A method for preparing rare earth-doped nickel-based OER catalyst for AEM electrolyzers

Abstract

This invention relates to the field of hydrogen production technology and discloses a method for preparing a rare earth-doped nickel-based OER catalyst for an AEM electrolyzer. The preparation method includes the following steps: S1, firstly, nickel chloride is ultrasonically dispersed in water to obtain solution one, and then ferric chloride is ultrasonically dispersed in water to obtain solution two; the two solutions are mixed and stirred evenly to obtain a precursor solution; S2, the precursor solution is added dropwise to a sodium borohydride solution to obtain a reaction solution; S3, after the reaction solution is allowed to stand, the black precipitate is separated and freeze-dried; S4, the black powder obtained in S3 is centrifuged and washed until neutral, and then vacuum-dried to obtain the catalyst; S5, the catalyst is tested. This method significantly improves the activity and stability of the catalyst under a strongly alkaline environment by optimizing the ratio of metal precursor to reducing agent, precursor concentration, dropping rate, rare earth doping, and drying process.

Description

Technical Field

[0001] This invention relates to the field of hydrogen production technology, specifically a method for preparing a rare earth-doped nickel-based OER catalyst for an AEM electrolyzer. Background Technology

[0002] Anion exchange membrane (AEM) electrolysis for hydrogen production is considered a crucial technology for large-scale, low-cost production of green hydrogen due to its combination of the material cost advantages of alkaline electrolyzers and the compact structure and rapid dynamic response of proton exchange membrane (PEM) electrolyzers. However, its commercialization is still constrained by the activity and stability of the catalyst, particularly the anolyte oxygen evolution reaction (OER) catalyst under high current density and strongly alkaline / oxidizing environments. Improving the catalyst performance of AEM electrolyzers is key to achieving high efficiency, long lifespan, and low-cost operation.

[0003] Currently, most AEM anodes use precious metal catalysts (such as IrO2 and RuO2), whose high cost and scarcity limit their large-scale application. While nickel-based non-precious metal catalysts are inexpensive, they generally suffer from the following drawbacks: 1. Activity decreases sharply at high current densities (>1 A / cm²); 2. Metal leaching in a strongly alkaline environment leads to structural collapse; 3. Catalyst particles prepared by traditional coprecipitation methods are prone to agglomeration and have insufficient specific surface area.

[0004] Therefore, developing a method for preparing nickel-based OER catalysts that combines high activity, high stability, and low cost is of great significance for promoting the commercialization of AEM electrolyzers. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a rare earth-doped nickel-based OER catalyst for an AEM electrolyzer, in order to solve the problems in the prior art.

[0006] The objective of this invention can be achieved through the following technical solutions: A method for preparing a rare earth-doped nickel-based OER catalyst for an AEM electrolyzer, the method comprising the following steps: S1. First, disperse nickel chloride in water using ultrasonication to obtain solution one, then disperse ferric chloride in water using ultrasonication to obtain solution two; mix the two solutions and stir evenly to obtain the precursor solution; S2. The precursor solution is added dropwise to the sodium borohydride solution to obtain the reaction solution; S3. After the reaction solution has been allowed to stand, the black precipitate is separated and freeze-dried. S4. The black powder obtained in S3 is centrifuged and washed until neutral, then vacuum dried to obtain the catalyst; S5. Test the catalyst.

[0007] Furthermore, the mixing ratio of the two solutions in S1 is Ni:Fe = 2:1-3:1.

[0008] Furthermore, the flow rate of the precursor solution added in S2 is 10 mL / min.

[0009] Furthermore, the concentration of the sodium borohydride solution in S2 is 2 M, and the solution volume is 100 mL.

[0010] Furthermore, the reaction solution in S3 is left to stand at room temperature for 24 hours.

[0011] Furthermore, a rare earth doping step is added between S2 and S3; The specific operation for rare earth doping is as follows: after the S2 reaction is completed, add the rare earth solution to S2, heat and stir for 1 h, and the reaction is complete.

[0012] Furthermore, the rare earth solution is one of praseodymium chloride, cerium chloride, lanthanum chloride, europium chloride, yttrium chloride, and samarium chloride, used to dope different rare earth elements.

[0013] The beneficial effects of this invention are: 1. This invention is prepared by in-situ reduction and liquid-phase doping. By first preparing NiFe LDH and then doping rare earth ions on NiFe LDH, a highly active OER catalyst for AEM is prepared.

[0014] 2. The catalyst prepared by this invention has improved activity, with a current density of "1 A / cm²" at a voltage of 1.67 V (compared to ≤0.5 A / cm² by traditional methods). 3. The catalyst prepared by this invention has an extended lifespan: stability in 1 M KOH >400 h; 4. Cost reduction: The amount of precious metals used is zero, and the raw material cost is only 1 / 20 of that of IrO2 catalyst. Attached Figure Description

[0015] The invention will now be further described with reference to the accompanying drawings.

[0016] Figure 1 This is a schematic diagram of the catalyst in Example 2 of the present invention; Figure 2 This is a TEM test image of the catalyst in Example 1 of the present invention; Figure 3 This is a half-cell performance evaluation diagram of the catalyst in Example 2 of the present invention; Figure 4 These are the full-cell performance evaluation diagrams for the catalyst in Example 1 and Example 2 of this invention; Figure 5This is a graph showing the AEM durability changes of the catalyst in Example 2 of this invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0018] A method for preparing a rare earth-doped nickel-based OER catalyst for an AEM electrolyzer, such as... Figures 1-5 As shown, the preparation method includes the following steps: S1. Precursor Preparation 2 g of nickel chloride was ultrasonically dispersed in 40 mL of water, and 2.1 g of ferric chloride was ultrasonically dispersed in 40 mL of water; the ratio of each solution was Ni:Fe = 3:1, and the mixtures were stirred evenly.

[0019] S2, solvent reduction The precursor solution was added dropwise to 100 mL of a 2 M sodium borohydride solution at a flow rate of 10 mL / min. The ratio of the total amount of metal to the amount of sodium borohydride was 1:25.

[0020] S3. Allow to stand and dry. The reaction solution was left to stand at room temperature for 24 hours, and the black precipitate was then freeze-dried to separate it.

[0021] S4. Washing and drying The black powder obtained from S3 was centrifuged and washed until neutral, then vacuum dried, and finally dried to obtain the NiFe catalyst.

[0022] S5, Test Half-cell tests were conducted in a 1 M KOH electrolyte solution. In the three-electrode system, Ag / AgCl, a carbon rod, and a glassy carbon electrode were used as the reference, counter, and working electrodes, respectively. Then, the oxygen evolution performance of the catalytic material was tested using linear sweep voltammetry within a potential range of 0-1 V at a scan rate of 50 mV∙s. -1 The obtained catalyst was at 20 mA / cm 2 At this point, the overpotential is only 218 mV.

[0023] The obtained catalyst was used to fabricate a membrane electrode assembly for testing: An AEM electrolytic cell was used with a nickel-based catalyst as the anode and 50%-Pt / C as the cathode in a 1 M KOH electrolyte solution at a temperature of 60°C and a flow rate of 30 mL / min. The test was conducted at 1 A / cm². 2 At the given current density, the voltage is 1.752V. Example

[0024] A method for preparing a rare earth-doped nickel-based OER catalyst for an AEM electrolyzer, the method comprising the following steps: S1. Precursor Preparation 2 g of nickel chloride was ultrasonically dispersed in 40 mL of water, and 2.1 g of ferric chloride was ultrasonically dispersed in 40 mL of water; the ratio of each solution was Ni:Fe = 3:1, and the mixtures were stirred evenly.

[0025] S2, solvent reduction The precursor solution was added dropwise to 100 mL of a 2 M sodium borohydride solution at a flow rate of 10 mL / min. The ratio of the total amount of metal to the amount of sodium borohydride was 1:25.

[0026] S3, rare earth doping After the reaction in S2 is complete, praseodymium chloride solution is added to S2, and the mixture is heated and stirred for 1 hour to complete the reaction.

[0027] S4. Allow to stand and dry. The reaction solution was left to stand at room temperature for 24 hours, and the black precipitate was then freeze-dried.

[0028] S5. Washing and Drying The black powder obtained from S4 was centrifuged and washed until neutral, then vacuum dried, and finally dried to obtain the Pr-Ni3Fe catalyst.

[0029] S6, Test Half-cell test: The obtained catalyst at 20 mA / cm 2 At this point, the overpotential is only 232 mV.

[0030] AEM electrolytic cell: at 1 A / cm 2 At a current density of 1 A / cm 2 At the given current density, the voltage is 1.672 V. Example

[0031] A method for preparing a rare earth-doped nickel-based OER catalyst for an AEM electrolyzer, the method comprising the following steps: S1. Precursor Preparation 2 g of nickel chloride was ultrasonically dispersed in 40 mL of water, and 2.1 g of ferric chloride was ultrasonically dispersed in 40 mL of water; the ratio of each solution was Ni:Fe = 3:1, and the mixtures were stirred evenly.

[0032] S2, solvent reduction The precursor solution was added dropwise to 100 mL of a 2 M sodium borohydride solution at a flow rate of 10 mL / min. The ratio of the total amount of metal to the amount of sodium borohydride was 1:25.

[0033] S3, rare earth doping After the S2 reaction is complete, add cerium chloride solution to S2, heat and stir for 1 h, and the reaction is complete.

[0034] S4. Allow to stand and dry. The reaction solution was left to stand at room temperature for 24 hours, and the black precipitate was then freeze-dried.

[0035] S5. Washing and Drying The black powder obtained from S4 was centrifuged and washed until neutral, then vacuum dried, and finally dried to obtain the Ce-Ni3Fe catalyst.

[0036] S6, Test Half-cell test: The obtained catalyst at 20 mA / cm 2 At this point, the overpotential is only 270 mV.

[0037] AEM electrolytic cell: at 1 A / cm 2 At a current density of 1 A / cm 2 At the given current density, the voltage is 1.68 V. Example

[0038] A method for preparing a rare earth-doped nickel-based OER catalyst for an AEM electrolyzer, the method comprising the following steps: S1. Precursor Preparation Disperse 1 g of nickel chloride in 40 mL of water by ultrasonication, and disperse 1 g of ferric chloride in 40 mL of water by ultrasonication; take the solutions in the ratio of Ni:Fe=2:1, and mix them evenly.

[0039] S2, solvent reduction The precursor solution was added dropwise to 100 mL of a 2 M sodium borohydride solution at a flow rate of 10 mL / min. The ratio of the total amount of metal to the amount of sodium borohydride was 1:25.

[0040] S3, rare earth doping After the reaction in S2 is complete, praseodymium chloride solution is added to S2, and the mixture is heated and stirred for 1 hour to complete the reaction.

[0041] S4. Allow to stand and dry. The reaction solution was left to stand at room temperature for 24 hours, and the black precipitate was then freeze-dried.

[0042] S5. Washing and Drying The black powder obtained from S4 was centrifuged and washed until neutral, then vacuum dried, and finally dried to obtain the Pr-Ni2Fe catalyst.

[0043] S6, Test Half-cell test: The obtained catalyst at 20 mA / cm 2 At this point, the overpotential is only 249 mV.

[0044] AEM electrolytic cell: at 1 A / cm 2 At a current density of 1 A / cm 2 At the given current density, the voltage is 1.688 V. Example

[0045] A method for preparing a rare earth-doped nickel-based OER catalyst for an AEM electrolyzer, the method comprising the following steps: S1. Precursor Preparation 2 g of nickel chloride was ultrasonically dispersed in 40 mL of water, and 2.1 g of ferric chloride was ultrasonically dispersed in 40 mL of water; the ratio of each solution was Ni:Fe = 2:1, and the mixtures were stirred evenly.

[0046] S2, solvent reduction The precursor solution was added dropwise to 100 mL of a 2 M sodium borohydride solution at a flow rate of 20 mL / min. The ratio of the total amount of metal to the amount of sodium borohydride was 1:25.

[0047] S3, rare earth doping After the S2 reaction is complete, lanthanum chloride solution is added to S2, and the mixture is heated and stirred for 1 h to complete the reaction.

[0048] S4. Allow the reaction solution to stand at room temperature for 24 hours, and then freeze-dry the black precipitate to separate it.

[0049] S5. Washing and Drying The black powder obtained from S4 was centrifuged and washed until neutral, then vacuum dried, and finally dried to obtain the La-Ni2Fe catalyst.

[0050] S6, Test Half-cell test: The obtained catalyst at 20 mA / cm 2 At this point, the overpotential is only 256 mV.

[0051] AEM electrolytic cell: at 1 A / cm 2 At a current density of 1 A / cm 2 At a current density of , the voltage is 1.681 V. Example

[0052] A method for preparing a rare earth-doped nickel-based OER catalyst for an AEM electrolyzer, the method comprising the following steps: S1. Precursor Preparation 2 g of nickel chloride was ultrasonically dispersed in 40 mL of water, and 2.1 g of ferric chloride was ultrasonically dispersed in 40 mL of water; the ratio of each solution was Ni:Fe = 3:1, and the mixtures were stirred evenly.

[0053] S2, solvent reduction The precursor solution was added dropwise to 100 mL of a 2 M sodium borohydride solution at a flow rate of 10 mL / min. The ratio of the total amount of metal to the amount of sodium borohydride was 1:10.

[0054] S3, rare earth doping After the S2 reaction is complete, lanthanum chloride solution is added to S2, and the mixture is heated and stirred for 1 h to complete the reaction.

[0055] S4. Allow to stand and dry. The reaction solution was left to stand at room temperature for 24 hours, and the black precipitate was then freeze-dried.

[0056] S5. Washing and Drying The black powder obtained from S4 was centrifuged and washed until neutral, then vacuum dried. Finally, the La-Ni3Fe catalyst was obtained after drying.

[0057] S6, Test Half-cell test: The obtained catalyst at 20 mA / cm 2 At this point, the overpotential is only 298 mV.

[0058] AEM electrolytic cell: at 1 A / cm 2 At a current density of 1 A / cm 2 At a current density of 1.723V, the voltage is 1.723V. Example

[0059] A method for preparing a rare earth-doped nickel-based OER catalyst for an AEM electrolyzer, the method comprising the following steps: S1. Precursor Preparation 2 g of nickel chloride was ultrasonically dispersed in 40 mL of water, and 2.1 g of ferric chloride was ultrasonically dispersed in 40 mL of water; the ratio of each solution was Ni:Fe = 3:1, and the mixtures were stirred evenly.

[0060] S2, solvent reduction The precursor solution was added dropwise to 100 mL of a 2 M sodium borohydride solution at a flow rate of 10 mL / min. The ratio of the total amount of metal to the amount of sodium borohydride was 1:15.

[0061] S3, rare earth doping After the S2 reaction is complete, europium chloride solution is added to S2, and the mixture is heated and stirred for 1 hour until the reaction is complete. S4. Allow to stand and dry. The reaction solution was left to stand at room temperature for 24 hours, and the black precipitate was then freeze-dried.

[0062] S5. Washing and Drying The black powder obtained from S4 was centrifuged and washed until neutral, then vacuum dried, and finally dried to obtain the Eu-Ni3Fe catalyst.

[0063] S6, Test Half-cell test: The obtained catalyst at 20 mA / cm 2 At this point, the overpotential is only 273 mV.

[0064] AEM electrolytic cell: at 1 A / cm 2 At a current density of 1 A / cm 2 At the given current density, the voltage is 1.712V. Example

[0065] A method for preparing a rare earth-doped nickel-based OER catalyst for an AEM electrolyzer, the method comprising the following steps: S1. Precursor Preparation 2 g of nickel chloride was ultrasonically dispersed in 40 mL of water, and 2.1 g of ferric chloride was ultrasonically dispersed in 40 mL of water; the ratio of each solution was Ni:Fe = 3:1, and the mixtures were stirred evenly.

[0066] S2, solvent reduction The precursor solution was added dropwise to 100 mL of a 2 M sodium borohydride solution at a flow rate of 10 mL / min. The ratio of the total amount of metal to the amount of sodium borohydride was 1:25.

[0067] S3, rare earth doping After the reaction in S2 is complete, yttrium chloride solution is added to S2, and the mixture is heated and stirred for 1 hour to complete the reaction.

[0068] S4. Allow to stand and dry. The reaction solution was allowed to stand at room temperature for 48 hours, and the black precipitate was then freeze-dried.

[0069] S5. Washing and Drying The black powder obtained from S4 was centrifuged and washed until neutral, then vacuum dried, and finally dried to obtain the Y-Ni3Fe catalyst.

[0070] S6, Test Half-cell test: The obtained catalyst at 20 mA / cm 2 At this point, the overpotential is only 278 mV.

[0071] AEM electrolytic cell: at 1 A / cm 2 At a current density of 1 A / cm 2 At a current density of 1.704 V, the voltage is 1.704 V. Example

[0072] A method for preparing a rare earth-doped nickel-based OER catalyst for an AEM electrolyzer, the method comprising the following steps: S1. Precursor Preparation 2 g of nickel chloride was ultrasonically dispersed in 40 mL of water, and 2.1 g of ferric chloride was ultrasonically dispersed in 40 mL of water; the ratio of each solution was Ni:Fe = 3:1, and the mixtures were stirred evenly.

[0073] S2, solvent reduction The precursor solution was added dropwise to 100 mL of a 2 M sodium borohydride solution at a flow rate of 10 mL / min. The ratio of the total amount of metal to the amount of sodium borohydride was 1:25.

[0074] S3, rare earth doping After the reaction in S2 is complete, samarium chloride solution is added to S2, and the mixture is heated and stirred for 1 hour to complete the reaction.

[0075] S4. Allow to stand and dry. The reaction solution was allowed to stand at room temperature for 24 hours to separate the black precipitate.

[0076] S5. Washing and Drying The black powder obtained from S4 was centrifuged and washed until neutral, then vacuum dried. Finally, the Sm-Ni3Fe catalyst was obtained after drying.

[0077] S6, Test Half-cell test: The obtained catalyst at 20 mA / cm 2 At this point, the overpotential is only 265 mV.

[0078] AEM electrolytic cell: at 1 A / cm 2 At a current density of 1 A / cm 2 At the given current density, the voltage is 1.697 V.

[0079] The catalyst of this invention is prepared by in-situ reduction and liquid-phase doping. By first preparing NiFe LDH and then doping rare earth ions on NiFeLDH, a highly active OER catalyst for AEM is prepared.

[0080] Specifically, the method involves ultrasonically dispersing nickel and iron precursors in water, then doping rare earth ions into a nickel-based catalyst via liquid-phase doping. The catalyst is then obtained through a secondary drying process following centrifugal washing. This method significantly improves the activity and stability of the catalyst under strongly alkaline conditions by optimizing the ratio of metal precursor to reducing agent, precursor concentration, dropping rate, rare earth doping, and drying process.

[0081] The nickel precursor used in the raw materials provides the nickel source, and the iron precursor provides the iron source. The oxygen evolution performance of the prepared catalyst was tested. The overpotential of the oxygen evolution reaction of the catalysts prepared in Examples 1-9 is no higher than 300 mV. This catalyst has good overall application prospects in the field of electrochemistry, promotes the development of water electrolysis in electrolyzer technology, helps to reduce energy costs, and achieve the goals of low-carbon economy and sustainable development.

[0082] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for preparing a rare earth-doped nickel-based OER catalyst for an AEM electrolyzer, characterized in that, The preparation method includes the following steps: S1. First, disperse nickel chloride in water using ultrasonication to obtain solution one, then disperse ferric chloride in water using ultrasonication to obtain solution two; mix the two solutions and stir evenly to obtain the precursor solution; S2. The precursor solution is added dropwise to the sodium borohydride solution to obtain the reaction solution; S3. After the reaction solution has been allowed to stand, the black precipitate is separated and freeze-dried. S4. The black powder obtained in S3 is centrifuged and washed until neutral, then vacuum dried to obtain the catalyst; S5. Test the catalyst.

2. The method for preparing rare earth-doped nickel-based OER catalyst for AEM electrolysis cells according to claim 1, characterized in that, The mixing ratio of the two solutions in S1 is Ni:Fe = 2:1-3:

1.

3. The method for preparing rare earth-doped nickel-based OER catalyst for AEM electrolysis cells according to claim 1, characterized in that, The flow rate of the precursor solution added in S2 is 10 mL / min.

4. The method for preparing rare earth-doped nickel-based OER catalyst for AEM electrolysis cells according to claim 3, characterized in that, The concentration of the sodium borohydride solution in S2 is 2 M, and the solution volume is 100 mL.

5. The method for preparing rare earth-doped nickel-based OER catalyst for AEM electrolysis cells according to claim 1, characterized in that, The reaction solution in S3 was left to stand at room temperature for 24 hours.

6. The method for preparing rare earth-doped nickel-based OER catalyst for AEM electrolysis cells according to claim 1, characterized in that, A rare earth doping step is added between S2 and S3; The specific operation for rare earth doping is as follows: after the S2 reaction is completed, add the rare earth solution to S2, heat and stir for 1 h, and the reaction is complete.

7. The method for preparing rare earth-doped nickel-based OER catalyst for AEM electrolyzers according to claim 6, characterized in that, The rare earth solution is one of praseodymium chloride, cerium chloride, lanthanum chloride, europium chloride, yttrium chloride, and samarium chloride, used to dope different rare earth elements.

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