High-entropy alloy atomic layer catalyst, preparation method and application

Abstract

The invention relates to the technical field of fuel cells and electrolyzed water, in particular to a high-entropy alloy atomic layer catalyst, a preparation method and application. The catalyst has a PGM (at) IGM-PGM-HEA core-shell nanocube structure, the core is a platinum group metal, the shell layer is a pentabasic alloy formed by 2-3 iron group metals and 2-3 platinum group metals, and the atomic ratio is (1-3): 1. The preparation method comprises two steps of seed preparation and IGM-PGM-HEA atomic layer growth. The catalyst is coated on an electrode substrate such as a carbon base, a metal or a metal oxide to prepare an electrode, the electrode is used for a hydrogen evolution reaction and a hydroxide reaction, in the hydrogen evolution reaction, a 0.5 mol / L sulfuric acid solution test shows that the activity is reduced by not more than 10% after 15000 times of circulation; in a hydroxide reaction, the intrinsic activity is reduced by not more than 20% after 3000 times of circulation in a 0.1 mol / L KOH solution test. Compared with a commercial Pt / C catalyst, the catalyst provided by the invention has high catalytic activity and good stability, can effectively reduce reaction activation energy, and has important application value.

Description

Technical Field

[0001] The present invention relates to the technical fields of fuel cells and water electrolysis, and particularly to a high-entropy alloy atomic layer catalyst, a preparation method and an application thereof. Background Art

[0002] As a representative of clean energy, the efficient preparation (HER, hydrogen evolution reaction) and utilization (HOR, hydrogen oxidation reaction) of hydrogen energy rely on high-performance catalysts. At present, although platinum group metals (PGMs), such as Pt and Ru catalysts, have excellent performance, their reserves are scarce and the cost is high. In recent years, high-entropy alloys (HEAs) have become a research hotspot due to their multi-element synergistic effect ("cocktail effect"). By combining platinum group metals with iron group metals (IGMs) with high terrestrial abundance, such as Fe, Co, and Ni, not only can the amount of precious metals be reduced, but also the catalytic performance can be optimized through the electronic interaction between multi-elements. However, the existing high-entropy alloy catalysts face many challenges: in terms of atomic arrangement control, the crystal structures of platinum group metals and iron group metals are very different, making it extremely difficult to achieve a specific atomic arrangement on the surface of nanocrystals, which directly affects the formation of active sites of the catalyst and the efficiency of catalytic reactions; in terms of component optimization, the existing technology lacks a systematic study on the catalytic performance of multi-element combinations, and it is impossible to fully exploit the potential of high-entropy alloys, making it difficult to screen out the optimal element combination and ratio; for the synergistic mechanism between multi-elements, it is not yet clear at present, and the interaction between multi-elements and active sites are not clear, which limits the in-depth understanding and effective improvement of catalyst performance improvement; in addition, whether the high-entropy alloy is a thermodynamically stable phase or a metastable phase remains to be verified, and its thermal stability is in doubt, which may lead to changes in the structure and performance of the catalyst during actual application, affecting its service life and reliability.

[0003] In summary, it is an urgent problem to be solved to develop a high-entropy alloy atomic layer catalyst with high catalytic reaction efficiency, reasonable alloy element ratio and thermodynamic stability. Summary of the Invention

[0004] In order to solve the problems of the existing technology, the present invention reports a high-entropy alloy atomic layer catalyst prepared by a wet chemical synthesis method, a preparation method and an application thereof. The specific technical solutions are as follows:

[0005] A high-entropy alloy atomic layer catalyst, the catalyst has a core-shell structure, the core is a platinum group metal, and the shell layer is an alloy formed by an iron group metal and a platinum group metal, and its structural formula is PGM@IGM-PGM-HEA; the catalyst has a cubic shape and a PGM@IGM-PGM-HEA core-shell nanocube structure with {100} crystal planes.

[0006] Furthermore, the core is a platinum group metal, and the shell layer is a quinary alloy formed by 2 - 3 iron group metals and 2 - 3 platinum group metals, with the shell layer thickness being 1 - 5 nm.

[0007] Furthermore, two or three of the iron group metals are Fe, Co, and Ni, and two or three of the platinum group metals are Ru, Rh, Pd, Os, Ir, and Pt.

[0008] Furthermore, in the shell layer, the atomic ratio of the platinum group metal to the iron group metal is 1 - 3:1.

[0009] A preparation method of a high - entropy alloy atomic layer catalyst, characterized by comprising two key steps: seed preparation and IGM - PGM - HEA atomic layer growth.

[0010] Furthermore, with Pd as the core, the preparation method of the high - entropy alloy atomic layer catalyst is as follows:

[0011] S1. Preparation of Pd cubic seeds: Add 0.01 - 0.1 g of ascorbic acid, 0.1 - 1 g of polyvinylpyrrolidone, and 0.1 - 1 g of KBr into 20 - 100 mL of deionized water, stir evenly, heat to 80 - 120 °C, then add 1 - 5 mL of an aqueous solution of Na2PdCl4 with a concentration of 0.05 - 0.2 mol / L for reaction at a temperature of 80 - 120 °C for 3 - 5 h, with a stirring rate of 500 - 800 r / min to obtain a reaction product. Wash the reaction product 3 - 5 times with deionized water, and then ultrasonically disperse it in 10 - 50 mL of oleylamine solvent to obtain a solution containing Pd cubic seeds;

[0012] S2. IGM - PGM - HEA atomic layer growth: Mix 5 - 20 mL of the solution containing Pd cubic seeds in S1 with 10 - 50 mL of 1 - octadecene evenly. First, preheat at 110 °C for 10 - 60 min, then preheat at 200 °C for 10 - 60 min, and then dropwise add it to 5 - 20 mL of the metal salt precursor solution at a rate of 0.8 - 2 mL / h, with a stirring rate of 300 - 500 r / min. After the reaction is completed, wash and centrifuge 3 - 5 times, and dry to obtain the high - entropy alloy atomic layer catalyst.

[0013] Furthermore, with Pd as the core, the preparation method of the high - entropy alloy atomic layer catalyst is as follows:

[0014] S1. Preparation of Pd octahedral seeds:

[0015] S1-1. Preparation of Pd nanocubes: In a flask, 60 - 100 mg of ascorbic acid, 100 - 200 mg of polyvinylpyrrolidone, and 300 - 500 mg of KBr were added to 20 - 30 mL of deionized water, stirred evenly, heated at 80 - 120 °C for 5 - 20 min, then quickly injected with 3 - 5 mL of an aqueous solution of Na2PdCl4 with a concentration of 15 - 30 g / L, magnetically stirred for 3 - 5 h under sealed conditions at a temperature of 80 - 120 °C and a stirring rate of 300 - 500 r / min; after stirring, it was naturally cooled to room temperature, then centrifuged and washed with deionized water 3 - 5 times, and the washed Pd nanocubes were ultrasonically dispersed in 1 - 5 mL of a formaldehyde solvent with a concentration of 0.1 - 0.5 mol / L to obtain a Pd nanocube solution;

[0016] S1-2. Add the Pd nanocube solution described in S1-1 and 0.5 - 5 g of polyvinylpyrrolidone to 50 - 100 mL of deionized water, then add 1 - 5 mL of a Na2PdCl4 solution with a concentration of 0.05 - 0.2 mol / L for reaction at a temperature of 80 - 120 °C for 3 - 5 h and a stirring rate of 500 - 800 r / min to obtain a reaction product. The reaction product was washed with deionized water 3 - 5 times and then ultrasonically dispersed in 10 - 50 mL of an oleylamine solvent to obtain a solution containing Pd octahedron seeds;

[0017] S2. IGM-PGM-HEA atomic layer growth: Mix 5 - 20 mL of the solution containing Pd octahedron seeds described in S1 evenly with 10 - 50 mL of 1-octadecene, preheat at 110 °C for 10 - 60 min first and then at 200 °C for 10 - 60 min, and then dropwise add it to 5 - 20 mL of a metal salt precursor solution at a rate of 0.8 - 2 mL / h with a stirring rate of 300 - 500 r / min. After the reaction is completed, wash and centrifuge 3 - 5 times, and dry to obtain the high-entropy alloy atomic layer catalyst.

[0018] Further, the precursor solution is an aqueous solution of a mixture of soluble salts of iron-group metals and platinum-group metals, and the concentration of each metal ion is 2×10-5 - 8×10-5 mol / L.

[0019] Further, the soluble salts of iron-group metals are soluble salts of iron (Fe), cobalt (Co), and nickel (Ni), and the soluble salts of platinum-group elements are soluble salts of platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), and ruthenium (Ru).

[0020] The present invention also provides an electrode coated with a high-entropy alloy atomic layer catalyst. The high-entropy alloy atomic layer catalyst is coated on an electrode substrate and dried to obtain the electrode.

[0021] Further, the electrode substrate is any one of a carbon-based material, a metal material, and a metal oxide material.

[0022] The present invention also provides a method for using a high-entropy alloy atomic layer catalyst for catalyzing hydrogen evolution reaction. The electrode coated with the high-entropy alloy atomic layer catalyst is applied to the electrochemical catalysis of hydrogen evolution reaction. An electrochemical test is carried out using a three-electrode system, and the electrolyte is a 0.5 mol / L sulfuric acid solution. The specific method is to use the electrode coated with the high-entropy alloy atomic layer catalyst as the working electrode, the Ag / AgCl electrode as the reference electrode, and the Pt electrode as the auxiliary electrode; wherein the activity of the high-entropy alloy atomic layer catalyst decreases by no more than 10% after 15,000 cycles.

[0023] The present invention also provides a method for using a high-entropy alloy atomic layer catalyst for hydrogen oxidation reaction. The electrode coated with the high-entropy alloy atomic layer catalyst is applied to the electrochemical catalysis of hydrogen oxidation reaction. An electrochemical test is carried out using a three-electrode system, and the electrolyte is a 0.1 mol / L KOH solution. The specific method is to use the electrode coated with the high-entropy alloy atomic layer catalyst as the working electrode, the Hg / HgO electrode as the reference electrode, and the Pt electrode as the auxiliary electrode; wherein the intrinsic activity of the high-entropy alloy atomic layer catalyst decreases by no more than 20% after 3,000 cycles.

[0024] Advantages of the present invention

[0025] 1. Enhanced catalytic activity through unique structure: The high-entropy alloy atomic layer catalyst of the present invention has a PGM@IGM-PGM-HEA core-shell nanocube structure, where the core is a platinum group metal and the shell is a quinary alloy formed by multiple iron group metals and platinum group metals. This structure unexpectedly exhibits the synergistic effect of each element. The platinum group metal as the inner core provides the basic active sites for catalytic reactions; the multi-element alloy structure of the shell optimizes the electron cloud distribution on the catalyst surface through the "cocktail effect". The difference in electronegativity of different metal atoms causes electrons to transfer between atoms, thereby changing the adsorption energy of reactants on the catalyst surface. Taking the Pd@PtRuFeCoNi atomic layer catalyst as an example, when the Pd@PtRuFeCoNi atomic layer catalyst is formed, the "cocktail effect" begins to take effect. Due to the different electronegativities of Pt, Ru, Fe, Co, and Ni atoms in the shell, electrons transfer between atoms. Pt and Ru with higher electronegativities will attract some electrons from Fe, Co, and Ni. For example, some electrons of the Fe atom will flow to Pt and Ru, making the electron cloud no longer confined around a single atom, but becoming more diffuse and uniform; at the same time, the newly formed chemical bonds and lattice structure during alloying further change the electron cloud distribution, making electrons more delocalized in the entire shell region; although the Pd core is relatively stable, it will also have a certain electron interaction with the shell atoms, and this interaction will fine-tune the overall electron cloud distribution of the core and the shell, enhancing the electron synergistic effect of the entire catalyst system; in the HOR, the optimized electron cloud distribution promotes the oxidation reaction of hydrogen molecules, and hydrogen molecules can transfer electrons to the catalyst more effectively, improving the efficiency of the catalytic reaction; therefore, the Pd@PtRuFeCoNi atomic layer catalyst exhibits excellent catalytic activity in the HER and HOR reactions due to the "cocktail effect-optimized electron cloud distribution.

[0026] 2. Precise control of atomic arrangement to improve catalytic selectivity: In the technical solution, the atomic arrangement is precisely controlled through a specific wet chemical synthesis method to form a structure with {100} crystal planes. This precise control is of great significance in catalytic reactions; the presence of {100} crystal planes makes the atomic arrangement on the catalyst surface orderly, and the atoms of different elements are evenly and regularly distributed on the crystal plane. During the catalytic reaction, reactants can interact more precisely with specific atoms or atomic combinations, thereby improving the selectivity of the catalytic reaction. Taking the HER reaction as an example, the specific atomic arrangement makes hydrogen atoms more likely to adsorb and react at specific positions on the catalyst surface, reducing unnecessary side reactions and improving the efficiency and purity of hydrogen generation, providing a guarantee for the efficient preparation of hydrogen.

[0027] 3. Good stability extends the service life of the catalyst: The catalyst of the present invention exhibits good stability in the HER and HOR reactions. For example, in the HER test, the catalytic activity decreases by no more than 10% after 15,000 cycles, and in the HOR test, the catalytic activity decreases by no more than 20% after 3,000 cycles. This is due to its core-shell structure and the synergistic effect between elements. The core-shell structure provides a stable framework for the catalyst. The inner platinum group metal core ensures the basic catalytic performance of the catalyst, and the outer alloy shell layer enhances the structural stability through the interaction between elements. During the reaction process, the iron group metal and platinum group metal in the shell cooperate with each other, inhibiting the migration and aggregation of atoms and reducing the structural change of the catalyst. At the same time, this structure also enhances the tolerance of the catalyst to the reaction environment. For example, in acidic (0.5 mol / L H2SO4 electrolyte in HER) and alkaline (0.1 mol / L KOH solution in HOR) environments, it can maintain stable catalytic activity, greatly extending the service life of the catalyst, reducing the use cost, and improving its feasibility in practical applications. Detailed implementation mode

[0028] To better explain the present invention, the exemplary embodiments of the present invention will be described in more detail below. Although the exemplary embodiments of the present invention are shown below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0029] Example 1: Preparation of Pd@PtRuFeCoNi atomic layer catalyst

[0030] S1. Preparation of Pd cubic seeds

[0031] Dissolve 60 mg of ascorbic acid, 105 mg of polyvinylpyrrolidone, and 300 mg of KBr in 8 mL of water, stir evenly, heat at 80 °C for 10 min, and then quickly inject 3 mL of an aqueous solution of Na2PdCl4 with a concentration of 19 g / L at one time. Stir magnetically for 3 h under sealed conditions at a temperature of 80 °C and a magnetic stirring rate of 300 r / min. After stirring, cool naturally to room temperature to obtain Pd nanocubes. Wash the Pd nanocubes 3 times with deionized water and then ultrasonically disperse them in 10 mL of oleylamine to obtain a Pd cubic seed solution.

[0032] S2. Growth of PtRuFeCoNi atomic layer

[0033] Mix 10 mL of the Pd cubic seed solution described in S1 with 20 mL of 1-octadecene evenly. First, preheat it at 110 °C for 30 min, then preheat it at 200 °C for 30 min. After that, add 10 mL of the metal salt precursor solution dropwise at a rate of 0.8 mL / h. The precursor solution is a mixed solution of H2PtCl6·6H2O, RuCl3·xH2O, Ni(C5H7O2)2, Co(C5H7O2)2, and Fe(C5H7O2)3. Among them, the concentration of each metal ion is 4.2×10 -5 mol / L, the stirring rate is 300 r / min. After the reaction is completed, wash and centrifuge 3 times, and obtain the Pd@PtRuFeCoNi atomic layer catalyst after drying.

[0034] Example 2: Preparation of Pd@PtRhFeCoNi atomic layer catalyst

[0035] S1. Preparation of Pd octahedral seeds:

[0036] S1-1. Preparation of Pd nanocubes: In a flask, add 60 mg of ascorbic acid, 105 mg of polyvinylpyrrolidone, and 300 mg of KBr to 8 mL of deionized water, stir evenly, heat at 80 °C for 10 min, then quickly inject 3 mL of an aqueous solution of Na2PdCl4 with a concentration of 19 g / L, and magnetically stir for 3 h under sealed conditions at a temperature of 80 °C and a stirring rate of 300 r / min; after the stirring is completed, cool to room temperature naturally, then centrifuge and wash 3 times with deionized water, and ultrasonically disperse the washed Pd nanocubes in 1 mL of a formaldehyde solvent with a concentration of 0.1 mol / L to obtain a Pd nanocube solution;

[0037] S1-2. Add the Pd nanocube solution described in S1-1 and 0.5 g of polyvinylpyrrolidone to 50 mL of deionized water, then add 1 mL of a Na2PdCl4 solution with a concentration of 0.05 mol / L to react at a temperature of 80 °C for 3 h and a stirring rate of 500 r / min to obtain a reaction product. Wash the reaction product 3 times with deionized water, and then ultrasonically disperse it in 10 mL of an oleylamine solvent to obtain a Pd octahedral seed solution;

[0038] S2. PtRhFeCoNi atomic layer growth

[0039] Mix 10 mL of the Pd octahedron seed solution described in S1 evenly with 10 mL of 1-octadecene. First, preheat it at 110 °C for 10 min, then preheat it at 200 °C for 10 min. After that, add 5 mL of the metal salt precursor solution dropwise at a rate of 1 mL / h. The precursor solution is a mixed solution of H2PtCl6·6H2O, RhCl3·xH2O, Ni(C5H7O2)2, Co(C5H7O2)2, and Fe(C5H7O2)3. Among them, the concentration of each metal ion is 4.2×10 -5 mol / L, the stirring rate is 350 r / min. After the reaction is completed, wash and centrifuge 3 times, and dry to obtain the Pd@PtRhFeCoNi atomic layer catalyst.

[0040] Example 3: Preparation of Pd@IrRuFeCoNi atomic layer catalyst

[0041] S1. Preparation of Pd cube seeds

[0042] Dissolve 60 mg of ascorbic acid, 105 mg of polyvinylpyrrolidone, and 300 mg of KBr in 8 mL of water, stir evenly, heat at 80 °C for 10 min, and then quickly inject 3 mL of an aqueous solution of Na2PdCl4 with a concentration of 19 g / L at one time. Stir magnetically for 3 h under sealed conditions at a temperature of 80 °C and a magnetic stirring rate of 300 r / min. After the stirring ends, cool naturally to room temperature to obtain Pd nanocubes. Wash the Pd nanocubes 3 times with deionized water, and then ultrasonically disperse them in 15 mL of oleylamine to obtain a Pd cube seed solution;

[0043] S2. Growth of IrRuFeCoNi atomic layer

[0044] Mix 15 mL of the Pd cube seed solution described in S1 evenly with 30 mL of 1-octadecene. First, preheat it at 110 °C for 50 min, then preheat it at 200 °C for 50 min. After that, add 15 mL of the metal salt precursor solution dropwise at a rate of 1.5 mL / h. The precursor solution is a mixed solution of IrCl3·xH2O, RuCl3·xH2O, Ni(C5H7O2)2, Co(C5H7O2)2, and Fe(C5H7O2)3. Among them, the concentration of each metal ion is 4.2×10 -5 mol / L, the stirring rate is 400 r / min. After the reaction is completed, wash and centrifuge 3 times, and dry to obtain the Pd@IrRuFeCoNi atomic layer catalyst.

[0045] Hydrogen evolution reaction test

[0046] A three - electrode system was adopted. The electrode coated with the atomic - layer catalyst prepared in Examples 1 - 3 was used as the working electrode, the Ag / AgCl electrode was used as the reference electrode, and the Pt electrode was used as the auxiliary electrode. The test was carried out in a 0.5 mol / L H2SO4 electrolyte. The test potential range was (-0.1) - 0.1 V relative to the reversible hydrogen electrode, and the scanning rate was 5 mV / s. The test results are shown in Table 1.

[0047] Hydrogen oxidation reaction test

[0048] A three - electrode system was adopted. The electrode coated with the atomic - layer catalyst prepared in Examples 1 - 3 was used as the working electrode, the Hg / HgO electrode was used as the reference electrode, and the Pt electrode was used as the auxiliary electrode. The test was carried out in a 0.1 mol / L KOH electrolyte. The geometric current density was - 10 mA·cm -2 , and the test potential increased from 0 to 0.2 V with a scanning rate of 10 mV / s. The test results are shown in Table 2.

[0049] Comparative example

[0050] The electrode coated with a commercial Pt / C catalyst (Microvent) was used as the working electrode, the Ag / AgCl electrode was used as the reference electrode, and the Pt electrode was used as the auxiliary electrode. The hydrogen evolution reaction test was carried out under the same conditions as in the examples, and the test results are shown in Table 1; the hydrogen oxidation reaction test was carried out, and the test results are shown in Table 2.

[0051] Table 1. Hydrogen evolution reaction test results of examples and comparative examples

[0052]

[0053] It can be seen from Table 1 that the PGM@IGM - PGM - HEA atomic - layer catalyst of the present invention can effectively reduce the activation energy of the HER reaction compared with the commercial Pt / C catalyst, promote the generation of hydrogen, and enable the reaction to proceed at a lower additional voltage, showing good catalytic activity. Especially for the Pd@PtRuFeCoNi atomic - layer catalyst, due to its specific composition and ratio, it can give full play to the "cocktail effect" to optimize the performance of the catalyst. Furthermore, during the long - term HER reaction process, the Pd@PtRuFeCoNi atomic - layer catalyst can maintain relatively stable catalytic activity and has good durability.

[0054] Table 2. Hydrogen oxidation reaction test results of examples and comparative examples

[0055]

[0056] As can be seen from Table 2, the PGM@IGM-PGM-HEA atomic layer catalyst of the present invention can effectively reduce the reaction resistance in the hydrogen oxidation reaction compared with the commercial Pt / C catalyst, promoting the progress of the hydrogen oxidation reaction. In particular, the Pd@PtRuFeCoNi atomic layer catalyst, with its unique composition and ratio, exhibits high catalytic activity in the HOR reaction, can efficiently catalyze the hydrogen oxidation reaction, and, in the HOR reaction, the Pd@PtRuFeCoNi atomic layer catalyst also has excellent stability and can still maintain high catalytic activity after multiple cycles of use.

[0057] The above is only a preferred embodiment of the present invention and is not a limitation of the present invention in any other form. Any modification or equivalent change made according to the technical essence of the present invention still belongs to the scope of protection required by the present invention.

Claims

1. A high-entropy alloy atomic layer catalyst, characterized in that, The catalyst has a core-shell structure. The core is a platinum group metal, and the shell is an alloy formed by a ferrous metal and a platinum group metal, with the structural formula PGM@IGM-PGM-HEA. The catalyst has a cubic shape and a PGM@IGM-PGM-HEA core-shell nanocube structure with {100} crystal planes.

2. The high-entropy alloy atomic layer catalyst according to claim 1, characterized in that, The core is a platinum group metal; the shell is a quinary alloy formed by 2-3 ferrous metals and 2-3 platinum group metals. The ferrous metals are two or three of Fe, Co, and Ni, and the platinum group metals are two or three of Ru, Rh, Pd, Os, Ir, and Pt. The shell thickness is 1-5 nm.

3. The high-entropy alloy atomic layer catalyst according to claim 1, characterized in that In the shell, the atomic ratio of the platinum group metal to the ferrous metal is 1-3:

1.

4. The preparation method of the high-entropy alloy atomic layer catalyst according to claim 1, characterized in that, It includes two steps, namely seed preparation and IGM-PGM-HEA atomic layer growth.

5. The preparation method according to claim 4, characterized in that, It is divided into the following steps: S1. Preparation of Pd cubic seeds: Add 0.01-0.1 g of ascorbic acid, 0.1-1 g of polyvinylpyrrolidone, and 0.1-1 g of KBr to 5-15 mL of deionized water, stir evenly, heat to 80-120 °C, and then quickly inject 1-5 mL of an aqueous Na2PdCl4 solution with a concentration of 15-30 g / L for reaction. The temperature is 80-120 °C, the time is 3-5 h, and the stirring rate is 300-500 r / min to obtain Pd nanocubes. Wash the Pd nanocubes with deionized water 3-5 times, and then ultrasonically disperse them in 5-10 mL of oleylamine to obtain a Pd cubic seed solution; S2. IGM-PGM-HEA atomic layer growth: Mix 5-20 mL of the Pd cubic seed solution in S1 with 10-50 mL of 1-octadecene evenly. First, preheat at 110-130 °C for 10-60 min, then preheat at 200 °C for 10-60 min, and then dropwise add 5-20 mL of the metal salt precursor solution at a rate of 0.8-2 mL / h. The stirring rate is 300-500 r / min. After the reaction is completed, wash and centrifuge 3-5 times, and dry to obtain the high-entropy alloy atomic layer catalyst.

6. The preparation method according to claim 4, characterized in that, It is divided into the following steps: S1. Preparation of Pd octahedral seeds: S1-1. Preparation of Pd nanocubes: In a flask, add 0.01-0.1 g of ascorbic acid, 0.1-1 g of polyvinylpyrrolidone, and 0.1-1 g of KBr to 5-15 mL of deionized water, stir evenly, heat at 80-120 °C for 5-20 min, and then quickly inject 3-5 mL of an aqueous Na2PdCl4 solution with a concentration of 15-30 g / L. Stir magnetically for 3-5 h under sealed conditions at a temperature of 80-120 °C and a stirring rate of 300-500 r / min; after the stirring ends, naturally cool to room temperature, then centrifuge and wash with deionized water 3-5 times. Ultrasonically disperse the washed Pd nanocubes in 1-5 mL of a formaldehyde solvent with a concentration of 0.1-0.5 mol / L to obtain a solution containing Pd nanocubes; S1-2. Add the solution containing Pd nanocubes described in S1-1 and 0.5 - 5 g of polyvinylpyrrolidone into 50 - 100 mL of deionized water, then add 1 - 5 mL of Na2PdCl4 solution with a concentration of 0.05 - 0.2 mol / L for reaction. The temperature is 80 - 120 °C, the time is 3 - 5 h, and the stirring rate is 500 - 800 r / min to obtain a reaction product. Wash the reaction product with deionized water 3 - 5 times, and then ultrasonically disperse it in 10 - 50 mL of oleylamine solvent to obtain a solution containing Pd octahedron seeds; S2. IGM - PGM - HEA atomic layer growth: Mix 5 - 20 mL of the solution containing Pd octahedron seeds described in S1 evenly with 10 - 50 mL of 1 - octadecene. First, preheat it at 110 - 130 °C for 10 - 60 min, then preheat it at 200 °C for 10 - 60 min, and then dropwise add it to 5 - 20 mL of the metal salt precursor solution at a rate of 0.8 - 2 mL / h. The stirring rate is 300 - 500 r / min. After the reaction is completed, wash and centrifuge 3 - 5 times, and dry to obtain the high - entropy alloy atomic layer catalyst.

7. The preparation method according to any one of claims 5 and 6, characterized in that, The precursor solution is an aqueous solution of a mixture of soluble salts of iron group metals and platinum group metals, wherein the concentration of each metal ion is 2×10 -5 -8×10 - 5 mol / L.

8. An electrode coated with a high-entropy alloy atomic layer catalyst, characterized in that, Coat the high - entropy alloy atomic layer catalyst described in Claim 1 on the electrode substrate and perform a drying treatment to obtain the electrode coated with the high - entropy alloy atomic layer catalyst, where the electrode substrate is any one of carbon - based materials, metal materials, and metal oxide materials.

9. A method for using a high-entropy alloy atomic layer catalyst to catalyze the hydrogen evolution reaction, characterized in that, Apply the electrode coated with the high - entropy alloy atomic layer catalyst described in Claim 8 to the electrochemical catalysis of hydrogen evolution reaction. Use a three - electrode system for electrochemical testing. The electrolyte is 0.5 mol / L sulfuric acid solution. The specific method is to use the electrode coated with the high - entropy alloy atomic layer catalyst as the working electrode, the Ag / AgCl electrode as the reference electrode, and the Pt electrode as the auxiliary electrode; among them, the activity of the high - entropy alloy atomic layer catalyst decreases by no more than 10% after 15000 cycles.

10. A method for using a high-entropy alloy atomic layer catalyst for the hydrogen evolution reaction, characterized in that, Apply the electrode coated with the high - entropy alloy atomic layer catalyst described in Claim 8 to the electrochemical catalysis of hydrogen oxidation reaction. Use a three - electrode system for electrochemical testing. The electrolyte is 0.1 mol / L KOH solution. The specific method is to use the electrode coated with the high - entropy alloy atomic layer catalyst as the working electrode, the Hg / HgO electrode as the reference electrode, and the Pt electrode as the auxiliary electrode; among them, the intrinsic activity of the high - entropy alloy atomic layer catalyst decreases by no more than 20% after 3000 cycles.

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