Nano high-entropy alloy electrocatalytic material, preparation thereof and application thereof in oer / orr

Abstract

The application belongs to the field of catalytic materials, and specifically discloses a preparation method of a nano high-entropy alloy material and application of the material in oxygen electrocatalysis. The preparation method is as follows: a multi-metal organic complex, a reactive metal and a molten salt are mixed and calcined, and then subjected to simple water washing treatment and alkali washing modification treatment to obtain the nano high-entropy alloy material; the multi-metal organic complex is a complex formed by a metal M source and an organic complexing agent, and the metal M contains five or more than five kinds of Fe, Co, Ni, Cr, Mn, Cu, V, Mo, Ti, Au, Ag, Pt, Pd, Ru, Ir and Rh. The application also includes the material prepared by the preparation method and application of the material in OER / ORR catalysis. The material prepared by the method has excellent OER / ORR catalytic activity and stability.

Description

Technical Field

[0001] This invention belongs to the field of electrode materials, specifically relating to an OER and ORR catalytic material. Background Technology

[0002] The overuse of traditional fossil fuels has triggered a series of severe energy and environmental problems, making the development of sustainable clean energy a current research hotspot. Zinc-air batteries, with their advantages of high safety, zero pollution, high specific energy, high power, low cost, and renewable materials, represent one of the important development directions for green and efficient energy storage technologies.

[0003] In zinc-air batteries, the oxygen reduction reaction (ORR) occurs during discharge and the oxygen evolution reaction (OER) occurs during charging. The slow kinetics of both ORR and OER lead to high overpotentials. Currently available commercially available Pt / Ru-based catalysts exhibit high catalytic activity and can reduce these overpotentials, but their high cost and poor durability are limiting factors. Therefore, reducing the noble metal loading while maintaining high activity and stability is crucial for high-performance catalyst design. Alloying non-noble metals or alloying non-noble metals with noble metals not only reduces the noble metal content but also adjusts the electronic structure of the noble metals, thereby improving the intrinsic catalytic activity and stability of the active sites.

[0004] High-entropy alloys (HEAs) refer to single-phase alloys containing five or more metallic elements with similar atomic ratios. They have become a research hotspot in multi-element alloy catalytic materials in recent years. Compared to few-element alloys, HEAs can achieve adjustment of the electronic structure and adsorption energy of the alloy surface through composition design. Moreover, thanks to their inherent high-entropy-driven thermodynamics and structural stability, HEAs typically exhibit excellent stability. For example, Chinese patent document CN116288477A discloses a bifunctional high-entropy nano-alloy electrocatalyst and its preparation method. This bifunctional high-entropy nano-alloy electrocatalyst includes a porous nickel foam matrix and an electrodeposited (Fe) material supported on the nickel foam matrix. 1 / 5 Co 1 / 5 Ni 1 / 5 Cu 1 / 5 Zn 1 / 5 ) 1-x Li x (x = 0.24–0.27) High-entropy nanoalloys, based on the ion molar ratio Fe 3+ Co 2+ Ni 2+ Cu 2+ Zn 2+ Li + = 1:1:1:1:1:(1.6~1.8), which has excellent catalytic activity and stability.

[0005] However, existing technologies for preparing high-entropy alloys mostly employ solid-state reaction methods and solution-phase wet chemical reduction methods. Among these, solid-state reaction methods tend to lead to the formation of metal carbides, and the resulting catalysts have poor size uniformity. In solution-phase wet chemical reduction methods, metals with high oxygen reduction potentials are easily reduced, while metals with very low oxygen reduction potentials are difficult to reduce, leading to alloy phase separation.

[0006] In summary, existing technologies for preparing high-entropy alloy catalysts struggle to simultaneously achieve both high economic efficiency and high catalytic activity. Therefore, developing a high-entropy alloy synthesis method that combines universality and high yield remains the future direction. Summary of the Invention

[0007] To address the problems existing in current electrocatalytic materials, the primary objective of this invention is to provide a method for preparing nano-high-entropy alloy electrocatalytic materials, aiming to obtain materials with excellent electrocatalytic activity.

[0008] The second objective of this invention is to provide a nano-high-entropy alloy electrocatalytic material prepared by the aforementioned method and its application in ORR and / or OER catalysis.

[0009] A third objective of this invention is to provide a battery comprising the aforementioned high-entropy nano-alloy electrocatalytic material.

[0010] A method for preparing a nano-high entropy alloy electrocatalytic material involves mixing a multi-metal organic complex, an active metal, and a molten salt, followed by calcination, and then water washing and alkali washing modification to obtain the nano-high entropy alloy electrocatalytic material.

[0011] The aforementioned multimetallic organic complex is a complex formed by a metal M source and an organic complexing agent, wherein the metal M comprises five or more of the following: Fe, Co, Ni, Cr, Mn, Cu, V, Mo, Ti, Au, Ag, Pt, Pd, Ru, Ir, and Rh.

[0012] This invention innovatively mixes multi-metal organic complexes, active metals, and molten salts, followed by calcination and alkali modification. This unexpectedly achieves synergy, allowing multiple transition metals to be reduced within the molten active metals in the liquid environment provided by the molten salt. Under the strong solvation effect of the molten salt, the materials are well dispersed, and the enthalpy of mixing of the molten metals is very low. This allows for the synthesis of uniformly mixed high-entropy alloy materials. Adjusting the composition and ratio of each metal can enable the high-entropy alloy catalyst material to obtain the target adsorption energy, thereby achieving optimal electrocatalytic performance, especially with excellent ORR and OER performance.

[0013] In this invention, the metal M comprises Fe, Co, Ni, Mn, and Cu. Research in this invention shows that this preferred metal combination can further synergistically improve the ORR and OER performance of the prepared materials.

[0014] In this invention, the molar content of each metal in metal M is the average molar percentage content ±20%.

[0015] In this invention, the organic complexing agent is a component capable of successfully complexing with metal M, for example, it can be an N-containing complexing agent; preferably, it is at least one of dopamine hydrochloride, 2-methylimidazole, and resorcinol; dopamine hydrochloride is preferred. Studies have shown that using the preferred complexing agent, combined with the process of this invention, can further synergistically regulate the physicochemical characteristics and active sites of the prepared material, and can further synergistically improve the ORR and OER performance of the prepared material.

[0016] In this invention, a metal M source and an organic complexing agent are subjected to a complexation reaction to obtain the aforementioned multi-metal organic complex;

[0017] In this invention, the metal M source is a water-soluble salt of metal M, preferably at least one of chloride, nitrate, sulfate, or acetate; more preferably, a nitrate. This invention demonstrates that using a preferred metal nitrate raw material can unexpectedly and synergistically enhance the process, contributing to further improvements in the electrocatalytic performance of the prepared material.

[0018] Preferably, the mass ratio of the metal M source to the organic complexing agent is 1:2-40; further, it can be 1:2-15; even further, it can be 1:4-12; and even further, it can be 1:9-11.

[0019] In this invention, a buffer is added during the complexation reaction stage;

[0020] Preferably, the buffer contains at least one of tris(hydroxymethyl)aminomethane, tris(hydroxymethyl)methylglycine, and formaldehyde; more preferably, it contains tris(hydroxymethyl)aminomethane.

[0021] Preferably, the weight ratio of the metal M source to the buffer is 1:2-40; further, it can be 1:2-15; even further, it can be 1:4-12; and even further, it can be 1:9-11.

[0022] In this invention, the active metal includes at least one of Zn, Al, and Mg, preferably Zn. Studies have shown that using a preferred active metal can further synergize with the process, contributing to further improvement in the ORR and OER performance of the prepared materials.

[0023] Preferably, the mass ratio of the polymetallic organic complex to the active metal is 1 to 5:1; more preferably 1.5 to 3:1.

[0024] In this invention, the molten salt includes one or more of NaCl, KCl, LiCl, CaCl2, Na2CO3, K2CO3, Li2CO3, NaNO3, KNO3, and LiNO3;

[0025] Preferably, the weight ratio of molten salt to polymetallic organic complex is 5 to 20:1; more preferably 8 to 12:1.

[0026] In this invention, the calcination temperature is 600-1000℃.

[0027] In this invention, the calcination process includes two holding stages, wherein the temperature of the first holding stage is 600–700°C, and the temperature of the second holding stage is 850–950°C. Studies have shown that this preferred process allows for further control of the physicochemical properties of the prepared material, which can help improve the ORR and OER performance of the prepared material.

[0028] Preferably, the calcination time is 2-4 hours. When the preferred two-stage heat preservation calcination process is selected, in this invention, the first stage heat preservation time can be 1-2 hours, and the second stage heat preservation time can be 1-2 hours.

[0029] Preferably, the alkaline solution used in the alkaline washing and modification process is an aqueous solution of an alkali metal hydroxide.

[0030] The present invention also provides a nano-high-entropy alloy electrocatalytic material prepared by the preparation method described above.

[0031] The preparation method described in this invention can endow the obtained material with physicochemical characteristics suitable for electrocatalysis, and can improve its performance in ORR and OER.

[0032] The present invention also provides an application of the nano high-entropy alloy electrocatalytic material prepared by the above preparation method, using it as a catalytic material for ORR and / or OER;

[0033] In this invention, the materials described herein can be used in any ORR and OER scenarios known in the industry. For example, they can be used as catalytic materials for ORR and / or OER in the preparation of batteries.

[0034] The present invention also provides a battery comprising the nano-high-entropy alloy electrocatalytic material prepared by the aforementioned preparation method.

[0035] The battery described in this invention, apart from containing the nano-high-entropy alloy electrocatalytic material described in this invention, may have other known components, structures, and parts.

[0036] Compared to existing technologies, it has the following advantages:

[0037] (1) The metal and carbon precursor are thoroughly and uniformly mixed under liquid phase conditions. The operation is simple, efficient and has a good dispersion effect.

[0038] (2) High-temperature calcination can fully reduce the active metal to the high-valence state of the metal precursor and make the metal uniformly mixed in the molten metal to obtain a high-entropy alloy.

[0039] (3) The strong solvation effect of molten salt can disperse carbon materials well, giving the materials a huge specific surface area and exposing more catalytic active sites.

[0040] (4) The preparation method of the carbon-supported nano high-entropy alloy catalyst is simple and easy to operate, and can be synthesized in batches. The synthesized carbon-supported nano high-entropy alloy catalyst has high ORR / OER catalytic activity and strong stability. Attached Figure Description

[0041] Figure 1 XRD pattern of sample 1;

[0042] Figure 2 SEM and EDS images of sample 1;

[0043] Figure 3 XPS diagram for implementation sample 1;

[0044] Figure 4 SEM image of sample 2;

[0045] Figure 5 SEM and EDS images of sample 3 were obtained;

[0046] Figure 6 SEM and EDS images of sample 4;

[0047] Figure 7 XRD pattern of catalyst for comparison sample 1;

[0048] Figure 8 For comparison, here are the SEM and TEM images of catalyst sample 1;

[0049] Figure 9 SEM and EDS images of catalyst for comparison sample 2;

[0050] Figure 10 SEM image of catalyst for comparison sample 3;

[0051] Figure 11 ORR linear sweep voltammetric curves for partial implementation and control samples;

[0052] Figure 12OER linear scan voltammetry curves for partial implementation and control samples;

[0053] Figure 13 Chronocurrent curves of sample 1 and commercial Pt / C at a constant potential of 0.7V (vs. RHE) were obtained. Detailed Implementation

[0054] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0055] This invention provides an optional method for preparing a nano-high-entropy alloy catalyst, comprising the following steps:

[0056] Step (1): Weigh a certain amount of metal salt and N-containing complexing agent, dissolve them in deionized water, stir thoroughly, carry out the complexation reaction, then filter the solution, and finally dry the filtered product to obtain the precursor.

[0057] Step (2): The precursor obtained in step (1) is ball-milled and mixed with active metal powder and molten salt components;

[0058] Step (3): The mixed product obtained in step (2) is placed into an alumina crucible and calcined at high temperature in an argon atmosphere;

[0059] Step (4): After water washing and alkali washing modification, the product is rinsed and filtered multiple times with deionized water. Finally, the product on the filter paper is dried to obtain the carbon-supported nano high-entropy alloy catalyst.

[0060] The metal salt described in step (1) contains five or more of the following metal elements: Fe, Co, Ni, Cr, Mn, Cu, V, Mo, Ti, Au, Ag, Pt, Pd, Ru, Ir, and Rh, and the number of moles of metal ions is equal.

[0061] In step (1), the mass ratio of metal salt to N-containing complexing agent is 1:2-40.

[0062] The metal salt in step (1) is one or more of chloride, nitrate, sulfate or acetate.

[0063] The nitrogen-containing complexing agent mentioned in step (1) includes one of dopamine hydrochloride, 2-methylimidazole, and resorcinol. If dopamine hydrochloride is selected as the nitrogen-containing complexing agent, tris(hydroxymethyl)aminomethane needs to be added as a buffer. If 2-methylimidazole is selected as the nitrogen-containing complexing agent, tris(hydroxymethyl)methylglycine needs to be added as a buffer. If resorcinol is selected as the nitrogen-containing complexing agent, formaldehyde needs to be added as a buffer. The mass ratio of metal salt, nitrogen-containing complexing agent, and buffer is 1:2-40:2-40.

[0064] The stirring time in step (1) is 12-24 hours, and the filtered product is placed in a vacuum oven at 60-70℃ for 8-10 hours.

[0065] In step (2), the active metal powder includes one of Zn, Al, and Mg powder; the molten salt composition includes one or more of NaCl, KCl, LiCl, CaCl2, Na2CO3, K2CO3, Li2CO3, NaNO3, KNO3, and LiNO3.

[0066] In step (2), the mass ratio of active metal powder to precursor (metal complex) is 1:1 to 5, and the mass ratio of molten salt component to precursor is 5-20:1.

[0067] The ball milling time in step (2) is 1-1.5 hours.

[0068] In step (3), the high-temperature calcination temperature is 600-1000℃, the heating rate is 3-10℃ / min, and the holding time is 2-4 hours.

[0069] In step (4), the concentration of potassium hydroxide solution is 1-5 mol / L, the reaction temperature is 60-80℃, the reaction time is 10-20 hours, and the filtered product is placed in a vacuum oven at 60-70℃ for 8-10 hours.

[0070] The present invention also provides a carbon-supported nano-high-entropy alloy catalyst, which is prepared by the aforementioned preparation method.

[0071] The following is the specific implementation plan:

[0072] Example 1

[0073] The preparation method of the carbon-supported nano-high-entropy alloy catalyst described in this embodiment specifically includes the following steps:

[0074] Step (1): Weigh 0.4g of metal nitrate (specifically, nitrates of Fe, Co, Ni, Cu, and Mn in a molar ratio of 1:1:1:1:1) and 4g of dopamine hydrochloride, dissolve them in 400mL of deionized water, then add 4g of tris(hydroxymethyl)aminomethane, stir on a magnetic stirrer for 12 hours, filter the solution, and finally place the filtered product in a vacuum oven at 60℃ for 10 hours to obtain the precursor;

[0075] Step (2): Weigh 1g of the precursor obtained in step (1) and mix it with 0.5g of zinc powder, 4.5g of LiCl and 5.5g of KCl by ball milling for 1 hour;

[0076] Step (3): The mixed product obtained in step (2) is placed in an alumina crucible and heated to 900°C in an argon atmosphere at a heating rate of 5°C / min and held for 3 hours, and then allowed to cool naturally.

[0077] Step (4): Wash away the molten salt components in the calcined sample in step (3) with deionized water, then add 100 mL of 5 mol / L potassium hydroxide solution and react for 12 hours in an oil bath at 80°C. Then rinse with deionized water and filter more than 3 times. Finally, place the product on the filter paper in a vacuum oven at 60°C and bake for 10 hours to obtain the carbon-supported nano high-entropy alloy catalyst, named Sample 1.

[0078] from Figure 1 The XRD pattern shows that the diffraction peaks at 43.3°, 50.4°, 74.0°, and 89.8° originate from the (111), (200), (220), and (311) crystal planes of FeCu4 (PDF#65-7002), respectively, while the diffraction peaks at 44.6°, 65.0°, and 82.3° originate from the (110), (200), and (211) crystal planes of elemental Fe (PDF#06-0696), respectively. This indicates that the metal supported by the catalyst has a similar lattice to iron and iron-copper alloys. Figure 2 The SEM images and EDS spectra of the material show that the catalyst material consists of multiple layers of stacked nanosheets with a large number of 50-100nm metal particles anchored between the layers. The EDS spectra are consistent with the XRD patterns. Figure 3 XPS full spectrum analysis shows that the material contains C, N, O, Fe, Co, Ni, Cu, and Mn elements, consistent with the added raw materials; among them, Fe, Cu, and Mn have a valence of 0, while the other metals exist in a high valence state; the presence of a relatively high proportion of pyrrole nitrogen also contributes to the improvement of ORR performance.

[0079] Example 2

[0080] Compared with Example 1, the only difference is that the metal nitrate is replaced with a metal chloride, while the amount of metal and the molar ratio of the elements are the same as in Example 1. All other operations and parameters are the same as in Example 1. The resulting sample is named Example 2.

[0081] Figure 4 SEM images show that Implementation Sample 2 is similar in morphology to Implementation Sample 1.

[0082] Example 3

[0083] Compared with Example 1, the only difference is that copper nitrate is replaced with chromium nitrate; all other operations and parameters are the same as in Example 1. The obtained sample is named Example 3.

[0084] Figure 5 SEM images and EDS spectra of the materials show that the catalyst material is stacked in a sheet-like manner, with five metals uniformly mixed.

[0085] Example 4

[0086] Compared with Example 1, the only difference is that copper nitrate is replaced with vanadium chloride; all other operations and parameters are the same as in Example 1. The resulting sample is named Example 4.

[0087] Figure 6 SEM images and EDS spectra of the materials show that the catalyst material is stacked in a sheet-like manner, with five metals uniformly mixed.

[0088] Example 5

[0089] Compared with Example 1, the only difference is that dopamine hydrochloride is replaced with 2-methylimidazole and (tris(hydroxymethyl)aminomethane) is replaced with tris(hydroxymethyl)methylglycine. All other operations and parameters are the same as in Example 1. The obtained sample is named Example 5.

[0090] Example 6

[0091] Compared with Example 1, the only difference is that 4.5g LiCl and 5.5g KCl are replaced with 10g NaCl, and all other operations and parameters are the same as in Example 1. The obtained sample is named Example 6.

[0092] Example 7

[0093] Compared with Example 1, the only difference is that zinc powder is replaced with magnesium powder, and the amount of magnesium powder used is 0.6g. All other operations and parameters are the same as in Example 1. The obtained sample is named Example 7.

[0094] Example 8

[0095] Compared with Example 1, the only difference is that the calcination temperature in step (3) is changed to 600°C and the holding time is 4 hours. All other operations and parameters are the same as in Example 1. The obtained sample is named Example 8.

[0096] Example 9

[0097] Compared with Example 1, the only difference is that step (3) is subjected to two-stage temperature control treatment. The temperature of the first stage is 600°C and the holding time is 3 hours, and the temperature of the second stage is 900°C and the holding time is 1 hour. All other operations and parameters are the same as in Example 1. The obtained sample is named Example 9.

[0098] Example 10

[0099] Compared with Example 1, the only difference is that the total mass of the metal nitrate is changed to 1g, while all other operations and parameters are the same as in Example 1. The obtained sample is named Example 10.

[0100] Comparative Example 1

[0101] Compared with Example 1, the only difference is that 0.4g of Fe, Co, Ni, Cu, Mn metal nitrates was replaced with 0.4g of Fe and Co metal nitrates (Fe and Co molar ratio of 1:1). All other operations and parameters are the same as in Example 1. The resulting sample is named Comparative Sample 1.

[0102] from Figure 8 Numerous distinct lattice fringes can be observed on the carbon support. High-resolution TEM images show visible lattice fringes at 0.309 nm, corresponding to Co... 0.72 Fe 0.28 The (220) crystal plane has nanoscale iron-cobalt alloy distributed on the surface carbon carrier.

[0103] Comparative Example 2

[0104] Compared with Example 1, the only difference is that no molten salt is added in step (2), while the other operations and parameters are the same as in Example 1. The obtained sample is named Comparative Sample 2.

[0105] from Figure 9 SEM images and EDS spectra show that the surface metal aggregates into micron-sized particles, exhibiting a phase-separated state.

[0106] Comparative Example 3

[0107] Compared with Example 1, the only difference is that no active metal powder is added in step (2), while the other operations and parameters are the same as in Example 1. The obtained sample is named Comparative Sample 3.

[0108] from Figure 10The SEM images show that the sample prepared without zinc powder is flaky and no obvious metal particles are visible on the surface.

[0109] Comparative Example 4

[0110] Compared with Example 1, the only difference is that dopamine hydrochloride is replaced with dicyandiamine; all other operations and parameters are the same as in Example 1. The resulting sample is named Comparative Sample 4.

[0111] Comparative Example 5

[0112] Compared with Example 1, the only difference is that step (2) is omitted, while all other operations and parameters are the same as in Example 1. The obtained sample is named Comparative Sample 5.

[0113] Comparative Example 6

[0114] Compared with Example 1, the only difference is that the complexation process in step (1) is not performed. Instead, the physical mixture of each metal raw material and dopamine hydrochloride in the specified amounts directly replaces the precursor in step 2, and step 2 and subsequent processing are performed. All other operations and parameters are the same as in Example 1. The resulting sample is named Comparative Sample 6.

[0115] Comparative Example 7

[0116] Compared with Example 1, the only difference is that the alkali treatment process in step (4) is not performed; all other operations and parameters are the same as in Example 1. The obtained sample is named Comparative Sample 7.

[0117] Comparative Example 8

[0118] Compared with Example 1, the only difference is that no metal salt component is added in step (1), and all other operations and parameters are the same as in Example 1. The obtained sample is named Comparative Sample 8.

[0119] Test case

[0120] Test samples: all implementation and control samples; commercial Pt / C catalyst (20 wt.%, Hesen); commercial RuO2 catalyst (analytical grade, Maclean).

[0121] Test method:

[0122] (1) Preparation of working electrode: Take 4 mg of catalyst sample, add 800 μL of alcohol and 170 μL of deionized water, sonicate for 15 minutes, then add 30 μL of 5 wt.% Nafion solution, continue sonication for 15 minutes to obtain uniform catalyst ink, and uniformly drop 10 μL of the prepared catalyst ink onto the glassy carbon surface of the rotating disk electrode and let it air dry naturally.

[0123] (2) Oxygen Electrocatalytic Performance Test: The oxygen electrocatalytic performance of the catalyst was tested using a standard three-electrode electrochemical workstation (Gamry). The rotating disk electrode supporting the catalyst was the working electrode, the platinum ring electrode was the counter electrode, and the Hg / HgO electrode was the reference electrode. For the test, the specific operating conditions were as follows: before conducting the electrochemical test, high-purity oxygen was passed into the electrolyte for 30 minutes to achieve oxygen saturation. For the oxygen reduction reaction (ORR) performance, the electrolyte was a 0.1 mol / L KOH solution. Linear sweep voltammetry (LSV) was used at a scan rate of 5 mV / s within a voltage range of 0.2 to -0.8 V, with a negative scan direction. Stability was obtained using the chronoamperometry method at 0.7 V (vs. RHE). For the oxygen evolution reaction (OER) performance, the electrolyte was a 1 mol / L KOH solution. Linear sweep voltammetry (LSV) was used at a scan rate of 5 mV / s within a voltage range of 0.2 to 1.1 V, with a positive scan direction. The results of oxygen electrocatalytic performance are shown in Tables 1 and 2.

[0124] Table 1

[0125]

[0126] Table 2

[0127]

[0128] From the performance data in Tables 1 and 2 and Figure 11-12 It can be seen that Example 1 has the highest ORR half-wave potential (0.84V) and the lowest OER overpotential (0.25V), which is superior to commercial Pt / C (half-wave potential 0.83V) and RuO2 (overpotential 0.30V) catalysts. Example 2, which uses chloride instead of nitrate, shows a slight decrease in performance. Examples 3 and 4, which use Cr and V to replace Cu respectively, also show reduced performance. In the examples, the carbon-supported nano-FeCoNiCuMn high-entropy alloy catalyst exhibits the best oxygen electrocatalytic performance. Comparative Example 1 contains only Fe and Co, and its ORR performance is similar to Example 1, but its OER performance is significantly lower than that of the carbon-supported nano-FeCoNiCuMn high-entropy alloy catalyst. Comparative Examples 2 and 3, lacking molten salt components and active metals respectively, show a significant decrease in catalytic performance. Figure 13 It can be seen that the ORR stability of the carbon-supported nano FeCoNiCuMn high-entropy alloy catalyst prepared in Example 1 is better than that of the commercial Pt / C catalyst.

[0129] In summary, the catalyst prepared by the method described in this invention can achieve both excellent ORR and OER performance.

[0130] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a nano-high-entropy alloy electrocatalytic material, characterized in that, The nano-high-entropy alloy electrocatalytic material is prepared by calcining a mixture of a multi-metal organic complex, an active metal, and a molten salt, followed by water washing and alkali washing modification. The metal M source and the organic complexing agent are subjected to a complexation reaction to obtain the aforementioned multi-metal organic complex; the metal M includes Fe, Co, Ni, Mn, and also includes at least one of Cr, Cu, and V; The metal M source is a water-soluble salt of metal M; The organic complexing agent is at least one of dopamine hydrochloride, 2-methylimidazole, and resorcinol; The mass ratio of the metal M source to the organic complexing agent is 1:2~40; The active metals mentioned include at least one of Zn, Al, and Mg; The molten salt includes one or more of NaCl, KCl, LiCl, CaCl2, Na2CO3, K2CO3, Li2CO3, NaNO3, KNO3, and LiNO3; The weight ratio of molten salt to polymetallic organic complex is 5~20:1; The mass ratio of the polymetallic organic complex to the active metal is 1~5:1; The calcination temperature is 600~1000 ℃.

2. The preparation method of the nano-high-entropy alloy electrocatalytic material as described in claim 1, characterized in that, The metal M source is at least one of the chloride, nitrate, sulfate, or acetate salts of metal M.

3. The preparation method of the nano-high-entropy alloy electrocatalytic material as described in claim 1, characterized in that, A buffer was added during the complexation reaction stage; The buffer contains at least one of tris(hydroxymethyl)aminomethane, tris(hydroxymethyl)methylglycine, and formaldehyde; The weight ratio of the metal M source to the buffer is 1:2~40.

4. The preparation method of the nano-high-entropy alloy electrocatalytic material as described in claim 1, characterized in that, The mass ratio of the polymetallic organic complex to the active metal is 1.5 to 3:

1.

5. The preparation method of the nano-high-entropy alloy electrocatalytic material as described in claim 1, characterized in that, The weight ratio of molten salt to polymetallic organic compounds is 8~12:

1.

6. The preparation method of the nano-high-entropy alloy electrocatalytic material as described in claim 1, characterized in that, The calcination time is 2 to 4 hours.

7. The preparation method of the nano-high-entropy alloy electrocatalytic material as described in claim 1, characterized in that, The calcination process includes two heat preservation processes. The temperature of the first heat preservation process is 600~700 ℃, and the temperature of the second heat preservation process is 850~950 ℃.

8. The method for preparing the nano-high-entropy alloy electrocatalytic material as described in claim 7, characterized in that, The first insulation period is 1-2 hours, and the second insulation period is 1-2 hours.

9. The preparation method of the nano-high-entropy alloy electrocatalytic material as described in claim 1, characterized in that, The alkaline solution used in the alkaline washing and modification process is an aqueous solution of alkali metal hydroxide.

10. A nano-high entropy alloy electrocatalytic material prepared by the preparation method according to any one of claims 1 to 9.

11. The application of a nano-high-entropy alloy electrocatalytic material prepared by the preparation method according to any one of claims 1 to 9, characterized in that, It is used as a catalyst for ORR and / or OER.

12. The application of the nano-high-entropy alloy electrocatalytic material prepared by the method described in claim 11, characterized in that, It was used as a catalyst for ORR and / or OER in the fabrication of batteries.

13. A battery, characterized in that, The nano-high-entropy alloy electrocatalytic material prepared by the preparation method according to any one of claims 1 to 9.

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