Composite catalytic electrode for hydrogen evolution by water electrolysis, preparation method therefor and use thereof

Abstract

Disclosed in the present disclosure are a composite catalytic electrode for hydrogen evolution by water electrolysis and a preparation method therefor. The composite catalytic electrode comprises a nickel substrate, a composite catalyst layer supported on the nickel substrate, and a metal oxide protective layer coated on the surface of the composite catalyst layer. The composite catalyst layer comprises platinum, ruthenium, and palladium noble metal catalysts and a catalytic promoter. The metal oxide protective layer is a nanoporous metal oxide layer, and the metal oxide is one or more of a valve metal oxide and a rare earth metal oxide. The composite catalytic electrode for hydrogen evolution by water electrolysis in the present disclosure comprises a composite catalyst layer made of platinum, ruthenium, palladium, and a promoter, and a metal oxide protective layer coated on the outer side of the composite catalyst layer; the metal components in the composite catalyst layer can be stably combined with the metal substrate; the metal oxide protective layer is structurally similar to oxides in the composite catalyst layer, and therefore can be firmly coated on the surface of the composite catalytic layer; thus, the composite catalytic electrode can exhibit high catalytic activity for hydrogen evolution by water electrolysis, high structural stability, long-time stability, strong resistance to polarity reversal, and strong resistance to deposition.

Description

Electrolytic water hydrogen evolution composite catalytic electrode and preparation method and application thereof TECHNICAL FIELD

[0001] The present disclosure belongs to the field of electrolytic water hydrogen production, and particularly relates to an electrolytic water hydrogen evolution composite catalytic electrode and a preparation method and application thereof. BACKGROUND

[0002] Currently, humans are facing the problems of energy and environmental pollution caused by overexploitation of fossil energy. Hydrogen, as an ideal energy storage carrier, has the advantages of high energy density, cleanliness, no pollution and zero carbon emission. As a promising efficient and clean energy, the current production of hydrogen is mainly restricted by the non-environmentally friendly production methods such as coal-to-hydrogen. In contrast, electrolytic water hydrogen production is not only clean and environmentally friendly, but also produces hydrogen with high purity, and is expected to become the next generation of large-scale hydrogen production method.

[0003] By electrolytic water hydrogen production, green electricity generated by wind energy, light energy and the like can be converted into chemical energy and stored in hydrogen, which can meet the convenient transportation and continuous supply of energy. The current mature commercial alkaline electrolytic water hydrogen production mainly uses a nickel mesh composite catalytic electrode, a KOH electrolyte with a concentration of about 30wt%, and a certain cell voltage is applied to electrolyze water to produce hydrogen under the working conditions of 80-90℃. The widely used nickel mesh composite catalytic electrode mainly works at low current density, and its intrinsic water electrolysis catalytic activity is not ideal, resulting in a large overpotential during the electrolysis process, which increases the power consumption and causes the cost of electrolytic water hydrogen production to be too high. Therefore, there is an urgent need for electrolytic water catalytic materials with high catalytic activity to reduce the cost of hydrogen production. Platinum has strong catalytic ability and good corrosion resistance, and therefore can be applied to the electrolytic water hydrogen production environment with high current density. For example, patent CN112877728B prepares a platinum-carbon supported foam nickel electrolytic water composite catalytic electrode by spraying and calcining; patent CN114016067B prepares a low-platinum nitrogen-sulfur co-doped nickel phosphide self-supporting electrolytic water composite catalytic electrode by hydrothermal growth, phosphating-nitriding-sulfurizing and rapid ultraviolet assisted growth; patent CN115627493A prepares a platinum doped composite catalytic electrode by hydrothermally growing a nickel hydroxide carrier on a nickel mesh and electrochemically depositing platinum, which is used to improve the catalytic activity of electrolytic water hydrogen production.

[0004] However, due to the scarcity of platinum group elements in the earth's crust, platinum is expensive, and this scarcity limits its large-scale use in industrial applications. Therefore, reducing the amount of platinum used and improving the efficiency of platinum use have become difficult problems to be solved. The existing technology usually uses electroplating method to prepare catalytic electrode, which often has problems such as poor adhesion between plating layer and substrate affecting the stability of plating layer and low efficiency of platinum use, and the electroplating method has high one-time investment and high equipment maintenance cost. SUMMARY

[0005] The present disclosure aims to provide a preparation method of an electrolytic water hydrogen evolution composite catalytic electrode suitable for large-scale production, and the composite catalytic electrode prepared by the method, which can efficiently, simply and at low cost prepare a hydrogen evolution composite catalytic electrode with low noble metal content, and the composite catalytic electrode has low hydrogen evolution potential, high stability, strong anti-reverse polarity and strong anti-deposition performance, and can meet the application requirements of industrial high current density electrolytic water.

[0006] The present disclosure provides an electrolytic water hydrogen evolution composite catalytic electrode, which comprises a nickel substrate, a catalyst layer loaded on the nickel substrate, and a protective layer coated on the surface of the composite catalytic layer; wherein the composite catalyst layer comprises a noble metal catalyst, and the protective layer is a nano-porous metal oxide layer, and the metal oxide is one or more of valve metal oxides and rare earth metal oxides.

[0007] According to an embodiment of the present disclosure, the noble metal is one or more of platinum, ruthenium and palladium; preferably, the composite catalyst layer further comprises a catalytic aid.

[0008] According to another embodiment of the present disclosure, the metal oxide is one or more of titanium oxide, cerium oxide, zirconium oxide, aluminum oxide, yttrium oxide, niobium oxide, tantalum oxide and lanthanum oxide.

[0009] According to another embodiment of the present disclosure, the total loading amount of the noble metal catalyst and the catalytic aid is 0.01-20 mg / cm 2 , preferably 0.05-1.0 mg / cm 2 , the molar ratio of the noble metal to the catalytic aid is 1:1-1000:1; and the loading amount of the metal oxide is 0.01-0.2 mg / cm 2 , preferably 0.02-0.05 mg / cm 2 .

[0010] According to another embodiment of the present disclosure, the catalytic aid is a metal element, an alloy or an oxide selected from one or more of Ni, Au, Ag, Zn, Ti, Ce, Mo, Co, Fe, Cu and La.

[0011] According to another embodiment of the present disclosure, the nickel substrate is a nickel mesh, a nickel alloy mesh, a nickel foam or a nickel alloy foam.

[0012] Another aspect of the present disclosure provides a method for preparing a water electrolysis hydrogen evolution composite catalytic electrode, comprising: adding a stabilizer to a noble metal catalyst precursor compound solution to form a catalyst solution, or adding a catalytic additive precursor compound and the stabilizer to the noble metal catalyst precursor compound solution to form a composite catalyst solution; sintering the catalyst solution after coating on the surface of the nickel substrate to form a composite catalyst layer; providing a metal oxide precursor solution and sintering the same after coating on the surface of the composite catalyst layer to form the protective layer.

[0013] According to an embodiment of the present disclosure, the stabilizer is one or more of hydrochloric acid, sulfuric acid, acetic acid, nitric acid, and citric acid.

[0014] According to another embodiment of the present disclosure, the sintering step for forming the composite catalyst layer comprises: sintering at 200-400°C for 10 min-10 h and then calcining at 400-600°C for 30 min-12 h in air, inert atmosphere or reducing atmosphere; preferably, sintering at 300-350°C for 10 min-2 h and then calcining at 450-550°C for 30 min-2 h.

[0015] According to another embodiment of the present disclosure, the sintering step for forming the protective layer comprises: calcining at 200-600°C for 5 min-12 h in air or inert atmosphere; preferably, calcining at 300-500°C for 30 min-2 h.

[0016] According to another embodiment of the present disclosure, the nickel substrate is subjected to roughening treatment.

[0017] Another aspect of the present disclosure also provides a water electrolysis hydrogen evolution device, wherein the above water electrolysis hydrogen evolution composite catalytic electrode is used as a cathode.

[0018] The present disclosure provides a water electrolysis hydrogen evolution composite catalytic electrode, wherein the catalyst layer of the composite catalytic electrode is coated with a protective layer. Since the composite catalyst layer comprises a noble metal main catalyst, a catalytic additive and a metal oxide, the noble metal main catalyst and the catalytic additive can be combined with the metal substrate to form a stable structure, and the metal oxide has a similar structure to the outer oxide protective layer, which can stably cover the surface of the composite catalyst layer, so that the composite catalytic electrode exhibits high water electrolysis hydrogen evolution catalytic activity, high structural stability, long-term stability, strong anti-reverse polarity and strong anti-deposition capacity. Compared with the method of preparing a noble metal electrode by electroplating and the method of preparing a hydrogen evolution composite catalytic electrode by adhering a noble metal catalyst to a nickel substrate using a binder, the method of the present disclosure is simple to operate, has high utilization rate of noble metal, and exhibits high structural stability, strong anti-reverse polarity and strong anti-deposition capacity, which has important industrial application value. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a SEM image of a platinum nickel composite catalytic electrode coated with cerium oxide prepared in Example 1.

[0020] Figure 2 is a plot of electrolysis voltage versus current density for a platinum nickel composite catalytic electrode coated with cerium oxide prepared in Example 1, a sandblasted nickel mesh of Comparative Example 1, and a platinum nickel composite catalytic electrode prepared in Comparative Example 2.

[0021] Figure 3 is a plot of electrolysis voltage versus electrolysis time for a platinum nickel composite catalytic electrode coated with cerium oxide prepared in Example 1, a sandblasted nickel mesh of Comparative Example 1, and a platinum nickel composite catalytic electrode prepared in Comparative Example 2.

[0022] Figure 4 is a SEM image of a sandblasted nickel mesh composite catalytic electrode after electrolysis.

[0023] Figure 5 is a SEM image of a platinum nickel composite catalytic electrode prepared in Comparative Example 2 after electrolysis.

[0024] Figure 6 is a SEM image of a platinum nickel composite catalytic electrode coated with cerium oxide prepared in Example 1 after electrolysis.

[0025] Figure 7 is a SEM image of a platinum cerium composite catalytic electrode coated with cerium oxide prepared in Example 2.

[0026] Figure 8 is a plot of electrolysis voltage versus current density for a platinum cerium composite catalytic electrode coated with cerium oxide prepared in Example 2.

[0027] Figure 9 is a plot of electrolysis voltage versus electrolysis time for a platinum cerium composite catalytic electrode coated with cerium oxide prepared in Example 2.

[0028] Figure 10 is a SEM image of a platinum cerium composite catalytic electrode coated with cerium oxide prepared in Example 2 after electrolysis.

[0029] Figure 11 is a SEM image of a platinum ruthenium composite catalytic electrode coated with titanium oxide prepared in Example 3.

[0030] Figure 12 is a plot of electrolysis voltage versus current density for a platinum ruthenium composite catalytic electrode coated with titanium oxide prepared in Example 3.

[0031] Figure 13 is a plot of electrolysis voltage versus electrolysis time for a platinum ruthenium composite catalytic electrode coated with titanium oxide prepared in Example 3.

[0032] Figure 14 is a SEM image of a platinum ruthenium composite catalytic electrode coated with titanium oxide prepared in Example 3 after electrolysis.

[0033] Figure 15 is a SEM image of a platinum iron composite catalytic electrode coated with zirconium oxide prepared in Example 4.

[0034] Figure 16 is a plot of electrolysis voltage versus current density for a platinum iron composite catalytic electrode coated with zirconium oxide prepared in Example 4.

[0035] Figure 17 is a plot of electrolysis voltage as a function of electrolysis time for the zirconium oxide-coated platinum-iron composite catalytic electrode prepared in Example 4.

[0036] Figure 18 is a SEM image of the zirconium oxide-coated platinum-iron composite catalytic electrode prepared in Example 4 after electrolysis.

[0037] Figure 19 is a SEM image of the aluminum oxide-coated platinum-ruthenium-cerium composite catalytic electrode prepared in Example 5.

[0038] Figure 20 is a plot of electrolysis voltage as a function of current density for the aluminum oxide-coated platinum-ruthenium-cerium composite catalytic electrode prepared in Example 5.

[0039] Figure 21 is a plot of electrolysis voltage as a function of electrolysis time for the aluminum oxide-coated platinum-ruthenium-cerium composite catalytic electrode prepared in Example 5.

[0040] Figure 22 is a SEM image of the aluminum oxide-coated platinum-ruthenium-cerium composite catalytic electrode prepared in Example 5 after electrolysis.

[0041] Figure 23 is a photograph of the cerium oxide-coated platinum-ruthenium-nickel composite catalytic electrode prepared in Example 6.

[0042] Figure 24 is a SEM image of the cerium oxide-coated platinum-ruthenium-nickel composite catalytic electrode prepared in Example 6.

[0043] Figure 25 is a plot of electrolysis voltage as a function of current density for the cerium oxide-coated platinum-ruthenium-nickel composite catalytic electrode prepared in Example 6.

[0044] Figure 26 is a plot of electrolysis voltage as a function of electrolysis time for the cerium oxide-coated platinum-ruthenium-nickel composite catalytic electrode prepared in Example 6.

[0045] Figure 27 is a SEM image of the cerium oxide-coated platinum-ruthenium-nickel composite catalytic electrode prepared in Example 6 after electrolysis. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions, and advantages of the present disclosure clearer, the technical solutions of the present disclosure will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of the present disclosure.

[0047] The electrolytic water hydrogen evolution composite catalytic electrode of the present disclosure comprises a nickel substrate, a composite catalyst layer loaded on the nickel substrate, and a protective layer coated on the surface of the catalyst layer; the composite catalyst layer comprises a noble metal catalyst, and the protective layer is a nano-porous metal oxide layer, wherein the metal oxide is one or more of valve metal oxides and rare earth metal oxides. Since the composite catalyst layer contains a noble metal main catalyst, a catalytic aid, and a metal oxide, the noble metal main catalyst and the catalytic aid can be combined with the metal substrate to form a stable structure, and the metal oxide, which has a similar structure to the outer oxide protective layer, can enable the oxide protective layer to be stably coated on the surface of the composite catalyst layer. The nano-porous metal oxide layer attached to the outer side of the noble metal catalyst can ensure the catalytic performance of the noble metal catalyst while preventing the noble metal catalyst from directly contacting the electrolyte, preventing impurities from depositing on the surface of the catalyst layer, and preventing the catalyst from falling off due to the protection of the protective layer, thereby improving the structural stability and service life of the catalyst layer.

[0048] The noble metal in the composite catalyst layer can be any catalyst suitable for electrolytic water hydrogen evolution, such as one or more of platinum, ruthenium, and palladium. Preferably, the noble metal catalyst comprises platinum. The composite catalyst layer can also comprise a catalytic aid. When containing a catalytic aid, the amount of noble metal can be reduced while achieving the same catalytic performance. In the composite catalytic electrode, the total loading of the noble metal catalyst and the catalytic aid is 0.01-20 mg / cm 2 , preferably 0.05-1.0 mg / cm 2 , relative to the apparent area of the composite catalytic electrode (the unit of loading in this patent is relative to the apparent area of the electrode).

[0049] The metal oxide in the protective layer can be one or more of titanium oxide, cerium oxide, zirconium oxide, aluminum oxide, yttrium oxide, niobium oxide, tantalum oxide, and lanthanum oxide. In the composite catalytic electrode, the loading of the metal oxide in the protective layer is 0.01-0.2 mg / cm 2 , preferably 0.02-0.05 mg / cm 2 .

[0050] In the composite catalytic electrode, the nickel substrate is preferably a nickel mesh, a nickel alloy mesh, a nickel foam, or a nickel alloy foam, etc.

[0051] The composite catalytic electrode for water electrolysis and hydrogen evolution is prepared by a chemical pyrolysis method. The preparation method can include: adding a stabilizer to a noble metal catalyst precursor compound solution to form a catalyst solution, or adding a catalytic additive precursor compound and a stabilizer to the solution to form a catalyst solution; sintering after coating the catalyst solution on the surface of a nickel substrate to form a composite catalyst layer; providing a metal oxide precursor solution and sintering after coating the metal oxide precursor solution on the surface of the catalyst layer to form a metal oxide protective layer.

[0052] The noble metal catalyst solution can be configured by any appropriate method before forming the catalyst solution. Taking platinum as an example, a platinum precursor compound solution is configured. The platinum precursor can be chloroplatinic acid, potassium chloroplatinate, tetraammine platinum nitrate, platinum acetylacetone, etc. When the noble metal is other noble metal catalyst, the corresponding precursor compound of the corresponding noble metal catalyst can be used. The solvent can be water or a mixed solution of water and an organic solvent. The organic solvent can be selected from alcohol, ether, lipid, etc., such as methanol, ethanol, isopropanol, n-butanol, ethyl acetate, etc. The ratio of water to organic solvent can be adjusted arbitrarily. The concentration of the noble metal catalyst precursor compound solution is 0.01-6.0 mol / L, preferably 0.1-1.0 mol / L. The stabilizer is added to the precursor compound solution to form the catalyst solution. When the catalyst solution also contains a catalytic additive, the catalytic additive and the stabilizer are added to the noble metal catalyst precursor compound solution. The catalytic additive can be a precursor compound of Ni, Au, Ag, Zn, Ti, Ce, Mo, Co, Fe, Cu, La, etc. The molar ratio of the noble metal catalyst to the additive is 1:1-1000:1, preferably 10:1-100:1. The stabilizer can be hydrochloric acid, sulfuric acid, acetic acid, nitric acid, citric acid. The molar ratio of platinum to stabilizer is 1:1-200:1.

[0053] Then, the composite catalyst solution is coated onto the surface of the nickel substrate. The coating method can be any suitable method, such as brushing, spraying, rolling, dipping, or printing, preferably automatic spraying and automatic brushing methods. After that, a drying step can be optionally included. The drying method can be room temperature air drying, 30-200°C oven drying, preferably 50-100°C oven drying. Of course, "optionally" means that it can or can not be included. Subsequently, a sintering process is performed. The sintering process can be sintering at 200-400°C for 10 min-10 h, and finally calcining at 400-600°C for 30 min-12 h. Preferably, sintering at 300-350°C for 10 min-2 h, and finally calcining at 450-550°C for 30 min-2 h. The sintering process is calcining in air, inert atmosphere (such as nitrogen), or reducing atmosphere (such as hydrogen, etc.), preferably calcining in air. Finally, a cooling process can also be included. The cooling method can be air blowing cooling, room temperature cooling, or condensation cooling, preferably air blowing cooling. The above coating, optionally drying, and sintering processes can be repeated, and the above processes can be performed 1-50 times, preferably 2-8 times. The catalyst reaches the desired loading by one or more repetitions of the above coating, optionally drying, and sintering processes.

[0054] After the composite catalyst layer is formed, a protective layer is coated. First, a metal oxide precursor solution is prepared. The metal oxide precursor solution can be a salt solution of titanium, cerium, zirconium, aluminum, yttrium, niobium, tantalum, lanthanum, etc. The concentration is 0.01-2 mol / L, preferably 0.1-0.5 mol / L. Then, the solution is coated onto the surface of the catalyst layer. The coating method can be brushing, spraying, rolling, dipping, or printing, preferably automatic spraying and automatic brushing methods. After coating, a drying step can be optionally performed. The conditions of the drying step are the same as the aforementioned drying step. After that, sintering is performed, and the sintering process is calcining at 200-600°C for 5 min-12 h in air or inert atmosphere (such as nitrogen, etc.), preferably calcining at 300-500°C for 30 min-2 h. After sintering, a nano-porous metal oxide layer is obtained. Finally, a cooling process can also be included. The cooling method is air blowing cooling, room temperature cooling, or condensation cooling, preferably air blowing cooling. The above coating, optionally drying, and sintering processes can be repeated, and the above processes can be performed 1-10 times, preferably 1-4 times. The metal oxide reaches the desired loading by one or more repetitions of the above coating, optionally drying, and sintering processes.

[0055] The electrolytic water hydrogen evolution composite catalytic electrode is prepared by the above steps. The electrode is prepared by a chemical pyrolysis method. The electrolytic water hydrogen evolution composite catalytic electrode is obtained by coating a noble metal-based composite precursor solution on a nickel substrate, optionally drying, calcining pyrolysis and coating a protective layer, and exhibits high electrolytic water hydrogen evolution catalytic activity, high structural stability, long-term stability, strong anti-reverse polarity and strong anti-deposition capacity. The method of the present disclosure is simple to operate compared with the preparation of noble metal electrodes by electroplating and the preparation of hydrogen evolution electrodes by adhering noble metal catalysts to a nickel substrate using a binder, has high utilization rate of noble metals, and exhibits high structural stability, strong anti-reverse polarity, strong anti-deposition capacity, and has important industrial application value.

[0056] In addition to the above steps, other auxiliary steps such as cleaning, drying, roughening treatment of the nickel substrate, etc. can also be included. By roughening the nickel substrate, the adhesion of the catalyst layer and the protective layer to the substrate can be improved. The treatment process can be to select a nickel mesh, a nickel alloy mesh, a nickel foam or a nickel alloy foam as the substrate, and then pretreat the substrate. The pretreatment process includes: using a sandblasting machine to sandblast the nickel substrate, preferably an automatic sandblasting machine; ultrasonic treatment to remove corundum particles on the surface of the substrate; preparing an acidic solution of hydrochloric acid, sulfuric acid, nitric acid or acetic acid to etch the sandblasted nickel substrate and remove the surface high-activity nickel particles; washing with water, drying to obtain a roughened nickel substrate, and then using a roller press to flatten the sandblasted nickel substrate. When the nickel substrate is a nickel mesh or a nickel alloy mesh, a plain or diagonal mesh with a mesh size of 10-500 mesh and a wire diameter of 0.03-4 mm can be used, preferably a plain nickel mesh with a mesh size of 20-80 mesh and a wire diameter of 0.1-0.5 mm. The sandblasting power of the sandblasting machine is 5-50 kW, preferably 10-20 kW; the sandblasting time is 5 min-2 h, preferably 10-40 min. The corundum type is 24, 46, 60, 80, preferably 46 and 60. The sandblasting treatment includes single-sided sandblasting or double-sided sandblasting of the nickel substrate, preferably double-sided sandblasting. The concentration of the acid etching solution is 0.005 mol / L-2.0 mol / L, preferably 0.02 mol / L-0.2 mol / L. The etching time is 10 min-24 h, preferably 1 h-4 h.

[0057] The present disclosure also discloses an electrolytic water hydrogen evolution device, which uses the above electrolytic water hydrogen evolution composite catalytic electrode as the cathode.

[0058] The present disclosure is further described below by specific examples. However, these examples are merely exemplary and do not constitute any limitation on the scope of protection of the present disclosure. In the following examples and comparative examples, the reagents, materials and instruments used are commercially available unless otherwise specified.

[0059] Example 1

[0060] Select 46 mesh plain nickel mesh as the substrate, use automatic sand blasting machine, 60 grit corundum, 15 kW power, sand blast the nickel mesh for 30 min. Ultrasonic treatment for 1 h to remove the surface corundum particles, then prepare 0.2 mol / L hydrochloric acid solution, etch the sand blasted nickel mesh for 1 h to remove the surface high activity Ni particles, water washing, drying to get rough nickel mesh substrate.

[0061] Prepare 0.05 mol / L aqueous solution of chloroplatinic acid, then add nickel chloride as an additive, the molar ratio of platinum to nickel is 5:1, at the same time add hydrochloric acid stabilizer, the molar ratio of platinum to hydrochloric acid is 10:1, mix well to get platinum-nickel precursor solution. Coating the platinum-nickel precursor on the surface of the nickel mesh by automatic spraying, drying in the oven at 100℃, then calcining at 300℃ for 2 h in air atmosphere, repeating the spraying-drying-calcining for 5 times, finally consolidating at 500℃ for 5 h, cooling to room temperature, the platinum-nickel loading is 0.4 mg / cm 2 .

[0062] Prepare cerium nitrate protective layer solution with a concentration of 0.02 mol / L, coat it on the surface of the platinum-nickel catalytic layer by automatic spraying, calcine at 450℃ for 2 h in air atmosphere, repeat the spraying-calcining for 2 times, the cerium oxide protective layer loading is 0.05 mg / cm 2 , to get cerium oxide coated platinum-nickel composite catalytic electrode (area about 100 cm 2 ), the SEM image of Figure 1 shows that the composite catalytic electrode has a smooth surface structure.

[0063] Comparative Example 1

[0064] This comparative example is compared with Example 1, the difference is that there is no platinum-nickel catalyst coated on the surface of the nickel mesh, directly using the sand blasted nickel mesh as the cathode to electrolyze water. Select 46 mesh plain nickel mesh as the substrate, use automatic sand blasting machine, 60 grit corundum, 15 kW power, sand blast the nickel mesh for 30 min. Ultrasonic treatment for 1 h to remove the surface corundum particles, then prepare 0.2 mol / L hydrochloric acid solution, etch the sand blasted nickel mesh for 1 h to remove the surface high activity Ni particles, water washing, drying to get rough nickel mesh composite catalytic electrode (area about 100 cm 2 ).

[0065] Comparative Example 2

[0066] This comparative example is compared with Example 1, the difference is that there is no cerium oxide protective layer coated on the surface of the platinum-nickel composite catalytic electrode, as the cathode to electrolyze water. Select 46 mesh plain nickel mesh as the substrate, use automatic sand blasting machine, 60 grit corundum, 15 kW power, sand blast the nickel mesh for 30 min. Ultrasonic treatment for 1 h to remove the surface corundum particles, then prepare 0.2 mol / L hydrochloric acid solution, etch the sand blasted nickel mesh for 1 h to remove the surface high activity Ni particles, water washing, drying to get rough nickel mesh substrate.

[0067] A 0.05 mol / L aqueous solution of chloroplatinic acid was prepared, then nickel chloride was added, the molar ratio of platinum to nickel was 5:1, and a hydrochloric acid stabilizer was added, the molar ratio of platinum to hydrochloric acid was 10:1, and the mixture was uniformly mixed to obtain a platinum-nickel precursor solution. The platinum-nickel precursor was coated on the surface of the nickel mesh by automatic spraying, and after drying in an oven at 100°C, calcination was carried out in air at 300°C for 2h, and the spraying-drying-calcination process was repeated 5 times, and finally sintering was carried out at 500°C for 5h, and the platinum-nickel composite catalytic electrode (area about 100cm 2 ) was prepared, and the platinum-nickel loading was 0.4mg / cm 2 .

[0068] Performance test

[0069] Test method: A two-chamber electrolytic cell was used, the cathode was the cerium oxide-coated platinum-nickel composite catalytic electrode prepared in Example 1, the sand-blasted nickel mesh composite catalytic electrode prepared in Comparative Example 1, and the platinum-nickel composite catalytic electrode prepared in Comparative Example 2, the anode was a nickel mesh electrode, and the diaphragm was a composite diaphragm. The working area of the anode and the cathode was 10cm 2 , 2 pieces of each composite catalytic electrode were used, a 6-chamber electrolytic cell was used for comparison test, and a peristaltic pump was used to introduce electrolyte into the electrolytic cell during the test. The anode and the cathode were respectively introduced into 30wt% KOH aqueous solution at a flow rate of 150rpm / min, and the test temperature was 80°C. (1) The full water splitting voltage was tested at current densities of 200mA / cm 2 , 400mA / cm 2 , 600mA / cm 2 , 800mA / cm 2 , and 1000mA / cm 2 ; (2) The stability was tested at a high current density of 1000mA / cm 2 for 500h, and the surface deposition was observed by SEM after the test to compare the anti-deposition performance; (3) The anti-reverse polarity performance was tested at a current density of 600mA / cm 2 , electrolysis for 1h, shutdown for 1h, electrolysis for 1h, shutdown for 1h, and repeated for 200 times, and the change of electrolysis voltage was compared.

[0070] Test results: When the cathode was the cerium oxide-coated platinum-nickel composite catalytic electrode (Example 1), the full water splitting voltage was between 1.60V and 1.99V at a current density of 200mA / cm 2 -1000mA / cm 2 , while when the cathode was the nickel mesh composite catalytic electrode (Comparative Example 1), the full water splitting voltage was between 1.94V and 2.41V, and the cerium oxide-coated platinum-nickel composite catalytic electrode could reduce the energy consumption by about 17.5% compared with the nickel mesh electrode (see Figure 2), and the anti-deposition performance was better than that of the platinum-nickel composite catalytic electrode (Comparative Example 2).2 After 500h operation at high current density, the full water splitting voltage of the ceria coated platinum-nickel composite catalytic electrode of the present disclosure can still be maintained at about 2.0V, while the voltage of the platinum-nickel composite catalytic electrode of Comparative Example 2 increases to 2.18V, and the voltage of the nickel mesh electrode of Comparative Example 1 increases to 2.83V (see Figure 3). It can be seen from the comparison that the ceria coated platinum-nickel composite catalytic electrode of the present disclosure exhibits higher water splitting catalytic activity and long-term stability than the nickel mesh electrode, thereby improving the service life of the composite catalytic electrode and reducing the energy consumption. After 500h electrolysis at high current density, a large number of particles are deposited on the surface of the nickel mesh electrode of Comparative Example 1 (see Figure 4), some large particles are deposited on the surface of the platinum-nickel composite catalytic electrode of Comparative Example 2 (see Figure 5), and only a small amount of particles are deposited on the surface of the ceria coated platinum-nickel electrode of Example 1 (see Figure 6), indicating that the composite catalytic electrode has strong anti-deposition capacity. After 200 times of repeated electrolysis-shutdown tests, the electrolysis voltage maintenance rate of the electrode of Example 1 is 95.5%, while the electrolysis voltage maintenance rate of the electrode of Comparative Example 1 is 78.3%, and the electrolysis voltage maintenance rate of the electrode of Comparative Example 2 is 86.8%, indicating that the composite catalytic electrode has strong anti-reverse polarity capacity.

[0071] Example 2

[0072] A 46-mesh plain nickel mesh was selected as the substrate, and the nickel mesh was sandblasted for 45 min using an automatic sandblasting machine with 46 grit corundum and a power of 15 kW. The surface of the sandblasted nickel mesh was treated with ultrasonic waves for 1 h to remove the corundum particles, and then a 0.2 mol / L hydrochloric acid solution was prepared to etch the surface of the sandblasted nickel mesh for 1 h to remove the high-activity Ni particles. After water washing and drying, a rough nickel mesh substrate was obtained.

[0073] A 0.1 mol / L chloroplatinic acid water / ethanol solution was prepared, then cerium nitrate was added as an additive, the molar ratio of platinum to cerium was 5:2, and nitric acid was added as a stabilizer, the molar ratio of platinum to nitric acid was 10:1, and the mixture was uniformly mixed to obtain a platinum-cerium precursor solution. The platinum-cerium precursor was coated on the surface of the nickel mesh by brushing, and then dried in an oven at 100°C. After calcination at 300°C for 2 h under a nitrogen atmosphere, the brushing-drying-calcination process was repeated three times, and finally solidified at 500°C for 5 h. After cooling to room temperature, the platinum-cerium loading was 0.5 mg / cm 2 .

[0074] A cerium nitrate protective layer solution with a concentration of 0.02 mol / L was prepared, and then coated on the surface of the platinum-cerium catalytic layer by brushing. After calcination at 450°C for 2 h in an air atmosphere, the brushing-calcination process was repeated twice. The cerium oxide protective layer had a loading of 0.05 mg / cm 2 , and a ceria coated platinum-cerium composite catalytic electrode (with an area of about 100 cm 2 ) was prepared. As can be seen from the SEM image of Figure 7, the composite catalytic electrode has a smooth surface structure.

[0075] Performance test

[0076] Test method: Two-chamber electrolyzer was used, the cathode was ceria-coated platinum-ceria composite catalytic electrode prepared in Example 2, the anode was nickel mesh electrode, the separator was composite separator, the electrode working area of the anode and the cathode was 10 cm 2 , the electrolysis voltage was the average value of the cell voltage, and a peristaltic pump was used to introduce electrolyte into the electrolyzer during the test. The anode and the cathode were respectively introduced into 30wt% KOH aqueous solution at a flow rate of 150 rpm / min, and the test temperature was 80℃. (1) The overall water splitting voltage was tested at current densities of 200 mA / cm 2 , 400 mA / cm 2 , 600 mA / cm 2 , 800 mA / cm 2 , and 1000 mA / cm 2 ; (2) The stability was tested at a high current density of 1000 mA / cm 2 for 500h, and the surface deposition was observed by SEM to compare the anti-deposition performance; (3) The anti-reverse performance was tested at a current density of 600 mA / cm 2 , electrolysis for 1h, shutdown for 1h, electrolysis for 1h, shutdown for 1h, and repeated for 200 times, and the change of electrolysis voltage was compared.

[0077] Test results: When the cathode was ceria-coated platinum-ceria composite catalytic electrode (Example 2), the overall water splitting voltage was between 1.65V and 2.04V (see Figure 8) at current densities of 200 mA / cm 2 -1000 mA / cm 2 , and the overall water splitting voltage could still be maintained at about 2.05V (see Figure 9) after running at a high current density of 1000 mA / cm 2 for 500h. It can be seen that the ceria-coated platinum-ceria composite catalytic electrode of the present disclosure exhibits high water electrolysis catalytic activity and long-term stability, improves the service life of the composite catalytic electrode and reduces the energy consumption. After electrolysis at a high current density for 500h, only a small amount of particles were deposited on the surface of the ceria-coated platinum-ceria electrode of Example 2 (SEM image is shown in Figure 10), indicating that the composite catalytic electrode has strong anti-deposition ability. After 200 times of electrolysis-shutdown repeated test, the electrolysis voltage maintenance rate of the composite catalytic electrode of Example 2 was 95.8%, indicating that the composite catalytic electrode has strong anti-reverse ability.

[0078] Example 3

[0079] A 46-mesh plain nickel mesh was selected as the substrate, and the nickel mesh was sandblasted for 45 min using an automatic sandblasting machine with a 46-mesh corundum and a 15-kW power. The surface corundum particles were removed by ultrasonic treatment for 1 h, and then the sandblasted nickel mesh was etched in a 0.2-mol / L hydrochloric acid solution for 1 h to remove the surface high-activity Ni particles. After water washing and drying, a rough nickel mesh substrate was obtained.

[0080] A 0.1-mol / L chloroplatinic acid ethanol solution was prepared, and then ruthenium chloride was added, with a molar ratio of platinum to ruthenium of 10:1. A hydrochloric acid stabilizer was also added, with a molar ratio of platinum to hydrochloric acid of 10:1. After mixing, a platinum-ruthenium precursor solution was obtained. The platinum-ruthenium precursor was coated onto the surface of the nickel mesh by automatic spraying, and then dried in an oven at 100°C. After calcination at 300°C for 2 h in an air atmosphere, the spraying-drying-calcination process was repeated three times. Finally, the platinum-ruthenium was consolidated at 500°C for 5 h, and then cooled to room temperature. The platinum-ruthenium loading was 0.55 mg / cm 2 .

[0081] A 0.02-mol / L tetrabutyl titanate protective layer solution was prepared, and then coated onto the surface of the platinum-ruthenium catalytic layer by automatic spraying. The titanium oxide protective layer was calcined at 450°C for 2 h in an air atmosphere, and the spraying-calcination process was repeated twice. The titanium oxide protective layer loading was 0.04 mg / cm 2 , and a titanium oxide-coated platinum-ruthenium composite catalytic electrode (with an area of about 100 cm 2 ) was prepared. As shown in the SEM image of FIG. 11, the prepared composite catalytic electrode had a smooth surface structure.

[0082] Performance test

[0083] Test method: A two-chamber electrolytic cell was used, the cathode was the titanium oxide-coated platinum-ruthenium composite catalytic electrode prepared in Example 3, the anode was a nickel mesh electrode, and the separator was a composite separator. The electrode working area of the anode and the cathode was 10 cm 2 . An electrolytic voltage was taken as the average value of the cell voltage, and a peristaltic pump was used to introduce an electrolyte into the electrolytic cell during the test. The anode and the cathode were respectively introduced into a 30wt% KOH aqueous solution at a flow rate of 150 rpm / min, and the test temperature was 80°C. (1) The overall water splitting voltage was tested at a current density of 200 mA / cm 2 , 400 mA / cm 2 , 600 mA / cm 2 , 800 mA / cm 2 , and 1000 mA / cm 2 ; (2) The stability was tested at a high current density of 1000 mA / cm 2 for 500 h, and the surface deposition was observed by SEM to compare the anti-deposition performance; and (3) The stability was tested at a current density of 600 mA / cm 2 .The anti-reverse performance of the current density, electrolysis 1 h, 1 h off, electrolysis 1 h, 1 h off, repeat 200 times, the change of the electrolysis voltage is compared.

[0084] Test results: when the cathode is a titanium oxide coated platinum ruthenium composite catalytic electrode (Example 3), the current density is 200 mA / cm 2 -1000 mA / cm 2 , the overall water splitting voltage is between 1.58 V-1.95 V (Figure 12), and after running at a high current density of 1000 mA / cm 2 for 500 h, the overall water splitting voltage can still be maintained at about 1.95 V (see Figure 13). It can be seen that the titanium oxide coated platinum ruthenium composite catalytic electrode of the present disclosure exhibits high water electrolysis catalytic activity and long-term stability, improves the service life of the composite catalytic electrode and reduces energy consumption. After electrolysis at a high current density for 500 h, only a small amount of particles are deposited on the surface of the titanium oxide coated platinum ruthenium electrode of Example 3 (SEM image see Figure 14), indicating that the composite catalytic electrode has strong anti-deposition ability. After 200 times of electrolysis-off repeated tests, the electrolysis voltage maintenance rate of the composite catalytic electrode of Example 3 is 95.3%, indicating that the composite catalytic electrode has strong anti-reverse ability.

[0085] Example 4

[0086] A 46-mesh plain nickel mesh is selected as the substrate, and an automatic sandblasting machine is used to sandblast the nickel mesh for 45 min with a 46-mesh corundum and a 15 kW power. The surface corundum particles are removed by ultrasonic treatment for 1 h, then a 0.2 mol / L hydrochloric acid solution is prepared to etch the sandblasted nickel mesh for 1 h to remove the surface high-activity Ni particles, and then washed with water and dried to obtain a rough nickel mesh substrate.

[0087] A 0.05 mol / L potassium chloroplatinate water / isopropyl alcohol solution is prepared, then a ferric chloride additive is added, the molar ratio of platinum to iron is 5:1, a hydrochloric acid stabilizer is added at the same time, the molar ratio of platinum to hydrochloric acid is 10:1, and the mixture is uniformly mixed to obtain a platinum-iron precursor solution. The platinum-iron precursor is coated on the surface of the nickel mesh by rolling, dried in an oven at 100°C, and then calcined at 300°C in air for 2 h. The rolling-drying-calcining process is repeated twice, and finally solidified at 500°C for 5 h, and cooled to room temperature. The platinum-iron loading is 0.1 mg / cm 2 .

[0088] A 0.02 mol / L zirconium nitrate protective layer solution is prepared, then coated on the surface of the platinum-iron catalytic layer by rolling, and calcined at 500°C in air for 2 h. The rolling-calcining process is repeated once, and the zirconium oxide protective layer loading is 0.02 mg / cm 2 , to obtain a zirconium oxide coated platinum-iron composite catalytic electrode (area about 100 cm 2The SEM image of Figure 15 shows that the prepared composite catalytic electrode has a smooth surface structure.

[0089] Performance test

[0090] Test method: A two-chamber electrolytic cell was used, the cathode was the zirconia-coated platinum-iron composite catalytic electrode prepared in Example 4, the anode was a nickel mesh electrode, and the separator was a composite separator. The working area of the anode and the cathode was 10 cm 2 . A six-chamber electrolytic cell was used for the test, the electrolysis voltage was the average value of the chamber voltage, and a peristaltic pump was used to introduce the electrolyte into the electrolytic cell during the test. The anode and the cathode were respectively introduced into 30 wt% KOH aqueous solution at a flow rate of 150 rpm / min, and the test temperature was 80°C. (1) The total water splitting voltage at current densities of 200 mA / cm 2 , 400 mA / cm 2 , 600 mA / cm 2 , 800 mA / cm 2 , and 1000 mA / cm 2 ; (2) The stability test at a high current density of 1000 mA / cm 2 for 500 h, the surface deposition after the test was observed by SEM, and the anti-deposition performance was compared; (3) The anti-reverse performance test at a current density of 600 mA / cm 2 , electrolysis for 1 h, shutdown for 1 h, electrolysis for 1 h, shutdown for 1 h, and repeated for 200 times, and the change of the electrolysis voltage was compared.

[0091] Test results: When the cathode was the zirconia-coated platinum-iron composite catalytic electrode (Example 4), the total water splitting voltage was between 1.75 V and 2.16 V (Figure 16) at current densities of 200 mA / cm 2 -1000 mA / cm 2 , and the total water splitting voltage could still be maintained at about 2.18 V after running at a high current density of 1000 mA / cm 2 for 500 h (see Figure 17). It can be seen that the zirconia-coated platinum-iron composite catalytic electrode of the present disclosure exhibits high water electrolysis catalytic activity and long-term stability, improves the service life of the composite catalytic electrode and reduces the energy consumption. After electrolysis at a high current density for 500 h, only a small amount of particles were deposited on the surface of the zirconia-coated platinum-iron electrode of Example 4 (SEM image shown in Figure 18), indicating that the composite catalytic electrode has strong anti-deposition ability. After the electrolysis-shutdown repeated test for 200 times, the electrolysis voltage maintenance rate of Example 4 was 95.2%, indicating that the composite catalytic electrode has strong anti-reverse ability.

[0092] Example 5

[0093] A 46-mesh plain nickel mesh was selected as the substrate, and the nickel mesh was sandblasted for 45 min using an automatic sandblasting machine with a 46-mesh corundum and a 20-kW power. The surface corundum particles were removed by ultrasonic treatment for 1 h, and then the sandblasted nickel mesh was etched in a 0.2-mol / L hydrochloric acid solution for 1 h to remove the surface high-activity Ni particles. After water washing and drying, a rough nickel mesh substrate was obtained.

[0094] A 0.05-mol / L chloroplatinic acid aqueous solution was prepared, and then ruthenium chloride and cerium nitrate promoters were added, with a molar ratio of platinum:ruthenium:cerium of 10:1:1. A hydrochloric acid stabilizer was also added, with a molar ratio of platinum:hydrochloric acid of 5:1. After mixing, a platinum-ruthenium-cerium precursor solution was obtained. The platinum-ruthenium-cerium precursor was coated onto the surface of the nickel mesh by automatic brushing, and then dried in an oven at 80°C. After calcination at 300°C for 2 h in an air atmosphere, the brushing-drying-calcination process was repeated once. Finally, the platinum-ruthenium-cerium was consolidated at 500°C for 5 h, and then cooled to room temperature. The platinum-ruthenium-cerium loading was 0.04 mg / cm 2 .

[0095] A 0.02-mol / L aluminum chloride protective layer solution was prepared, and then coated onto the surface of the platinum-ruthenium-cerium catalytic layer by automatic brushing. The aluminum oxide protective layer was calcined at 450°C for 2 h in an air atmosphere, and the aluminum oxide protective layer loading was 0.01 mg / cm 2 . An aluminum oxide-coated platinum-ruthenium-cerium composite catalytic electrode (with an area of about 100 cm 2 ) was prepared. As can be seen from the SEM image in FIG. 19, the prepared composite catalytic electrode has a smooth surface structure.

[0096] Performance test

[0097] Test method: A two-chamber electrolytic cell was used, the cathode was the aluminum oxide-coated platinum-ruthenium-cerium composite catalytic electrode prepared in Example 5, the anode was a nickel mesh electrode, and the separator was a composite separator. The electrode working area of the anode and the cathode was 10 cm 2 . An electrolytic voltage was taken as the average value of the cell voltage. During the test process, a peristaltic pump was used to introduce an electrolyte into the electrolytic cell. The anode and the cathode were respectively introduced into a 30wt% KOH aqueous solution at a flow rate of 150 rpm / min. The test temperature was 80°C. (1) The overall water splitting voltage was tested at a current density of 200 mA / cm 2 , 400 mA / cm 2 , 600 mA / cm 2 , 800 mA / cm 2 , and 1000 mA / cm 2 ; (2) The stability was tested at a high current density of 1000 mA / cm 2 for 500 h. The surface deposition after the test was observed by SEM, and the anti-deposition performance was compared; (3) The stability was tested at a current density of 600 mA / cm 2The anti-reverse performance of the current density, electrolysis for 1 h, stop for 1 h, electrolysis for 1 h, stop for 1 h, repeat 200 times, and the change of the electrolysis voltage of the comparative example.

[0098] Test results: when the cathode is the aluminum oxide coated platinum ruthenium cerium composite catalytic electrode (Example 5), the current density is 200 mA / cm 2 - 1000 mA / cm 2 , the overall water splitting voltage is between 1.71 V and 2.10 V (Figure 20), and the overall water splitting voltage can still be maintained at about 2.11 V after running for 500 h at a high current density of 1000 mA / cm 2 . It can be seen that the aluminum oxide coated platinum ruthenium cerium composite catalytic electrode of the present disclosure exhibits high water electrolysis catalytic activity and long-term stability, improves the service life of the composite catalytic electrode and reduces energy consumption. After electrolysis for 500 h at a high current density, only a small amount of particles is deposited on the surface of the aluminum oxide coated platinum ruthenium cerium electrode of Example 5 (SEM image shown in Figure 22), indicating that the composite catalytic electrode has strong anti-deposition ability. After 200 times of electrolysis-stop-repetition test, the electrolysis voltage maintenance rate of Example 5 is 95.6%, indicating that the composite catalytic electrode has strong anti-reverse ability.

[0099] Example 6

[0100] A 46-mesh plain nickel mesh is selected as the substrate, and the nickel mesh is sandblasted for 45 min using an automatic sandblasting machine with 46-mesh corundum and a power of 20 kW. The surface of the sandblasted nickel mesh is treated by ultrasonic treatment for 1 h to remove the corundum particles, and then a 0.2 mol / L hydrochloric acid solution is prepared to etch the sandblasted nickel mesh for 1 h to remove the high-activity Ni particles on the surface. After water washing and drying, a rough nickel mesh substrate is obtained.

[0101] A 0.05 mol / L chloroplatinic acid water / ethanol solution is prepared, and then ruthenium chloride and nickel chloride additives are added, with a molar ratio of platinum:ruthenium:nickel of 10:1:1. A hydrochloric acid stabilizer is also added, with a molar ratio of platinum:hydrochloric acid of 5:1. The mixture is uniformly mixed to obtain a platinum ruthenium nickel precursor solution. The platinum ruthenium nickel precursor is coated on the surface of the nickel mesh by automatic spraying, and then dried in an oven at 80°C. After calcination at 300°C for 2 h in an air atmosphere, the process of spraying-drying-calcination is repeated 4 times. Finally, the platinum ruthenium nickel is consolidated at 500°C for 3 h, and then cooled to room temperature. The platinum ruthenium nickel loading is 0.15 mg / cm 2 .

[0102] A 0.02 mol / L cerium nitrate protective layer solution is prepared, and then coated on the surface of the platinum ruthenium nickel catalytic layer by automatic spraying. The cerium oxide protective layer is calcined at 500°C for 2 h in an air atmosphere, and the process is repeated twice. The cerium oxide protective layer loading is 0.02 mg / cm 2 , and a cerium oxide coated platinum ruthenium nickel composite catalytic electrode (area about 3600 cm 2The electrode photo of Figure 23 shows that the method of the present disclosure can produce a large-area composite catalytic electrode, and the SEM photo of Figure 24 shows that the composite catalytic electrode produced has a smooth surface structure.

[0103] Performance test

[0104] Test method: A two-chamber electrolytic cell was used, the cathode was the cerium oxide-coated platinum-ruthenium-nickel composite catalytic electrode prepared in Example 6, the anode was a nickel mesh electrode, the separator was a composite separator, and the electrode working area of the anode and the cathode was 10 cm 2 . A six-chamber electrolytic cell was used for testing, the electrolysis voltage was the average value of the chamber voltage, and a peristaltic pump was used to introduce electrolyte into the electrolytic cell during the test. The anode and the cathode were respectively introduced into 30wt% KOH aqueous solution at a flow rate of 150 rpm / min, and the test temperature was 80°C. (1) The overall water splitting voltage at current densities of 200 mA / cm 2 , 400 mA / cm 2 , 600 mA / cm 2 , 800 mA / cm 2 , and 1000 mA / cm 2 ; (2) The stability at a high current density of 1000 mA / cm 2 for 500 h was tested, and the surface deposition after the test was observed using SEM to compare the anti-deposition performance; (3) The anti-reverse performance at a current density of 600 mA / cm 2 was tested, the electrolysis was stopped for 1 h, then the electrolysis was restarted for 1 h, and the process was repeated 200 times to compare the change in electrolysis voltage.

[0105] Test results: When the cathode was the cerium oxide-coated platinum-ruthenium-nickel composite catalytic electrode (Example 6), the overall water splitting voltage was between 1.64 V and 2.05 V (Figure 25) at current densities of 200 mA / cm 2 - 1000 mA / cm 2 , and the overall water splitting voltage could still be maintained at about 2.06 V (Figure 26) after running at a high current density of 1000 mA / cm 2 for 500 h. It can be seen that the cerium oxide-coated platinum-ruthenium-nickel composite catalytic electrode of the present disclosure exhibits high water electrolysis catalytic activity and long-term stability, improves the service life of the composite catalytic electrode, and reduces energy consumption. After electrolysis at a high current density for 500 h, only a small amount of particles was deposited on the surface of the cerium oxide-coated platinum-ruthenium-nickel electrode of Example 6 (SEM photo shown in Figure 27), indicating that the composite catalytic electrode has strong anti-deposition ability. After the electrolysis-stop-restart test was repeated 200 times, the electrolysis voltage maintenance rate of Example 6 was 95.9%, indicating that the composite catalytic electrode has strong anti-reverse ability.

[0106] Example 7

[0107] Select 46 mesh plain nickel mesh as substrate, use automatic sand blasting machine, 46# corundum, 15kW power, sand blast the nickel mesh for 45min. Ultrasonic treatment for 1h to remove the surface corundum particles, then prepare 0.2mol / L hydrochloric acid solution, etch the sand blasted nickel mesh for 1h to remove the surface high activity Ni particles, wash with water, dry to obtain the rough nickel mesh substrate.

[0108] Prepare 0.1mol / L chloroplatinic acid water / ethanol solution. Coating the platinum precursor on the surface of the nickel mesh by brushing, dry in the oven at 100℃, then calcine at 300℃ for 2h under nitrogen atmosphere, repeat brushing-drying-calcining for 3 times, finally consolidate at 500℃ for 5h, cool to room temperature, the platinum loading is 0.6mg / cm 2 .

[0109] Prepare cerium nitrate protective layer solution with concentration of 0.02mol / L, then coat on the surface of the platinum catalytic layer by brushing, calcine at 450℃ for 2h under air atmosphere, repeat brushing-calcining for 2 times, the cerium oxide protective layer loading is 0.05mg / cm 2 , to obtain the cerium oxide coated platinum composite catalytic electrode (area about 100cm 2 ).

[0110] Performance test

[0111] Test method: use two-chamber electrolytic cell, the cathode is the cerium oxide coated platinum composite catalytic electrode prepared in Example 7, the anode is nickel mesh electrode, the diaphragm is composite diaphragm, the electrode working area of the anode and cathode is 10cm 2 , use 6-chamber electrolytic cell for testing, the electrolysis voltage is the average value of the chamber voltage, use peristaltic pump to pass the electrolyte into the electrolytic cell during the testing process. Pass 30wt% KOH aqueous solution into the anode and cathode at a flow rate of 150rpm / min, the testing temperature is 80℃. (1) test the overall water splitting voltage at current density of 200mA / cm 2 , 400mA / cm 2 , 600mA / cm 2 , 800mA / cm 2 , 1000mA / cm 2 ; (2) test the stability at high current density of 1000mA / cm 2 for 500h, use SEM to observe the surface deposition after testing, compare the anti-deposition performance; (3) test the anti-reverse performance at current density of 600mA / cm 2 , electrolyze for 1h, stop for 1h, electrolyze for 1h, stop for 1h, repeat for 200 times, compare the change of electrolysis voltage.

[0112] Test results: when the cathode is the cerium oxide coated platinum composite catalytic electrode (Example 7), the current density is 200 mA / cm 2 - 1000 mA / cm 2 , the overall water splitting voltage is between 1.63 V and 2.10 V, and after 500 h of operation at a high current density of 1000 mA / cm 2 , the overall water splitting voltage can still be maintained at about 2.15 V. It can be seen that the cerium oxide coated platinum composite catalytic electrode of the present disclosure exhibits high water electrolysis catalytic activity and long-term stability, thereby improving the service life of the composite catalytic electrode and reducing energy consumption. After 500 h of electrolysis at a high current density, only a small amount of particles is deposited on the surface of the cerium oxide coated platinum electrode of Example 7, indicating that the composite catalytic electrode has strong anti-deposition capacity. After 200 times of electrolysis-shutdown repeated tests, the electrolysis voltage maintenance rate of the composite catalytic electrode of Example 7 is 94.3%, indicating that the composite catalytic electrode has strong anti-reverse polarity capacity.

[0113] Example 8

[0114] A 46-mesh plain nickel mesh is selected as the substrate, and the nickel mesh is sandblasted for 45 min using an automatic sandblasting machine with a 46-mesh corundum and a 15 kW power. The surface corundum particles are removed by ultrasonic treatment for 1 h, and then a 0.2 mol / L hydrochloric acid solution is prepared to etch the sandblasted nickel mesh for 1 h to remove the surface high-activity Ni particles. After water washing and drying, a rough nickel mesh substrate is obtained.

[0115] A 0.1 mol / L ruthenium chloride ethanol / isopropanol solution is prepared, and then a nickel chloride additive is added, with a molar ratio of ruthenium to nickel of 10:1. A hydrochloric acid stabilizer is also added, with a molar ratio of ruthenium to hydrochloric acid of 10:1. The mixture is uniformly mixed to obtain a ruthenium-nickel precursor solution. The ruthenium-nickel precursor is coated onto the surface of the nickel mesh by automatic spraying, and then dried in an oven at 100°C. After calcination at 300°C for 2 h in an air atmosphere, the spraying-drying-calcination process is repeated three times. Finally, the ruthenium-nickel is consolidated at 500°C for 5 h, and then cooled to room temperature. The ruthenium-nickel loading is 0.52 mg / cm 2 .

[0116] A 0.02 mol / L butyl titanate protective layer solution is prepared, and then coated onto the surface of the ruthenium-nickel catalytic layer by automatic spraying. The titanium oxide protective layer is calcined at 450°C for 2 h in an air atmosphere, and the spraying-calcination process is repeated twice. The titanium oxide protective layer loading is 0.04 mg / cm 2 , and a titanium oxide coated ruthenium-nickel composite catalytic electrode (with an area of about 100 cm 2 ) is prepared.

[0117] Performance test

[0118] Test method: A two-chamber electrolytic cell was used, the cathode was the titanium oxide coated ruthenium-nickel composite catalytic electrode prepared in Example 8, the anode was a nickel mesh electrode, the separator was a composite separator, and the electrode working area of the anode and the cathode was 10 cm 2 . The electrolysis voltage was the average value of the cell voltage. During the test, a peristaltic pump was used to introduce the electrolyte into the electrolytic cell. The anode and the cathode were respectively introduced into 30 wt% KOH aqueous solution at a flow rate of 150 rpm / min, and the test temperature was 80°C. (1) The overall water splitting voltage at current densities of 200 mA / cm 2 , 400 mA / cm 2 , 600 mA / cm 2 , 800 mA / cm 2 , and 1000 mA / cm 2 ; (2) The stability at a high current density of 1000 mA / cm 2 for 500 h was tested, and the surface deposition after the test was observed using SEM to compare the anti-deposition performance; (3) The anti-reversal performance at a current density of 600 mA / cm 2 was tested, the electrolysis was stopped for 1 h, and then the electrolysis was repeated for 200 times, and the change in the electrolysis voltage was compared.

[0119] Test results: When the cathode was the titanium oxide coated ruthenium-nickel composite catalytic electrode (Example 8), the overall water splitting voltage was between 1.60 V and 1.97 V at current densities of 200 mA / cm 2 -1000 mA / cm 2 , and the overall water splitting voltage could still be maintained at about 2.03 V after running at a high current density of 1000 mA / cm 2 for 500 h. It can be seen that the titanium oxide coated ruthenium-nickel composite catalytic electrode of the present disclosure has high water electrolysis catalytic activity and long-term stability, which improves the service life of the composite catalytic electrode and reduces the energy consumption. After electrolysis at a high current density for 500 h, only a small amount of particles was deposited on the surface of the titanium oxide coated ruthenium-nickel electrode of Example 8, indicating that the composite catalytic electrode has strong anti-deposition ability. After the electrolysis-stop test was repeated for 200 times, the electrolysis voltage maintenance rate of the composite catalytic electrode of Example 8 was 75.3%, indicating that the anti-reversal ability of the ruthenium-based composite catalytic electrode is weaker than that of the platinum-based composite catalytic electrode.

[0120] Example 9

[0121] A 46-mesh plain nickel mesh was selected as the substrate, and the nickel mesh was sandblasted using an automatic sandblasting machine, 46-garnet, 15 kW power, for 45 min. The surface garnet particles were removed by ultrasonic treatment for 1 h, then a 0.2 mol / L hydrochloric acid solution was prepared, and the sandblasted nickel mesh was etched for 1 h to remove the surface high-activity Ni particles, washed with water, and dried to obtain a rough nickel mesh substrate.

[0122] A 0.1 mol / L palladium chloride ethanol / isopropanol solution was prepared, then a nickel chloride promoter was added, the molar ratio of palladium to nickel being 10:1, and a hydrochloric acid stabilizer was added, the molar ratio of palladium to hydrochloric acid being 10:1, and the mixture was uniformly mixed to obtain a palladium-nickel precursor solution. The palladium-nickel precursor was coated onto the surface of the nickel mesh by automatic spraying, and after drying in an oven at 100°C, calcination was carried out in air at 300°C for 2 h. The spraying-drying-calcination process was repeated 3 times, and finally sintering was carried out at 500°C for 5 h, and the electrode was cooled to room temperature. The palladium-nickel loading was 0.54 mg / cm 2 .

[0123] A 0.02 mol / L butyl titanate protective layer solution was prepared, and then coated onto the surface of the palladium-nickel catalytic layer by automatic spraying, and calcination was carried out in air at 450°C for 2 h. The spraying-calcination process was repeated 2 times, and the titanium oxide protective layer loading was 0.04 mg / cm 2 , to obtain a titanium oxide-coated palladium-nickel composite catalytic electrode (area about 100 cm 2 ).

[0124] Performance test

[0125] Test method: A two-chamber electrolytic cell was used, the cathode was the titanium oxide-coated palladium-nickel composite catalytic electrode prepared in Example 9, the anode was a nickel mesh electrode, and the separator was a composite separator. The electrode working area of the anode and the cathode was 10 cm 2 . A six-chamber electrolytic cell was used for testing, the electrolysis voltage was the average value of the chamber voltage, and a peristaltic pump was used to introduce the electrolyte into the electrolytic cell during the test. The anode and the cathode were respectively introduced into 30 wt% KOH aqueous solution at a flow rate of 150 rpm / min, and the test temperature was 80°C. (1) The overall water splitting voltage was tested at a current density of 200 mA / cm 2 , 400 mA / cm 2 , 600 mA / cm 2 , 800 mA / cm 2 , and 1000 mA / cm 2 ; (2) The stability was tested at a high current density of 1000 mA / cm 2 for 500 h, and the surface deposition was observed by SEM to compare the anti-deposition performance; (3) The anti-reverse performance was tested at a current density of 600 mA / cm 2 , electrolysis was carried out for 1 h, stopped for 1 h, then electrolysis was carried out again for 1 h, stopped for 1 h, and the process was repeated 200 times, and the change in electrolysis voltage was compared.

[0126] Test results: When the cathode was the titanium oxide-coated palladium-nickel composite catalytic electrode (Example 9), the current density was 200 mA / cm 2 -1000 mA / cm 2The full water electrolysis voltage is between 1.76 V and 2.15 V, and can be maintained at about 2.26 V after 500 h of operation at a high current density of 1000 mA / cm 2 It can be seen that the titanium oxide-coated palladium-nickel composite catalytic electrode of the present disclosure exhibits high water electrolysis catalytic activity and long-term stability, improves the service life of the composite catalytic electrode and reduces energy consumption. After 500 h of electrolysis at a high current density, only a small amount of particles is deposited on the surface of the titanium oxide-coated palladium-nickel electrode of Example 9, indicating that the composite catalytic electrode has strong anti-deposition capacity. After 200 times of electrolysis-shutdown repeated tests, the electrolysis voltage maintenance rate of the composite catalytic electrode of Example 9 is 81.5%, indicating that the palladium-based composite catalytic electrode has weaker anti-reverse polarity capacity than the platinum-based composite catalytic electrode.

[0127] The preferred embodiments of the present disclosure disclosed above are only used to help explain the present disclosure. The preferred embodiments do not describe all the details and limit the present disclosure to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of the present disclosure. The present disclosure selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present disclosure, so that those skilled in the art can well understand and utilize the present disclosure. The present disclosure is limited only by the claims and their full scope and equivalents.

Claims

1. An electrolytic water hydrogen evolution composite catalytic electrode, characterized by, The composite catalyst layer includes a nickel matrix, a composite catalyst layer loaded on the nickel matrix, and a protective layer coated on the surface of the composite catalyst layer. The composite catalyst layer includes a noble metal catalyst, and the protective layer is a nano-porous metal oxide layer, and the metal oxide is one or more of valve metal oxides and rare earth metal oxides.

2. The water electrolysis hydrogen evolution composite catalytic electrode according to claim 1, characterized in that, The noble metal is one or more of platinum, ruthenium, and palladium; preferably, the composite catalyst layer further includes a catalytic aid; and / or The metal oxide is one or more of titanium oxide, cerium oxide, zirconium oxide, aluminum oxide, yttrium oxide, niobium oxide, tantalum oxide, and lanthanum oxide. 3.The water electrolysis hydrogen evolution composite catalytic electrode according to claim 2, characterized in that, The total loading of the noble metal catalyst and the catalytic adjuvant is 0.01-20 mg / cm 2 , preferably 0.05-1.0 mg / cm 2 , the molar ratio of the noble metal catalyst to the catalytic adjuvant is 1:1-1000:1; the loading of the metal oxide is 0.01-0.2 mg / cm 2 , preferably 0.02-0.05 mg / cm 2 . 4.The water electrolysis hydrogen evolution composite catalytic electrode according to claim 1, characterized in that, The catalytic aid is a metal element, an alloy, or an oxide selected from one or more of Ni, Au, Ag, Zn, Ti, Ce, Mo, Co, Fe, Cu, and La.

5. The water electrolysis hydrogen evolution composite catalytic electrode according to claim 1, characterized in that, The nickel matrix is a nickel mesh, a nickel alloy mesh, a nickel foam, or a nickel alloy foam.

6. A method for preparing a composite catalytic electrode for hydrogen evolution through water electrolysis, characterized in that, The method comprises: adding a stabilizer to a noble metal catalyst precursor compound solution to form a catalyst solution, or adding a catalytic aid precursor compound and the stabilizer to the noble metal catalyst precursor compound solution to form a catalyst solution; sintering the catalyst solution coated on the surface of the nickel matrix to form a composite catalyst layer; providing a metal oxide precursor solution and sintering the solution coated on the surface of the composite catalyst layer to form the protective layer.

7. The preparation method according to claim 6, characterized in that, The stabilizer is one or more of hydrochloric acid, sulfuric acid, acetic acid, nitric acid, and citric acid.

8. The preparation method according to claim 6, characterized in that, The sintering step for forming the composite catalyst layer includes sintering at 200-400°C for 10 min-10 h and then calcining at 400-600°C for 30 min-12 h in air, an inert atmosphere, or a reducing atmosphere; preferably, sintering at 300-350°C for 10 min-2 h and then calcining at 450-550°C for 30 min-2 h; and / or The sintering step for forming the protective layer includes calcining at 200-600°C for 5 min-12 h in air or an inert atmosphere; preferably, calcining at 300-500°C for 30 min-2 h.

9. The preparation method according to claim 6, characterized in that, The nickel matrix is subjected to roughening treatment.

10. An apparatus for hydrogen evolution from water electrolysis, characterized by The electrolytic water hydrogen evolution composite catalytic electrode of any one of claims 1-5 is used as a cathode.

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