Amorphous cobalt oxide@nitrogen-doped carbon material, preparation method and application thereof

Abstract

The application relates to the technical field of electrode material preparation, in particular to an amorphous cobalt oxide@nitrogen-doped carbon material and a preparation method and application thereof. The preparation method comprises the following steps: taking a soluble cobalt salt as a cobalt source, mixing the cobalt source with a carbon-nitrogen compound, and performing calcination treatment to obtain the amorphous cobalt oxide@nitrogen-doped carbon material. With the confinement and crystallization suppression synergistic effect of the carbon-nitrogen compound, the amorphous cobalt oxide@nitrogen-doped carbon material can be prepared through one-step air calcination; the preparation process is simple, and a harsh atmosphere condition is not needed, so that the problem of a complex preparation process in the prior art is solved; meanwhile, the material has a lamellar structure, and the particle agglomeration problem is effectively avoided. When the material is prepared into an electrode and applied to electrocatalytic hydrogen evolution, the oxygen evolution reaction overpotential of the electrode is lower than that of a traditional cobalt tetroxide catalyst, and the electrode has good stability.

Description

An amorphous cobalt oxide@nitrogen-doped carbon material, its preparation method and application Technical Field

[0001] This invention relates to the field of electrode material preparation technology, specifically to an amorphous cobalt oxide@nitrogen-doped carbon material, its preparation method, and its application. Background Technology

[0002] In the field of energy storage and conversion devices, such as water electrolysis for hydrogen production, regenerative fuel cells, and rechargeable metal-air battery systems, the oxygen evolution reaction plays a crucial role and has therefore attracted much attention. However, the oxygen reduction reaction process occurring at the anode is extremely complex, which has become a key factor restricting the development of the entire system. This is because the reaction process involves the oxidation of four electrons and requires the participation of two water molecules to form one oxygen molecule.

[0003] Therefore, developing efficient electrocatalysts to accelerate the slow oxygen evolution reaction and reduce its overpotential is particularly important. To date, some noble metal-based catalysts, such as ruthenium and iridium, have been reported, exhibiting high intrinsic catalytic activity. However, their high cost and poor long-term stability significantly limit their widespread adoption in large-scale commercial applications.

[0004] As is well known, researchers worldwide have been dedicated to developing oxygen evolution reaction (OER) catalysts based on transition metals, such as cobalt, nickel, iron, copper, and manganese. Of particular note are some cobalt-based oxides, hydroxides, chalcogenides, nitrides, and phosphides, which have been proven to be excellent OER catalysts. However, current technologies require the preparation of these catalysts under high temperature, high pressure, and inert atmospheres, resulting in complex preparation processes, easy particle agglomeration, poor stability, and high overpotentials in the OER reaction. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an amorphous cobalt oxide@nitrogen-doped carbon material, its preparation method, and its applications. Using a soluble cobalt salt as the cobalt source, the cobalt source is mixed with a carbon-nitrogen compound, and the amorphous cobalt oxide@nitrogen-doped carbon material is obtained through a one-step calcination process. The preparation process is simple, requiring no stringent atmospheric conditions, thus solving the problem of complex preparation processes in existing technologies. Furthermore, the material of this invention has a sheet-like structure, effectively avoiding particle agglomeration. When used as an electrode in electrocatalytic hydrogen evolution, its oxygen evolution reaction overpotential is lower than that of traditional cobalt tetroxide catalysts, and it exhibits good stability.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The first objective of this invention is to provide a method for preparing amorphous cobalt oxide@nitrogen-doped carbon material, characterized by comprising the following steps:

[0008] Using soluble cobalt salt as the cobalt source, the cobalt source is mixed with carbonitride compounds and calcined. During the calcination process, the carbonitride compounds decompose rapidly during the heating stage, generating nitrogen-containing two-dimensional sheets in situ and releasing NH3 and CO2. At the same time, the nitrogen-containing sheets bind the cobalt-based compounds in the cobalt source to migrate and change their electronic environment, preventing them from forming a long-range ordered structure, thus maintaining amorphous cobalt oxide, and obtaining amorphous cobalt oxide@nitrogen-doped carbon material. The calcination conditions are: annealing at 250℃~500℃ for 1h~6h in an air atmosphere.

[0009] Generally, high temperatures favor the formation of crystalline substances, while low temperatures mostly result in amorphous substances; amorphous structures expose more active sites. In the low-temperature oxidation stage, such as 250℃~500℃, the cobalt source is oxidized to Co3O4 or CoO, but due to the nitrogen-containing two-dimensional sheet and the encapsulation of the carbon matrix and the limitation of oxygen diffusion, a long-range ordered structure cannot be formed, and it is ultimately retained as amorphous cobalt oxide.

[0010] Preferably, the molar ratio of soluble cobalt salt to carbon and nitrogen compounds is 1:0.5~20.

[0011] Preferably, the carbon-nitrogen compound is selected from dimethylimidazole, benzidine, hexamethylenetetramine, or urea.

[0012] Preferably, the soluble cobalt salt is selected from cobalt acetate, cobalt nitrate, cobalt chloride, or cobalt acetylacetonate.

[0013] A second objective of this invention is to provide an amorphous cobalt oxide@nitrogen-doped carbon material prepared by the above method.

[0014] Preferably, the amorphous cobalt oxide@nitrogen-doped carbon material is in the form of thin sheets, and the four elements of cobalt, carbon, nitrogen and oxygen are uniformly distributed within the amorphous cobalt oxide@nitrogen-doped carbon material.

[0015] The third objective of this invention is to provide an oxygen evolution reaction electrode, which is prepared from the above-mentioned amorphous cobalt oxide@nitrogen-doped carbon material, conductive agent, binder, solvent and current collector. The amorphous cobalt oxide@nitrogen-doped carbon material, conductive agent and binder are dispersed together in a solvent to prepare a slurry; the slurry is loaded onto a substrate and dried to obtain the oxygen evolution reaction electrode.

[0016] Preferably, the mass ratio of amorphous cobalt oxide@nitrogen-doped carbon material, conductive agent, and binder is 75~80:10~15:10.

[0017] A fourth objective of this invention is to provide the application of the above-described oxygen evolution reaction electrode in the preparation of electrode materials for water electrolysis to produce hydrogen, metal-air batteries, or regenerative fuel cells.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. This invention provides a method for preparing amorphous cobalt oxide@nitrogen-doped carbon material. A soluble cobalt salt is used as the cobalt source. The cobalt source is mixed with a carbonitride compound and then calcined. During calcination, the carbonitride compound rapidly decomposes during the heating stage, generating nitrogen-containing two-dimensional flakes in situ and releasing NH3 and CO2. Simultaneously, the nitrogen-containing flakes confine the cobalt-based compounds in the cobalt source, altering their electronic environment and preventing them from forming a long-range ordered structure, thus maintaining the amorphous cobalt oxide state and obtaining the amorphous cobalt oxide@nitrogen-doped carbon material. This invention utilizes the confinement and crystal-suppressing synergistic effect of carbonitride compounds to prepare amorphous cobalt oxide@nitrogen-doped carbon material in a single air calcination step. The preparation process is simple, requiring no stringent atmospheric conditions, thus solving the problem of complex preparation processes in existing technologies. Furthermore, the material of this invention has a flake-like structure, effectively avoiding particle agglomeration.

[0020] 2. The amorphous cobalt oxide@nitrogen-doped carbon material of this invention has a high-density amorphous phase rich in active sites and is strongly coupled with the nitrogen-doped carbon framework, exhibiting both high activity and high stability. It demonstrates excellent performance in electrocatalytic oxygen evolution reaction (OER), metal-air batteries, and energy storage devices. An OER electrode prepared using this material was used in a 1 mol / L potassium hydroxide electrolyte at a current density of 10 mA / cm². 2 It exhibits an overpotential of 285 mV and a Tafel slope of only 60 mV / decade. Furthermore, the amorphous cobalt oxide@nitrogen-doped carbon material demonstrates excellent stability in the oxygen evolution reaction in alkaline media, with almost no significant voltage drop during a 24-hour constant current measurement. This is attributed to the unique flake morphology of the amorphous cobalt oxide@nitrogen-doped carbon material; the amorphous cobalt oxide possesses abundant active sites, while the nitrogen-doped carbon material exhibits high conductivity, resulting in a synergistic effect between the two.

[0021] 3. Compared with existing technologies that use precious metal-based catalysts, this invention uses inexpensive cobalt acetate tetrahydrate as the cobalt source and urea as both the nitrogen and carbon source, which significantly reduces costs and enables its widespread commercial application. Attached Figure Description

[0022] Figure 1 shows the sheet-like CoO in Example 1. x XRD patterns of @NC material and Co3O4 nanoparticles of Comparative Example 1.

[0023] Figure 2 shows the sheet-like CoO from Example 1. xTransmission electron microscope (TEM) images of the @NC material at different magnifications, where (a) is 1 μm, (b) is 0.5 μm, (c) is 200 nm, and (d) is 20 nm.

[0024] Figure 3 shows transmission electron microscopy (TEM) images of Co3O4 nanoparticles from Comparative Example 1 at different magnifications, where (a) is 200 nm, (b) is 50 nm, (c) is 20 nm, and (d) is 10 nm.

[0025] Figure 4 shows the CoO from Example 1. x High-resolution XPS spectra of @NC, where (a) represents Co 2p, (b) represents C 1s, (c) represents N 1s, and (d) represents O 1s.

[0026] Figure 5 shows the Co3O4-CP electrode and CoO4-CP electrode. x @NC-CP electrode and electrocatalytic test results for CP, where (a) shows the Co3O4-CP electrode and CoO x @NC-CP electrode and LSV curve of CP, (b) is CoO x @NC-CP constant current density is 20mA / cm² 2 The chronopotential curves at time (c) show the Co3O4-CP electrode and CoO2 electrode. x @NC-CP electrode and Tafel diagram of CP, (d) is Co3O4-CP electrode, CoO x @NC-CP electrode and CP at 10mA / cm 2 A comparison graph of overpotential and Tafel slope.

[0027] Figure 6 shows CoO x The NC-CP electrode was used in a KOH electrolyte solution with a fixed current density of 20 mA / cm². 2 Faraday efficiency diagram for water electrolysis; the black line represents the theoretical amount of O2 passing through the charge at 100% Faraday efficiency, and the red line represents the actual amount of O2.

[0028] Figure 7 shows the Co3O4-CP electrode and CoO4-CP electrode. x @NC-CP electrode and CP CV curve and i c The graph shows the relationship between the scanning rate and the electrode, where (a) represents the Co3O4-CP electrode and (b) represents the CoO4-CP electrode. x @NC-CP electrode, (c) is the CP electrode; (d) is the i c Relationship with scan rate. Detailed Implementation

[0029] The technical solution of the present invention will be clearly and completely described below with reference to the data in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be noted that the technical terms used in this invention are for the purpose of describing specific embodiments only and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased commercially or prepared by existing methods. Among them, carbon paper is abbreviated as CP.

[0031] In existing technologies, cobalt-based oxygen evolution catalysts generally employ multi-step hydrothermal-annealing or hydrogen reduction processes, which are cumbersome and energy-intensive. The resulting materials are mostly crystalline Co3O4 nanoparticles, which are prone to agglomeration and have insufficient exposure of active sites, resulting in high overpotentials and poor long-term stability of the oxygen evolution reaction. In addition, although noble metal alternatives have excellent activity, they are expensive and difficult to apply on a large scale.

[0032] To address the problems of the existing technologies, this invention employs a one-step air calcination strategy of "soluble cobalt salt-carbonitridium compound," eliminating the need for inert / reducing atmospheres and multiple post-processing steps, thus simplifying the preparation process. This invention utilizes nitrogen-containing two-dimensional sheets generated from the in-situ decomposition of carbonitridium compounds to spatially confine and electronically regulate the cobalt-based compound, blocking long-range lattice ordering and forming amorphous cobalt oxide, significantly inhibiting particle aggregation and exposing high-density active sites. Furthermore, this invention constructs a highly conductive and corrosion-resistant sheet structure through strong coupling between the amorphous phase and the nitrogen-doped carbon framework, achieving a current density of 10 mA / cm². 2 At that time, the oxygen evolution reaction overpotential dropped to 285mV, and there was no significant voltage decay in the 24h constant current test. At the same time, the use of inexpensive cobalt acetate and urea to replace precious metals significantly reduced the cost of raw materials and processes.

[0033] To enable those skilled in the art to more clearly understand the technical solution of the present invention, the following will provide a detailed description in conjunction with specific embodiments:

[0034] Example 1

[0035] A method for preparing amorphous cobalt oxide@nitrogen-doped carbon material includes the following steps:

[0036] S1. Raw material mixing and grinding:

[0037] Cobalt acetate tetrahydrate and urea were ground and mixed at a molar ratio of 6:75, and the mixture was ground thoroughly for 30 minutes to obtain the pyrolysis precursor.

[0038] S2. Annealing in air atmosphere: The pyrolysis precursor was transferred to an alumina crucible, which was then placed in a muffle furnace and annealed at 350°C for 6 hours in air atmosphere. After annealing, the mixture was allowed to cool naturally to room temperature to obtain amorphous cobalt oxide@nitrogen-doped carbon material, denoted as CoO. x @NC.

[0039] Example 2

[0040] A method for preparing amorphous cobalt oxide@nitrogen-doped carbon material includes the following steps:

[0041] S1. Raw material mixing and grinding:

[0042] Cobalt acetate tetrahydrate and urea were ground and mixed at a molar ratio of 1:0.5, and the mixture was ground thoroughly for 30 minutes to obtain the pyrolysis precursor.

[0043] S2. Annealing in air atmosphere: The pyrolysis precursor was transferred to an alumina crucible, which was then placed in a muffle furnace and annealed at 350°C for 6 hours in air atmosphere. After annealing, the mixture was allowed to cool naturally to room temperature to obtain amorphous cobalt oxide@nitrogen-doped carbon material, denoted as CoO. x @NC.

[0044] Example 3

[0045] A method for preparing amorphous cobalt oxide@nitrogen-doped carbon material includes the following steps:

[0046] S1. Raw material mixing and grinding:

[0047] Cobalt acetate tetrahydrate and urea were ground and mixed at a molar ratio of 1:20, and the mixture was ground thoroughly for 30 minutes to obtain the pyrolysis precursor.

[0048] S2. Annealing in air atmosphere: The pyrolysis precursor was transferred to an alumina crucible, which was then placed in a muffle furnace and annealed at 350°C for 6 hours in air atmosphere. After annealing, the mixture was allowed to cool naturally to room temperature to obtain amorphous cobalt oxide@nitrogen-doped carbon material, denoted as CoO. x @NC.

[0049] Example 4

[0050] A method for preparing amorphous cobalt oxide@nitrogen-doped carbon material includes the following steps:

[0051] S1. Raw material mixing and grinding:

[0052] Cobalt acetate tetrahydrate and dimethylimidazole were ground and mixed at a molar ratio of 6:75, and the mixture was ground thoroughly for 30 minutes to obtain the pyrolysis precursor.

[0053] S2. Annealing in air atmosphere: The pyrolysis precursor is transferred to an alumina crucible, which is then placed in a muffle furnace and annealed at 500°C for 1 hour in air atmosphere. After annealing, it is naturally cooled to room temperature to obtain amorphous cobalt oxide@nitrogen-doped carbon material, denoted as CoO. x @NC.

[0054] Example 5

[0055] A method for preparing amorphous cobalt oxide@nitrogen-doped carbon material includes the following steps:

[0056] S1. Raw material mixing and grinding:

[0057] Cobalt acetate tetrahydrate and benzidine were ground and mixed at a molar ratio of 6:75, and the mixture was ground thoroughly for 30 minutes to obtain the pyrolysis precursor.

[0058] S2. Annealing in air atmosphere: The pyrolysis precursor was transferred to an alumina crucible, which was then placed in a muffle furnace and annealed at 250°C for 6 hours in air atmosphere. After annealing, the mixture was allowed to cool naturally to room temperature to obtain amorphous cobalt oxide@nitrogen-doped carbon material, denoted as CoO. x @NC.

[0059] Example 6

[0060] A method for preparing amorphous cobalt oxide@nitrogen-doped carbon material includes the following steps:

[0061] S1. Raw material mixing and grinding:

[0062] Cobalt acetate tetrahydrate and hexamethylenetetrahydrate were ground and mixed at a molar ratio of 6:75, and the mixture was ground thoroughly for 30 minutes to obtain the pyrolysis precursor.

[0063] S2. Annealing in air atmosphere: The pyrolysis precursor was transferred to an alumina crucible, which was then placed in a muffle furnace and annealed at 350°C for 5 hours in air atmosphere. After annealing, the mixture was allowed to cool naturally to room temperature to obtain amorphous cobalt oxide@nitrogen-doped carbon material, denoted as CoO. x @NC.

[0064] Comparative Example 1

[0065] A method for preparing Co3O4 nanoparticles includes the following steps:

[0066] Cobalt acetate tetrahydrate was placed in an alumina crucible, which was then placed in a muffle furnace and annealed at 350°C for 6 hours in air. After annealing, the crucible was naturally cooled to room temperature to obtain Co3O4 nanoparticles, denoted as Co3O4.

[0067] Observe Figure 1 to obtain CoOx @NC exhibits a relatively weak and broad peak between 15° and 30°, primarily corresponding to amorphous carbon. Besides the carbon peak, cobalt oxide shows no other diffraction peaks. Therefore, CoO... x @NC is essentially amorphous, and this structure is conducive to the exposure of active sites, thereby improving the catalytic performance of this amorphous cobalt oxide@nitrogen-doped carbon material. For Co3O4 nanoparticles, the diffraction peaks that appear at 2θ of 19°, 31.2°, 36.8°, 44.8°, 55.6°, 59.3°, 65.2° and 77.3° correspond to the (111), (220), (311), (400), (422), (511), (440) and (533) crystal planes of cobalt, respectively. This is consistent with the standard spectrum of Co3O4 PDF#43-1003, indicating that Co3O4 nanoparticles can be obtained by one-step pyrolysis of cobalt acetate.

[0068] Observing Figure 2, we can see that CoO x @NC is in the form of thin flakes, and there are no obvious lattice fringes in the entire flake, which further proves the CoO of the present invention. x @NC represents an amorphous structure, which is consistent with the XRD analysis results.

[0069] As shown in Figure 3, lattice fringes belonging to Co3O4 are clearly observed in the TEM image of Co3O4, which is consistent with the results of XRD testing, further demonstrating that the synthesized Co3O4 has a good crystal structure.

[0070] Referring to Figure 4, it can be seen that the CoO in Example 1 x @NC contains four elements: cobalt, carbon, nitrogen, and oxygen, and the chemical states of each element are clearly defined. From Figure 4(a), the peak at 780.5 eV is attributed to Co. 2+ Coordination of ions with O or N atoms, Co 2p 3 / 2 In the spectrum, the peaks at 783.3 eV and 786.6 eV correspond to Co, respectively. 3+The satellite peaks at 796.7 eV and 802.3 eV, representing the -N / O and Co-OH bonds respectively, further confirm that Co exists primarily in the di- or tri-valent states. Furthermore, the C 1s high-resolution spectrum in Figure 4(b) shows three main peaks with binding energies of 284.8 eV, 287.9 ​​eV, and 286.6 eV, which are attributed to aromatic CC, CNC, and CO bonds, respectively. The N 1s high-resolution spectrum in Figure 4(c) shows the CNC group and tertiary nitrogen group with binding energies of 398.9 eV and 399.6 eV, respectively, as well as a metal nitride peak with a lower binding energy of 398.1 eV. In Figure 4(d), the two O 1s peaks are attributed to Co–O and absorbed oxygen from water, with binding energies of 531.5 eV and 533.0 eV, respectively. In summary, this invention further demonstrates that it successfully prepared sheet-like amorphous cobalt oxide@nitrogen-doped carbon materials via a one-step calcination process.

[0071] The electrode was prepared by: taking 5.0 mg of CoO from Example 1... x @NC and Co3O4 were co-dispersed with 20 μL and 5 wt.% Nafion solution, respectively, in a 980 μL mixture consisting of 490 μL ethanol and 490 μL water. The mixture was sonicated for 60 min to form a homogeneous dispersion. 50 μL of the dispersion was dropped onto a 1 cm × 1 cm CP plate and dried using infrared light to obtain the working electrodes, which were CoO4 and Co3O4. x @NC-CP electrode and Co3O4-CP electrode; on carbon paper, CoO x The mass loading of either NC or Co3O4 remained at 0.25 mg / cm³. 2 .

[0072] Test methods and conditions: Using 1.0 mol / L KOH as the electrolyte, the relationship between potential and RHE is: E (RHE) =E (Ag / AgCl) +0.196 +0.059 × pH.

[0073] The slope of the double-layer capacitor's charging current density j versus scan rate at 1.09V vs. RHE potential was determined, with the slope value taken as twice C. dl The Faraday efficiency test was performed in a closed electrolytic cell with a total volume of 126 mL; dissolved oxygen in the electrolyte was removed by argon bubbling for 1 hour before electrolysis; subsequently, the electrolyte was dissolved in a static electrolyte solution of potassium hydroxide (1.0 mol / L, pH 13.6) at 10 mA / cm². 2 Electrolysis was performed at a constant current for 2.0 h without iR compensation. During the electrolysis process, the headspace oxygen content was measured using a GC 7890T gas chromatograph equipped with a thermal conductivity detector. The Faraday efficiency was calculated using the formula η = (actual O2 / theoretical O2) × 100%.

[0074] CoO₂ was evaluated using a standard three-electrode system in a 1.0 mol / L potassium hydroxide solution. x @NC-CP electrode, Co3O4-CP electrode, and CP oxygen evolution electrocatalytic performance. Polarization curves were obtained by linear sweep voltammetry at a scan rate of 5.0 mV / s, as shown in Figure 5(a). When the current density is 10 mA / cm²... 2 At that time, CoO x The overpotentials required for the @NC-CP electrode and the Co3O4-CP electrode are 285mV and 370mV, respectively, and CP has almost no activity for the water oxidation reaction.

[0075] Besides OER activity, stability is also an important criterion for evaluating advanced electrocatalysts. To evaluate CoO... x The durability of @NC was tested under alkaline conditions using a chronopotential test at a constant current density. As shown in Figure 5(b), at 20 mA / cm²... 2 At the specified current density, after 24 hours of continuous operation, the voltage decay was negligible, confirming the effectiveness of the CoO obtained in Example 1. x @NC exhibits good long-term stability. Further evidence from Figure 5(c) shows that CoO... x The Tafel slope of @NC is only 60 mV / dec, higher than that of Co3O4 (66 mV / dec) and CP (104 mV / dec). From plot (d) in Figure 5, it can be seen that CoO... x @NC exhibits the best catalytic activity, namely a higher current density and a faster OER rate. During electrolysis, CoO x The continuous release of a large number of bubbles on the surface of the @NC-CP electrode further verifies its excellent oxygen evolution capability.

[0076] In Figure 6, through CoO x The Faradaic efficiency of the OER catalyzed by the @NC-CP electrode was close to 100%, indicating that the current density is related to water splitting. To further investigate the active sites of the catalyst in this reaction, cyclic voltammetry was performed in a 1 mol / L potassium hydroxide solution.

[0077] Within the commonly used potential window of 1.065V vs. RHE to 1.115V vs. RHE, CoO was subjected to different scan rates from 4mV / s to 20mV / s. x CV tests were performed using the @NC-CP electrode and the Co3O4-CP electrode. Figures (a), (b), and (c) in Figure 7 show that CoO... xThe scanning results for both the @NC-CP electrode and the Co3O4-CP electrode exhibited typical "ice crystal"-like responses. The electrochemical double-layer capacitance, C0, was obtained by linear fitting of current density and scan rate. dl From Figure 7(d), we can see that CoO x @NC-CP electrode C dl Up to 13.6 μF / cm 2 It is approximately 15 times that of the Co3O4-CP electrode, compared to 0.0675 μF / cm of CP. 2 This represents an improvement of two orders of magnitude. This result directly proves the effectiveness of CoO. x @NC has a richer number of active sites, which provides decisive support for its significantly enhanced OER activity.

[0078] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

Claims

1. An oxygen evolution reaction electrode, characterized in that, The oxygen evolution reaction electrode is prepared from amorphous cobalt oxide@nitrogen-doped carbon material, a conductive agent, a binder, a solvent, and a current collector. The amorphous cobalt oxide@nitrogen-doped carbon material, the conductive agent, and the binder are dispersed together in a solvent to prepare a slurry. The slurry is then loaded onto a substrate and dried to obtain the oxygen evolution reaction electrode. The amorphous cobalt oxide@nitrogen-doped carbon material is prepared according to the following steps: using a soluble cobalt salt as the cobalt source, the cobalt source is ground and mixed with a carbonitride compound, and then calcined. During calcination, the carbonitride compound rapidly decomposes during the heating phase. In-situ generation of nitrogen-containing two-dimensional sheets releases NH3 and CO2; simultaneously, the nitrogen-containing sheets bind the cobalt-based compounds in the cobalt source to migrate and change their electronic environment, preventing them from forming long-range ordered structures, thus maintaining them as amorphous cobalt oxide, resulting in amorphous cobalt oxide@nitrogen-doped carbon materials; the calcination conditions are: annealing at 250℃~500℃ for 1h~6h in air atmosphere; the molar ratio of soluble cobalt salt to carbon-nitrogen compound is 1:0.5~20; the carbon-nitrogen compound is selected from dimethylimidazole, benzidine, hexamethylenetetramine or urea.

2. The oxygen evolution reaction electrode according to claim 1, characterized in that, Soluble cobalt salts are selected from cobalt acetate, cobalt nitrate, cobalt chloride, or cobalt acetylacetonate.

3. The oxygen evolution reaction electrode according to claim 1, characterized in that, The amorphous cobalt oxide@nitrogen-doped carbon material is in the form of thin sheets, and the four elements cobalt, carbon, nitrogen and oxygen are evenly distributed within the amorphous cobalt oxide@nitrogen-doped carbon material.

4. The oxygen evolution reaction electrode according to claim 1, characterized in that, The mass ratio of amorphous cobalt oxide@nitrogen-doped carbon material, conductive agent, and binder is 75~80:10~15:

10.

5. The application of the oxygen evolution reaction electrode according to any one of claims 1 to 4 in the preparation of electrode materials for hydrogen production by water electrolysis, metal-air batteries, or regenerative fuel cells.

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