Electrolysis water catalyst, and preparation method and application thereof

Abstract

The application belongs to the technical field of electrolytic water catalyst preparation, and particularly relates to an electrolytic water catalyst, a preparation method and application thereof, and a preparation method of the electrolytic water catalyst, which comprises the following steps: adding Ru salt into an alcohol solution to dissolve, then adding CeO2 nanospheres into the solution, uniformly dispersing to obtain a dispersion liquid; adding alkali into the dispersion liquid in batches, stirring, and reacting for 1-5 hours; after the reaction is completed, the obtained catalyst precursor is separated, calcined in an oxidizing atmosphere, and then a RuO2 / CeO2 catalyst is obtained. The RuO2 / CeO2 catalyst prepared by the application can etch away CeO2 under the test conditions of electrolytic water, form a porous structure, greatly improve the specific surface area of active sites, and thus can improve the utilization rate of noble metals.

Description

Technical Field

[0001] This invention belongs to the field of water electrolysis catalyst preparation technology, specifically relating to a water electrolysis catalyst, its preparation method and application. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Ir-based and Ru-based catalysts are commonly used catalysts in proton exchange membrane (PEM) water electrolysis, but their high cost and scarcity greatly increase their commercialization costs. How to reduce the amount of precious metals used is a direction that researchers have been working towards.

[0004] In existing technologies, water electrolysis catalysts mainly focus on adjusting the catalyst structure, using a large specific surface area support to improve the dispersion of the noble metal Ir, thereby increasing its utilization rate and reducing costs; or preparing nanoscale catalyst particles to improve utilization by reducing catalyst size. To ensure high dispersion and high activity, the prepared catalysts are generally nanoscale. However, nanoparticles have high surface energy, are thermodynamically unstable, and are prone to aggregation or dissolution. Furthermore, preparing uniformly sized nanocatalysts usually requires complex synthetic routes, leading to increased costs. Moreover, batch reproducibility and scale-up are difficult, hindering their industrial application. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide an electrolysis catalyst, its preparation method, and its application.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a method for preparing an electrolytic water catalyst, comprising the following steps: dissolving Ru salt in an alcohol solution, then adding CeO2 nanospheres therein and dispersing them evenly to obtain a dispersion; Add the alkali to the dispersion in portions and stir, allowing the reaction to proceed for 1-5 hours; After the reaction was completed, the obtained catalyst precursor was separated and calcined in an oxidizing atmosphere to obtain the RuO2 / CeO2 catalyst.

[0007] Secondly, the present invention provides a water electrolysis catalyst prepared by the aforementioned preparation method.

[0008] Thirdly, the present invention provides the application of the water electrolysis catalyst in the preparation of water electrolysis membrane electrodes.

[0009] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows: The RuO2 / CeO2 catalyst prepared by this invention can etch away CeO2 under the test conditions of water electrolysis to form a porous structure, which greatly increases the specific surface area of ​​active sites and thus improves the utilization rate of precious metals.

[0010] The method for improving the catalyst layer proposed in this invention involves spraying RuO2 / CeO2 onto a certain layer of the catalyst layer, which can create pores at specific locations in the catalyst layer. At the same time, changing the particle size of CeO2 can adjust the pore size of the catalyst layer, thereby flexibly adjusting the structure of the catalyst layer, exposing more active area, improving catalytic performance, and reducing the amount of precious metals used. Attached Figure Description

[0011] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0012] Figure 1 This is a SEM image of CeO2 in Embodiment 1 of the present invention; Figure 2 This is a SEM image of RuO2 / CeO2 from Embodiment 1 of the present invention; Figure 3 This is a SEM image of the RuO2 / CeO2 membrane electrode of Embodiment 1 of the present invention; Figure 4 This is a SEM image of the RuO2 / CeO2 film electrode of Embodiment 1 of the present invention after etching; Figure 5 This is a performance comparison diagram of the film electrode before and after etching in Embodiment 1 of the present invention; Figure 6 This is a performance comparison diagram of the film electrode before and after etching in Embodiment 2 of the present invention; Figure 7 This is a performance comparison diagram of the film electrode before and after etching in Embodiment 3 of the present invention. Detailed Implementation

[0013] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0014] To address the technical problems mentioned in the background art, the present invention provides a method for preparing an electrolytic water catalyst, comprising the following steps: dissolving Ru salt in an alcohol solution, then adding CeO2 nanospheres therein and dispersing them evenly to obtain a dispersion; Add the alkali to the dispersion in portions and stir, allowing the reaction to proceed for 1-5 hours; After the reaction was completed, the obtained catalyst precursor was separated and calcined in an oxidizing atmosphere to obtain the RuO2 / CeO2 catalyst.

[0015] Ru salts (such as RuCl3) were dissolved in an alcohol solution to form a homogeneous Ru ion solution. CeO2 nanospheres were then added and dispersed uniformly. The polar environment of the alcohol solution promoted the stable dispersion of the CeO2 nanospheres, providing a support for subsequent loading reactions. Ammonia was added to the dispersion to provide OH- ions. - Ions, with Ru 3+ A precipitation reaction occurs to generate a Ru(OH)3 precursor. This precursor is loaded onto the surface of CeO2 nanospheres through adsorption or chemical bonding to form a Ru(OH)3 / CeO2 composite structure. When the precursor is calcined in an oxidizing atmosphere (such as air), Ru(OH)3 undergoes thermal decomposition and oxidation to generate RuO2, ultimately yielding a RuO2 / CeO2 catalyst in which RuO2 nanoparticles are uniformly loaded onto the surface of CeO2 nanospheres.

[0016] In the subsequent etching process, CeO2 is removed, forming a porous structure on RuO2, which increases the specific surface area of ​​RuO2 and improves the catalytic activity of the catalyst.

[0017] In this preparation process, RuO2 is not prepared in the form of nanoparticles. The preparation method is simple and easy to operate, thus facilitating mass production.

[0018] At the same time, changing the CeO2 particle size can adjust the pore size of the catalyst layer, thereby flexibly adjusting the catalyst layer structure, exposing more active area, improving catalytic performance, and reducing the amount of precious metals used.

[0019] In some embodiments, the Ru salt is RuCl3·xH2O.

[0020] In some embodiments, the mass ratio of Ru salt to CeO2 in the dispersion is 0.5-5:1.

[0021] In some embodiments, the alkali is sodium hydroxide, potassium hydroxide, or ammonia.

[0022] In some embodiments, the calcination temperature is 200-600℃ and the calcination time is 1-5h.

[0023] Within this temperature range, the Ru(OH)3 precursor can undergo thermal decomposition and be oxidized to RuO2. If the temperature is below 200℃, the precursor decomposition is incomplete and a stable RuO2 crystalline phase cannot be formed. If the temperature is too high (above 600℃), it may lead to the aggregation of RuO2 nanoparticles or the collapse of CeO2 nanosphere structure, reducing the catalyst dispersion and specific surface area.

[0024] Calcination conditions of 200-600℃ can prevent excessive solid-phase reaction between RuO2 and CeO2, maintain the structural integrity of CeO2 nanospheres, and lay the foundation for subsequent etching and pore formation (removing CeO2 to form a porous structure), thereby increasing the specific surface area of ​​the catalyst.

[0025] Preferably, the calcination temperature is 400-600℃ and the calcination time is 2-5h.

[0026] In some embodiments, the method for preparing CeO2 nanospheres is as follows: after mixing Ce salt and solution A, polyvinylpyrrolidone is added to the mixture and stirred until homogeneous to obtain a reaction solution; wherein A is ammonia water, sodium hydroxide solution and / or ethylene glycol; The reaction solution is reacted under closed conditions at a temperature of 80-200℃ for 6-20 hours. After the reaction was completed, the obtained solid material was separated, washed, dried, and then pyrolyzed in an oxidizing atmosphere to obtain CeO2 nanospheres.

[0027] Mix Ce salt (e.g., Ce(NO3)3·6H2O) with solution A (ammonia, sodium hydroxide solution, and / or ethylene glycol), where solution A provides an alkaline environment (OH-). - (or solvent medium, so that Ce³) + Hydrolysis or precipitation reactions generate cerium hydroxide / hydroxyl compound precursors; added polyvinylpyrrolidone (PVP) acts as a surfactant and structure directing agent, inhibiting particle aggregation by adsorption on the precursor surface and regulating the size uniformity of nanospheres; the reaction solution is heated at 80-200℃ for 6-20h under closed conditions (such as a high-pressure reactor), promoting the dissolution and recrystallization of the precursor through hydrothermal or solvothermal processes to form Ce-based compounds with spherical morphology; high temperature conditions accelerate ion diffusion and crystal growth, ensuring the integrity of the nanosphere structure; After washing and drying, the solid precursor is pyrolyzed at 500-800℃ for 5-10 hours in an oxidizing atmosphere (such as air). The Ce-based compound is converted into CeO2 through dehydration and oxidation reactions, while PVP is decomposed and removed, ultimately forming CeO2 nanospheres with high crystallinity and stable structure.

[0028] Preferably, the mass ratio of Ce salt to polyvinylpyrrolidone is 1-5:1-3.

[0029] Preferably, the washing is performed using a mixed solution of water and ethanol.

[0030] More preferably, the volume ratio of water to ethanol is 1:0.8-1.2.

[0031] Preferably, the pyrolysis temperature is 500-800℃ and the pyrolysis time is 5-10h.

[0032] Within this temperature range, cerium hydroxide / hydroxyl compound precursors (such as Ce(OH)3 or CeO2·xH2O) can undergo dehydration and oxidation reactions, completely transforming into the CeO2 crystalline phase. If the temperature is below 500℃, the precursor decomposes incompletely, and may leave residual hydroxyl or organic impurities, affecting the crystallinity and structural stability of CeO2. If the temperature exceeds 800℃, it may cause CeO2 nanospheres to sinter and agglomerate, increasing the particle size and reducing the specific surface area.

[0033] The pyrolysis process allows for the complete decomposition and removal of polyvinylpyrrolidone (PVP), preventing its residue from affecting the surface properties of CeO2 nanospheres and the subsequent loading effect of RuO2. An oxidizing atmosphere (such as air) at 500-800℃ promotes the oxidation of PVP to CO2 and H2O, ensuring product purity.

[0034] Secondly, the present invention provides a water electrolysis catalyst prepared by the aforementioned preparation method.

[0035] Thirdly, the present invention provides the application of the water electrolysis catalyst in the preparation of water electrolysis membrane electrodes.

[0036] In some embodiments, when preparing the membrane electrode, RuO2 / CeO2 catalyst and Pt / C catalyst are dispersed in a mixed solution of isopropanol and water, respectively, and ultrasonically pulverized to obtain anode catalyst slurry and cathode catalyst slurry. The anode catalyst slurry and cathode catalyst slurry are coated on both sides of the proton exchange membrane, and then dried to obtain the final product.

[0037] Preferably, in the mixed solution of isopropanol and water, the volume ratio of isopropanol to water is 10-20:1, more preferably 12-17:1.

[0038] In some embodiments, when preparing the membrane electrode, the RuO2 / CeO2 catalyst is prepared into a slurry, and the slurry is coated onto a predetermined position of the membrane electrode catalyst layer during the membrane electrode preparation process.

[0039] Preferably, the method further includes an etching step for the prepared membrane electrode, specifically: assembling the membrane electrode into an electrolytic cell, using titanium felt for the anode diffusion layer and carbon paper for the cathode diffusion layer, with bipolar plates, current collectors, and end plates arranged sequentially on the outside; tightening the clamp with a tightening force of 1-5N; connecting the external water and hydrogen pipelines, external power supply, and heater; adjusting the program to supply water to the clamp and controlling the water flow rate at 2-100 ml / min; then turning on the heating power supply to bring the clamp to 60-80℃; waiting for the target temperature to be reached; gradually loading the voltage to 1.5-3 V, with a load step of 1-100 mV and a residence time of 1-120 min; and finally gradually reducing the voltage to 0 to obtain the etched RuO2 / CeO2 membrane electrode.

[0040] Etching: Selectively removing specific areas from the surface of a material using chemical or physical methods.

[0041] The present invention will be further described below with reference to the embodiments.

[0042] Example 1 A method for preparing a water electrolysis catalyst includes the following steps: (1) Preparation of CeO2 nanospheres: Mix 2.2g of Ce(NO3)3·6H2O solid particles, 10ml of 27% concentrated ammonia solution, and 50ml of ethylene glycol thoroughly in a beaker; Then add 1.2g of polyvinylpyrrolidone and stir thoroughly to obtain a mixture; The above mixture was placed in a high-pressure reactor and reacted at a temperature of 100°C for 10 hours. After the reaction was completed, the solid material was centrifuged and washed three times with a 1:1 mixture of deionized water and ethanol. The washed solid was then dried in a 60°C oven for 12 hours for later use. Finally, the washed solid was placed in a tube furnace and pyrolyzed in an oxidizing atmosphere to obtain CeO2 nanospheres. The pyrolysis temperature was 600℃ and the pyrolysis time was 8 h. The SEM image of CeO2 is shown below. Figure 1 As shown, the average particle size of CeO2 nanospheres is 200 nm.

[0043] (2) Preparation of RuO2 / CeO2 catalyst: Weigh 0.3g of RuCl3·xH2O into a beaker, add 60ml of ethanol and sonicate until completely dissolved. Then weigh 0.2g of CeO2 and add it to the beaker. Sonicate until evenly dispersed to obtain solution B. Ammonia water is added dropwise to solution B at a certain rate using a syringe pump while stirring is started. After the addition is complete, the mixture is stirred for another 2 hours to obtain solution C. Solution C was centrifuged to obtain the RuO2 / CeO2 precursor, which was then placed in a tube furnace and calcined in an oxidizing atmosphere at 400℃ for 3 h. The SEM image of the RuO2 / CeO2 catalyst is shown below. Figure 2 As shown.

[0044] (3) Preparation of RuO2 / CeO2 film electrode: 0.1 g of RuO2 / CeO2 catalyst and 0.18 g of JM60% Pt / C catalyst were weighed and dispersed in a mixed solution of isopropanol and water, with an alcohol-to-water ratio of 15:1 and a solid content of 1%. Then, 1 ml and 2 ml of 5wt% D520 membrane solution were added respectively to make the I / C ratio of the slurry 0.5. Both were ultrasonically pulverized in a cell ultrasonic pulverizer for 40 min to obtain anolyte catalyst slurry and cathode catalyst slurry; The anode catalyst slurry and cathode catalyst slurry were sprayed onto both sides of the proton exchange membrane using an ultrasonic spraying machine. After drying, the membrane electrode was obtained. The SEM image of the RuO2 / CeO2 membrane electrode is shown below. Figure 3 As shown.

[0045] The membrane electrode assembly was formed into an electrolytic cell. Titanium felt was used for the anode diffusion layer, and carbon paper for the cathode diffusion layer. The outer layers consisted of a bipolar plate, a current collector, and an end plate. The clamp was tightened with a 3 N tightening force. External water and hydrogen pipelines, an external power supply, and a heater were connected. The program was adjusted to supply water to the clamp, controlling the flow rate at 20 ml / min. The heating power was then turned on to raise the clamp temperature to 60°C. Once the target temperature was reached, the voltage was slowly increased to 2 V, and the residence time was 60 min, yielding the etched membrane electrode. The SEM image of the etched RuO2 / CeO2 membrane electrode is shown below. Figure 4 As shown, after etching, a uniformly distributed porous structure is obtained on the RuO2 / CeO2 film electrode.

[0046] (4) RuO2 / CeO2 membrane electrode performance test A constant current testing method was used, with the current density ranging from 0.1 mA / cm². 2 Gradually load up to 2A / cm 2 The step size is 0.1 mA / cm. 2 Each current value was held for approximately 2 minutes, and the voltage corresponding to each current density value was observed. The performance of the RuO2 / CeO2 membrane electrode was tested before and after the test, and the results are as follows: Figure 5 As shown, at a current density of 1 A / cm 2 At that time, the voltages before and after etching of the RuO2 / CeO2 film electrode were 1.658 V and 1.610 V, respectively, and the overpotentials were 428 mV and 380 mV, respectively, which shows that the performance of the film electrode was greatly improved after etching.

[0047] Example 2 A method for preparing a water electrolysis catalyst includes the following steps: (1) Preparation of CeO2 nanospheres: Mix 3.6g of Ce(NO3)3·6H2O solid particles, 20ml of 27% concentrated ammonia solution, and 40ml of ethylene glycol thoroughly in a beaker; Then add 1g of polyvinylpyrrolidone and stir thoroughly to obtain a mixture; The above mixture was placed in a high-pressure reactor and reacted at a temperature of 150°C for 12 hours. After the reaction was completed, the solid material was centrifuged and washed three times with a 1:1 mixture of deionized water and ethanol. The washed solid was then dried in a 70°C oven for 12 hours for later use. Finally, the washed solid was placed in a tube furnace and pyrolyzed in an oxidizing atmosphere to obtain CeO2 nanospheres. The pyrolysis temperature was 800℃ and the pyrolysis time was 5 h. The average particle size of the CeO2 nanospheres was 400 nm.

[0048] (2) Preparation of RuO2 / CeO2 catalyst: Weigh 0.4g of RuCl3·xH2O into a beaker, add 30ml of ethanol and sonicate until completely dissolved. Then weigh 0.25g of CeO2 and add it to the beaker. Sonicate until evenly dispersed to obtain solution B. Ammonia water is added dropwise to solution B at a certain rate using a syringe pump while stirring is started. After the addition is complete, the mixture is stirred for another 2 hours to obtain solution C. Solution C was centrifuged to obtain the RuO2 / CeO2 precursor, which was then placed in a tube furnace and calcined in an oxidizing atmosphere at a temperature of 600℃ for 4 h to obtain the RuO2 / CeO2 catalyst.

[0049] (3) Preparation of RuO2 / CeO2 film electrode: 0.1 g of RuO2 / CeO2 catalyst and 0.18 g of JM60% Pt / C catalyst were weighed and dispersed in a mixed solution of isopropanol and water, wherein the alcohol-to-water ratio was 20:1 and the solid content was 1%. Then, 0.5 ml and 1.5 ml of 5wt% D520 membrane solution were added respectively to make the I / C ratio of the slurry 0.5. Both were ultrasonically pulverized in a cell ultrasonic pulverizer for 50 min to obtain anolyte catalyst slurry and cathode catalyst slurry; An ultrasonic spraying machine was used to spray the anode catalyst slurry and the cathode catalyst slurry onto both sides of the proton exchange membrane, and after drying, the membrane electrode was obtained.

[0050] The membrane electrode was assembled into an electrolytic cell. The anode diffusion layer used titanium felt, and the cathode diffusion layer used carbon paper. The outer side consisted of a bipolar plate, a current collector, and an end plate. The clamp was tightened with a 3 N tightening force. The external water and hydrogen pipelines, external power supply, and heater were connected. The program was adjusted to supply water to the clamp and the water flow rate was controlled at 10 ml / min. Then, the heating power supply was turned on to bring the clamp to a temperature of 80°C. After the target temperature was reached, the voltage was slowly applied to 2 V and the residence time was 60 min to obtain the etched membrane electrode. After etching, a uniformly distributed porous structure was obtained on the RuO2 / CeO2 membrane electrode.

[0051] (4) RuO2 / CeO2 membrane electrode performance test A constant current testing method was used, with the current density ranging from 0.1 mA / cm². 2 Gradually load up to 2A / cm 2 The step size is 0.2 mA / cm. 2 Each current value was held for approximately 2 minutes, and the voltage corresponding to each current density value was observed. The performance of the RuO2 / CeO2 membrane electrode was tested before and after the test, and the results are as follows: Figure 6 As shown, at a current density of 1 A / cm 2 At that time, the voltages before and after etching of the RuO2 / CeO2 film electrode were 1.677 V and 1.640 V, respectively, and the overpotentials were 447 mV and 410 mV, respectively, which shows that the performance of the film electrode was greatly improved after etching.

[0052] Example 3 A method for preparing a water electrolysis catalyst includes the following steps: (1) Preparation of CeO2 nanospheres: Mix 4.8g of Ce(NO3)3·6H2O solid particles, 30ml of 27% concentrated ammonia solution, and 30ml of ethylene glycol thoroughly in a beaker; Then add 1.6g of polyvinylpyrrolidone and stir thoroughly to obtain a mixture; The above mixture was placed in a high-pressure reactor and reacted at a temperature of 200°C for 7 hours. After the reaction was completed, the solid material was centrifuged and washed three times with a 1:1 mixture of deionized water and ethanol. The washed solid was then dried in a 70°C oven for 12 hours for later use. Finally, the washed solid was placed in a tube furnace and pyrolyzed in an oxidizing atmosphere to obtain CeO2 nanospheres. The pyrolysis temperature was 500℃ and the pyrolysis time was 10 h. The average particle size of the CeO2 nanospheres was 500 nm.

[0053] (2) Preparation of RuO2 / CeO2 catalyst: Weigh 0.5g of RuCl3·xH2O into a beaker, add 60ml of ethanol and sonicate until completely dissolved. Then weigh 0.3g of CeO2 and add it to the beaker. Sonicate until evenly dispersed to obtain solution B. Ammonia water is added dropwise to solution B at a certain rate using a syringe pump while stirring is started. After the addition is complete, the mixture is stirred for another 5 hours to obtain solution C. Solution C was centrifuged to obtain the RuO2 / CeO2 precursor, which was then placed in a tube furnace and calcined in an oxidizing atmosphere at a temperature of 200℃ for 5 hours to obtain the RuO2 / CeO2 catalyst.

[0054] (3) Preparation of RuO2 / CeO2 film electrode: 0.1 g of RuO2 / CeO2 catalyst and 0.18 g of JM60% Pt / C catalyst were weighed and dispersed in a mixed solution of isopropanol and water, wherein the alcohol-to-water ratio was 20:1 and the solid content was 1%. Then, 0.5 ml and 1.5 ml of 5wt% D520 membrane solution were added respectively to make the I / C ratio of the slurry 0.5. Both were ultrasonically pulverized in a cell ultrasonic pulverizer for 40 min to obtain anolyte catalyst slurry and cathode catalyst slurry; An ultrasonic spraying machine was used to spray the anode catalyst slurry and the cathode catalyst slurry onto both sides of the proton exchange membrane, and after drying, the membrane electrode was obtained.

[0055] The membrane electrode assembly was formed into an electrolytic cell. Titanium felt was used for the anode diffusion layer, and carbon paper for the cathode diffusion layer. The outer layers consisted of a bipolar plate, a current collector, and an end plate. The clamp was tightened with a 3 N tightening force. External water and hydrogen pipelines, an external power supply, and a heater were connected. The program was adjusted to supply water to the clamp, controlling the flow rate at 20 ml / min. The heating power was then turned on to raise the clamp temperature to 70°C. Once the target temperature was reached, the voltage was slowly increased to 3 V, and the residence time was 60 min, resulting in the etched membrane electrode. After etching, a uniformly distributed porous structure was obtained on the RuO2 / CeO2 membrane electrode.

[0056] (4) RuO2 / CeO2 membrane electrode performance test A constant current testing method was used, with the current density ranging from 0.1 mA / cm². 2 Gradually load up to 2A / cm 2 The step size is 0.3 mA / cm. 2 Each current value was held for approximately 2 minutes, and the voltage corresponding to each current density value was observed. The performance of the RuO2 / CeO2 membrane electrode was tested before and after the test, and the results are as follows: Figure 7 As shown, at a current density of 1 A / cm 2 At that time, the voltages before and after etching of the RuO2 / CeO2 film electrode were 1.710 V and 1.671 V, respectively, and the overpotentials were 480 mV and 441 mV, respectively, which shows that the performance of the film electrode was greatly improved after etching.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a water electrolysis catalyst, characterized in that: The steps include: dissolving Ru salt in an alcohol solution, then adding CeO2 nanospheres and dispersing them evenly to obtain a dispersion; Add the alkali to the dispersion in portions and stir, allowing the reaction to proceed for 1-5 hours; After the reaction was completed, the obtained catalyst precursor was separated and calcined in an oxidizing atmosphere to obtain the RuO2 / CeO2 catalyst.

2. The method for preparing the water electrolysis catalyst according to claim 1, characterized in that: The Ru salt is RuCl3·xH2O; Preferably, the mass ratio of Ru salt to CeO2 in the dispersion is 0.5-5:

1.

3. The method for preparing the water electrolysis catalyst according to claim 1, characterized in that: The alkali is sodium hydroxide, potassium hydroxide, or ammonia.

4. The method for preparing the water electrolysis catalyst according to claim 1, characterized in that: The calcination temperature is 200-600℃, and the calcination time is 1-5h; Preferably, the calcination temperature is 400-600℃ and the calcination time is 2-5h.

5. The method for preparing the water electrolysis catalyst according to claim 1, characterized in that: The method for preparing CeO2 nanospheres is as follows: Ce salt and solution A are mixed, polyvinylpyrrolidone is added to the mixture, and the mixture is stirred evenly to obtain a reaction solution; wherein A is ammonia water, sodium hydroxide solution and / or ethylene glycol; The reaction solution is reacted under closed conditions at a temperature of 80-200℃ for 6-20 hours. After the reaction was completed, the obtained solid material was separated, washed, dried, and then pyrolyzed in an oxidizing atmosphere to obtain CeO2 nanospheres. Preferably, the mass ratio of Ce salt to polyvinylpyrrolidone is 1-5:1-3; Preferably, the washing is performed using a mixed solution of water and ethanol; Preferably, the volume ratio of water to ethanol is 1:0.8-1.

2.

6. The method for preparing the water electrolysis catalyst according to claim 5, characterized in that: The pyrolysis temperature is 500-800℃, and the pyrolysis time is 5-10h.

7. A water electrolysis catalyst, characterized in that: It is prepared by any one of the preparation methods described in claims 1-6.

8. The application of the water electrolysis catalyst according to claim 7 in the preparation of water electrolysis membrane electrodes.

9. The application according to claim 8, characterized in that: In the preparation of membrane electrodes, RuO2 / CeO2 catalyst and Pt / C catalyst were dispersed in a mixed solution of isopropanol and water, respectively, and ultrasonically pulverized to obtain anode catalyst slurry and cathode catalyst slurry. The anode catalyst slurry and cathode catalyst slurry are coated on both sides of the proton exchange membrane, and then dried to obtain the final product. Preferably, in the mixed solution of isopropanol and water, the volume ratio of isopropanol to water is 10-20:1, more preferably 12-17:1; Alternatively, during the preparation of the membrane electrode, the RuO2 / CeO2 catalyst can be prepared into a slurry, and the slurry can be coated onto a predetermined position on the catalyst layer of the membrane electrode during the membrane electrode preparation process.

10. The application according to claim 8, characterized in that: The process also includes an etching step for the prepared membrane electrode, specifically: assembling the membrane electrode into an electrolytic cell, using titanium felt as the anode diffusion layer and carbon paper as the cathode diffusion layer, tightening the clamp with 1-5 N, passing water through the clamp and controlling the water flow rate at 2-100 ml / min, then heating the clamp to 60-80℃, gradually applying the voltage to 1.5-3 V, with a load step of 1-100 mV and a residence time of 1-120 min, and finally gradually reducing the voltage to 0 to obtain the etched RuO2 / CeO2 membrane electrode.

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