A multi-metal-based oxide electrocatalyst, a preparation method and application thereof

Abstract

This invention provides a multi-metal-based oxide electrocatalyst, its preparation method, and its application, relating to the field of electrocatalysis technology. The method involves: uniformly mixing a metal salt and a solvent; adding an organic ligand containing a specific functional group to the mixed solution and stirring until homogeneous; sequentially centrifuging and freeze-drying the mixture; calcining the freeze-dried sample under a protective atmosphere; and then ball-milling the calcined sample to obtain the multi-metal-based oxide electrocatalyst. The catalyst prepared by this invention exhibits good conductivity, diverse catalytic active sites, rich hierarchical structure, and excellent pore size distribution. Furthermore, by temperature-regulating the crystal structure distribution of the catalyst, a heterostructure with optimal OER catalytic activity is formed, resulting in superior oxygen evolution activity and stability compared to the commercial catalyst IrO2. As a highly active and stable oxygen evolution electrode for water electrolysis, it has broad industrial application prospects.

Description

Technical Field

[0001] This invention relates to the field of electrocatalysis technology, and in particular to a multi-metal-based oxide electrocatalyst, its preparation method, and its application. Background Technology

[0002] Accelerated global industrialization, energy crisis, and pollutants (SO4) x NO x The increase in emissions of particulate matter (PM2.5) has expanded public demand for sustainable and clean energy. Among numerous new energy technologies, electrochemical hydrogen production, with its advantages of environmental friendliness, zero carbon emissions, and high energy density, has become one of the most promising technologies to replace fossil fuels. However, the practical application of water electrolysis technology is severely hampered by the slow kinetics of the oxygen evolution reaction (OER), thus requiring the development of efficient OER catalysts to improve OER reaction kinetics. Currently, most commercially available OER catalysts are noble metal-based catalysts, such as IrO2 and RuO2. However, these catalysts cannot be used on a large scale in actual production due to their low global abundance, high cost, poor durability, and slow kinetics. Therefore, developing efficient and low-cost non-noble metal OER catalysts is key to the large-scale production of hydrogen through water electrolysis.

[0003] Transition metal oxides (TMOs) are considered among the most promising OER catalysts due to their abundant resources, simple preparation processes, controllable structure and composition, and high stability. In recent years, researchers have conducted in-depth studies on TMOs, discovering that multi-metal oxides exhibit higher catalytic activity and better stability than single-metal oxides. This can be attributed to the fixed electronic structure of single metals, whose catalytic activity is relatively singular and dependent on reaction intermediates. In contrast, multi-metal oxides exhibit synergistic effects between atoms, possess a larger electronic tunable space, and multiple active sites, thus demonstrating greater advantages in OER applications. However, considering the interactions between metals and the influence of thermodynamic factors, the internal crystal structure of complex multi-metal oxides obtained by conventional preparation methods cannot be adjusted, and dominant crystal faces are not fully exposed, thus affecting the catalytic performance and stability of the catalyst and hindering its large-scale industrial application.

[0004] Metal-organic frameworks (MOFs) are novel porous materials composed of metal clusters or metal ions and organic ligands, possessing immense application potential due to their superior tunability. Furthermore, using MOFs as sacrificial templates allows for the synthesis of numerous novel and high-performance MOF derivatives, such as metal oxides, opening an effective pathway for OER catalyst design. Highly efficient electrocatalysts can be obtained by controlling the pyrolysis conditions of MOF precursors or by customizing organic ligands. Organic ligands are crucial components of MOFs and are key factors in regulating the structure and performance of MOF derivatives. Appropriate pyrolysis conditions can regulate the crystal structure distribution of MOF derivatives, optimizing the internal metal ion distribution to fully leverage the synergistic effects between different metals and enhance the catalytic activity of the material. Therefore, preparing multi-metal oxides using MOFs as precursors is an effective method for controlling the crystal structure distribution of multi-metal oxides. However, careful consideration of the type of organic ligand and the selection of pyrolysis conditions is necessary. Therefore, developing simple and efficient techniques to regulate the crystal structure distribution of multi-metal oxides for large-scale application remains a significant challenge. Summary of the Invention

[0005] This invention provides a multi-metal-based oxide electrocatalyst, its preparation method, and its application, with the aim of solving the aforementioned problems existing in the background art.

[0006] To achieve the above objectives, embodiments of the present invention provide a multi-metal-based oxide electrocatalyst, its preparation method, and its application. The specific method involves: first, ultrasonically mixing five metal salt solutions to achieve uniform mixing; then, adding an organic ligand containing specific substituents to the uniformly mixed solution and stirring at room temperature for a certain time; followed by centrifugation and freeze-drying; then, rapidly heating and cooling the freeze-dried sample, and finally grinding the sample to obtain the multi-metal-based oxide electrocatalyst. The catalyst prepared by rapidly annealing to control the crystal phase distribution of multi-metal-based oxides possesses advantages such as adjustable crystal structure, good conductivity, diverse catalytic active sites, rich hierarchical structure, and pore size distribution, thus exhibiting superior oxygen evolution activity and stability compared to the commercial catalyst IrO2. As a highly active and stable oxygen evolution electrode for water electrolysis, it has broad industrial application prospects.

[0007] This invention provides a method for preparing a multi-metal-based oxide electrocatalyst, comprising the following steps:

[0008] S1. Add the metal salt to the solvent and mix it evenly by ultrasonication to obtain a mixed solution;

[0009] S2. Add an organic ligand containing a specific functional group to the mixed solution, stir at room temperature, and then centrifuge and freeze-dry to obtain the precursor powder.

[0010] S3. The precursor powder is placed in a tube furnace and calcined under a protective atmosphere;

[0011] S4. The calcined sample is ball-milled to obtain the multi-metal-based oxide electrocatalyst.

[0012] According to one aspect of this embodiment, in step S1, the metal in the metal salt includes chromium, manganese, iron, cobalt, and nickel; wherein the molar ratio of chromium, manganese, iron, cobalt, and nickel is (1-3):(1-3):(1-3):(1-3):(1-3); and the solvent is water or ethanol. More preferably, the metal salt is a nitrate; the molar ratio of chromium, manganese, iron, cobalt, and nickel is 1:1:1:1:1; and the solvent is ethanol.

[0013] According to one aspect of this embodiment, in step S1, the ultrasonic treatment time is 30 minutes.

[0014] According to one aspect of this embodiment, in step S2, the organic ligand is selected from at least one of 2,3-dihydroxybenzoic acid, thiophenol, and phenol, and the molar ratio of the organic ligand to the metal in the metal salt is 1:1 to 3:1.

[0015] According to one aspect of this embodiment, in step S2, the stirring instrument is selected from a magnetic stirrer or a mechanical stirrer, and the stirring time is 8 to 12 hours.

[0016] More preferably, the organic ligand is 2,3-dihydroxybenzoic acid, the molar ratio of the organic ligand to the metal in the metal salt is 1:1, the stirring instrument is a mechanical stirrer, and the stirring time is 12 hours. The stirring treatment is to ensure that the organic ligand and the metal ions react fully, and the stirring instrument is preferably a mechanical stirrer to avoid the magnetic field affecting the uniform mixing of the organic chelate.

[0017] According to one aspect of this embodiment, in step S3, the protective atmosphere is argon; the heating rate is 5–30 °C / min, the calcination temperature is 600–1000 °C, and the holding time is 0–4 h. More preferably, under an argon atmosphere, the temperature is increased to 600–1000 °C at a rate of 20 °C / min without holding time, and then naturally cooled to room temperature. In this process, the heating rate of 20 °C / min without holding time is used to allow the dominant unit cell to grow rapidly, forming a stable crystal structure without interference from the diffusion of other metal ions.

[0018] According to one aspect of this embodiment, in step S4, the ball milling speed is 200–500 r / min, and the ball milling time is 2–5 h. Excessive ball milling speed and time will damage the material's structure, thereby affecting its catalytic performance and stability. More preferably, the ball milling speed is 300 r / min, and the ball milling time is 3 h.

[0019] Based on a general inventive concept, embodiments of the present invention provide a multi-metal-based oxide electrocatalyst obtained by the above preparation method.

[0020] The embodiments of the present invention also provide the application of the multi-metal-based oxide electrocatalyst obtained by the above preparation method in the electrolytic oxygen reaction.

[0021] According to one aspect of this embodiment, the multi-metal-based oxide electrocatalyst is prepared into a slurry and coated onto a conductive substrate to form a multi-metal-based oxide electrode; the conductive substrate is selected from carbon paper, nickel foam, and titanium mesh. More preferably, the conductive substrate is nickel foam.

[0022] The above-described solution of the present invention has the following beneficial effects:

[0023] (1) This invention proposes for the first time the preparation of multi-metal-based oxide electrocatalysts using 2,3-dihydroxybenzoic acid as an organic ligand. In the metal-organic framework structure formed by metal ions and 2,3-dihydroxybenzoic acid, the conjugation effect between the carbonyl carbon and hydroxyl oxygen in the molecular structure of 2,3-dihydroxybenzoic acid leads to a redistribution of electron density between the carbonyl carbon and hydroxyl oxygen, thereby weakening the attraction of carbonyl carbon to electrons. This results in different coordination abilities between the two and the metal ions, which is beneficial for further structural modification and improvement. Based on the structural characteristics of the selected organic ligand, appropriate pyrolysis conditions can be selected to control the diffusion rate of metal ions, allowing them to diffuse to suitable positions to form unit cells and grow rapidly, ultimately forming a stable crystal structure. In heterogeneous catalysts, the performance of the catalyst is closely related to its crystal structure. Therefore, temperature is used to adjust the crystal structure distribution of the catalyst to form a heterostructure with optimal OER catalytic activity. This adjustment method is simple and efficient, and its application in the field of electrocatalytic reactions makes it easy to produce on a large scale.

[0024] (2) The catalyst synthesized in this invention exhibits FeCo / Cr 0.5 Mn 1.5 NiO4 heterostructure, in which the FeCo(111) crystal plane and Cr 0.5 Mn 1.5 The heterostructure formed by NiO4 induces charge redistribution through electronic interactions at the heterostructure interface, and the alteration of the electronic structure optimizes the adsorption strength of reaction intermediates at different adsorption sites on the catalyst. As a result, this catalyst exhibits highly efficient and stable OER performance in alkaline media.

[0025] (3) The catalyst synthesized in this invention exhibits a layered structure. Compared to a dense bulk structure, the layered structure has a higher specific surface area, thereby increasing the exposure of catalytic active sites and helping to improve the activity and efficiency of the catalytic reaction. In addition, the layered structure facilitates the diffusion and transport of reactants and products, and can reduce the aggregation and loss of active components to a certain extent, further improving the stability of the catalyst. Furthermore, compared with other multimetal catalysts, the catalyst of this invention has high purity, good dispersibility, rich hierarchical structure and pore size distribution, and exhibits excellent catalytic activity and stability in the oxygen evolution reaction, making it suitable for large-scale production.

[0026] (4) The polymetallic oxide catalyst prepared in this invention exhibits excellent catalytic performance and outstanding stability when applied to the oxygen evolution reaction, at a current density of 10 mA / cm². 2 50mA / cm 2 At that time, the overpotentials of its electrocatalytic oxygen evolution reaction were 280mV and 339mV, respectively. After 5000 CV cycles, the LSV curves before and after the cycles did not show significant shifts, indicating excellent stability. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in 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.

[0028] Figure 1 These are scanning electron microscope images of the multimetal oxides (MOs) in the embodiments of the present invention, wherein (a) is MOs-600, (b) is MOs-700, (c) is MOs-800, (d) is MOs-900, and (e) is MOs-1000.

[0029] Figure 2 This is an X-ray diffraction pattern of the multi-metal oxide in an embodiment of the present invention;

[0030] Figure 3 This is an OER activity test curve of the multi-metal oxides in the embodiments of the present invention;

[0031] Figure 4 This is a comparison of the OER polarization curves during the first and 5000th cycles after the stability was tested using the cyclic voltammetry method in Embodiment 3 of the present invention. Detailed Implementation

[0032] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0033] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0034] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0035] This invention addresses existing problems by providing a multi-metal-based oxide electrocatalyst, its preparation method, and its application.

[0036] Example 1

[0037] This embodiment protects a method for preparing a multi-metal-based oxide electrocatalyst.

[0038] The method in this embodiment specifically includes the following steps:

[0039] (1) Dissolve 2 mmol each of manganese nitrate, nickel nitrate, ferric nitrate, cobalt nitrate and chromium nitrate in 60 mL of ethanol by sonication for 30 min.

[0040] (2) Add 10 mmol of 2,3-dihydroxybenzoic acid to the sonicated solution, then stir with a mechanical stirrer for 12 h, followed by centrifugation and freeze-drying;

[0041] (3) Place the freeze-dried sample in a tube furnace and heat it to 600°C at a rate of 20°C / min under an argon atmosphere without holding time, and then let it cool naturally to room temperature.

[0042] (4) The calcined sample was ball-milled to obtain a polymetallic oxide, wherein the ball milling speed was 300 r / min and the ball milling time was 3 h;

[0043] (5) Weigh 5 mg of sample into a 3 mL centrifuge tube using a balance, then add 350 μL of water, 150 μL of ethanol and 40 μL of Nafion solution to the centrifuge tube to prepare a slurry, and then coat it onto a nickel foam substrate to form a multi-metal oxide electrode.

[0044] The multi-metal oxide catalyst (MOs-600) prepared in this embodiment has a layered structure. Figure 1 ). By analyzing the X-ray diffraction pattern ( Figure 2 It was found that no obvious crystallization peak appeared inside the material when the temperature was raised to 600℃. Its oxygen evolution reaction activity was tested, such as... Figure 3 As shown, at a current density of 10 mA / cm² 250mA / cm 2 At that time, its overpotentials for the electrocatalytic oxygen evolution reaction were 318 mV and 397 mV, respectively, which are superior to those of commercial IrO2 catalysts (355 mV @ 10 mA / cm). 2 449mV@50mA / cm 2 ).

[0045] Example 2

[0046] This embodiment protects a method for preparing a multi-metal-based oxide electrocatalyst.

[0047] The method in this embodiment specifically includes the following steps:

[0048] (1) Dissolve 2 mmol each of manganese nitrate, nickel nitrate, ferric nitrate, cobalt nitrate and chromium nitrate in 60 mL of ethanol by sonication for 30 min.

[0049] (2) Add 10 mmol of 2,3-dihydroxybenzoic acid to the sonicated solution, then stir with a mechanical stirrer for 12 h, followed by centrifugation and freeze-drying;

[0050] (3) Place the freeze-dried sample in a tube furnace and heat it to 700°C at a rate of 20°C / min under an argon atmosphere without holding time, and then let it cool naturally to room temperature.

[0051] (4) The calcined sample was ball-milled to obtain a polymetallic oxide, wherein the ball milling speed was 300 r / min and the ball milling time was 3 h;

[0052] (5) Weigh 5 mg of sample into a 3 mL centrifuge tube using a balance, then add 350 μL of water, 150 μL of ethanol and 40 μL of Nafion solution to the centrifuge tube to prepare a slurry, and then coat it onto a nickel foam substrate to form a multi-metal oxide electrode.

[0053] The multi-metal oxide catalyst (MOs-700) prepared in this embodiment has a layered structure. Figure 1 ). By analyzing the X-ray diffraction pattern ( Figure 2 As the calcination temperature increases, two broad peaks are visible in the XRD pattern of MOs-700, indicating the presence of obvious crystallization peaks within the material. Its oxygen evolution reaction activity was tested, such as... Figure 3 As shown, at a current density of 10 mA / cm² 2 50mA / cm 2 At that time, its overpotentials for the electrocatalytic oxygen evolution reaction were 287 mV and 357 mV, respectively, which are superior to those of commercial IrO2 catalysts (355 mV @ 10 mA / cm). 2 449mV@50mA / cm 2).

[0054] Example 3

[0055] This embodiment protects a method for preparing a multi-metal-based oxide electrocatalyst.

[0056] The method in this embodiment specifically includes the following steps:

[0057] (1) Dissolve 2 mmol each of manganese nitrate, nickel nitrate, ferric nitrate, cobalt nitrate and chromium nitrate in 60 mL of ethanol by sonication for 30 min.

[0058] (2) Add 10 mmol of 2,3-dihydroxybenzoic acid to the sonicated solution, then stir with a mechanical stirrer for 12 h, followed by centrifugation and freeze-drying;

[0059] (3) Place the freeze-dried sample in a tube furnace and heat it to 800°C at a rate of 20°C / min under an argon atmosphere without holding time, and then let it cool naturally to room temperature.

[0060] (4) The calcined sample was ball-milled to obtain a polymetallic oxide, wherein the ball milling speed was 300 r / min and the ball milling time was 3 h;

[0061] (5) Weigh 5 mg of sample into a 3 mL centrifuge tube using a balance, then add 350 μL of water, 150 μL of ethanol and 40 μL of Nafion solution to the centrifuge tube to prepare a slurry, and then coat it onto a nickel foam substrate to form a multi-metal oxide electrode.

[0062] The multi-metal oxide catalyst (MOs-800) prepared in this embodiment has a layered structure. Figure 1 ). By analyzing the X-ray diffraction pattern ( Figure 2 When the temperature is raised to 800℃, obvious diffraction peaks can be observed. Comparing with standard cards (PDF#04-008-7199, PDF#04-002-3694, PDF#04-014-0165), the most obvious XRD diffraction peak (44.01°) corresponds to the FeCo(111) crystal plane. Its oxygen evolution reaction activity was tested, such as... Figure 3 As shown, at a current density of 10 mA / cm² 2 50mA / cm 2 At that time, its overpotentials for the electrocatalytic oxygen evolution reaction were 280 mV and 339 mV, respectively, which are superior to those of commercial IrO2 catalysts (355 mV @ 10 mA / cm). 2 449mV@50mA / cm 2 After 5000 CV cycles, as... Figure 4As shown, the LSV curves before and after the cycle did not show any significant shift, indicating its excellent stability.

[0063] Example 4

[0064] This embodiment protects a method for preparing a multi-metal-based oxide electrocatalyst.

[0065] The method in this embodiment specifically includes the following steps:

[0066] (1) Dissolve 2 mmol each of manganese nitrate, nickel nitrate, ferric nitrate, cobalt nitrate and chromium nitrate in 60 mL of ethanol by sonication for 30 min.

[0067] (2) Add 10 mmol of 2,3-dihydroxybenzoic acid to the sonicated solution, then stir with a mechanical stirrer for 12 h, followed by centrifugation and freeze-drying;

[0068] (3) Place the freeze-dried sample in a tube furnace and heat it to 900°C at a rate of 20°C / min under an argon atmosphere without holding time, and then let it cool naturally to room temperature.

[0069] (4) The calcined sample was ball-milled to obtain a polymetallic oxide, wherein the ball milling speed was 300 r / min and the ball milling time was 3 h;

[0070] (5) Weigh 5 mg of sample into a 3 mL centrifuge tube using a balance, then add 350 μL of water, 150 μL of ethanol and 40 μL of Nafion solution to the centrifuge tube to prepare a slurry, and then coat it onto a nickel foam substrate to form a multi-metal oxide electrode.

[0071] The multi-metal oxide catalyst (MOs-900) prepared in this embodiment has a layered structure. Figure 1 ). By analyzing the X-ray diffraction pattern ( Figure 2 When the temperature rises to 900℃, the XRD diffraction peak (44.94°) corresponding to the FeCo(110) crystal surface becomes sharper, while the XRD diffraction peak (44.01°) corresponding to the FeCo(111) crystal surface weakens. Its oxygen evolution reaction activity was tested, such as... Figure 3 As shown, at a current density of 10 mA / cm² 2 50mA / cm 2 At that time, its overpotentials for the electrocatalytic oxygen evolution reaction were 313 mV and 408 mV, respectively, which are superior to those of commercial IrO2 catalysts (355 mV @ 10 mA / cm). 2 449mV@50mA / cm 2 This indicates that temperature can be used to control the dominant crystal plane of FeCo(111) and Cr. 0.5 Mn 1.5The interaction with NiO4 leads to higher OER catalytic activity.

[0072] Example 5

[0073] This embodiment protects a method for preparing a multi-metal-based oxide electrocatalyst.

[0074] The method in this embodiment specifically includes the following steps:

[0075] (1) Dissolve 2 mmol each of manganese nitrate, nickel nitrate, ferric nitrate, cobalt nitrate and chromium nitrate in 60 mL of ethanol by sonication for 30 min.

[0076] (2) Add 10 mmol of 2,3-dihydroxybenzoic acid to the sonicated solution, then stir with a mechanical stirrer for 12 h, followed by centrifugation and freeze-drying;

[0077] (3) Place the freeze-dried sample in a tube furnace and heat it to 1000°C at a rate of 20°C / min under an argon atmosphere without holding time, and then let it cool naturally to room temperature.

[0078] (4) The calcined sample was ball-milled to obtain a polymetallic oxide, wherein the ball milling speed was 300 r / min and the ball milling time was 3 h;

[0079] (5) Weigh 5 mg of sample into a 3 mL centrifuge tube using a balance, then add 350 μL of water, 150 μL of ethanol and 40 μL of Nafion solution to the centrifuge tube to prepare a slurry, and then coat it onto a nickel foam substrate to form a multi-metal oxide electrode.

[0080] The multi-metal oxide catalyst (MOs-1000) prepared in this embodiment has a layered structure. Figure 1 ). By analyzing the X-ray diffraction pattern ( Figure 2 When the temperature continued to rise to 1000℃, the XRD diffraction peak (44.94°) corresponding to the FeCo(110) crystal surface became sharper, while the XRD diffraction peak (44.01°) corresponding to the FeCo(111) crystal surface continued to weaken. Its oxygen evolution reaction activity was tested, such as... Figure 3 As shown, at a current density of 10 mA / cm² 2 50mA / cm 2 At that time, its overpotentials for the electrocatalytic oxygen evolution reaction were 335 mV and 433 mV, respectively, which are superior to those of commercial IrO2 catalysts (355 mV @ 10 mA / cm). 2 449mV@50mA / cm 2 This further illustrates the role of Cr. 0.5 Mn 1.5The heterostructure formed by NiO4 and FeCo(111) crystal planes has a better catalytic effect on OER.

[0081] Comparative Example 1

[0082] This comparative example is based on Example 3, except that the organic ligand 2,3-dihydroxybenzoic acid is replaced with 1,10-phenanthroline, while the other steps and parameters are the same as in Example 3.

[0083] At a temperature of 800℃, compared to Example 3, the crystal structure corresponding to the XRD diffraction peaks of the catalyst prepared in this comparative example changed. Comparing with the standard card, it was found that the XRD diffraction peaks corresponded to MnCr2O4 and Fe, respectively. 0.75 Ni 0.25 Co7Fe3. Its oxygen evolution reaction activity was tested at a current density of 10 mA / cm². 2 At that time, the overpotential of the comparative example was 368mV@10mA / cm. 2 The value is much greater than that of Example 3 (280mV@10mA / cm). 2 ), illustrating the Cr of the present invention 0.5 Mn 1.5 The heterostructure formed by NiO4 and FeCo alloys plays a key role in electrocatalytic OER.

[0084] Comparative Example 2

[0085] This comparative example is based on Example 3, except that the organic ligand 2,3-dihydroxybenzoic acid is replaced with benzoic acid, while the other steps and parameters are the same as in Example 3.

[0086] At a temperature of 800℃, compared to Example 3, the crystal structure corresponding to the XRD diffraction peaks of the catalyst prepared in this comparative example changed. Comparing with the standard card, it was found that the XRD diffraction peaks corresponded to Cr... 0.5 Mn 1.5 NiO4 and FeCo were tested, with the FeCo(200) crystal plane exhibiting the strongest diffraction peak intensity. Their oxygen evolution reaction activity was measured at a current density of 10 mA / cm². 2 Its oxygen evolution overpotential is 335mV, compared to Example 3 (280mV@10mA / cm). 2 The increased overpotential indicates that only by selecting organic ligands containing specific functional groups can the temperature-controlled preferential crystal planes of FeCo alloys and Cr be utilized. 0.5 Mn 1.5 NiO4 forms a heterostructure with optimal OER catalytic activity.

[0087] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the 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 multi-metal-based oxide electrocatalyst, characterized by, The preparation method comprises the following steps: S1, adding a metal salt into a solvent, ultrasonic mixing to obtain a mixed solution; the metal in the metal salt comprises chromium, manganese, iron, cobalt and nickel; the molar ratio of the chromium, manganese, iron, cobalt and nickel is 1-3:1-3:1-3:1-3:1-3; S2, adding an organic ligand containing a specific functional group into the mixed solution, stirring at room temperature, sequentially performing centrifugation and freeze-drying to obtain a precursor powder; the organic ligand is selected from 2,3-dihydroxybenzoic acid; the molar ratio of the organic ligand to the metal in the metal salt is 1:1-3:1; S3, placing the precursor powder into a tube furnace, performing calcination under a protective atmosphere; the heating rate is 20-30 ℃ / min, the calcination temperature is 600-1000 ℃, and the holding time is 0; S4, performing ball milling on the calcined sample to obtain the multi-metal-based oxide electrocatalyst.

2. The method for preparing a multi-metal-based oxide electrocatalyst according to claim 1, characterized in that, In step S1, the solvent is water or ethanol.

3. The method for preparing a multi-metal-based oxide electrocatalyst according to claim 1, characterized in that, In step S1, the ultrasonic treatment time is 30-60 min.

4. The method for preparing a multi-metal-based oxide electrocatalyst according to claim 1, characterized in that, In step S2, the stirring instrument is selected from a magnetic stirrer or a mechanical stirrer, and the stirring time is 8-12 h.

5. The method for preparing a multi-metal-based oxide electrocatalyst according to claim 1, characterized in that, In step S3, the protective atmosphere is argon.

6. The method for preparing a multi-metal-based oxide electrocatalyst according to claim 1, characterized in that, In step S4, the ball milling speed is 200-500 r / min, and the ball milling time is 2-5 h.

7. A multi-metal-based oxide electrocatalyst obtained by the preparation method in any one of claims 1-6.

8. Application of a multi-metal-based oxide electrocatalyst obtained by the preparation method in any one of claims 1-6 in an electrolytic oxygen evolution reaction.

9. Use according to claim 8, characterized in that, The multi-metal-based oxide electrocatalyst is prepared into a slurry to be coated on a conductive substrate to prepare a multi-metal-based oxide electrode; the conductive substrate is selected from one of carbon paper, foamed nickel and titanium mesh.

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