Electrode and preparation method and application thereof

Abstract

The invention belongs to the technical field of water electrolysis hydrogen production, and particularly relates to an electrode and a preparation method and application thereof. The electrode comprises a conductive substrate, a transition layer located on the conductive substrate and an active material layer located on the transition layer, the transition layer comprises a conductive polymer; the active layer comprises an active component, the active component comprises one or more of a noble metal oxide, a noble metal simple substance and a noble metal alloy, and the noble metal is at least one noble metal element of Ir, Ru and Pt. The electrode has relatively low noble metal load and a continuous three-dimensional conductive network, not only has relatively good catalytic activity and stability in water electrolysis reaction, but also has a good charge transmission function and a good gas-liquid transmission channel, and can greatly reduce the use amount of noble metal and reduce the power consumption of unit hydrogen production when being applied to a PEM electrolytic bath; therefore, the PEM water electrolysis hydrogen production cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen production by electrolyzing water, and particularly relates to an electrode, a preparation method thereof and an application thereof. Background Art

[0002] In the existing hydrogen production technology by electrolyzing water, the proton exchange membrane (PEM) electrolysis water hydrogen production technology has many advantages such as high hydrogen production purity, fast dynamic response speed, wide load range, high safety, etc., and is considered to be one of the best electrolysis water technologies coupled with renewable energy. For the PEM electrolysis water hydrogen production technology, improving the hydrogen production efficiency and reducing the hydrogen production cost are the only way for it to move towards industrialization and scale. However, there are still many bottleneck problems in the current PEM technology. Among them, the use of expensive and low-earth-abundance noble metal iridium (Ir) catalyst for the oxygen evolution reaction on the anode side is one of the main problems. On the other hand, the acidic, strongly oxidative environment and relatively high electrolysis voltage of PEM electrolyzing water have oxidative corrosiveness to other electrolytic cell components such as the porous transport layer and the bipolar plate. Therefore, these components need to be coated and protected, and usually noble metals platinum or gold are used. Therefore, designing and developing low-noble-metal catalysts with high activity and stability and reducing the noble metal dosage in the PEM electrolytic cell meet the long-term development needs of the PEM electrolysis water hydrogen production technology.

[0003] Currently, in the PEM electrolytic cell, usually non-supported iridium black or iridium oxide catalyst is coated on the surface of the proton exchange membrane as the oxygen evolution electrode. Reducing the noble metal loading will reduce the thickness of the catalyst layer. Since there is a lack of uniform electrical contact between the thin catalyst layer and the surface of the porous transport layer, in the long run, it will inevitably lead to a rapid decline in the performance of PEM electrolyzing water. Preparing supported catalysts is a way to increase the thickness of the catalytic layer. However, the titanium oxide support commonly used for acidic electrolyzing water has poor conductivity and usually relies on the iridium-based catalyst particles on the surface layer to conduct electricity. On the one hand, the noble metal iridium loading is still relatively high, and on the other hand, the electron transport will be interrupted due to the discontinuity of the iridium-based catalyst particles. Summary of the Invention

[0004] Aiming at the defects existing in the prior art, the purpose of the present invention is to provide an electrode, a preparation method thereof and an application thereof suitable for PEM electrolysis water hydrogen production. This electrode has a low noble metal loading and a continuous three-dimensional conductive network, not only has good catalytic activity and stability in the electrolyzing water reaction, but also has good charge transport function and gas-liquid transport channels. When applied to the PEM electrolytic cell, it can greatly reduce the noble metal dosage, reduce the unit hydrogen production power consumption, and thus reduce the PEM electrolysis water hydrogen production cost.

[0005] Specifically, the present invention provides the following technical solutions:

[0006] An electrode, comprising a conductive substrate, a transition layer located on the conductive substrate, and an active substance layer located on the transition layer;

[0007] The transition layer includes a conductive polymer;

[0008] The active layer includes active components, and the active components include one or more of noble metal oxides, noble metal elements, and noble metal alloys. The noble metal is at least one noble metal element among Ir, Ru, and Pt.

[0009] In the electrode provided by the present invention, the transition layer is coated on the surface of the conductive substrate to protect it from oxidation and corrosion under strong oxidation and high electrode potential, and serves as a carrier for the active layer to achieve good dispersion of the active components.

[0010] Preferably, the material of the conductive substrate includes titanium, niobium, tungsten, nickel, stainless steel, or carbon material, and is a high-conductivity material with a three-dimensional porous structure.

[0011] Preferably, the conductive polymer is one or more of polyaniline and its derivatives, polypyrrole and its derivatives, polythiophene and its derivatives, polyacetylene and its derivatives, and polyphenylene and its derivatives.

[0012] The present invention also provides a method for preparing the above electrode, including the following steps:

[0013] S1: After pre-treating the conductive substrate, it is placed in an electrolyte containing a conductive polymer precursor, and a conductive polymer is in-situ grown on the surface of the conductive substrate through electrochemical polymerization to form a transition layer. After washing, an electrode precursor is obtained;

[0014] S2: A solution containing a noble metal precursor is prepared, and the electrode precursor is placed therein. The active components are in-situ self-assembled on the surface of the transition layer through a solvothermal reaction to form an active layer. After washing, the electrode is obtained.

[0015] Preferably, in S1, the pre-treatment includes: surface degreasing and acid etching treatment of the conductive substrate. In a preferred embodiment, the pre-treatment process is degreasing with one or more of acetone, ethanol, methanol, water, sodium hydroxide, and sodium carbonate, and then acid etching with one or more of hydrochloric acid, nitric acid, hydrofluoric acid, oxalic acid, citric acid, and hydrogen peroxide at 50 - 100 °C for 0.1 - 8 h.

[0016] Preferably, in S1, the conductive polymer precursor is one or more of aniline, pyrrole, thiophene, acetylene, and phenylene.

[0017] Preferably, in S1, in the electrolyte containing the conductive polymer precursor, the content of the conductive polymer precursor is 0.05 - 0.5 mol / L.

[0018] Preferably, in S1, the electrolyte is an acidic electrolyte, more preferably one or more of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, tungstic acid, phosphotungstic acid, perchloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, boric acid, camphorsulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid, and benzoic acid.

[0019] Preferably, in S1, the electrolyte containing the conductive polymer precursor also includes one or more of metal salts, metal elements, metal alloys, metal oxides, metal hydroxides, metal nitrides, protonic acids, Mxene, Nafion, and graphene; and the metal is at least one metal element selected from the group consisting of Pt, Au, Ag, Sn, Sb, Nb, Ti, Mn, W, Ce, La, Zr, Cr, Mo, Co, In, Hf, and Ta.

[0020] Preferably, in S1, the process conditions of the electrochemical polymerization are: the working mode is constant current mode, and the current density is 0.1-20 mA / cm 2 The present invention adopts electrochemical polymerization to grow conductive polymer on conductive substrate, and the obtained polymer film has uniform thickness, good coating property on substrate, high reproducibility, and is suitable for batch preparation of electrodes of various sizes.

[0021] Preferably, in S2, the precious metal precursor is one or more of an Ir precursor, a Ru precursor, and a Pt precursor; wherein the Ir precursor is one or more of iridium trichloride, iridium tetrachloride, chloroiridic acid, iridium nitrate, iridium acetate, iridium acetylacetonate, ammonium chloroiridate, potassium chloroiridate, and sodium chloroiridate; the Ru precursor is one or more of ruthenium trichloride, ruthenium acetate, ruthenium nitrate, potassium ruthenate, ruthenium acetylacetonate, and ruthenium nitrosyl nitrate; the Pt precursor is one or more of chloroplatinic acid, sodium chloroplatinate, potassium chloroplatinate, ammonium chloroplatinate, and platinum acetylacetonate.

[0022] Preferably, in S2, the content of the noble metal precursor in the solution containing the noble metal precursor is 0.01 to 0.5 mol / L.

[0023] Preferably, in S2, the solvent in the solution containing the precious metal precursor is one or more of water, methanol, ethanol, polyols, formaldehyde, formic acid, and acetonitrile; more preferably, it is a mixed solvent of water and ethylene glycol in a volume ratio of 1:0.5 to 1.5. By using the above-mentioned mixed solvent, the reducing property of ethylene glycol can reduce the precious metal precursor, and at the same time, the mixed solvent can regulate the morphology and dispersibility of the formed particles, thereby in situ self-assembling ultrafine precious metal elements or precious metal alloys on the surface of the transition layer.

[0024] Preferably, in S2, the solution containing the noble metal precursor further includes one or more of a Cr precursor, a Zr precursor, a Sn precursor, a Ta precursor, an Os precursor, a Co precursor, a Mo precursor, a Mg precursor, a Ni precursor, a Mn precursor, a W precursor, a Zn precursor, a La precursor, a Ce precursor, a Hf precursor, an Er precursor, a Tm precursor, and a Yb precursor.

[0025] Preferably, in S2, the solution containing the noble metal precursor further includes a chelating agent, and the chelating agent is one or more of citric acid, cetyltrimethylammonium bromide, sodium dodecyl sulfate, ammonium fluoride, triethanolamine, o-phenanthroline, and melamine. The addition of the above chelating agents can significantly improve the dispersion of noble metal nanoparticles on the carrier surface and enhance the catalytic reaction activity.

[0026] Preferably, in S2, the temperature of the solvothermal reaction is 50 - 300 °C, and the time is 0.5 - 72 h.

[0027] The electrode of the present invention has a continuous three-dimensional network structure, integrating multiple functions of catalysis, charge conduction, gas-liquid transport, and support.

[0028] The present invention also provides the application of the above electrode, or the electrode prepared by the above preparation method, in the oxygen evolution and / or hydrogen evolution reaction of electrolytic water; preferably in the oxygen evolution and / or hydrogen evolution reaction of proton exchange membrane electrolytic water. For the electrode of the present invention, if it is mainly composed of noble metal Ir, it is mainly used for the anodic oxygen evolution reaction application, and if it is mainly composed of Pt, it can be used for the cathodic hydrogen evolution reaction application.

[0029] The beneficial effects achieved by the present invention:

[0030] (1) An electrode suitable for PEM electrolytic water hydrogen production provided by the present invention forms a continuous three-dimensional conductive network by sequentially coating a three-dimensional conductive substrate with a transition layer and an active layer. Using a conductive polymer as the intermediate transition layer not only protects the base layer but also provides a large surface area and roughness for the loading of active components, which can significantly increase the number of reaction active sites and the interfacial strong interaction, thereby helping to reduce the noble metal usage, enhance the noble metal anchoring force and electrode stability, and having high intrinsic activity and stability during the catalytic electrolytic water reaction process.

[0031] (2) An electrode suitable for PEM electrolytic water hydrogen production provided by the present invention has multiple functions of catalytic reaction, mass transfer, and support. It serves as both a highly active catalytic reaction electrode and integrates charge conduction and gas-liquid transport, effectively solving the problem of excessive impedance caused by uneven interfacial contact between a low noble metal loading and a porous transport layer. Therefore, it can effectively reduce the energy consumption of electrolytic water and the hydrogen production cost, and has high practical application value.

[0032] (3) The present invention provides an electrode suitable for PEM water electrolysis to produce hydrogen. The conductive polymer is grown on a conductive substrate by electrochemical polymerization. The resulting polymer film has uniform thickness, good coating properties on the substrate, and high reproducibility, and is suitable for batch preparation of electrodes of various sizes.

[0033] (4) The present invention provides an electrode suitable for PEM water electrolysis to produce hydrogen. The precious metal precursor solution preferably uses a mixed solvent of water and ethylene glycol. The reducing property of ethylene glycol can reduce the precious metal precursor. At the same time, the mixed solvent can regulate the morphology and dispersibility of the formed particles, thereby in situ self-assembling ultrafine precious metal elements or precious metal alloys on the surface of the transition layer. DETAILED DESCRIPTION

[0034] The present invention provides a low-noble metal electrode suitable for PEM water electrolysis and a preparation method thereof, wherein the electrode is composed of three layers: a conductive substrate, a transition layer and an active layer. The conductive substrate is a high-conductivity material with a three-dimensional porous structure, and has multiple functions of conduction, material transmission and support in the water electrolysis reaction, not only providing a fast channel for the efficient transmission of electrons, water and gas, but also providing a large carrier for the loading of active components, forming a continuous conductive three-dimensional reactive network, improving the utilization rate of active components, helping to reduce the amount of precious metals, and promoting the rapid arrival of the reaction substance water and the rapid precipitation of gas, thereby improving the reaction efficiency; in addition, the conductive substrate also supports the proton exchange membrane, so that the inside of the actual electrolyzer can withstand a large pressure or differential pressure. The transition layer is a conductive polymer or a doped conductive polymer. On the one hand, it is coated on the surface of the conductive substrate to protect it from oxidation corrosion under strong oxidizing properties and high electrode potential, which can avoid or reduce the use of precious metals such as platinum or gold; on the other hand, as a carrier for effective anchoring of active sites, it helps to disperse the active components well and obtain a high intrinsic activity reaction electrode; in addition, the conductive polymer is appropriately doped, such as by adding proton acid, sulfonic acid groups, etc., which also has the function of proton conduction, which can avoid the use of proton conductors such as Nafion when preparing catalyst coated membrane electrodes by traditional methods, and can avoid the active sites of the catalytic electrode being covered due to excessive use of Nafion, thereby reducing the effective reaction area, hindering electronic conduction, blocking gas diffusion, etc. The main components of the active layer are one or more of Ir, Ru or Pt. The precious metals Ir, Ru, and Pt are proven to be excellent oxygen evolution and hydrogen evolution reaction active substances suitable for acidic media. On the one hand, the present invention can reduce the use of precious metals by loading, and on the other hand, the preparation method of the present invention can construct a large-area, efficient three-phase reaction interface to accelerate the reaction process. The electrode integrates catalytic reaction, conduction and transmission of electrons, protons and water, and support for proton exchange membranes, which helps to greatly reduce the use of precious metals and reduce the cost of PEM hydrogen production.

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following clearly and completely describes the technical solutions in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not intended to limit the scope of the present invention. For those without specific technical or conditions noted in the embodiments, they shall be in accordance with the technologies or conditions described in the literature in the field or in accordance with the product specifications.

[0036] Example 1

[0037] Cut the titanium felt into small pieces of 1 cm × 2 cm, perform ultrasonic degreasing treatment in acetone and ethanol solution for 10 minutes, then etch it with 10% oxalic acid in a water bath at 80 °C for 0.5 h, rinse it with deionized water, and store it in deionized water for later use;

[0038] Using the pretreated titanium felt as the anode, a pure titanium plate as the cathode, and an Ag / AgCl electrode as the reference electrode, prepare polyaniline by electrochemical polymerization on the surface of the titanium felt using the constant current method in a three-electrode system. The electrolyte is 0.5 mol / L sulfuric acid, the electrolyte contains 0.3 mol / L aniline, and the current density is 0.5 mA / cm 2 , the electrochemical polymerization time is 0.5 h, and polyaniline@titanium felt is obtained;

[0039] Prepare a mixed solution of water and ethylene glycol containing 0.03 mol / L IrCl 3 (volume ratio 1:1), immerse the polyaniline@titanium felt, react and reflux at 195 °C for 5 h, wash with deionized water and ethanol to obtain an Ir@polyaniline@titanium felt integrated electrode, and use XRF to test the Ir loading amount to be 0.12 mg / cm 2 .

[0040] Using 0.5 M H 2 SO 4 as the electrolyte solution to test the performance of the above electrode in a three-electrode system. The oxygen evolution overpotential is 230 mV at 10 mA / cm 2 , and the oxygen evolution overpotential is 347 mV at 100 mA / cm 2 . Perform step cyclic voltammetry tests for 5000 cycles in the potential range of 1.1 - 2 V relative to the reversible hydrogen electrode, and the attenuation rate is 1.3%.

[0041] Example 2

[0042] Cut the titanium felt into small pieces of 1 cm × 2 cm, perform ultrasonic degreasing treatment in acetone and ethanol solution for 10 minutes, then etch it with 10% oxalic acid in a water bath at 80 °C for 0.5 h, rinse it with deionized water, and store it in deionized water for later use;

[0043] Using the pretreated titanium felt as the anode, a pure titanium plate as the cathode, and an Ag / AgCl electrode as the reference electrode, Pt-polyaniline was electrochemically polymerized on the surface of the titanium felt by the constant current method in a three-electrode system. The electrolyte was 0.5 mol / L sulfuric acid, and the electrolyte contained 0.3 mol / L aniline and 0.5 mol / L H 2 PtCl 2 , the current density was 0.5 mA / cm 2 , the electrochemical polymerization time was 0.5 h, and Pt-polyaniline@titanium felt was obtained; (In Example 2, the electrolyte contained aniline and H 2 PtCl 2 platinum salt, depositing polyaniline and platinum onto the substrate together)

[0044] Prepare a mixed solution of water and ethylene glycol containing 0.03 mol / L IrCl 3 (volume ratio 1:1), immerse the Pt-polyaniline@titanium felt, react and reflux at 195 °C for 5 h, wash with deionized water and ethanol to obtain an integrated Ir@Pt-polyaniline@titanium felt electrode, and use XRF to test that the loading amount of Ir is 0.11 mg / cm 2 .

[0045] Using 0.5 M H 2 SO 4 as the electrolyte solution to test the performance of the above electrode in a three-electrode system. The oxygen evolution overpotential was 206 mV at 10 mA / cm 2 , and the oxygen evolution overpotential was 331 mV at 100 mA / cm2. A staircase cyclic voltammetry test was carried out 5000 cycles in the potential range of 1.1 - 2 V relative to the reversible hydrogen electrode, and the attenuation rate was 0.87%.

[0046] Example 3

[0047] Cut the titanium felt into small pieces of 1 cm × 2 cm, ultrasonically degrease it in an acetone and ethanol solution for 10 minutes, then acid-etch it with 10% oxalic acid in an 80 °C water bath for 0.5 h, rinse it with deionized water, and store it in deionized water for later use;

[0048] Using the pretreated titanium felt as the anode, a pure titanium plate as the cathode, and an Ag / AgCl electrode as the reference electrode, Nafion-polypyrrole was electrochemically polymerized on the surface of the titanium felt by the constant current method in a three-electrode system. The electrolyte was acetonitrile, and the electrolyte contained 0.1 mol / L pyrrole and 0.25 wt% Nafion, and the current density was 0.3 mA / cm 2 , the electrochemical polymerization time was 0.5 h, and Nafion-polypyrrole@titanium felt was obtained;

[0049] Prepare a solution containing 0.03 mol / L IrCl 3A water and ethylene glycol mixed solution (volume ratio 1:1) was immersed in Nafion-polypyrrole@titanium felt and reacted under reflux at 195 °C for 5 h. It was washed with deionized water and ethanol to obtain an Ir@Nafion-polypyrrole@titanium felt integrated electrode. The loading amount of Ir was measured to be 0.13 mg / cm by XRF. 2 。

[0050] Using 0.5 M H 2 SO 4 as the electrolyte solution, the performance of the above electrode was tested in a three-electrode system. The oxygen evolution overpotential was 211 mV at 10 mA / cm 2 and 327 mV at 100 mA / cm 2 . A staircase cyclic voltammetry test was carried out 5000 cycles in the potential range of 1.1 - 2 V relative to the reversible hydrogen electrode, and the attenuation rate was 1.06%.

[0051] Example 4

[0052] The titanium felt was cut into small pieces of 1 cm × 2 cm, ultrasonically degreased in an acetone and ethanol solution for 10 minutes, then pickled with 10% oxalic acid in a water bath at 80 °C for 0.5 h, rinsed with deionized water and stored in deionized water for use.

[0053] Using the pretreated titanium felt as the anode, a pure titanium plate as the cathode, and an Ag / AgCl electrode as the reference electrode, polyaniline was electrochemically polymerized on the surface of the titanium felt by a constant current method in a three-electrode system. The electrolyte was 0.5 mol / L sulfuric acid containing 0.3 mol / L aniline, the current density was 0.5 mA / cm 2 , and the electrochemical polymerization time was 0.5 h to obtain polyaniline@titanium felt.

[0054] A water and ethylene glycol mixed solution (volume ratio 1:1) containing 0.05 mol / L RuCl 3 was immersed in polyaniline@titanium felt and reacted under reflux at 140 °C for 3 h. It was washed with deionized water and ethanol to obtain a Ru@polyaniline@titanium felt integrated electrode. The loading amount of Ru was measured to be 0.35 mg / cm by XRF. 2 。

[0055] Using 0.5 M H 2 SO 4 as the electrolyte solution, the performance of the above electrode was tested in a three-electrode system. The oxygen evolution overpotential was 178 mV at 10 mA / cm 2 and 318 mV at 100 mA / cm 2 . A staircase cyclic voltammetry test was carried out 5000 cycles in the potential range of 1.1 - 2 V relative to the reversible hydrogen electrode, and the attenuation rate was 3.78%.

[0056] Example 5

[0057] The titanium felt was cut into small pieces of 1 cm×2 cm, ultrasonically degreased in acetone and ethanol solution for 10 minutes, then pickled with 10% oxalic acid in a water bath at 80 °C for 0.5 h, rinsed with deionized water, and stored in deionized water for use;

[0058] Using the pretreated titanium felt as the anode, a pure titanium plate as the cathode, and an Ag / AgCl electrode as the reference electrode, polyaniline was electrochemically polymerized on the surface of the titanium felt by a constant current method in a three-electrode system. The electrolyte was 0.5 mol / L sulfuric acid, the electrolyte contained 0.3 mol / L aniline, and the current density was 0.5 mA / cm 2 , and the electrochemically polymerization time was 0.5 h to obtain polyaniline@titanium felt;

[0059] Prepare a mixed solution of water and ethylene glycol containing 0.03 mol / L IrCl 3 (volume ratio 1:1), add 1 wt% cetyltrimethylammonium bromide to it, immerse the polyaniline@titanium felt, react and reflux at 195 °C for 5 h, wash with deionized water and ethanol to obtain an Ir@polyaniline@titanium felt integrated electrode, and the loading amount of Ir was measured to be 0.12 mg / cm by XRF 2 .

[0060] Using 0.5 M H 2 SO 4 as the electrolyte solution to test the performance of the above electrode in a three-electrode system. The oxygen evolution overpotential was 217 mV at 10 mA / cm 2 , and the oxygen evolution overpotential was 329 mV at 100 mA / cm 2 . A staircase cyclic voltammetry test was carried out 5000 cycles in the potential range of 1.1 - 2 V relative to the reversible hydrogen electrode, and the attenuation rate was 0.92%.

[0061] Example 6

[0062] The titanium felt was cut into small pieces of 1 cm×2 cm, ultrasonically degreased in acetone and ethanol solution for 10 minutes, then pickled with 10% oxalic acid in a water bath at 80 °C for 0.5 h, rinsed with deionized water, and stored in deionized water for use;

[0063] Using the pretreated titanium felt as the anode, a pure titanium plate as the cathode, and an Ag / AgCl electrode as the reference electrode, polyaniline was electrochemically polymerized on the surface of the titanium felt by a constant current method in a three-electrode system. The electrolyte was 0.5 mol / L sulfuric acid, the electrolyte contained 0.3 mol / L aniline, and the current density was 0.5 mA / cm 2 , and the electrochemically polymerization time was 0.5 h to obtain polyaniline@titanium felt;

[0064] Prepare a mixed solution of water and ethylene glycol containing 0.03 mol / L H 2 PtCl 2 with a volume ratio of 1:1, immerse the polyaniline@titanium felt in it, react and reflux at 140 °C for 3 h, wash with deionized water and ethanol to obtain a Pt@polyaniline@titanium felt integrated electrode, and use XRF to test that the loading amount of Pt is 0.12 mg / cm 2 .

[0065] Using 0.5 M H 2 SO 4 as the electrolyte solution, perform performance tests on the above electrode in a three-electrode system. At 10 mA / cm 2 , the hydrogen evolution overpotential is 41 mV, and it can stably operate for more than 600 h without attenuation at a current density of 100 mA / cm 2 .

[0066] Comparative Example 1

[0067] Cut the titanium felt into small pieces of 1 cm × 2 cm, perform ultrasonic degreasing treatment in acetone and ethanol solution for 10 minutes, then acid-etch it with 10% oxalic acid in an 80 °C water bath for 0.5 h, rinse with deionized water, and store it in deionized water for later use;

[0068] Prepare a mixed solution of water and ethylene glycol containing 0.03 mol / L IrCl3 with a volume ratio of 1:1, immerse the above titanium felt in it, react and reflux at 195 °C for 5 h, wash with deionized water and ethanol to obtain an Ir@titanium felt integrated electrode, and use XRF to test that the loading amount of Ir is 0.09 mg / cm 2 .

[0069] Using 0.5 M H 2 SO 4 as the electrolyte solution, perform performance tests on the above electrode in a three-electrode system. At 10 mA / cm 2 , the overpotential is 293 mV, and at 100 mA / cm 2 , the overpotential is 502 mV. Perform 5000 cycles of staircase cyclic voltammetry tests in the potential range of 1.1 - 2 V relative to the reversible hydrogen electrode, and the attenuation rate is 30.6%.

[0070] Comparative Example 2

[0071] Cut the titanium felt into small pieces of 1 cm × 2 cm, perform ultrasonic degreasing treatment in acetone and ethanol solution for 10 minutes, then acid-etch it with 10% oxalic acid in an 80 °C water bath for 0.5 h, rinse with deionized water, and store it in deionized water for later use;

[0072] Prepare a solution containing 0.05 mol / L RuCl3 A water and ethylene glycol mixed solution (volume ratio 1:1) was used to immerse the titanium felt, and the reaction was refluxed at 140 °C for 3 h. It was washed with deionized water and ethanol to obtain the Ru@titanium felt integrated electrode. The loading amount of Ru was measured to be 0.14 mg / cm 2 .

[0073] Using 0.5 M H 2 SO 4 as the electrolyte solution, the performance of the above electrode was tested in a three-electrode system. The overpotential was 202 mV at 10 mA / cm 2 and 335 mV at 100 mA / cm 2 . A staircase cyclic voltammetry test was carried out for 5000 cycles in the potential range of 1.1 - 2 V relative to the reversible hydrogen electrode, and the attenuation rate was 55.9%.

[0074] From the results of the above examples and comparative examples, it can be seen that by coating a conductive polymer transition layer on the surface of the conductive substrate and then depositing noble metal particles, an electrode with good oxygen evolution or hydrogen evolution activity can be obtained, and it shows good stability in acidic media. The method described in the present invention has scalability. In addition to being used for proton exchange membrane water electrolysis, the method described in the present invention can also be used to prepare electrodes for traditional alkaline water electrolysis, anion exchange membrane water electrolysis, and seawater electrolysis for hydrogen production.

[0075] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, based on the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. An electrode, characterized in that: It includes a conductive substrate, a transition layer located on the conductive substrate, and an active material layer located on the transition layer; The transition layer includes a conductive polymer; The active layer includes active components, and the active components include one or more of noble metal oxides, noble metal elements, and noble metal alloys. The noble metal is at least one noble metal element selected from Ir, Ru, and Pt.

2. The electrode according to claim 1, characterized in that The conductive substrate is made of titanium, niobium, tungsten, nickel, stainless steel or carbon material.

3. The electrode according to claim 1 or 2, characterized in that The conductive polymer is one or more of polyaniline and its derivatives, polypyrrole and its derivatives, polythiophene and its derivatives, polyacetylene and its derivatives, polyphenylene and its derivatives.

4. The method for preparing the electrode according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1: placing the pretreated conductive substrate in an electrolyte containing a conductive polymer precursor, in-situ growing a conductive polymer on the surface of the conductive substrate by electrochemical polymerization to form a transition layer, and washing to obtain an electrode precursor; S2: Prepare a solution containing a noble metal precursor, place the electrode precursor therein, and self-assemble the active components on the surface of the transition layer through a solvothermal reaction to form an active layer. After washing, the electrode is obtained.

5. The preparation method according to claim 4, characterized in that: In S1, the pretreatment includes: performing surface degreasing and acid etching treatment on the conductive substrate.

6. The preparation method according to claim 4 or 5, characterized in that: In S1, the conductive polymer precursor is one or more of aniline, pyrrole, thiophene, acetylene, and phenylene; and / or, in the electrolyte containing the conductive polymer precursor, the content of the conductive polymer precursor is 0.05 to 0.5 mol / L; And / or, the electrolyte is an acidic electrolyte, preferably one or more of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, tungstic acid, phosphotungstic acid, perchloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, boric acid, camphorsulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid, and benzoic acid; And / or, the electrolyte containing the conductive polymer precursor also includes one or more of metal salts, metal elements, metal alloys, metal oxides, metal hydroxides, metal nitrides, protonic acids, Mxene, Nafion, and graphene; the metal is at least one metal element selected from Pt, Au, Ag, Sn, Sb, Nb, Ti, Mn, W, Ce, La, Zr, Cr, Mo, Co, In, Hf, and Ta.

7. The preparation method according to claim 4 or 5, characterized in that: In S1, the process conditions of the electrochemical polymerization are: the working mode is constant current mode, and the current density is 0.1-20 mA / cm 2 , time is 5 to 60 minutes.

8. The preparation method according to claim 4 or 5, characterized in that: In S2, the noble metal precursor is one or more of an Ir precursor, a Ru precursor, and a Pt precursor; wherein the Ir precursor is one or more of iridium trichloride, iridium tetrachloride, chloroiridic acid, iridium nitrate, iridium acetate, iridium acetylacetonate, ammonium chloroiridate, potassium chloroiridate, and sodium chloroiridate; the Ru precursor is one or more of ruthenium trichloride, ruthenium acetate, ruthenium nitrate, potassium ruthenate, ruthenium acetylacetonate, and ruthenium nitrosyl nitrate; the Pt precursor is one or more of chloroplatinic acid, sodium chloroplatinate, potassium chloroplatinate, ammonium chloroplatinate, and platinum acetylacetonate; And / or, in the solution containing the noble metal precursor, the content of the noble metal precursor is 0.01 to 0.5 mol / L; And / or, in the solution containing the precious metal precursor, the solvent is one or more of water, methanol, ethanol, polyol, formaldehyde, formic acid, and acetonitrile; preferably, a mixed solvent of water and ethylene glycol in a volume ratio of 1:0.5 to 1.5; And / or, the solution containing the precious metal precursor also includes one or more of a Cr precursor, a Zr precursor, a Sn precursor, a Ta precursor, an Os precursor, a Co precursor, a Mo precursor, a Mg precursor, a Ni precursor, a Mn precursor, a W precursor, a Zn precursor, a La precursor, a Ce precursor, a Hf precursor, an Er precursor, a Tm precursor, and a Yb precursor; And / or, the solution containing the noble metal precursor also includes a chelating agent, and the chelating agent is one or more of citric acid, hexadecyltrimethylammonium bromide, sodium dodecyl sulfate, ammonium fluoride, triethanolamine, o-phenanthroline, and melamine.

9. The preparation method according to claim 4 or 5, characterized in that: In S2, the temperature of the solvent thermal reaction is 50-300°C and the time is 0.5-72h.

10. Use of the electrode according to any one of claims 1 to 3, or the electrode prepared by the preparation method according to any one of claims 4 to 9, in oxygen evolution and / or hydrogen evolution reactions in water electrolysis; preferably in oxygen evolution and / or hydrogen evolution reactions in proton exchange membrane water electrolysis.