Electrode for water electrolysis and method for preparing and using the same

Abstract

The application belongs to the technical field of water electrolysis, and particularly relates to an electrode for water electrolysis and a preparation method and application thereof. The application utilizes polystyrene microspheres to be orderly assembled to form a template, Ru is filled in the gap of the template through electro-deposition, the template is removed to obtain a reverse opal structure, a good gas transmission channel is established by loading Ir through cyclic voltammetry electro-deposition technology, and good catalyst activity and stability are also obtained, and corrosion of the gas diffusion layer can be better prevented. The application utilizes an evaporation self-assembly method to control synthesis under relatively mild conditions, and a porous interconnected ordered electrode with uniform size and good dispersion is obtained. The catalyst can still maintain the original appearance after calcination, and has good thermal stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water electrolysis, and particularly relates to an electrode for water electrolysis and a preparation method and application thereof. BACKGROUND

[0002] In 1966, proton exchange membrane (PEM) was first applied to water electrolysis by General Electric Company, and water electrolysis provides a clean conversion route from water to hydrogen. If renewable energy is used to produce electricity for water electrolysis, CO2 zero emission can be truly realized. The basic principle of water electrolysis to produce hydrogen is to use external electric energy to decompose water into hydrogen and oxygen. In theory, the theoretical electromotive force of 0 and 1.23 V needs to be applied to the anode and cathode respectively, but due to polarization, a voltage greater than 1.23 V needs to be applied to make the water electrolysis reaction occur. In the electrolysis process, water molecules are oxidized into oxygen at the anode, and are reduced into hydrogen at the cathode.

[0003] Unfortunately, expensive noble metals, perfluorosulfonic acid membranes, gas diffusion layers and bipolar plates and other components increase the cost of PEMWE, which seriously hinders commercial application. Therefore, the cost of PEMWE needs to be reduced from multiple angles, and the performance of PEMWE needs to be improved. This is also one of the focuses of the current researchers. The core of the electrolysis process is the membrane electrode required for the electrochemical reaction, which directly affects the electrolysis efficiency, electrolysis energy consumption, electrolysis cost and the service life of the electrolysis cell.

[0004] At the same time, the gas diffusion layer titanium felt also has the following problems: 1. The internal pore structure of the titanium fiber felt is randomly distributed, and when the reactant water (H2O) and the reaction product oxygen bubbles (O2) pass through it, greater resistance will be generated. Especially at a large current, the mass transfer loss will be more obvious, thereby affecting the electrolysis efficiency; 2. Due to the random distribution of the pore structure on the surface of the titanium fiber felt, there are fewer electrochemical reaction sites at the three-phase connection, which greatly limits the speed and efficiency of the electrolysis reaction, resulting in low efficiency of the entire electrolysis process; 3. In order to maintain the conductivity of the titanium felt, platinum, iridium and other noble metals need to be plated on the surface of the titanium felt. This not only increases the production cost, but also makes the titanium coating poor in stability and has problems such as falling off. SUMMARY

[0005] The purpose of the present application is to provide an electrode for water electrolysis and a preparation method and application thereof, which overcomes the problem of excessive noble metal load in the traditional electrode, and at the same time ensures that the electrode prepared according to the method can make the water electrolysis reaction occur efficiently under a smaller applied bias.

[0006] The present application utilizes monodisperse polystyrene microspheres orderly assembled together to form a template, after filling a substance in the gap of the template, the template is removed to obtain a porous structure with high ordered periodicity and pore interconnection system, which is inverse opal structure. The evaporation self-assembly method is utilized to control the synthesis of the porous interconnection ordered oxygen electrode with uniform size and good dispersion under relatively mild conditions, and the catalyst can maintain the original appearance after calcination and has good thermal stability. The inverse opal structure has a continuous nano-structure skeleton with large interface area and a three-dimensional interconnection pore system with low bending degree, and the titanium felt is considered as the best transport layer of PEMWE due to its high porosity and corrosion resistance of Ti surface passivation layer under oxidation conditions. The electrode prepared from the inverse opal structure has a highly ordered pore structure, good catalyst dispersion and excellent diffusion performance, which enables a relatively low noble metal loading to obtain high catalytic activity. The present application introduces the inverse opal structure into the electrode, constructs the inverse opal structure on the titanium felt, loads Ir by cyclic voltammetry electrodeposition technology to establish a good gas transmission channel and also has good catalyst activity and stability, and can better prevent the corrosion of the gas diffusion layer.

[0007] In order to achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0008] In one aspect, the present application provides an electrode for water electrolysis, which comprises a gas diffusion layer and a catalyst, wherein the catalyst is loaded on the gas diffusion layer.

[0009] The catalyst is Ir-coated RuO2, and the catalyst is an inverse opal structure.

[0010] The gas diffusion layer is a titanium felt.

[0011] In the above technical scheme, further, the outer pore diameter of the catalyst is 100-600 nm, the inner pore diameter is 82-470 nm, and the pore wall thickness is 25-50 nm; and in the catalyst, the mass ratio of Ir element to Ru element is 1:1.2-1.8.

[0012] In another aspect, the present application provides a preparation method of the above-mentioned oxygen electrode, which comprises the following steps:

[0013] (1) sequentially ultrasonic cleaning the titanium felt with acetone, dilute hydrochloric acid, ethanol and deionized water, and drying;

[0014] (2) adding a non-ionic surfactant and polystyrene microspheres into water, ultrasonic, to obtain a dispersion liquid, and placing the titanium felt obtained in step (1) into the dispersion liquid, drying until the liquid is completely volatilized, to obtain a titanium felt with a 3D template;

[0015] (3) vacuum drying the titanium felt with a 3D template obtained in step (2);

[0016] (4) placing the titanium felt with 3D template dried in step (3) into an aqueous solution of RuCl3 for first electrodeposition, drying, and then calcination to obtain inverse opal structure RuO2 loaded titanium felt;

[0017] (5) placing the inverse opal structure RuO2 loaded titanium felt obtained in step (4) into an aqueous solution of IrCl4 for second electrodeposition, and then annealing under inert gas atmosphere to obtain the electrode.

[0018] In the technical solution, further, in step (1), the ultrasonic time is 15-30 min.

[0019] In the technical solution, further, in step (2), the diameter of the polystyrene microspheres is 50-500 nm; the mass ratio of the non-ionic surfactant to the polystyrene microspheres is 1: (0.8-1.6), more preferably 1:1.2; the ultrasonic time is 30-60 min; the non-ionic surfactant is nonylphenol polyoxyethylene ether; the drying temperature is 65-80 o C.

[0020] In the technical solution, further, in step (3), the temperature of vacuum drying is 50-80 o C, and the time of vacuum drying is 6-12 h.

[0021] In the technical solution, further, in step (4), the first electrodeposition is constant current electrodeposition, the electrodeposition time is 100-400 s, the current density is -10--30 mAcm -2 ; the calcination temperature is 400-450 o C, and the calcination time is 2-3 h.

[0022] In the technical solution, further, in step (5), the second electrodeposition adopts cyclic voltammetry electrodeposition, the cyclic voltammetry voltage is -0.7-0.2 VSCE, and the cyclic voltammetry number is 25-100 times.

[0023] In the technical solution, further, in step (5), the annealing temperature is 400-450℃, and the annealing time is 2-3 h.

[0024] The application further provides an application of the oxygen evolution electrode, which is applied as an oxygen evolution catalyst in a photoelectrocatalytic water electrolysis reaction, an AEM water electrolysis cell or an acidic water electrolysis hydrogen generator.

[0025] The application has the following beneficial effects:

[0026] 1. The porous opal structure oxygen electrode with different pore diameters provided by the present application has a large specific surface area, can expose more active sites, increases the contact active sites with electrolyte, thereby enhancing the charge transmission capacity, and the coating of Ir greatly restrains the dissolution of Ru, the porous structure with different pore diameters can provide additional gas-liquid transmission channels, the catalyst has good stability, the specific surface area is improved by regulating the structure, and the purpose of improving the active sites is achieved.

[0027] 2. The preparation method of the present application can effectively regulate the morphology of the product by controlling the reaction conditions and preparation parameters, and the porous interconnected pores (i.e. opal structure) with uniform morphology and good dispersion are synthesized, the pores formed under the action of polystyrene microspheres with different sizes also show obvious differences, and the pore size and pore wall thickness also have obvious influence on the stability of the structure and the catalyst activity; in addition, the self-assembly and electrodeposition technology adopted in the present application has the advantages of simple process, low cost and easy industrialization, and the electrode can be effectively controlled and synthesized under mild conditions.

[0028] 3. Compared with nanorods and nanotubes and other nanometer arrays, the opal structure catalyst prepared by the method of the present application has higher specific surface area and oxygen evolution catalytic activity, and the required additional bias for water electrolysis cell to decompose water to produce hydrogen is smaller, and has better stability, the prepared electrode as an oxygen electrode used for PEM acid water electrolysis hydrogen production has good performance, and has wide utilization value in renewable fuel cells (RFC), photoelectric catalytic electrolysis of water, and electrolytic hydrogen generator devices. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 SEM images of the titanium felt with 3D templates prepared in Example 1, a is 1 μm, and b is 100 nm;

[0030] Figure 2 TEM images of the titanium felt with 3D templates prepared in Examples 1-4, a is Example 2, b is Example 3, c is Example 1, and d is Example 4;

[0031] Figure 3 Morphology diagram of the oxygen electrode prepared in Example 1;

[0032] Figure 4 Stability test results of the oxygen electrode prepared in Example 1, Comparative Example 1 and Comparative Example 3;

[0033] Figure 5 Polarization curves obtained by linear voltammetry scanning of the oxygen electrode prepared in Examples 1-4 and Comparative Example 2;

[0034] Figure 6 Polarization curves obtained by linear voltammetry scan for the oxygen evolution electrode prepared in Example 1, Example 5-6;

[0035] Figure 7 Polarization curves obtained by linear voltammetry scan for the oxygen evolution electrode prepared in Example 1, Example 7-9. DETAILED DESCRIPTION

[0036] The technical solutions of the electrode preparation method, characteristics and application of water electrolysis are further explained below in combination with the drawings, which cannot be used to limit the protection scope of the present application.

[0037] Example 1

[0038] (1) The titanium felt was cleaned with acetone, dilute hydrochloric acid, ethanol and deionized water respectively for 15 min by ultrasonic, so as to remove the impurities and oil stains on the surface of the titanium felt, and then dried;

[0039] (2) 0.3 g of non-ionic surfactant nonylphenol polyoxyethylene ether (NP-40) and 0.36 g of polystyrene microspheres (diameter 300 nm) were added to 100 ml of deionized water, and ultrasonic was performed for 30 min to obtain a polystyrene microsphere dispersion liquid. The titanium felt obtained in step (1) was placed in the polystyrene microsphere dispersion liquid, and dried at 65°C until the liquid was completely volatilized, to obtain a titanium felt with 3D template;

[0040] (3) The titanium felt with 3D template obtained in step (2) was dried in a vacuum drying box at 60°C for 6h;

[0041] (4) 0.38 g of RuCl3 was dissolved in 75 mL of deionized water and stirred for 3h. The titanium felt with 3D template dried in step (3) was placed in the aqueous solution of RuCl3, and a graphite sheet electrode (4 cm x 4 cm) was used as the counter electrode and a saturated calomel electrode (SCE) was used as the reference electrode. The cyclic voltammetry was performed at a scan rate of 50 mV / s in the potential range of (-0.2~0.8 V) VS SCE, and the deposition was performed at (-0.2 V) VS SCE for 240 s. After the preparation was completed, the sample was placed in a vacuum drying box and dried at 80°C for 3h, and then calcined in a tube furnace at 400°C in an air atmosphere for 3h to obtain a titanium felt loaded with inverse opal structure RuO2. -2 (5) 0.167 g of iridium tetrachloride was dissolved in 100 mL of deionized water, and the titanium felt loaded with inverse opal structure RuO2 obtained in step (4) was placed in the aqueous solution of IrCl4, and the cyclic voltammetry was performed at a scan rate of 50 mV / s in the potential range of (-0.7~0.2 V) VS SCE for 100 times, and then annealed in a tube furnace at 450°C in an argon atmosphere for 3h to obtain the electrode.

[0042] (5) 0.167 g of iridium tetrachloride was dissolved in 100 mL of deionized water, and the titanium felt loaded with inverse opal structure RuO2 obtained in step (4) was placed in the aqueous solution of IrCl4, and the cyclic voltammetry was performed at a scan rate of 50 mV / s in the potential range of (-0.7~0.2 V) VS SCE for 100 times, and then annealed in a tube furnace at 450°C in an argon atmosphere for 3h to obtain the electrode.

[0043] AsFigures 1-2 As shown, polystyrene microspheres are successfully loaded on the titanium felt surface to form a multi-layer and hierarchical layered structure, as shown in Figure 3 As shown, after loading of noble metal and removal of the template, a porous and hierarchical inverse opal structure is formed, in which the outer pore diameter is 357 nm, the inner pore diameter is 323 nm, and the pore wall thickness is 32 nm.

[0044] Example 2

[0045] The same preparation process as in Example 1 is adopted, except that the diameter of the polystyrene microspheres is 50 nm.

[0046] Example 3

[0047] The same preparation process as in Example 1 is adopted, except that the diameter of the polystyrene microspheres is 100 nm.

[0048] Example 4

[0049] The same preparation process as in Example 1 is adopted, except that the diameter of the polystyrene microspheres is 500 nm.

[0050] Example 5

[0051] (1) The titanium felt was sequentially cleaned with acetone, dilute hydrochloric acid, ethanol, and deionized water for 15 min each by ultrasonic cleaning, so as to remove impurities and oil stains on the surface of the titanium felt, and then dried;

[0052] (2) 0.3 g of non-ionic surfactant nonylphenol polyoxyethylene ether (NP-40) and 0.24 g of polystyrene microspheres (diameter of 300 nm) were added to 100 ml of deionized water, and ultrasonic treatment was performed for 30 min to obtain a polystyrene microsphere dispersion liquid. The titanium felt obtained in step (1) was placed in the polystyrene microsphere dispersion liquid, and dried at 65°C until the liquid was completely volatilized, to obtain a titanium felt with a 3D template;

[0053] (3) The titanium felt with a 3D template obtained in step (2) was dried in a vacuum drying oven at 60°C for 6 h;

[0054] (4) 0.38 g of RuCl3 was dissolved in 75 mL of deionized water, and stirred for 3 h. The titanium felt with a 3D template after drying in step (3) was placed in the RuCl3 aqueous solution, and a graphite sheet electrode (4 cm x 4 cm) was used as a counter electrode, and a saturated calomel electrode (SCE) was used as a reference electrode. A three-electrode system was established, and RuO2 was deposited on the titanium felt with a 3D template at -10 mA cm -2 for 240 s. After the preparation was completed, the sample was placed in a vacuum drying oven and dried at 80°C for 3 h, and then calcined at 400°C in a tube furnace under an air atmosphere for 3 h, to obtain a titanium felt loaded with inverse opal structure RuO2;

[0055] (5) 0.167 g of iridium tetrachloride was dissolved in 100 mL of deionized water, and the inverse opal structure RuO2-loaded titanium felt obtained in step (4) was placed in the aqueous solution of IrCl4and cycled 100 times at (-0.7~0.2 V) vs SCE, followed by annealing in a tube furnace under an argon atmosphere at 450°C for 3 h to obtain the electrode.

[0056] Example 6

[0057] (1) The titanium felt was cleaned with acetone, dilute hydrochloric acid, ethanol and deionized water, respectively, for 15 min each time by ultrasonic cleaning, so as to remove impurities and oil stains on the surface of the titanium felt, and then dried;

[0058] (2) 0.3 g of non-ionic surfactant nonylphenol polyoxyethylene ether (NP-40) and 0.48 g of polystyrene microspheres (diameter 300 nm) were added to 100 mL of deionized water, and ultrasonic treatment was performed for 30 min to obtain a dispersion liquid, and the titanium felt obtained in step (1) was placed in the polystyrene microsphere dispersion liquid and dried at 65°C until the liquid was completely volatilized to obtain a titanium felt with a 3D template;

[0059] (3) The titanium felt with a 3D template obtained in step (2) was dried in a vacuum drying oven at 60°C for 6 h;

[0060] (4) 0.38 g of RuCl3was dissolved in 75 mL of deionized water and stirred for 3 h, and the titanium felt with a 3D template dried in step (3) was placed in the aqueous solution of RuCl3, and a graphite sheet electrode (4 cm x 4 cm) was used as the counter electrode and a saturated calomel electrode (SCE) was used as the reference electrode, and deposition was performed at -10 mA cm -2 The sample was placed in a vacuum drying oven at 80°C for 3 h to dry, and then calcined at 400°C for 3 h in a tube furnace under an air atmosphere to obtain a RuO2-loaded titanium felt;

[0061] (5) 0.167 g of iridium tetrachloride was dissolved in 100 mL of deionized water, and the RuO2-loaded titanium felt obtained in step (4) was placed in the aqueous solution of IrCl4and cycled 100 times at (-0.7~0.2 V) vs SCE, followed by annealing in a tube furnace under an argon atmosphere at 450°C for 3 h to obtain the electrode.

[0062] Example 7

[0063] (1) The titanium felt was cleaned with acetone, dilute hydrochloric acid, ethanol and deionized water, respectively, for 15 min each time by ultrasonic cleaning, so as to remove impurities and oil stains on the surface of the titanium felt, and then dried;

[0064] (2) 0.3 g of non-ionic surfactant nonylphenol polyoxyethylene ether (NP-40) and 0.36 g of polystyrene microspheres (300 nm in diameter) were added to 100 ml of deionized water, and ultrasonic treatment was performed for 30 min to obtain a dispersion liquid. The titanium felt obtained in step (1) was placed in the polystyrene microsphere dispersion liquid, and drying was performed at 65°C until the liquid was completely volatilized to obtain a titanium felt with a 3D template;

[0065] (3) The titanium felt with a 3D template obtained in step (2) was dried in a vacuum drying box at 60°C for 6 h;

[0066] (4) 0.38 g of RuCl3 was dissolved in 75 mL of deionized water, and stirring was performed for 3 h. The titanium felt with a 3D template after drying in step (3) was placed in the RuCl3 aqueous solution, and electrodeposition was performed at -10 mA cm-2 for 240 s with the titanium felt with a 3D template as a working electrode, a graphite sheet electrode (4 cm x 4 cm) as a counter electrode, and a saturated calomel electrode (SCE) as a reference electrode. After the preparation was completed, the sample was placed in a vacuum drying box and dried at 80°C for 3 h, and then calcination was performed in a tube furnace under an air atmosphere at 400°C for 3 h to obtain a titanium felt loaded with inverse opal structure RuO2. -2

[0067] (5) 0.167 g of iridium tetrachloride was dissolved in 100 mL of deionized water. The titanium felt loaded with inverse opal structure RuO2 obtained in step (4) was placed in the IrCl4 aqueous solution, and cyclic voltammetry was performed 75 times at (-0.7~0.2 V) vs SCE. Subsequently, annealing was performed in a tube furnace under an argon atmosphere at 450°C for 3 h to obtain an electrode.

[0068] Example 8

[0069] (1) The titanium felt was sequentially cleaned with acetone, dilute hydrochloric acid, ethanol, and deionized water by ultrasonic treatment for 15 min each to remove impurities and oil stains on the surface of the titanium felt, and then dried;

[0070] (2) 0.3 g of non-ionic surfactant nonylphenol polyoxyethylene ether (NP-40) and 0.36 g of polystyrene microspheres (300 nm in diameter) were added to 100 ml of deionized water, and ultrasonic treatment was performed for 30 min to obtain a dispersion liquid. The titanium felt obtained in step (1) was placed in the polystyrene microsphere dispersion liquid, and drying was performed at 65°C until the liquid was completely volatilized to obtain a titanium felt with a 3D template;

[0071] (3) The titanium felt with a 3D template obtained in step (2) was dried in a vacuum drying box at 60°C for 6 h;

[0072] ​(4) 0.38 g RuCl3 was dissolved in 75 mL deionized water, and stirred for 3 h. The titanium felt with 3D template dried in step (3) was placed in the aqueous solution of RuCl3, and the titanium felt with 3D template was used as the working electrode, a graphite sheet electrode (4 cm x 4 cm) was used as the counter electrode, and a saturated calomel electrode (SCE) was used as the reference electrode. The electrodeposition was carried out at -10 mA cm-2 for 240 s. After the preparation was completed, the sample was dried in a vacuum drying box at 80 °C for 3 h, and then calcined at 400 °C for 3 h in a tube furnace in an argon atmosphere to obtain a titanium felt loaded with inverse opal structure RuO2. -2 After deposition for 240 s, the sample was dried in a vacuum drying box at 80 °C for 3 h, and then calcined at 400 °C for 3 h in a tube furnace in an argon atmosphere to obtain a titanium felt loaded with inverse opal structure RuO2.

[0073] (5) 0.167 g iridium tetrachloride was dissolved in 100 mL deionized water. The titanium felt loaded with RuO2 obtained in step (4) was placed in the aqueous solution of IrCl4, and 50 cycles were carried out at (-0.7 ~ 0.2 V) vs SCE, and then annealed at 450 °C for 3 h in a tube furnace in an argon atmosphere to obtain an electrode.

[0074] Example 9

[0075] (1) The titanium felt was sequentially cleaned with acetone, dilute hydrochloric acid, ethanol and deionized water for 15 min each time under ultrasonic cleaning, so as to remove impurities and oil stains on the surface of the titanium felt, and then dried.

[0076] (2) 0.3 g of non-ionic surfactant nonylphenol polyoxyethylene ether (NP-40) and 0.36 g of polystyrene microspheres (diameter 300 nm) were added to 100 mL deionized water, and ultrasonic treatment was carried out for 30 min to obtain a dispersion liquid. The titanium felt obtained in step (1) was placed in the polystyrene microsphere dispersion liquid, and dried at 65 °C until the liquid was completely volatilized to obtain a titanium felt with 3D template.

[0077] (3) The titanium felt with 3D template obtained in step (2) was dried in a vacuum drying box at 60 °C for 6 h.

[0078] (4) 0.38 g RuCl3 was dissolved in 75 mL deionized water, and stirred for 3 h. The titanium felt with 3D template dried in step (3) was placed in the aqueous solution of RuCl3, and the titanium felt with 3D template was used as the working electrode, a graphite sheet electrode (4 cm x 4 cm) was used as the counter electrode, and a saturated calomel electrode (SCE) was used as the reference electrode. The electrodeposition was carried out at -10 mA cm-2 for 240 s. After the preparation was completed, the sample was dried in a vacuum drying box at 80 °C for 3 h, and then calcined at 400 °C for 3 h in a tube furnace in an argon atmosphere to obtain a titanium felt loaded with inverse opal structure RuO2. -2 After deposition for 240 s, the sample was dried in a vacuum drying box at 80 °C for 3 h, and then calcined at 400 °C for 3 h in a tube furnace in an argon atmosphere to obtain a titanium felt loaded with inverse opal structure RuO2.

[0079] (5) 0.167 g of iridium tetrachloride was dissolved in 100 mL of deionized water, the RuO2-loaded titanium felt obtained in step (4) was placed in the aqueous solution of IrCl4, and was cycled 25 times at (-0.7 ~ 0.2 V) VS SCE, and then was annealed in an argon atmosphere in a tube furnace at 450°C for 3 h to obtain the electrode.

[0080] Comparative Example 1

[0081] (1) The titanium felt was cleaned with acetone, dilute hydrochloric acid, ethanol and deionized water in sequence for 15 min each time by ultrasonic cleaning, so as to remove impurities and oil stains on the surface of the titanium felt, and was dried;

[0082] (2) 0.3 g of non-ionic surfactant nonylphenol polyoxyethylene ether (NP-40) and 0.36 g of polystyrene microspheres (diameter 300 nm) were added to 100 mL of deionized water, and were ultrasonically dispersed for 30 min to obtain a dispersion liquid, and the titanium felt obtained in step (1) was placed in the polystyrene microsphere dispersion liquid, and was dried at 65°C until the liquid was completely volatilized to obtain a titanium felt with a 3D template;

[0083] (3) The titanium felt with a 3D template obtained in step (2) was dried in a vacuum drying oven at 60°C for 6 h;

[0084] (4) 0.167 g of iridium tetrachloride was dissolved in 100 mL of deionized water, the titanium felt with a 3D template obtained in step (3) was placed in the aqueous solution of IrCl4, and was cycled 100 times at (-0.7 ~ 0.2 V) VS SCE with the titanium felt as the working electrode, a graphite sheet electrode (4 cm x 4 cm) as the counter electrode, and a saturated calomel electrode (SCE) as the reference electrode, and then was annealed in an argon atmosphere in a tube furnace at 450°C for 3 h to obtain the electrode.

[0085] Comparative Example 2

[0086] (1) The titanium felt was cleaned with acetone, dilute hydrochloric acid, ethanol and deionized water in sequence for 15 min each time by ultrasonic cleaning, so as to remove impurities and oil stains on the surface of the titanium felt, and was dried in a vacuum drying oven at 65°C;

[0087] (2) 0.38 g of RuCl3 was dissolved in 75 mL of deionized water, and was stirred for 3 h, and the titanium felt obtained in step (1) was placed in the aqueous solution of RuCl3, and was deposited at -10 mA cm -2 for 240 s with the titanium felt as the working electrode, a graphite sheet electrode (4 cm x 4 cm) as the counter electrode, and a saturated calomel electrode (SCE) as the reference electrode, and after the preparation was completed, the sample was placed in a vacuum drying oven and was dried at 80°C for 3 h, and then was calcined at 400°C in a tube furnace for 3 h;

[0088] (3) 0.167 g of iridium tetrachloride was dissolved in 100 mL of deionized water, and the sample obtained in step (2) was placed in the aqueous solution of IrCl4, and cyclic voltammetry was performed at (-0.7 ~ 0.2 V) VS SCE for 100 cycles, secondary electrodeposition was performed, and then annealing was performed in an argon atmosphere at 450°C for 3h in a tube furnace to obtain an electrode.

[0089] Comparative Example 3

[0090] (1) The titanium felt was cleaned with acetone, dilute hydrochloric acid, ethanol and deionized water respectively for 15 min under ultrasonic wave to remove impurities and oil stains on the surface of the titanium felt, and then dried;

[0091] (2) 0.3 g of non-ionic surfactant nonylphenol polyoxyethylene ether (NP-40) and 0.36 g of polystyrene microspheres (diameter 300 nm) were added to 100 mL of deionized water, and ultrasonic wave was applied for 30 min to obtain a dispersion liquid, and the titanium felt obtained in step (1) was placed in the polystyrene microsphere dispersion liquid and dried at 65°C until the liquid was completely volatilized to obtain a titanium felt with a 3D template;

[0092] (3) The titanium felt with a 3D template obtained in step (2) was dried in a vacuum drying oven at 60°C for 6h;

[0093] (4) 0.38 g of RuCl3 was dissolved in 75 mL of deionized water and stirred for 3h, and the titanium felt with a 3D template dried in step (3) was placed in the aqueous solution of RuCl3, and the titanium felt with a 3D template was used as a working electrode, a graphite sheet electrode (4 cm x 4 cm) was used as a counter electrode, and a saturated calomel electrode (SCE) was used as a reference electrode, and electrodeposition was performed at -10 mA cm -2 for 240 s, and after the preparation was completed, the sample was placed in a vacuum drying oven and dried at 80°C for 3h, and then calcined at 400°C for 3h in a tube furnace to obtain an electrode.

[0094] The electrodes prepared in Examples 1-9 and Comparative Examples 1-3 were subjected to electrochemical test, and half-cell test was performed in a three-electrode system at room temperature, a saturated calomel electrode (SCE) was used as a reference electrode, graphite was used as a counter electrode, and 0.5 M H2SO4 solution was used as an electrolyte, and water bath was performed at 30°C.

[0095] The electrodes prepared in Example 1, Comparative Example 1 and Comparative Example 3 were subjected to stability test, and the experimental results showed that Example 1 > Comparative Example 1 > Comparative Example 3 in the stability test, indicating that the coating of Ir had a good improvement effect on the stability.

[0096] The electrodes prepared in Examples 1-4 and Comparative Example 2 were subjected to stability test as Figure 5As shown, the structure with 300 nm polystyrene microspheres after loading has more excellent performance advantages, and the stability is greatly improved compared with the electrode without inverse opal structure, which can be attributed to the fact that the inverse opal ordered nanoarray has a large specific surface area, can expose more active sites, increases the contact active sites with electrolyte, thereby enhancing the charge transmission capacity, and the Ir coating greatly restrains the dissolution of Ru, and the large pore structure can provide additional gas-liquid transmission channels.

[0097] The polarization curves obtained by linear voltammetry scanning of the electrodes prepared in Example 1 and Examples 5-6 with different polystyrene microsphere contents are shown in Figure 6 As shown, within a certain proportion range, with the increase of the polystyrene microsphere content, the electrode performance is obviously improved.

[0098] The polarization curves obtained by linear voltammetry scanning of the electrodes prepared in Example 1 and Examples 7-9 with different cycle numbers are shown in Figure 7 As shown, the results show that within a certain CV number range, with the increase of the CV number, the electrode performance is obviously improved, indicating that the Ru coating is better and better, and the synergistic effect between Ir and RuO2 is enhanced.

[0099] The above examples are only preferred examples of the present application, and are not limited to the embodiments. The protection scope of the present application should be limited by the scope defined in the claims. Other different forms of changes or variations can be made on the basis of the above description. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. An electrode for water electrolysis, characterized in that: The electrode includes a gas diffusion layer and a catalyst, wherein the catalyst is supported on the gas diffusion layer; The catalyst is Ir-coated RuO2, and the catalyst has an inverse opal structure; The gas diffusion layer is a titanium felt; The electrode preparation method includes the following steps: (1) Clean the titanium felt with acetone, dilute hydrochloric acid, ethanol and deionized water in sequence by ultrasonic cleaning, and then dry it; (2) Add nonionic surfactant and polystyrene microspheres to water, sonicate to obtain dispersion, put the titanium felt obtained in step (1) into dispersion, dry until the liquid completely evaporates to obtain titanium felt with 3D template; (3) Vacuum dry the titanium felt with 3D template obtained in step (2); (4) The titanium felt with 3D template dried in step (3) was placed in an aqueous solution of RuCl3 for the first electrodeposition, dried, and then calcined to obtain titanium felt supported by RuO2 with an inverse opal structure. (5) The titanium felt loaded with RuO2 and the anti-opal structure obtained in step (4) is placed in an aqueous solution of IrCl4 for a second electrodeposition, and then annealed in an inert gas atmosphere to obtain the electrode.

2. The electrode for water electrolysis according to claim 1, characterized in that: The catalyst has an outer pore size of 100~600 nm, an inner pore size of 82~470 nm, and a pore wall thickness of 25~50 nm; the mass ratio of Ir to Ru in the catalyst is 1:(1.2~1.8).

3. A method for preparing an electrode for water electrolysis according to any one of claims 1-2, characterized in that: Includes the following steps: (1) Clean the titanium felt with acetone, dilute hydrochloric acid, ethanol and deionized water in sequence by ultrasonic cleaning, and then dry it; (2) Add nonionic surfactant and polystyrene microspheres to water, sonicate to obtain dispersion, put the titanium felt obtained in step (1) into dispersion, dry until the liquid completely evaporates to obtain titanium felt with 3D template; (3) Vacuum dry the titanium felt with 3D template obtained in step (2); (4) The titanium felt with 3D template dried in step (3) was placed in an aqueous solution of RuCl3 for the first electrodeposition, dried, and then calcined to obtain titanium felt supported by RuO2 with an inverse opal structure. (5) The titanium felt loaded with RuO2 and the anti-opal structure obtained in step (4) is placed in an aqueous solution of IrCl4 for a second electrodeposition, and then annealed in an inert gas atmosphere to obtain the electrode.

4. The method for preparing an electrode for water electrolysis according to claim 3, characterized in that: In step (1), each ultrasound session lasts 15 to 30 minutes.

5. The method for preparing an electrode for water electrolysis according to claim 3, characterized in that: In step (2), the diameter of the polystyrene microspheres is 50~500nm; The mass ratio of the nonionic surfactant to the polystyrene microspheres is 1:(0.8~1.6). The ultrasound time is 30-60 minutes; The nonionic surfactant is nonylphenol polyoxyethylene ether; The drying temperature is 65~80℃. o C.

6. The method for preparing an electrode for water electrolysis according to claim 3, characterized in that: In step (3), the vacuum drying temperature is 50~80℃. o C, the vacuum drying time is 6~12h.

7. The method for preparing the electrode for water electrolysis according to claim 3, characterized in that: In step (4), the first electrodeposition is a constant current electrodeposition, with an electrodeposition time of 100~400s and a current density of -10~-30 mAcm. -2 ; The calcination temperature is 400~450℃. o C, roasting time is 2~3 hours.

8. The method for preparing the electrode for water electrolysis according to claim 3, characterized in that: In step (5), the second electrodeposition is performed using cyclic voltammetric electrodeposition, with a cyclic voltammetric voltage of -0.7 to 0.2 VSCE and a cyclic voltammetric cycle number of 25 to 100.

9. The method for preparing an electrode for water electrolysis according to claim 3, characterized in that: In step (5), the annealing temperature is 400~450℃ and the annealing time is 2~3h.

10. The application of an electrode for water electrolysis according to any one of claims 1-2 or an electrode prepared by the method of preparing an electrode for water electrolysis according to any one of claims 3-9, characterized in that: The electrode is used as an oxygen evolution electrode in photoelectrocatalytic water electrolysis, AEM water electrolysis cells, or acidic water electrolysis hydrogen generators.

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