitted, and the anode catalyst slurry and cathode catalyst slurry are directly mixed at a depth of 4×4cm. 2 The effective area is coated on the surface of the PTFE substrate to form the anode catalyst layer and the cathode catalyst layer, which are then transferred to both sides of the proton exchange membrane N212 by the peeling and transfer method, thus omitting the platinum-supported catalyst layer.

[0042] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that steps (1) to (2) are omitted, and in step (3), Pt is used instead of Pt / PEDOT-PFSA. The specific experimental procedure is as follows: 0.1g of Pt powder, 3.3g of ultrapure water, and 6.6g of isopropanol are ultrasonically mixed evenly. The resulting slurry is then sized to 4×4 cm. 2 The effective area was sprayed onto the anode side of the proton exchange membrane N212 to form a platinum-supported catalyst layer; then, an anode catalyst slurry was prepared from iridium oxide, water, isopropanol, and Nafion solution, wherein the mass ratio of Nafion solution to iridium oxide was 1:9, and the mass ratio of water to isopropanol was 1:2; the cathode slurry used was a commercially available 50wt% Pt / C catalyst slurry; the anode and cathode catalyst slurries were respectively spaced at 4×4cm... 2 The effective area is coated on the surface of the PTFE substrate to form an anode catalyst layer and a cathode catalyst layer. Then, the catalyst is transferred to the surface of the above-mentioned platinum-supported catalyst layer and the cathode side of the proton exchange membrane N212 by a peeling transfer method, respectively, to obtain the catalyst coating membrane product that reduces hydrogen cross-linking and is resistant to high-voltage oxidation.

[0043] The coating films prepared in Example 1 and Comparative Example 1 are cut to a preset size (e.g., 5 cm × 5 cm), and diffusion layers (such as titanium felt, carbon paper, etc.) are attached to the anode and cathode sides respectively. They are then clamped between the anode and cathode bipolar plates and fastened with bolts to assemble a proton exchange membrane water electrolysis full cell. Figure 3 The polarization curves were obtained from a full-cell test. The test conditions were conducted under pure water conditions, maintaining an inlet temperature of 80℃, a water flow rate of 100 ml / min, and a current density of 2 A / cm². 2 .Depend on Figure 3It can be seen that the voltage rise rate of the example with added Pt / PEDOT-PFSA is significantly lower than that of the comparative example with added platinum. This indicates that the PEDOT-PFSA support has an anchoring and protective effect on platinum particles, which can slow down the oxidation, dissolution and corrosion of platinum under high anodic potential, thereby improving the durability of the catalyst and the service life of the water electrolysis device. Figure 4 A schematic diagram of the working mechanism of the Pt / PEDOT-PFSA catalyst layer under electrochemical high voltage environment is shown.

[0044] Figure 5 The hydrogen content in oxygen was measured during a full-cell test. The test was conducted under pure water conditions, maintaining an inlet temperature of 80°C and a water flow rate of 100 ml / min. Figure 5 It can be seen that, under the same test conditions, the hydrogen content in the oxygen of Examples 1-4 was significantly lower than that of Comparative Example 1. Specifically, in Example 1, the hydrogen content was significantly lower when the current density was increased to 4.5 A / cm². 2 At this time, the hydrogen concentration in oxygen remained at its lowest level. This confirms that the Pt / PEDOT-PFSA catalyst layer has an extremely excellent hydrogen crossing suppression capability, and the hydrogen elimination capability increases with the Pt loading. Due to the effective anchoring of platinum particles by the composite support PEDOT-PFSA and its good three-phase transport interface, hydrogen crossing to the anode side can be rapidly catalytically eliminated, improving the operational safety of the water electrolysis unit.

[0045] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A catalyst coating membrane that reduces hydrogen cross-linking and is resistant to high-voltage oxidation, comprising a proton exchange membrane substrate, an anode catalyst layer, and a cathode catalyst layer, characterized in that, A platinum-supported catalyst layer, with a perfluorosulfonic acid resin grafted with poly(3,4-ethylenedioxythiophene) as a carrier, is disposed between the anode catalyst layer and the proton exchange membrane. The platinum-supported catalyst layer is disposed on the anode side of the proton exchange membrane, the anode catalyst layer is disposed on the surface of the platinum-supported catalyst layer, and the cathode catalyst layer is disposed on the cathode side of the proton exchange membrane. The layers are combined to form an integrated catalyst coating membrane.

2. The method for preparing a catalyst coating film that reduces hydrogen cross-linking and is resistant to high-voltage oxidation as described in claim 1, characterized in that, Perfluorosulfonic acid resin was mixed with monomer 3,4-ethylenedioxythiophene and then subjected to oxidative polymerization to obtain a grafted poly(3,4-ethylenedioxythiophene) perfluorosulfonic acid resin, namely the PEDOT-PFSA composite. The PEDOT-PFSA composite was used as a support and mixed with a platinum source, and then reduced to obtain a supported platinum catalyst. The supported platinum catalyst was formulated into a slurry and sprayed onto the anode side of a proton exchange membrane. Then, an iridium oxide catalyst and a platinum-carbon cathode catalyst were respectively composited onto the anode and cathode sides of the proton exchange membrane by exfoliation transfer method, thereby obtaining the catalyst coating membrane that reduces hydrogen cross-linking and is resistant to high-voltage oxidation.

3. The method for preparing a catalyst coating film that reduces hydrogen cross-linking and is resistant to high-voltage oxidation as described in claim 1, characterized in that, Specifically, the steps include the following: (1) The perfluorosulfonic acid resin solution was mixed with the monomer 3,4-ethylenedioxythiophene, and water and iron oxide were added and stirred evenly to obtain a dark blue dispersion. The dark blue dispersion was dialyzed to remove unreacted monomers and iron ions, and then centrifuged to obtain a perfluorosulfonic acid resin grafted with poly(3,4-ethylenedioxythiophene), namely PEDOT-PFSA complex. (2) Dissolve soluble platinum salt in water to form a transparent solution, add PEDOT-PFSA complex and then ultrasonically disperse it evenly. After rotary evaporation and vacuum drying, grind it evenly and perform reduction heat treatment under a reducing atmosphere to obtain Pt / PFSA-PEDOT catalyst powder, i.e. platinum supported catalyst. (3) Pt / PFSA-PEDOT catalyst powder is mixed with water and alcohol to form a slurry, and then sprayed onto the anode side of the proton exchange membrane to form a supported platinum catalyst layer on the anode side of the proton exchange membrane with a perfluorosulfonic acid resin grafted with poly(3,4-ethylenedioxythiophene) as the support. (4) The anode catalyst layer is transferred to the surface of the supported platinum catalyst layer by the stripping transfer method, and the cathode catalyst layer is transferred to the cathode side of the proton exchange membrane by the same stripping transfer method, so as to obtain the catalyst coating film that reduces hydrogen cross-linking and is resistant to high voltage oxidation.

4. The method for preparing a catalyst coating film that reduces hydrogen cross-linking and is resistant to high-voltage oxidation according to claim 3, characterized in that, In step (1), the solid content of the perfluorosulfonic acid resin solution is in the range of 5-15%, and the EW value of the perfluorosulfonic acid resin is in the range of 500-1500; the mass ratio of 3,4-ethylenedioxythiophene to perfluorosulfonic acid resin is between (0.5-4):

1.

5. The method for preparing a catalyst coating film that reduces hydrogen cross-linking and is resistant to high-voltage oxidation according to claim 3, characterized in that, In step (1), the molecular weight cutoff for dialysis is 600-1200 Da; the dialysis solution needs to be changed 3-5 times during the dialysis process, with an interval of 2-3 hours between each change.

6. The method for preparing a catalyst coating film that reduces hydrogen cross-linking and is resistant to high-voltage oxidation according to claim 3, characterized in that, In step (2), the mass ratio of the PEDOT-PFSA complex to platinum nitrate is (0.5-5):1.

67.

7. The method for preparing a catalyst coating film that reduces hydrogen cross-linking and is resistant to high-voltage oxidation according to claim 3, characterized in that, In step (2), the temperature of the reduction heat treatment is 125-175℃ and the time is 2-4h; the reduction atmosphere is a mixture of hydrogen and nitrogen or inert gas, wherein the mass fraction of hydrogen is 3-6%.

8. The method for preparing a catalyst coating film that reduces hydrogen cross-linking and is resistant to high-voltage oxidation according to claim 3, characterized in that, In step (3), the mass percentage of Pt / PFSA-PEDOT catalyst powder in the slurry is 0.5%-2%, and the coating amount of the slurry on the proton exchange membrane surface is 0.5-0.8 g / cm³. 2 .

9. The method for preparing a catalyst coating film that reduces hydrogen cross-linking and is resistant to high-voltage oxidation according to claim 3, characterized in that, In step (4), the cathode catalyst layer and the anode catalyst layer are formed by coating the cathode catalyst slurry and the anode catalyst slurry onto the surface of the PTFE substrate, respectively; wherein, the anode catalyst slurry is prepared by iridium oxide, water, isopropanol and Nafion solution; and the cathode catalyst slurry is a slurry of Pt / C catalyst.

10. The application of the catalyst coating membrane of claim 1, which reduces hydrogen cross-linking and is resistant to high-voltage oxidation, in water electrolysis.

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