A method for preparing a surface-supported rare earth metal alloy catalyst for alkaline water electrolysis

Abstract

This invention discloses a method for preparing a surface-supported rare earth metal alloy catalyst for alkaline water electrolysis, comprising the following steps: preparing a mixed solution A by mixing a non-precious metal salt and deionized water; immersing a substrate membrane electrode in the mixed solution A; ultrasonically impregnating and drying the electrode; hydrothermally heating the electrode for a period of time; and removing the sample after the reaction has cooled to room temperature. The sample is then rinsed with ethanol and deionized water, dried, immersed in a rare earth metal salt solution, removed, and calcined at high temperature to obtain a precursor for the supported rare earth metal alloy catalyst. A measured amount of phosphate is dissolved in deionized water to form a solution B. Under a three-electrode system, the obtained precursor is placed in solution B for electrochemical activation to obtain a rare earth metal-supported alloy catalyst for water electrolysis to produce hydrogen. The catalyst prepared by this invention exhibits significantly higher activity, higher stability, and higher cost-effectiveness than traditional catalysts.

Description

Technical Field

[0001] This invention relates to the field of electrocatalysis, and in particular to a method for preparing a surface-supported rare earth metal alloy catalyst for alkaline water electrolysis. Background Technology

[0002] The urgent global demand for clean energy is driving the rapid development of hydrogen energy technology. Hydrogen, as a high-energy-density, zero-carbon-emission energy carrier, is widely regarded as one of the most promising alternatives to fossil fuels. When produced using renewable energy through water electrolysis, "green hydrogen"—a completely zero-carbon-emission clean energy carrier—is obtained. According to a report by the International Energy Agency (IEA), global electrolysis capacity is projected to double annually to 205 gigawatts by 2030, a significant increase compared to less than 1 GW in 2022.

[0003] Against this backdrop, catalysts play a crucial role in the hydrogen economy's industrial chain, particularly in water electrolysis hydrogen production technology. Catalysts significantly improve hydrogen production efficiency by lowering the activation energy of the water splitting reaction, directly determining the economics and feasibility of the hydrogen production system. Noble metal catalysts, especially alloy catalysts based on metals such as platinum (Pt), palladium (Pd), ruthenium (Ru), and iridium (Ir), are considered one of the most promising technological routes due to their superior catalytic activity and stability.

[0004] However, precious metal catalysts face the dual challenges of high cost and scarce resources. Platinum group metals are extremely rare and concentrated in the Earth's crust, resulting in high prices and unstable supply. According to market reports, the global market for precious metal hydrogen production catalysts was worth approximately US$120 million in 2024 and is projected to reach US$215 million by 2031, with a CAGR of 8.8% (2025-2031). This growth reflects both the rapid development of the hydrogen energy industry and the urgent need for more economical and efficient catalysts.

[0005] Advances in catalyst technology are crucial for reducing the cost of green hydrogen. To be competitive with traditional fossil fuels, the cost of clean hydrogen needs to be reduced to below $2 per kilogram by 2030. Currently, the cost of hydrogen production using PEM electrolyzers is approximately $4-6 per kilogram, with catalyst costs accounting for over 35%. Therefore, developing high-performance alloy catalysts with low precious metal loadings has become a key research focus for research institutions and companies worldwide.

[0006] Catalysts improve hydrogen production efficiency by lowering reaction energy barriers and optimizing reaction pathways. In water electrolysis, the hydrogen evolution reaction (HER) requires overcoming a certain energy barrier, and a suitable catalyst can significantly lower this barrier and increase the reaction rate. Rare earth elements can be incorporated into the crystal lattice of the catalyst support, stabilizing its crystal structure and preventing it from collapsing in the high-temperature and high-humidity reaction environment, thus greatly extending the catalyst's lifespan. Simultaneously, they can alter the electronic environment around active sites, optimizing the adsorption and activation behavior of reactants (such as carbon monoxide or water) on the catalyst surface, thereby enhancing intrinsic catalytic activity. Rare earth oxides can also act as "anchors," effectively fixing and dispersing tiny active metal particles (such as nickel or platinum) to prevent them from migrating, agglomerating, and growing during long-term use, thus maintaining the catalyst's high activity. Summary of the Invention

[0007] To address some shortcomings of current water electrolysis technology, this invention provides a method for preparing a surface-supported rare earth metal alloy catalyst for alkaline water electrolysis. The rare earth metal can be uniformly dispersed on the surface of a support, and by increasing the loading, an alloy is generated to enhance the hydrogen evolution performance of the catalyst.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] A method for preparing a surface-supported rare earth metal alloy catalyst for alkaline water electrolysis includes the following steps:

[0010] (1) Substrate pretreatment: Prepare a mixed solution A by taking non-precious metal salt and deionized water, immerse the substrate membrane electrode in the mixed solution A, ultrasonically soak it for a period of time, take out the substrate membrane, dry it, and then transfer the substrate membrane and alkaline solution together to a hydrothermal reactor. Hydrothermal treatment is carried out for a period of time, and the sample is taken out after the reaction cools down to room temperature.

[0011] (2) Preparation of rare earth metal alloy catalyst precursor: The sample obtained after hydrothermal treatment was rinsed with ethanol and deionized water respectively, dried, immersed in rare earth metal salt solution, soaked for a period of time, and then placed in muffle furnace for high-temperature calcination to obtain the precursor of supported rare earth metal alloy catalyst.

[0012] (3) Preparation of rare earth metal alloy catalyst samples: A quantitative amount of phosphate was weighed and dissolved in deionized water to form solution B. Under a three-electrode system, the obtained precursor was... Placed Electrochemical activation was performed in solution B to obtain an alloy-type water electrolysis catalyst loaded with rare earth metals for hydrogen production.

[0013] In embodiments of the present invention, the non-precious metal salt is one or more of iron salt, cobalt salt, nickel salt, and copper salt, and the content of the non-precious metal salt is 0.01 mol to 0.5 mol.

[0014] In embodiments of the present invention, the base film electrode is one or more of nickel mesh, titanium film, and titanium plate.

[0015] In an embodiment of the present invention, in step 1, the amount of deionized water is 50-500 mL, the ultrasonic impregnation time is 10-60 min, the hydrothermal temperature is 120-180 °C, and the hydrothermal time is 1-5 h.

[0016] In an embodiment of the present invention, the alkaline solution is one or more of potassium hydroxide and sodium hydroxide, with a concentration of 0.5~3 mol / L and a volume of 50~100 mL.

[0017] In an embodiment of the present invention, in step 1, the drying temperature is 60~80℃ and the drying time is 10~30min.

[0018] In an embodiment of the present invention, in step 2, the calcination temperature is 300~700℃, the calcination time is 1h~5h, and the calcination atmosphere is one or more of argon, nitrogen, and helium.

[0019] In an embodiment of the present invention, the rare earth metal salt solution is one or more of lanthanum nitrate solution, cerium nitrate solution, lanthanum acetate solution, and cerium acetate, and the concentration of the rare earth metal salt solution is 0.1~1 mol / L.

[0020] In an embodiment of the present invention, in step 3, the phosphate is one or more of disodium hydrogen phosphate and sodium hypophosphite, the concentration of the phosphate is 0.1~0.8 mol / L, and the amount of deionized water is 10~60 mL.

[0021] In an embodiment of the present invention, in step 3, the electrochemical activation potential is -0.2 to -1V, and the electrochemical activation time is 10 to 60 min.

[0022] The beneficial effects of this invention are as follows: This invention employs a multi-step synergistic synthesis method of "hydrothermal-calcination-electroactivation" to successfully prepare a rare earth metal catalyst with a unique electronic structure and multi-level pore structure. The electronic structure is optimized through alloying effect, high crystallinity and high specific surface area are obtained through calcination, and surface reconstruction is achieved through electroactivation. As a result, it ultimately exhibits high activity, high stability and high cost performance far exceeding that of traditional catalysts, providing a key material for efficient and sustainable water electrolysis hydrogen production technology. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0024] Figure 1 This is a SEM image of the rare earth metal alloy catalyst of the present invention;

[0025] Figure 2 This is a graph showing the electrochemical performance test results of the rare earth metal alloy catalyst of this invention.

[0026] Figure 3 This is a graph showing the electrochemical performance test results of the rare earth metal alloy catalyst of this invention. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. 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.

[0028] Please see Figure 1-3 The present invention includes: a method for preparing a surface-supported rare earth metal alloy catalyst for alkaline water electrolysis, comprising the following steps:

[0029] (1) Substrate pretreatment: Prepare a mixed solution A by taking non-precious metal salt and deionized water, immerse the substrate membrane electrode in the mixed solution A, ultrasonically soak it for a period of time, take out the substrate membrane, dry it, and then transfer the substrate membrane and alkaline solution together to a hydrothermal reactor. Hydrothermal treatment is carried out for a period of time, and the sample is taken out after the reaction cools down to room temperature.

[0030] (2) Preparation of rare earth metal alloy catalyst precursor: The sample obtained after hydrothermal treatment was rinsed with ethanol and deionized water respectively, dried, immersed in rare earth metal salt solution, soaked for a period of time, and then placed in muffle furnace for high-temperature calcination to obtain the precursor of supported rare earth metal alloy catalyst.

[0031] (3) Preparation of rare earth metal alloy catalyst samples: A quantitative amount of phosphate was weighed and dissolved in deionized water to form solution B. Under a three-electrode system, the obtained precursor was... Placed Electrochemical activation was performed in solution B to obtain an alloy-type water electrolysis catalyst loaded with rare earth metals for hydrogen production.

[0032] In embodiments of the present invention, the non-precious metal salt is one or more of iron salt, cobalt salt, nickel salt, and copper salt, and the content of the non-precious metal salt is 0.01 mol to 0.5 mol.

[0033] In embodiments of the present invention, the base film electrode is one or more of nickel mesh, titanium film, and titanium plate.

[0034] In an embodiment of the present invention, in step 1, the amount of deionized water is 50-500 mL, the ultrasonic impregnation time is 10-60 min, the hydrothermal temperature is 120-180 °C, and the hydrothermal time is 1-5 h.

[0035] In an embodiment of the present invention, the alkaline solution is one or more of potassium hydroxide and sodium hydroxide, with a concentration of 0.5~3 mol / L and a volume of 50~100 mL.

[0036] In an embodiment of the present invention, in step 1, the drying temperature is 60~80℃ and the drying time is 10~30min.

[0037] In an embodiment of the present invention, in step 2, the calcination temperature is 300~700℃, the calcination time is 1h~5h, and the calcination atmosphere is one or more of argon, nitrogen, and helium.

[0038] In an embodiment of the present invention, the rare earth metal salt solution is one or more of lanthanum nitrate solution, cerium nitrate solution, lanthanum acetate solution, and cerium acetate, and the concentration of the rare earth metal salt solution is 0.1~1 mol / L.

[0039] In an embodiment of the present invention, in step 3, the phosphate is one or more of disodium hydrogen phosphate and sodium hypophosphite, the concentration of the phosphate is 0.1~0.8 mol / L, and the amount of deionized water is 10~60 mL.

[0040] In an embodiment of the present invention, in step 3, the electrochemical activation potential is -0.2 to -1V, and the electrochemical activation time is 10 to 60 min.

[0041] Example 1

[0042] A method for preparing a surface-supported rare earth metal alloy catalyst for alkaline water electrolysis includes the following steps:

[0043] 1) Substrate pretreatment:

[0044] Prepare a mixed solution A by mixing 0.5 mol cobalt nitrate and 150 mL deionized water. Immerse the nickel mesh in the mixed solution and sonicate for 30 min. Remove the nickel mesh and dry it at 60 °C. Then transfer the substrate and 80 mL of 2 mol / L NaOH solution to a hydrothermal reactor and hydrothermally heat it at 140 °C for 2 h. Remove the substrate after the reaction has cooled to room temperature.

[0045] 2) Preparation of rare earth metal alloy catalyst precursors:

[0046] After hydrothermal treatment, the substrate was rinsed and dried with ethanol and deionized water. It was then immersed in a 0.1 mol / L lanthanum nitrate solution for 30 min. After removal, it was placed in a muffle furnace and calcined at 400 °C under a nitrogen atmosphere for 2 h to obtain a precursor loaded with rare earth metal alloys.

[0047] 3) Preparation of rare earth metal alloy catalysts:

[0048] The alloy precursor obtained above was placed in a 0.2 mol / L, 60 mL sodium hypophosphite solution. In a three-electrode system, the precursor obtained in step 2 was electrochemically activated in this solution. The working electrode was the precursor, the counter electrode was a platinum sheet, and the reference electrode was a silver chloride electrode. The potential was -0.5 V, and the activation time was 10 min. This yielded an alloy catalyst supported on rare earth metals.

[0049] 4) SEM scanning

[0050] The morphology of the obtained rare earth metal alloy catalyst was examined using electron microscopy, and the test results are as follows: Figure 1 As shown.

[0051] 5) Electrochemical testing

[0052] Hydrogen evolution and oxygen evolution performance testing: The electrocatalytic hydrogen evolution performance of the prepared rare earth metal alloy catalyst was tested using an electrochemical workstation with a three-electrode system. The catalyst obtained in step 3) was used as the working electrode, Ag / AgCl as the reference electrode, and a platinum sheet electrode as the counter electrode. The electrolyte was a 1 mol / L KOH solution, simulating alkaline conditions. The test was conducted using linear sweep voltammetry at a scan rate of 5 mV / s on the electrochemical workstation. The test results are as follows: Figure 2 As shown, none of the test results were compensated.

[0053] The stability of the prepared rare-earth metal alloy catalyst was tested in a three-electrode system. The test solution was 1 mol / L KOH, and the test results are as follows. Figure 3 As shown.

[0054] The beneficial effects of the preparation method of the surface-supported rare earth metal alloy catalyst for alkaline water electrolysis of the present invention are as follows: The present invention adopts a multi-step synergistic synthesis method of "hydrothermal-calcination-electroactivation" to successfully prepare a rare earth metal alloy catalyst with a unique electronic structure and multi-level pore structure. The electronic structure is optimized through alloying effect, high crystallinity and high specific surface area are obtained through calcination, and surface reconstruction is achieved through electroactivation. Thus, it ultimately exhibits high activity, high stability and high cost performance far exceeding that of traditional catalysts, providing a key material for efficient and sustainable water electrolysis hydrogen production technology.

[0055] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing a surface-supported rare earth metal alloy catalyst for alkaline water electrolysis, characterized in that, Includes the following steps: (1) Substrate pretreatment: Prepare a mixed solution A by taking non-precious metal salt and deionized water, immerse the substrate membrane electrode in the mixed solution A, ultrasonically soak it for a period of time, take out the substrate membrane, dry it, and then transfer the substrate membrane and alkaline solution together to a hydrothermal reactor. Hydrothermal treatment is carried out for a period of time, and the sample is taken out after the reaction cools down to room temperature. (2) Preparation of rare earth metal alloy catalyst precursor: The sample obtained after hydrothermal treatment was rinsed with ethanol and deionized water respectively, dried, immersed in rare earth metal salt solution, soaked for a period of time, and then placed in muffle furnace for high-temperature calcination to obtain the precursor of supported rare earth metal alloy catalyst. (3) Preparation of rare earth metal alloy catalyst samples: A quantitative amount of phosphate was weighed and dissolved in deionized water to form solution B. Under a three-electrode system, the obtained precursor was... Placed Electrochemical activation was performed in solution B to obtain an alloy-type water electrolysis hydrogen production catalyst supported on rare earth metals.

2. The method for preparing the surface-supported rare earth metal alloy catalyst for alkaline water electrolysis according to claim 1, characterized in that, The non-precious metal salt is one or more of iron salt, cobalt salt, nickel salt, and copper salt, and the content of the non-precious metal salt is 0.01 mol to 0.5 mol.

3. The method for preparing the surface-supported rare earth metal alloy catalyst for alkaline water electrolysis according to claim 1, characterized in that, The base film electrode is one or more of nickel mesh, titanium film, and titanium plate.

4. The method for preparing the surface-supported rare earth metal alloy catalyst for alkaline water electrolysis according to claim 1, characterized in that, In step 1, the amount of deionized water is 50-500 mL, the ultrasonic impregnation time is 10-60 min, the hydrothermal temperature is 120-180℃, and the hydrothermal time is 1-5 h.

5. The method for preparing the surface-supported rare earth metal alloy catalyst for alkaline water electrolysis according to claim 1, characterized in that, The alkaline solution is one or more of potassium hydroxide and sodium hydroxide, with a concentration of 0.5~3 mol / L and a volume of 50~100 mL.

6. The method for preparing the surface-supported rare earth metal alloy catalyst for alkaline water electrolysis according to claim 1, characterized in that, In step 1, the drying temperature is 60~80℃ and the drying time is 10~30min.

7. The method for preparing the surface-supported rare earth metal alloy catalyst for alkaline water electrolysis according to claim 1, characterized in that, In step 2, the calcination temperature is 300~700℃, the calcination time is 1h~5h, and the calcination atmosphere is one or more of argon, nitrogen, and helium.

8. The method for preparing the surface-supported rare earth metal alloy catalyst for alkaline water electrolysis according to claim 1, characterized in that, The rare earth metal salt solution is one or more of lanthanum nitrate solution, cerium nitrate solution, lanthanum acetate solution, and cerium acetate, and the concentration of the rare earth metal salt solution is 0.1~1 mol / L.

9. The method for preparing the surface-supported rare earth metal alloy catalyst for alkaline water electrolysis according to claim 1, characterized in that, In step 3, the phosphate is one or more of disodium hydrogen phosphate and sodium hypophosphite, the concentration of the phosphate is 0.1~0.8 mol / L, and the amount of deionized water is 10~60 mL.

10. The method for preparing the surface-supported rare earth metal alloy catalyst for alkaline water electrolysis according to claim 1, characterized in that, In step 3, the electrochemical activation potential is -0.2 to -1 V, and the electrochemical activation time is 10 to 60 min.

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