Preparation method and application of super-aerophobic multilayer three-dimensional integrated membrane electrode

Abstract

The invention relates to a preparation method and application of a super-aerophobic multilayer three-dimensional integrated membrane electrode. The membrane electrode comprises a proton exchange membrane and a multi-layer three-dimensional catalyst layer grown on the surface of the proton exchange membrane by an in-situ wet chemical method; a hydrophilic surfactant is introduced into an aqueous solution system to induce in-situ direct growth of a catalyst layer, so that the use of a hydrophobic ionomer in a traditional membrane electrode preparation process is avoided, and the hydrophilic and hydrophobic properties of the membrane electrode are improved; and when the second catalytic layer and the second catalytic layer are constructed, metal with an autocatalysis function is introduced as a nucleation center, so that aggregation and growth of particles of the catalytic layers are avoided, formation of a multi-layer three-dimensional structure is guaranteed, the utilization rate of the catalyst is increased, and water vapor transmission is optimized. The membrane electrode constructed by the invention has the advantages of high catalyst utilization rate, excellent electrode performance and the like. The prepared membrane electrode can be used for a reaction device for producing hydrogen by electrolyzing water.

Description

Technical Field

[0001] The present invention belongs to the field of electrochemistry (membrane electrode preparation technology), and particularly relates to a preparation method and application of a super-hydrophobic multi-layer three-dimensional integrated membrane electrode. The prepared membrane electrode can be used in the reaction device for water electrolysis. Background Art

[0002] Proton exchange membrane water electrolyzers (PEMWEs) have the advantages of high electrolysis efficiency, small volume, high hydrogen production pressure, high gas purity, fast dynamic response, wide load range, and no pollution. They are highly adaptable to the volatility of renewable energy power generation and are one of the most promising hydrogen production technologies. The membrane electrode composed of the cathode and anode catalyst layers sandwiching the PEM is the core component of PEMWEs. By decomposing the cost of an annual production of 30 MW electrolyzer, it can be known that the membrane electrode accounts for 73% of the total cost of the stack, and the anode oxygen evolution OER catalyst accounts for 48%. This is because the OER kinetics is slow and a large amount of Ir-based noble metal catalysts are needed to accelerate the reaction (1 - 3 mg / cm 2 ). And the traditional construction method of the MEA catalyst layer is mainly to coat the slurries composed of the cathode and anode catalysts / water-alcohol mixed solvent / polymer electrolyte on both sides of the membrane respectively. This preparation process has low catalyst utilization rate, fewer three-phase reaction interfaces (ion channel / electron channel / gas-liquid channel), and large polarization loss. Currently, the performance of the membrane electrode is about 2 A / cm 2 @1.9 V. Therefore, optimizing the material composition and microstructure of the membrane electrode catalyst layer is the key factor to improve the performance of the membrane electrode.

[0003] To solve the problem of high noble metal loading in the catalyst layer, a large number of studies focus on preparing catalysts with high activity, but still adopt the traditional membrane electrode preparation process; to solve the problem of weak bonding force between the catalyst layer and the proton exchange membrane, some studies focus on developing new integrated membrane electrode preparation processes, but the catalyst dosage is still high.

[0004] 3M Company in the United States (M.J. Burch, et al. Journal of Power Sources, 2021, 500, 229978) uses organic dye whisker arrays as carriers, vacuum sputters an Ir thin layer on the surface of the whiskers, and transfers the nanostructured thin film electrode to the PEM by hot pressing. The current density at 2 V is 6 A / cm 2 , and the Ir dosage is 0.5 mg / cm 2。The Charles University in the Czech Republic (Tomas Hrbek, et al. International Journal of Hydrogen Energy, 2020, 45, 20776 - 20786) selected conductive Nafion as the array, and performed dot etching on the Nafion membrane through plasma bombardment to obtain nanoribbons with a length of about 5 μm and a width of 200 nm. An Ir catalyst loading layer was prepared by magnetron sputtering technology. The performance of the membrane electrode was 4.0 A / cm 2 under the condition of an Ir dosage of 0.113 mg / cm 2 @2.0 V. The University of Tennessee in the United States (Zhiqiang Xie, et al. Applied Catalysis B: Environmental, 2024, 341, 123298) deposited porous Ir nanosheets on a macroporous Ti thin film substrate, and the current density at 2.02 V was 4 A / cm 2 , with an Ir dosage of 0.28 mg / cm 2 . The Dalian Institute of Chemical Physics, Chinese Academy of Sciences (Guang Jiang, et al. Journal of Materials Chemistry A, 2022, 10, 11893) electrochemically deposited a heterogeneous IrRu-coated WO3 nanorod array electrode, and the current density at 2.16 V was 4.5 A / cm 2 , with an IrRu dosage of 0.15 mg / cm 2 .

[0005] Although the above research has made some progress in reducing the catalyst dosage, the cost of the membrane electrode remains high, and the activity and durability still need to be further improved. Summary of the Invention

[0006] The purpose of the present invention is to provide a preparation method and application of a super-hydrophobic multi-layer three-dimensional integrated membrane electrode in view of the deficiencies of the prior art. The prepared membrane electrode can be used in the reaction device for water electrolysis. The present invention directly grows a super-hydrophobic multi-layer three-dimensional structure catalytic layer in-situ on the surface of the proton exchange membrane. The super-hydrophobic property accelerates the bubble detachment speed, and the multi-layer three-dimensional structure ensures the full exposure of the catalyst active sites, and is also conducive to the removal of bubbles, thereby improving the performance. The membrane electrode constructed by the present invention has the advantages of low noble metal consumption of the catalyst and excellent electrode performance. The prepared membrane electrode can be used in the reaction device for hydrogen production by electrolyzing water.

[0007] The technical solution of the present invention is as follows:

[0008] A super-hydrophobic gas multi-layer three-dimensional integrated membrane electrode, comprising a proton exchange membrane and a multi-layer three-dimensional catalyst layer grown on the surface of the proton exchange membrane by an in-situ wet chemical method; the multi-layer three-dimensional catalyst layer includes two or more catalyst layers. In the presence of a hydrophilic surfactant, the first catalyst layer is grown in-situ and wet chemically on the surface of the proton exchange membrane, and the next catalyst layer with nucleation centers is grown in-situ on the surface of the previous catalyst layer (for example, the second catalyst layer with nucleation centers is grown in-situ on the surface of the first catalyst layer, and the third catalyst layer with nucleation centers is grown in-situ on the surface of the second catalyst layer, and so on); the preparation system is an aqueous solution system; a hydrophilic surfactant is introduced into the aqueous solution system to guide the in-situ direct growth of the catalyst layer; when constructing the second and above catalyst layers, a metal with self-catalytic function is introduced as the nucleation center to avoid the agglomeration and growth of catalyst layer particles, ensure the formation of the multi-layer three-dimensional structure, improve the utilization rate of the catalyst, and optimize the water and gas transmission.

[0009] In the present invention, the proton exchange membrane is at least one of a perfluorosulfonic acid proton exchange membrane, a sulfonated polyether ether ketone membrane, a polyimide membrane, and a polybenzimidazole membrane, with a thickness of 5 - 200 μm.

[0010] In the present invention, the hydrophilic surfactant is at least one of a polyoxypropylene polyoxyethylene copolymer, a polyoxypropane polyoxyethane copolymer, a polyoxyethylene fatty alcohol ether, a lauryl alcohol polyoxyethylene ether, a polyethylene glycol octylphenyl ether, an alkylphenol polyoxyethylene ether, a castor oil polyoxyethylene ether polyoxyethylene sorbitan, a fatty alcohol polyoxyethylene ether sodium sulfate, a sodium dodecylbenzenesulfonate, a sodium dodecyl sulfate, a sodium dodecylaminopropionate, a sodium hexadecyl sulfate, a cetyltrimethylammonium bromide, an octadecyltrimethylammonium chloride, a sodium lauryl sulfate, an alkenylsulfonate, a polyvinylpyrrolidone, a polyvinyl alcohol, and a polyacrylic acid.

[0011] In the present invention, the metal of the catalyst layer is at least one of Pt, Ir, Pd, Au, Ru, Rh, Ag, Cu, Fe, Co, Ni, Zn, W, and Mn, preferably at least one of Ir, Ru, Fe, Co, Ni, and Mn; the metal loading is 0.001 - 0.5 mg / cm 2 , preferably 0.05 - 0.2 mg / cm 2 ; the thickness of the catalyst layer is 5 - 2000 nm, preferably 300 - 1000 nm.

[0012] In the present invention, the metal of the nucleation center is at least one of Pt, Co, Fe, Ni, Cu, Pd, and Rh, preferably at least one of Pt, Co, Cu, and Pd, and the metal loading is 0.0001 - 0.1 mg / cm 2 , preferably 0.0005 - 0.05 mg / cm 2 .

[0013] The preparation method of the super-hydrophobic gas multi-layer three-dimensional integrated membrane electrode described in the present invention includes the following steps:

[0014] (1) Preparation of the first catalyst layer:

[0015] Add the reaction solution into the reaction device fixed with the proton exchange membrane, and react at 0-100 °C for 1 min-48 h, preferably react at 30-95 °C for 3 h-24 h; wherein, the reaction solution 1 is an aqueous solution containing metal salts, hydrophilic surfactants, and reducing agents for preparing the catalyst layer, and is prepared from an aqueous solution of metal salts for preparing the catalyst layer, an aqueous solution of hydrophilic surfactants, and an aqueous solution of reducing agents;

[0016] The concentration of the aqueous solution of the metal salt for preparing the catalyst layer is 0.1-1000 mmol / L, preferably 5-90 mmol / L;

[0017] The concentration of the aqueous solution of the hydrophilic surfactant is 0.01-100 mmol / L, preferably 0.1-1 mmol / L;

[0018] The volume ratio of the aqueous solution of the hydrophilic surfactant to the aqueous solution of the metal salt for preparing the catalyst layer is 1-10:1;

[0019] The concentration of the reducing agent is 0.01-10 mol / L;

[0020] The volume ratio of the aqueous solution of the reducing agent to the aqueous solution of the metal salt for preparing the catalyst layer is 1-100:1;

[0021] (2) Preparation of the second catalyst layer:

[0022] For the second catalyst layer, the synchronous or stepwise growth of the nucleation center and the catalyst layer can be carried out;

[0023] The steps of synchronous growth are: Remove the reaction solution, wash with deionized water, and then add reaction solution 2 and react at 0-100 °C for 1 min-48 h, preferably react at 30-95 °C for 3 h-24 h; wherein, the reaction solution 2 is an aqueous solution containing metal salts for preparing the catalyst layer, metal salts of the nucleation center, hydrophilic surfactants, and reducing agents, and is prepared from an aqueous solution of metal salts for preparing the catalyst layer, an aqueous solution of metal salts of the nucleation center, an aqueous solution of hydrophilic surfactants, and an aqueous solution of reducing agents; the concentration ratio of the metal salt of the nucleation center to the metal salt of the catalyst layer in the reaction solution 2 is 1:100-50:100, preferably 2:100-20:100;

[0024] The steps of stepwise growth are as follows: Remove the reaction solution, wash it with deionized water, add reaction solution 3 and react at 0 - 100°C for 1 min - 48 h, preferably react at 20 - 85°C for 5 min - 12 h, then remove the reaction solution; after washing with deionized water, add reaction solution 4 and react at 0 - 100°C for 1 min - 48 h, preferably react at 30 - 95°C for 3 h - 24 h

[0025] The volume ratio of the reducing agent aqueous solution to the metal salt aqueous solution of the nucleation center is 1 - 100:1; wherein, reaction solution 3 is an aqueous solution containing the metal salt of the nucleation center, a hydrophilic surfactant, and a reducing agent, and is prepared from the metal salt aqueous solution of the nucleation center, the hydrophilic surfactant aqueous solution, and the reducing agent aqueous solution; reaction solution 4 is an aqueous solution containing the metal salt for preparing the catalytic layer, a hydrophilic surfactant, and a reducing agent, and is prepared from the metal salt aqueous solution for preparing the catalytic layer, the hydrophilic surfactant aqueous solution, and the reducing agent aqueous solution;

[0026] The concentration of the metal salt aqueous solution for preparing the catalytic layer is 0.1 - 1000 mmol / L, preferably 5 - 90 mmol / L;

[0027] The concentration of the metal salt aqueous solution of the nucleation center is 0.1 - 1000 mmol / L, preferably 5 - 90 mmol / L;

[0028] The concentration of the hydrophilic surfactant aqueous solution is 0.01 - 100 mmol / L, preferably 0.1 - 1 mmol / L;

[0029] The volume ratio of the hydrophilic surfactant aqueous solution to the metal salt aqueous solution for preparing the catalytic layer is 1 - 10:1;

[0030] The volume ratio of the hydrophilic surfactant aqueous solution to the metal salt aqueous solution of the nucleation center is 1 - 10:1;

[0031] The concentration of the reducing agent aqueous solution is 0.01 - 10 mol / L;

[0032] The volume ratio of the reducing agent aqueous solution to the metal salt aqueous solution for preparing the catalytic layer is 1 - 100:1;

[0033] The volume ratio of the reducing agent aqueous solution to the metal salt aqueous solution of the nucleation center is 1 - 100:1;

[0034] (3) Preparation of the catalytic layer above the third layer:

[0035] Repeat step (2) 0 to multiple times according to the number of catalyst layers required; when the multi-layer three-dimensional catalyst layer includes 2 catalyst layers, repeat step (2) 0 times; when the multi-layer three-dimensional catalyst layer includes 3 catalyst layers, repeat step (2) 1 time, and so on;

[0036] (4) After separating the proton exchange membrane with the in-situ constructed catalyst layer from the reaction device, treat it with an aqueous solution of 0.3 - 1M H2SO4 at 50 - 90 °C for 20 minutes to 1 hour, and then wash it clean with deionized water to obtain the integrated membrane electrode.

[0037] The metal salts for preparing the catalyst layer in the present invention are at least one of chloroplatinic acid, chloroplatinous acid, potassium chloroplatinate, potassium chloroplatinate, sodium chloroplatinate, sodium chloroplatinate, ammonium chloroplatinate, ammonium chloroplatinate, iridium trichloride, iridium tetrachloride, chloroiridic acid, potassium chloroiridate, sodium chloroiridate, tetrachloropalladic acid, potassium chloropalladate, sodium chloropalladate, ammonium chloropalladate, potassium chloropalladite, sodium chloropalladite, ammonium chloropalladite, gold trichloride, chloroauric acid, potassium chloroaurate, sodium chloroaurate, ammonium chloroaurate, ruthenium trichloride, potassium chlororuthenate, sodium chlororuthenate, ammonium chlororuthenate, potassium chlororhodate, ammonium chlororhodate, silver nitrate, copper chloride, copper sulfate, copper nitrate, iron chloride, iron sulfate, iron nitrate, cobalt chloride, cobalt sulfate, cobalt nitrate, nickel chloride, nickel sulfate, nickel nitrate, zinc chloride, zinc sulfate, zinc nitrate, manganese sulfate, manganese chloride, manganese carbonate, manganese nitrate, potassium manganate, potassium permanganate, sodium tungstate, ammonium tungstate, cobalt tungstate, tungsten hexachloride.

[0038] The metal salts of the nucleation centers in the present invention are at least one of chloroplatinic acid, chloroplatinous acid, potassium chloroplatinate, potassium chloroplatinate, sodium chloroplatinate, sodium chloroplatinate, ammonium chloroplatinate, ammonium chloroplatinate, cobalt chloride, cobalt sulfate, cobalt nitrate, iron chloride, iron sulfate, iron nitrate, nickel chloride, nickel sulfate, nickel nitrate, copper chloride, copper sulfate, copper nitrate, tetrachloropalladic acid, potassium chloropalladate, sodium chloropalladate, ammonium chloropalladate, potassium chloropalladite, sodium chloropalladite, ammonium chloropalladite, potassium chlororhodate, ammonium chlororhodate.

[0039] The reducing agents in the present invention are at least one of formic acid, acetic acid, formaldehyde, acetaldehyde, ascorbic acid, sodium ascorbate, hydrazine hydrate, ethylene glycol, lithium borohydride, sodium borohydride, potassium borohydride, glucose, sodium sulfite, sodium bisulfite, sodium metabisulfite, sodium dithionite, 2-mercaptoethanol.

[0040] During the preparation process of the reaction solution of the present invention, mixing can be carried out by ultrasonic means.

[0041] The present invention also provides the application of the above super-hydrophobic multi-layer three-dimensional integrated membrane electrode in water electrolysis.

[0042] Compared with the prior art, the present invention has the following advantages:

[0043] 1) The super-hydrophobic gas multi-layer three-dimensional integrated membrane electrode prepared by the present invention has the characteristics of low catalyst loading, high utilization efficiency, and flexible adjustable composition, which can greatly reduce the cost of the membrane electrode;

[0044] 2) The super-hydrophobic gas multi-layer three-dimensional integrated membrane electrode prepared by the present invention has high hydrophilicity of the super-hydrophobic property, which can accelerate the bubble detachment speed. In addition, the multi-layer three-dimensional structure ensures the full exposure of the catalyst active sites, which can improve the performance of the membrane electrode;

[0045] 3) The super-hydrophobic gas multi-layer three-dimensional integrated membrane electrode prepared by the present invention is prepared by in-situ growth, the catalytic layer is not easy to fall off, and the durability is better;

[0046] 4) The membrane electrode preparation system described in the present invention is an aqueous solution system, and the preparation method is advanced, simple and easy to operate, which has more advantages in large-area preparation, and provides a new technical route for the preparation of water electrolysis membrane electrodes. Description of the Drawings

[0047] The attached drawings of the present invention Figure 12 sheets,

[0048] Figure 1 is the scanning electron microscope (SEM) photograph of the single-layer growth of the catalytic layer of the membrane electrode in Example 1;

[0049] Figure 2 is the scanning electron microscope (SEM) photograph of the double-layer catalytic layer of the membrane electrode in Example 1 with the introduction of Pt nucleation centers and the synchronous growth of the nucleation centers and the catalytic layer;

[0050] Figure 3 is the transmission electron microscope (TEM) photograph of the catalytic layer of the membrane electrode with the introduction of Pt nucleation centers and the stepwise growth of the nucleation centers and the catalytic layer in Example 2;

[0051] Figure 4 is the TEM line scan result of the membrane electrode in Example 2;

[0052] Figure 5 is the X-ray diffraction (XRD) spectrum of the catalytic layer of the membrane electrode in Example 2;

[0053] Figure 6 is the contact angle test comparison diagram of the super-hydrophobic gas multi-layer three-dimensional integrated membrane electrode in Example 2 and the catalytic layer of the traditional membrane electrode in Comparative Example 1;

[0054] Figure 7 is the I-V curve comparison diagram of the super-hydrophobic gas multi-layer three-dimensional integrated membrane electrode in Example 2 and the traditional membrane electrode in the water electrolysis cell of Comparative Example 1;

[0055] Figure 8AC impedance spectra comparison diagram of the super-hydrophobic multi-layer three-dimensional integrated membrane electrode in Example 2 and the traditional membrane electrode in Comparative Example 1 in the water electrolyzer;

[0056] Figure 9 Cyclic voltammetry test result diagram of the super-hydrophobic multi-layer three-dimensional integrated membrane electrode in Example 2 and the traditional membrane electrode in Comparative Example 1;

[0057] Figure 10 Constant current stability test curve of the super-hydrophobic multi-layer three-dimensional integrated membrane electrode in Example 2 and the traditional membrane electrode in Comparative Example 1;

[0058] Figure 11 SEM photos of the catalytic layer grown in a single layer in Comparative Example 2 and the catalytic layer of the double-layer integrated membrane electrode grown without a nucleation center;

[0059] Figure 12 I-V curve comparison diagram of the double-layer integrated membrane electrode grown without a nucleation center in Comparative Example 2 and the double-layer integrated membrane electrode grown with Pt as the nucleation center in Example 1 in the water electrolyzer. Detailed implementation mode

[0060] The present invention will be further described below in conjunction with the embodiments, but the present invention is not limited thereby.

[0061] Example 1

[0062] Install the N212 proton exchange membrane (50 μm) into the reaction device, with a reaction area of 2 * 2 cm 2 , the volume of the reaction device solution is 0.75 mL. Take an aqueous solution of chloroiridic acid (20 mM), an aqueous solution of polyoxypropylene polyoxyethylene copolymer (0.1 mM), and an aqueous solution of formic acid (2 M), and mix them evenly in a volume ratio of 1:1:1 to obtain a mixed solution. After adding the mixed solution to the reaction device, react at 70 °C for 24 h, and the growth of the first catalytic layer is completed.

[0063] Then pour out the reaction solution, rinse it three times with clean water, and then re-add a new reaction solution. The new reaction solution is a mixed solution obtained by mixing an aqueous solution of potassium chloroplatinate (2 mM), an aqueous solution of chloroiridic acid (20 mM), an aqueous solution of polyoxypropylene polyoxyethylene copolymer (0.1 mM), and an aqueous solution of formic acid (2 M) evenly in a volume ratio of 1:1:2:2. After adding the new reaction solution to the reaction device, react at 70 °C for 24 h, and the growth of the second catalytic layer is completed.

[0064] Take out the reacted membrane electrode, place it in 0.5 mol / L H2SO4, treat it at 80 °C for 30 min, then soak it in deionized water at 80 °C for 30 min, and dry it to obtain a super-hydrophobic multi-layer three-dimensional integrated membrane electrode with synchronous growth of the catalytic layer and the nucleation center.

[0065] Figure 1 The scanning electron microscope (SEM) photo of the single-layer growth of the catalytic layer shows that the catalyst layer has a nanoflower-like structure. The structure of the nanoflowers can fully expose the active sites, with a uniform size distribution. The particle size of the nanoflowers is about 300 nm.

[0066] Figure 2 The scanning electron microscope (SEM) photo of the double-layer growth of the catalytic layer shows the formation of the multi-layer catalytic layer structure, and at the same time, there is no phenomenon of agglomeration and growth of the nanoflower particles.

[0067] Example 2

[0068] Load the N212 proton exchange membrane (50 μm) into the reaction device, with a reaction area of 2 * 2 cm 2 , and the volume of the solution in the reaction device is 0.75 mL. Then, take an aqueous solution of iridium chloride (20 mM), an aqueous solution of poly(oxypropylene)poly(oxyethylene) copolymer (0.1 mM), and an aqueous solution of formic acid (2 M), and mix them evenly in a volume ratio of 1:1:1 to obtain a mixed solution. After adding the mixed solution to the reaction device, react at 70 °C for 24 h, and the growth of the first catalytic layer is completed.

[0069] After that, pour out the reaction solution, rinse it three times with clear water, and then re-add a new reaction solution. The new reaction solution is a mixed solution obtained by mixing an aqueous solution of chloroplatinic acid (6.67 mM), an aqueous solution of poly(oxypropylene)poly(oxyethylene) copolymer (0.067 mM), and an aqueous solution of ascorbic acid (50 mM) evenly in a volume ratio of 1:1:1. After adding the new reaction solution to the reaction device, react at 30 °C for 8 h, and the growth of the Pt nucleation centers is completed.

[0070] Pour out the reaction solution again, rinse it three times with clear water, and then re-add a new reaction solution. The new reaction solution is a mixed solution obtained by mixing an aqueous solution of iridium chloride (20 mM), an aqueous solution of poly(oxypropylene)poly(oxyethylene) copolymer (0.1 mM), and an aqueous solution of formic acid (2 M) evenly in a volume ratio of 1:1:1. After adding the new reaction solution to the reaction device, react at 70 °C for 24 h, and the growth of the second catalytic layer is completed.

[0071] Take out the membrane electrode after the reaction, and the post-treatment steps are the same as those in Example 1. After drying, a super-hydrophobic and multi-layer three-dimensional integrated membrane electrode with step-by-step growth of the catalytic layer and nucleation centers is obtained.

[0072] Figure 3 The transmission electron microscope (TEM) photo of the catalyst layer shows that the Ir catalytic layer grows epitaxially with Pt as the nucleation center;

[0073] Figure 4 The TEM line scan result of the catalytic layer also verifies that Pt is the nucleation center of the catalytic layer;

[0074] Figure 5It is the X-ray diffraction (XRD) spectrum of the membrane electrode, which verifies the successful preparation of the Ir catalytic layer with Pt as the nucleation center;

[0075] Figure 6 It is the contact angle test comparison chart between the super-hydrophobic and multi-layer three-dimensional integrated membrane electrode and the catalytic layer of the traditional membrane electrode in Comparative Example 1. The contact angle of the super-hydrophobic and multi-layer three-dimensional integrated membrane electrode is 48.4°, and the contact angle of the catalytic layer of the traditional membrane electrode is 102.0°, indicating that the super-hydrophobic and multi-layer three-dimensional integrated membrane electrode has better hydrophilic and hydrophobic properties, which is conducive to the entry of reactant water and the smooth removal of bubbles;

[0076] Figure 7 It is the comparison chart of the I-V curve of water electrolysis at 80 °C between the super-hydrophobic and multi-layer three-dimensional integrated membrane electrode and the traditional membrane electrode in Comparative Example 1, which proves that the super-hydrophobic and multi-layer three-dimensional integrated membrane electrode has ultra-high performance. When the Ir loading is only 0.12 mg / cm 2 and the electrolysis voltage is 2 V, the current density can reach 4.8 A / cm 2 , which is more than twice that of the commercial membrane electrode;

[0077] Figure 8 It is the comparison chart of the AC impedance spectra between the super-hydrophobic and multi-layer three-dimensional integrated membrane electrode and the traditional membrane electrode in Comparative Example 1 in the water electrolysis cell, which proves that the super-hydrophobic and multi-layer three-dimensional integrated membrane electrode has lower electrochemical polarization and mass transfer polarization losses;

[0078] Figure 9 It is the cyclic voltammetry test result chart of the super-hydrophobic and multi-layer three-dimensional integrated membrane electrode and the traditional membrane electrode in Comparative Example 1, which proves that the super-hydrophobic and multi-layer three-dimensional integrated membrane electrode has more active area, which is the reason for the reduction of electrochemical polarization;

[0079] Figure 10 It is the constant current stability test curve of the super-hydrophobic and multi-layer three-dimensional integrated membrane electrode and the traditional membrane electrode in Comparative Example 1 at 500 mA cm -2 under, which proves that the super-hydrophobic and multi-layer three-dimensional integrated membrane electrode has better stability and no obvious attenuation occurs in 200 h.

[0080] Example 3

[0081] Install the N212 proton exchange membrane (50 μm) into the reaction device, the reaction area is 2*2 cm 2 , the volume of the reaction device solution is 0.75 mL. Then take the aqueous solution of iridium chloride (20 mM), the aqueous solution of polyoxypropylene polyoxyethylene copolymer (0.1 mM) and the aqueous solution of formic acid (2 M), mix them evenly in a volume ratio of 1:1:1 to obtain a mixed solution. After adding the mixed solution to the reaction device, react at 70 °C for 24 h, and the growth of the first catalytic layer is completed.

[0082] After pouring out the reaction solution, rinse it three times with clear water, and then re-add the new reaction solution. The new reaction solution is a mixed solution obtained by uniformly mixing an aqueous solution of potassium chloroplatinate (2 mM), an aqueous solution of iridium chloride (20 mM), an aqueous solution of poly(oxypropyleneoxyethylene) copolymer (0.1 mM), and an aqueous solution of formic acid (2 M) in a volume ratio of 1:1:2:2. After adding the new reaction solution to the reaction device, react at 70 °C for 24 h, and the growth of the second catalytic layer is completed.

[0083] Repeat the steps for growing the second catalytic layer again, take out the reacted membrane electrode for post-treatment, and the post-treatment steps are the same as those in Example 1. After drying, a super-hydrophobic gas multi-layer three-dimensional integrated membrane electrode with 3 layers of growth is obtained.

[0084] Example 4

[0085] Place the N212 proton exchange membrane (50 μm) into the reaction device, with a reaction area of 2*2 cm 2 , and the volume of the solution in the reaction device is 0.75 mL. Then, take an aqueous solution of iridium chloride (30 mM), an aqueous solution of poly(oxypropyleneoxyethylene) copolymer (0.2 mM), and an aqueous solution of formic acid (3 M), and mix them uniformly in a volume ratio of 2:1:2 to obtain a mixed solution. After adding the mixed solution to the reaction device, react at 60 °C for 12 h, and the growth of the first catalytic layer is completed.

[0086] After pouring out the reaction solution, rinse it three times with clear water, and then re-add the new reaction solution. The new reaction solution is a mixed solution obtained by uniformly mixing an aqueous solution of cobalt chloride (3 mM), an aqueous solution of iridium chloride (30 mM), an aqueous solution of poly(oxypropyleneoxyethylene) copolymer (0.2 mM), and an aqueous solution of formic acid (3 M) in a volume ratio of 1:1:2:2. After adding the new reaction solution to the reaction device, react at 60 °C for 12 h, and the growth of the second catalytic layer is completed.

[0087] The post-treatment steps are the same as those in Example 1. After drying, a super-hydrophobic gas multi-layer three-dimensional integrated membrane electrode with cobalt as the nucleation center is obtained.

[0088] Comparative Example 1

[0089] Spray Pt / C (Pt loading 40 wt%) and Ir black on both sides of the N212 proton exchange membrane (50 μm) as the cathode catalytic layer and the anode catalytic layer, respectively. First, disperse the catalyst in a water and ethanol solution with a mass ratio of water:alcohol of 1:9, and the mass ratio of the catalyst to water and alcohol is 1:50. Ultrasonic uniformly, add Nafion resin solution, and the mass ratio of Nafion to C in the cathode catalyst Pt / C is 0.65:1, and the mass ratio of Nafion to the anode catalyst Ir is 0.3:1. After ultrasonic uniformly, spray. The cathode catalyst loading is 0.1 mg Pt / cm 2, the anodic catalyst loading is 0.1 mg Ir / cm 2 . The traditional membrane electrode is prepared therefrom.

[0090] Comparative Example 2

[0091] Install the N212 proton exchange membrane (50 μm) into the reaction device, and the reaction area is 2 * 2 cm 2 , the volume of the solution in the reaction device is 0.75 mL. Then, take an aqueous solution of iridium chloride (20 mM), an aqueous solution of polyoxypropylene-polyoxyethylene copolymer (0.1 mM), and an aqueous solution of formic acid (2 M), and mix them evenly in a volume ratio of 1:1:1 to obtain a mixed solution. After adding the mixed solution to the reaction device, react at 70 °C for 12 h.

[0092] Remove the reaction solution, rinse it three times with deionized water, and then add a new reaction solution. The new reaction solution is an aqueous solution of iridium chloride (20 mM), an aqueous solution of polyoxypropylene-polyoxyethylene copolymer (0.1 mM), and an aqueous solution of formic acid (2 M), which are mixed evenly in a volume ratio of 1:1:1 to obtain a mixed solution. After adding the new reaction solution to the reaction device, react at 70 °C for 12 h.

[0093] The post-treatment steps are the same as those in Example 1, and a multilayer integrated membrane electrode without nucleation centers can be obtained.

[0094] Figure 11 are SEM photos of the catalytic layer of the bilayer integrated membrane electrode grown without nucleation centers and the catalytic layer grown monolayer. The nanoflowers without nucleation centers are significantly agglomerated and grown;

[0095] Figure 12 is a comparison chart of the I-V curves of the bilayer integrated membrane electrode grown without nucleation centers and the bilayer integrated membrane electrode grown with Pt as the nucleation center in Example 1 in a water electrolyzer. The electrolysis performance of the bilayer integrated membrane electrode without nucleation centers decreases. When the electrolysis voltage is 2 V, the current density is only 3.0 A / cm 2 , which is the adverse effect brought by the agglomeration of the catalytic layer. The Pt nucleation center can effectively prevent the agglomeration of the catalytic layer. When the electrolysis voltage is 2 V, the current density can reach 4.8 A / cm 2 .

[0096] The above embodiments are only for illustrating the technical concept and characteristics of the present invention, and the purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it accordingly. It should not be used to limit the protection scope of the present invention. Any simple modification, equivalent change, and modification made to the above embodiments according to the technical essence of the present invention without departing from the technical solution of the present invention should be covered within the protection scope of the present invention.

Claims

1. A super-hydrophobic multi-layer three-dimensional integrated membrane electrode, characterized in that, It includes a proton exchange membrane and a multi-layer three-dimensional catalyst layer grown on the surface of the proton exchange membrane by an in-situ wet chemical method; the multi-layer three-dimensional catalyst layer includes more than 2 catalyst layers. In the presence of a hydrophilic surfactant, the first catalyst layer is grown in-situ on the surface of the proton exchange membrane by wet chemical method, and the next catalyst layer with nucleation centers is grown in-situ on the surface of the previous catalyst layer.

2. The super-hydrophobic multi-layer three-dimensional integrated membrane electrode according to claim 1, characterized in that, The proton exchange membrane is at least one of a perfluorosulfonic acid proton exchange membrane, a sulfonated polyether ether ketone membrane, a polyimide membrane, and a polybenzimidazole membrane, with a thickness of 5 - 200 μm.

3. The super-hydrophobic multi-layer three-dimensional integrated membrane electrode according to claim 1, characterized in that, The hydrophilic surfactant is at least one of a polyoxypropylene polyoxyethylene copolymer, a polyoxypropane polyoxyethane copolymer, a polyoxyethylene fatty alcohol ether, a lauryl alcohol polyoxyethylene ether, a polyethylene glycol octylphenyl ether, an alkylphenol polyoxyethylene ether, a castor oil polyoxyethylene ether polysorbate, a fatty alcohol polyoxyethylene ether sodium sulfate, a sodium dodecylbenzenesulfonate, a sodium dodecyl sulfate, a sodium dodecyl aminopropionate, a sodium hexadecyl sulfate, a cetyltrimethylammonium bromide, an octadecyltrimethylammonium chloride, a sodium lauryl sulfate, an alkenyl sulfonate, a polyvinylpyrrolidone, a polyvinyl alcohol, and a polyacrylic acid.

4. The super-hydrophobic multi-layer three-dimensional integrated membrane electrode according to claim 1, wherein The metal in the catalytic layer is at least one of Pt, Ir, Pd, Au, Ru, Rh, Ag, Cu, Fe, Co, Ni, Zn, W, and Mn, and the metal loading is 0.001 - 0.5 mg / cm 2 , and the thickness of the catalytic layer is 5 - 2000 nm.

5. The super-hydrophobic multi-layer three-dimensional integrated membrane electrode according to claim 1, wherein The metal of the nucleation center is at least one of Pt, Co, Fe, Ni, Cu, Pd, and Rh, and the metal loading is 0.0001 - 0.1 mg / cm 2 .

6. The preparation method of the super-hydrophobic multi-layer three-dimensional integrated membrane electrode according to any one of claims 1-5, characterized in that, The preparation method includes the following steps: (1) Preparation of the first catalyst layer: Add the reaction solution 1 into the reaction device fixed with the proton exchange membrane, and react at 0 - 100 °C for 1 min - 48 h; wherein, the reaction solution 1 is an aqueous solution containing a metal salt for preparing the catalyst layer, a hydrophilic surfactant, and a reducing agent, and is prepared from an aqueous solution of the metal salt for preparing the catalyst layer, an aqueous solution of the hydrophilic surfactant, and an aqueous solution of the reducing agent; The concentration of the aqueous solution of the metal salt for preparing the catalyst layer is 0.1 - 1000 mmol / L; The concentration of the aqueous solution of the hydrophilic surfactant is 0.01 - 100 mmol / L; The volume ratio of the aqueous solution of the hydrophilic surfactant to the aqueous solution of the metal salt for preparing the catalyst layer is 1 - 10:1; The concentration of the aqueous solution of the reducing agent is 0.01 - 10 mol / L; The volume ratio of the aqueous solution of the reducing agent to the aqueous solution of the metal salt for preparing the catalyst layer is 1 - 100:1; (2) Preparation of the second catalyst layer: For the second catalyst layer, the synchronous or stepwise growth of the nucleation center and the catalyst layer can be carried out; The steps of synchronous growth are: Remove the reaction solution, wash with deionized water, and then add the reaction solution 2 and react at 0 - 100 °C for 1 min - 48 h; wherein, the reaction solution 2 is an aqueous solution containing a metal salt for preparing the catalyst layer, a metal salt of the nucleation center, a hydrophilic surfactant, and a reducing agent, and is prepared from an aqueous solution of the metal salt for preparing the catalyst layer, an aqueous solution of the metal salt of the nucleation center, an aqueous solution of the hydrophilic surfactant, and an aqueous solution of the reducing agent; the concentration ratio of the metal salt of the nucleation center to the metal salt for preparing the catalyst layer in the reaction solution 2 is 1:100 - 50:100; The steps of the stepwise growth are as follows: remove the reaction solution, wash with deionized water, add reaction solution 3, react at 0 - 100 °C for 1 min - 48 h, and then remove the reaction solution; after washing with deionized water, add reaction solution 4 and react at 0 - 100 °C for 1 min - 48 h; wherein, reaction solution 3 is an aqueous solution containing a metal salt with a nucleation center, a hydrophilic surfactant, and a reducing agent, and is prepared from an aqueous solution of the metal salt with a nucleation center, an aqueous solution of the hydrophilic surfactant, and an aqueous solution of the reducing agent; reaction solution 4 is an aqueous solution containing a metal salt for preparing a catalytic layer, a hydrophilic surfactant, and a reducing agent, and is prepared from an aqueous solution of the metal salt for preparing a catalytic layer, an aqueous solution of the hydrophilic surfactant, and an aqueous solution of the reducing agent; The concentration of the aqueous solution of the metal salt for preparing the catalytic layer is 0.1 - 1000 mmol / L; The concentration of the aqueous solution of the metal salt with the nucleation center is 0.1 - 1000 mmol / L; The concentration of the aqueous solution of the hydrophilic surfactant is 0.01 - 100 mmol / L; The volume ratio of the aqueous solution of the hydrophilic surfactant to the aqueous solution of the metal salt for preparing the catalytic layer is 1 - 10:1; The volume ratio of the aqueous solution of the hydrophilic surfactant to the aqueous solution of the metal salt with the nucleation center is 1 - 10:1; The concentration of the aqueous solution of the reducing agent is 0.01 - 10 mol / L; The volume ratio of the aqueous solution of the reducing agent to the aqueous solution of the metal salt for preparing the catalytic layer is 1 - 100:1; The volume ratio of the aqueous solution of the reducing agent to the aqueous solution of the metal salt with the nucleation center is 1 - 100:1; (3) Preparation of the catalytic layer above the third layer: Repeat step (2) 0 to multiple times according to the number of required catalytic layers; (4) After separating the proton exchange membrane with the in-situ constructed catalytic layer from the reaction device, treat it with a 0.3 - 1 M H2SO4 aqueous solution at 50 - 90 °C for 20 minutes - 1 hour, and then wash with deionized water to obtain the integrated membrane electrode.

7. The preparation method of the super-hydrophobic multi-layer three-dimensional integrated membrane electrode according to claim 6, characterized in that, The metal salt for preparing the catalytic layer is at least one of chloroplatinic acid, chloroplatinous acid, potassium chloroplatinate, potassium chloroplatinate, sodium chloroplatinate, sodium chloroplatinate, ammonium chloroplatinate, ammonium chloroplatinate, iridium trichloride, iridium tetrachloride, chloroiridic acid, potassium chloroiridate, sodium chloroiridate, tetrachloropalladic acid, potassium chloropalladate, sodium chloropalladate, ammonium chloropalladate, potassium chloropalladite, sodium chloropalladite, ammonium chloropalladite, gold trichloride, chloroauric acid, potassium chloroaurate, sodium chloroaurate, ammonium chloroaurate, ruthenium trichloride, potassium chlororuthenate, sodium chlororuthenate, ammonium chlororuthenate, potassium chlororhodate, ammonium chlororhodate, silver nitrate, copper chloride, copper sulfate, copper nitrate, iron chloride, iron sulfate, iron nitrate, cobalt chloride, cobalt sulfate, cobalt nitrate, nickel chloride, nickel sulfate, nickel nitrate, zinc chloride, zinc sulfate, zinc nitrate, manganese sulfate, manganese chloride, manganese carbonate, manganese nitrate, potassium manganate, potassium permanganate, sodium tungstate, ammonium tungstate, cobalt tungstate, tungsten hexachloride.

8. The preparation method of a super-hydrophobic multi-layer three-dimensional integrated membrane electrode according to claim 6, characterized in that, The nucleation center metal salt is at least one of chloroplatinic acid, chloroplatinous acid, potassium chloroplatinate, potassium chloroplatinate, sodium chloroplatinate, sodium chloroplatinate, ammonium chloroplatinate, ammonium chloroplatinate, cobalt chloride, cobalt sulfate, cobalt nitrate, ferric chloride, ferric sulfate, ferric nitrate, nickel chloride, nickel sulfate, nickel nitrate, copper chloride, copper sulfate, copper nitrate, tetrachloropalladic acid, potassium chloropalladate, sodium chloropalladate, ammonium chloropalladate, potassium chloropalladite, sodium chloropalladite, ammonium chloropalladite, potassium chlororhodate, ammonium chlororhodate.

9. The preparation method of the super-hydrophobic multi-layer three-dimensional integrated membrane electrode according to claim 6, wherein, The reducing agent is at least one of formic acid, acetic acid, formaldehyde, acetaldehyde, ascorbic acid, sodium ascorbate, hydrazine hydrate, ethylene glycol, lithium borohydride, sodium borohydride, potassium borohydride, glucose, sodium sulfite, sodium bisulfite, sodium metabisulfite, sodium dithionite, hydroxyethyl mercaptan.

10. Application of the super-hydrophobic gas multi-layer three-dimensional integrated membrane electrode according to any one of claims 1-5 in water electrolysis.

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