Preparation method and application of nitrogen and phosphorus co-doped cobalt metal catalyst
By preparing a nitrogen-phosphorus co-doped cobalt metal catalyst through electrospinning, the problems of high cost and poor stability of noble metal HER catalysts were solved, and efficient and stable hydrogen production through water electrolysis was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-05
- Publication Date
- 2026-04-03
AI Technical Summary
Existing HER catalysts mainly rely on precious metals, resulting in high costs, low catalytic performance, and poor long-term stability, which limits the commercial application of hydrogen production through water electrolysis.
A co-doped cobalt metal catalyst with nitrogen and phosphorus was prepared by electrospinning to form a three-dimensional network structure. Co metal and heteroatoms formed a Co-N/PC complex, achieving uniform distribution and improving catalytic activity.
It reduces the overpotential of the hydrogen evolution reaction, improves catalytic performance and stability, and exhibits excellent electrocatalytic performance, especially under high potential conditions where its stability is superior to that of noble metal catalysts.
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Figure CN121775892A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of catalyst technology, and in particular to a method for preparing and applying a nitrogen-phosphorus co-doped cobalt metal catalyst. Background Technology
[0002] Hydrogen (H2) has a high energy density and produces no carbon emissions during energy release, making it widely considered an ideal alternative to fossil fuels. Currently, hydrogen is mainly produced through coal, natural gas, or methane reforming, but these processes generate significant carbon emissions, resulting in high energy consumption and involvement in carbon cycling. Photocatalysis and electrochemical water splitting have become one of the most sustainable and cleanest methods for producing high-purity hydrogen, operating under mild conditions and relying on abundant water resources. Typically, the electrochemical water splitting process consists of two key reactions: the hydrogen evolution reaction (HER) at the cathode and the oxygen evolution reaction (OER) at the anode.
[0003] However, the HER reaction is affected by slow kinetics, thus limiting the overall water splitting efficiency. To overcome the kinetic barrier and improve the electrocatalytic efficiency of HER, state-of-the-art HER catalysts are based on platinum (Pt) nanomaterials, but the natural scarcity and high cost of noble metals such as Ir, Ru, and Pt limit the economical production of "green" hydrogen. Therefore, the development of efficient and stable non-noble metal HER catalysts is crucial for the commercialization of water electrolysis. Summary of the Invention
[0004] The purpose of this invention is to provide a method for preparing and applying a nitrogen-phosphorus co-doped cobalt metal catalyst, in order to solve the problems that the above-mentioned HER catalysts are mainly based on precious metals, whose high cost limits the development and commercial application of the catalysts, and whose catalytic performance is not high and whose long-term stability is poor.
[0005] To achieve the above objectives, the first aspect of the present invention provides a method for preparing a nitrogen-phosphorus co-doped cobalt metal catalyst, comprising the following steps: (1) Dissolve the nitrogen-containing polymer and phosphoric acid together in an organic solvent to obtain a mixture; (2) Add cobalt salt to the mixture to obtain a precursor solution; (3) Electrospinning the precursor solution to obtain a precursor membrane; (4) The precursor film is heated and kept warm in a nitrogen atmosphere to obtain a nitrogen-phosphorus co-doped cobalt metal catalyst.
[0006] Preferably, in step (1), the nitrogen-containing polymer is polyvinylpyrrolidone, and the concentration of polyvinylpyrrolidone in the mixture is 80~120g / L.
[0007] Preferably, in step (1), the organic solvent is N,N-dimethylformamide, and the volume ratio of phosphoric acid to N,N-dimethylformamide is 0~4:60.
[0008] Preferably, in step (2), the cobalt salt is cobalt acetate tetrahydrate, and the concentration of the cobalt salt in the precursor solution is 0.15~0.20 mol / L.
[0009] Preferably, in step (3), the electrospinning process is as follows: In an environment with constant air humidity, the precursor solution is ejected from the spinneret at a constant thrust rate and runs under the action of an external constant high voltage electric field. Due to the electric field force, it is stretched and split, and at the same time, the organic solvent evaporates rapidly. Subsequently, the jet is deposited on the receiver and solidified into a precursor film.
[0010] Preferably, in step (3), the air humidity index is 60~70%, the pushing speed is 0.0001~0.0005mm / s, and the voltage is 15~20kV.
[0011] Preferably, in step (4), the heating temperature is 850~950℃ and the holding time is 2~3h.
[0012] A second aspect of the present invention provides a nitrogen-phosphorus co-doped cobalt metal catalyst, which is prepared by the above-described preparation method.
[0013] The precursor film formed by electrospinning in this invention consists of a large number of smooth nanofibers interwoven to form a three-dimensional network structure with lengths reaching tens of micrometers. This precursor film provides the foundation for subsequent nitrogen-phosphorus co-doped cobalt metal catalysts, enabling the prepared nitrogen-phosphorus co-doped cobalt metal catalysts to also possess a similar three-dimensional network morphology to the precursor film, with fiber diameters of approximately several hundred nanometers. This three-dimensional network morphology enhances the electrocatalytic activity of the catalyst and provides an excellent surface microenvironment for the catalytic reaction.
[0014] In nitrogen-phosphorus co-doped cobalt metal catalysts, Co metal particles form Co-N / PC complexes with heteroatoms, and no obvious particle morphology is observed. This is conducive to the uniform distribution of Co in the catalyst. The highly dispersed Co atoms greatly improve the utilization rate of the metal, and the heteroatoms at the same time improve the coordination environment around the Co metal, thereby enhancing the catalytic activity of the Co metal.
[0015] The third aspect of this invention provides an application of a nitrogen-phosphorus co-doped cobalt metal catalyst in the electrolysis of water.
[0016] The nitrogen-phosphorus co-doped cobalt metal catalyst prepared in this invention, when used as an anode catalyst in the water electrolysis reaction, can effectively reduce the voltage required for the water splitting reaction to occur. The catalyst operates at a current density of 100 mA / cm². 2 The overpotential at that time is 201mV, and its Tafel slope is 48.12mV dec. -1 Its electrocatalytic performance can remain stable for more than 50 hours, and it has good application prospects in the field of water electrolysis.
[0017] Therefore, the present invention, employing the above-described method for preparing and applying a nitrogen-phosphorus co-doped cobalt metal catalyst, has the following beneficial effects: (1) The present invention uses abundant and inexpensive non-precious metals to prepare a hydrogen production catalyst for water electrolysis, which can reduce the overpotential of the slower hydrogen evolution reaction. Compared with the noble metal-based catalyst platinum carbon (Pt / C), its catalytic performance and stability under high potential conditions are excellent.
[0018] (2) In the nitrogen-phosphorus co-doped cobalt metal catalyst prepared by the present invention, the cobalt element is coordinated with the nitrogen and phosphorus elements, thereby achieving a uniform distribution of the cobalt element in the catalyst and improving the electrocatalytic performance of the catalyst.
[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0020] Figure 1 Here is a SEM image of the precursor membrane from Example 3; Figure 2 The images shown are SEM, TEM, and HRTEM images of the catalyst in Example 3. Figure 2 In the image, 'a' represents a SEM image of Co@P3PCFs with a 400nm scale. Figure 2 In the image, b is a TEM image of Co@P3PCFs with a 500nm scale. Figure 2 In the image, 'c' represents a TEM image of Co@P3PCFs with a 200 nm scale. Figure 2 In the image, d represents a TEM image of Co@P3PCFs with a 50nm scale. Figure 2 In the image, 'e' represents a high-resolution transmission electron microscope (HRTEM) image of Co@P3NCFs. Figure 3 The XRD pattern of the catalyst in Example 3 is shown below. Figure 4 The EDS spectrum of the catalyst in Example 3 is shown below. Figure 5 The XPS spectrum of the catalyst in Example 3 is shown below. Figure 5In the image, 'a' represents the high-resolution XPS spectrum of the 2p orbital of cobalt (Co). Figure 5 In the image, b represents the high-resolution XPS spectrum of the 1s orbital of nitrogen (N). Figure 6 The linear sweep voltammetry results are for the catalysts in the examples and comparative examples; Figure 7 Tafel curves for the catalysts in the examples and comparative examples; Figure 8 The time-current curves are for the catalysts in the examples and comparative examples. Detailed Implementation
[0021] The present invention will be further described below. It should be noted that this embodiment is based on the present technical solution and provides detailed implementation methods and specific operation processes, but the present invention is not limited to this embodiment.
[0022] Example 1 A method for preparing a nitrogen-phosphorus co-doped cobalt metal catalyst includes the following steps: (1) Dissolve 6.0 g of polyvinylpyrrolidone (PVP) in 60.0 mL of N,N-dimethylformamide (DMF) to obtain a mixture; (2) Slowly add 2.5g of cobalt acetate tetrahydrate to the mixture and stir continuously for 6 hours to obtain a uniform precursor solution; (3) The prepared precursor solution is loaded into an injection container. Under the conditions of constant humidity of 65%, a high voltage of 18kV is applied to it. Under the conditions of pushing speed of 0.0001mm / s and receiving distance of 25cm, the precursor solution forms a jet stream and finally falls on the receiver to complete the electrospinning process and solidify to form a precursor film. (4) The dried precursor membrane was heated to 900°C in a nitrogen atmosphere and kept at that temperature for 2 hours to obtain a three-dimensional layered porous cobalt metal catalyst, denoted as Co@P0NPCF.
[0023] Example 2 A method for preparing a nitrogen-phosphorus co-doped cobalt metal catalyst includes the following steps: (1) Dissolve 6.0 g of polyvinylpyrrolidone (PVP) and 1 mL of phosphoric acid together in 60.0 mL of N,N-dimethylformamide (DMF) to obtain a mixture; (2) Slowly add 2.5g of cobalt acetate tetrahydrate to the mixture and stir continuously for 6 hours to obtain a uniform precursor solution; (3) The prepared precursor solution is loaded into an injection container. Under the conditions of constant humidity of 65%, a high voltage of 18kV is applied to it. Under the conditions of pushing speed of 0.0001mm / s and receiving distance of 25cm, the precursor solution forms a jet stream and finally falls on the receiver to complete the electrospinning process and solidify to form a precursor film. (4) The dried precursor film was heated to 900°C in a nitrogen atmosphere and kept at that temperature for 2 hours to obtain a three-dimensional layered porous nitrogen-phosphorus co-doped cobalt metal catalyst, denoted as Co@P1NPCF.
[0024] Example 3 A method for preparing a nitrogen-phosphorus co-doped cobalt metal catalyst includes the following steps: (1) Dissolve 6.0 g of polyvinylpyrrolidone (PVP) and 2 mL of phosphoric acid together in 60.0 mL of N,N-dimethylformamide (DMF) to obtain a mixture; (2) Slowly add 2.5g of cobalt acetate tetrahydrate to the mixture and stir continuously for 6 hours to obtain a uniform precursor solution; (3) The prepared precursor solution is loaded into an injection container. Under the conditions of constant humidity of 65%, a high voltage of 18kV is applied to it. Under the conditions of pushing speed of 0.0001mm / s and receiving distance of 25cm, the precursor solution forms a jet stream and finally falls on the receiver to complete the electrospinning process and solidify to form a precursor film. (4) The dried precursor film was heated to 900°C in a nitrogen atmosphere and kept at that temperature for 2 hours to obtain a three-dimensional layered porous nitrogen-phosphorus co-doped cobalt metal catalyst, denoted as Co@P2NPCF.
[0025] Example 4 A method for preparing a nitrogen-phosphorus co-doped cobalt metal catalyst includes the following steps: (1) Dissolve 6.0 g of polyvinylpyrrolidone (PVP) and 3 mL of phosphoric acid together in 60.0 mL of N,N-dimethylformamide (DMF) to obtain a mixture; (2) Slowly add 2.5g of cobalt acetate tetrahydrate to the mixture and stir continuously for 6 hours to obtain a uniform precursor solution; (3) The prepared precursor solution is loaded into an injection container. Under the conditions of constant humidity of 65%, a high voltage of 18kV is applied to it. Under the conditions of pushing speed of 0.0001mm / s and receiving distance of 25cm, the precursor solution forms a jet stream and finally falls on the receiver to complete the electrospinning process and solidify to form a precursor film. (4) The dried precursor film was heated to 900°C in a nitrogen atmosphere and kept at that temperature for 2 hours to obtain a three-dimensional layered porous nitrogen-phosphorus co-doped cobalt metal catalyst, denoted as Co@P3NPCF.
[0026] Example 5 A method for preparing a nitrogen-phosphorus co-doped cobalt metal catalyst includes the following steps: (1) Dissolve 6.0 g of polyvinylpyrrolidone (PVP) and 4 mL of phosphoric acid together in 60.0 mL of N,N-dimethylformamide (DMF) to obtain a mixture; (2) Slowly add 2.5g of cobalt acetate tetrahydrate to the mixture and stir continuously for 6 hours to obtain a uniform precursor solution; (3) The prepared precursor solution is loaded into an injection container. Under the conditions of constant humidity of 65%, a high voltage of 18kV is applied to it. Under the conditions of pushing speed of 0.0001mm / s and receiving distance of 25cm, the precursor solution forms a jet stream and finally falls on the receiver to complete the electrospinning process and solidify to form a precursor film. (4) The dried precursor film was heated to 900°C in a nitrogen atmosphere and kept at that temperature for 2 hours to obtain a three-dimensional layered porous nitrogen-phosphorus co-doped cobalt metal catalyst, denoted as Co@P4NPCF.
[0027] Comparative Example 1 The catalyst prepared in this comparative example is Pt / C, and the specific preparation process is as follows: Water and Nafion were mixed in a 9:1 ratio to prepare a water / Nafion mixed solution. 20wt% Pt / C powder was taken out and mixed with the water / Nafion mixed solution at a concentration of 3mg / mL. The mixture was placed in an ultrasonic bath and sonicated for 30min to obtain a dispersion solution. The resulting mixture was slowly dropped onto the surface of a glassy carbon electrode with a diameter of 3mm and allowed to dry naturally to obtain the Pt / C catalyst.
[0028] Experimental Example 1 The catalyst prepared in Example 4 was characterized.
[0029] (1) The precursor membrane prepared in Example 4 was characterized by SEM. Figure 1 As can be seen, the precursor membrane is composed of a large number of smooth nanofibers interwoven to form a three-dimensional network structure with a length of up to tens of micrometers.
[0030] (2) The catalyst prepared in Example 4 was characterized by SEM, TEM, and HRTEM. Figure 2 It can be seen from this that Figure 2In the figure, 'a' represents the SEM images of Co@P3PCFs at different magnification sizes. As can be seen from the figures, Co@P3NCFs exhibit a three-dimensional network morphology similar to the precursor membrane. The fiber diameter is approximately several hundred nanometers. The fibers show a smooth surface and there are no obvious particles attached or growing on the outside of the fibers. Figure 2 The bd in the figure are TEM images of Co@P3PCFs at different magnification sizes. As can be seen from the figure, the diameter of the nanofibers is less than 300 nm, and there are no obvious large metal particles inside the fibers. In addition, there are a large number of mesopores on the surface of Co@P3NCFs fibers, which provides an excellent surface microenvironment for the catalytic reaction. Figure 2 The image 'e' in the figure is a high-resolution transmission electron microscope (HRTEM) image of Co@P3NCFs. As can be seen from the image, no obvious particle morphology was observed, indicating that a coordination structure was formed between the Co metal and the carbon layer.
[0031] (3) The catalyst prepared in Example 4 was characterized by XRD, such as... Figure 3 As shown, the phase composition of Co@P3NPCFs was further confirmed, with diffraction peaks located at ~44.22°, ~51.52° and ~75.85°, pointing to the (111), (200) and (220) crystal planes of cubic Co crystal, respectively.
[0032] (4) The catalyst prepared in Example 4 was characterized by EDS energy dispersive spectroscopy, such as... Figure 4 As shown in the figure, the distribution of C, B, N, O and Co elements is illustrated. It can be seen from the figure that the EDS line scan data shows that the Co, N and P signals alternately increase in intensity, and there are sites with consistent signal intensity trends, indicating that Co forms a coordination structure with N and P.
[0033] (5) The catalyst prepared in Example 4 was characterized by XPS, such as... Figure 5As shown in a and b, the N 1s spectrum reveals the presence of PN (~397.8 eV), pyridine nitrogen / MNC (~398.4 eV), pyrrole nitrogen (~400.6 eV), graphitic nitrogen (~401.8 eV), and nitrogen oxide (~403.3 eV) species. The high-resolution Co 2p XPS spectrum of Co@P3NPCFs exhibits two complex characteristic peaks: typical Co 2p3 / 2 (between 775 and 792 eV) and Co 2p1 / 2 (between 792 and 810 eV). Furthermore, peak decomposition analysis revealed that the two main peaks of Co 2p3 / 2 and Co 2p3 / 2 could each be broken down into four constituent peaks: the peaks at 778.6 eV and 793.8 eV corresponded to metallic Co; the peaks at 780.4 eV and 796.3 eV belonged to cobalt oxide (Co-O); the peaks at 781.5 eV and 797.3 eV corresponded to the characteristic peaks of the Co-N / PC coordination structure; and the peaks at 785.5 eV and 803.2 eV were related to the satellite structure. This indicates that Co metal particles form Co-N / PC complexes with heteroatoms. The highly dispersed Co atoms significantly improve the utilization rate of the metal, and the heteroatoms improve the coordination environment around the Co metal, thereby enhancing the catalytic activity of the Co metal.
[0034] Furthermore, the XPS spectra show that the Co-N / PC peak is the dominant signal in the catalyst sample, indicating that Co forms a stable coordination structure with N and P heteroatoms. The Co metal forms complexes with N and P heteroatoms, and due to the fine size of the metal particles, some of the metal on the material surface is oxidized, resulting in a high-valence oxidation state. This result confirms that Co in the material exists as ultrafine particles coordinated with heteroatoms. The pyridine nitrogen, pyrrole nitrogen, and graphitic nitrogen species can also effectively promote the electrocatalytic activity of HER.
[0035] Experimental Example 2 The electrocatalytic performance of the catalysts in the examples and comparative examples was tested. The specific test procedure is as follows: Using 1 mol / L KOH as the alkaline electrolyte, and Co@P3PCFs, Co@P0PCFs, Co@P1PCFs, Co@P2PCFs, Co@P4PCFs and Pt / C as working electrodes, and Hg / HgO as the reference electrode, a platinum sheet (2×2 cm) was used. 2A three-electrode system was constructed using a catalyst as the counter electrode. The electrolytic cell of this three-electrode system was connected to an electrochemical workstation for electrochemical testing. First, the catalyst was activated by CV at different scan rates, followed by linear sweep voltammetry testing. The process parameters for CV activation at different scan rates were as follows: scan rates from high to low were 0.1 V / s, 0.09 V / s, 0.08 V / s, 0.07 V / s, 0.06 V / s, 0.05 V / s, 0.04 V / s, 0.03 V / s, 0.02 V / s, and 0.01 V / s; the voltage ranged from 0.5 to 1.0 V; and the linear sweep voltammetry was used for testing. The process parameters for the ammeter test were as follows: LSV electrochemical hydrogen evolution was performed at different scan rates, from highest to lowest: 0.1 V / S, 0.009 V / S, 0.008 V / S, 0.007 V / S, 0.006 V / S, 0.005 V / S, 0.004 V / S, 0.003 V / S, 0.002 V / S, and 0.001 V / S; the voltage ranged from -0.7 to -1.7 V.
[0036] The linear voltammetric test results of the water electrolysis hydrogen evolution catalysts with Co@P3PCFs, Co@P0PCFs, Co@P1PCFs, Co@P2PCFs, Co@P4PCFs and Pt / C are as follows: Figure 6 As shown in the figure, at 100 mA / cm 2 At the given current density, the overpotentials for each catalyst were -202.3 mV, -552.0 mV, -532.7 mV, -441.0 mV, -367.7 mV, and -481.1 mV, respectively. The results show that the Co@P3NCFs catalyst exhibits significantly better performance in water electrolysis for hydrogen production than Co@P0PCFs, Co@P1PCFs, Co@P2PCFs, Co@P4PCFs, and Pt / C.
[0037] Experimental Example 3 The Tafel slope of the catalysts in the examples and comparative examples was tested. The test procedure is as follows: The Tafel slope is calculated using the Tafel formula μ = a + b log 10 j is calculated using the formula where μ represents the overpotential, a and b are empirical constants, where b is the Tafel slope and j is the current density. A smaller Tafel slope indicates a smaller overpotential required for the same current density, meaning better catalytic performance. Using the results of linear sweep voltammetry, the overpotential μ is expressed as a + blog 10 Plotting the equation, the slope of the straight line segment is the Tafel slope. The Tafel curves for the water electrolysis hydrogen production catalysts Co@P3PCFs, Co@P0PCFs, Co@P1PCFs, Co@P2PCFs, Co@P4PCFs, and Pt / C in this embodiment are shown below. Figure 7As shown. The Tafel slopes of the water electrolysis hydrogen production catalysts Co@P3PCFs, Co@P0PCFs, Co@P1PCFs, Co@P2PCFs, Co@P4PCFs and Pt / C are 48.12 mV dec. - ¹、102.33mV dec - ¹、97.74mV dec - ¹、90.28mV dec - ¹、86.74mV dec - ¹、53.65mV dec - ¹ This indicates that the Co@P3NCFs catalyst outperforms Co@P0PCFs, Co@P1PCFs, Co@P2PCFs, Co@P4PCFs, and Pt / C. The Co@P3NCFs obtained in Example 4 of this invention exhibit a three-dimensional hierarchical porous structure, exposing more active sites, accelerating the reaction rate, and demonstrating excellent electrocatalytic activity in water splitting and oxygen evolution. At the same current density, a smaller overpotential and a lower Tafel slope indicate better catalyst performance. Furthermore, the Co@P3NCFs catalyst maintains stable performance under different potentials, especially under high potential conditions, where its stability is significantly better than that of the noble metal catalyst Pt / C.
[0038] Test Example 4 The stability of the catalyst prepared in Example 4 was tested. The specific testing procedure is as follows: The Co@P3NCFs and Pt / C catalysts obtained in Example 4 of this invention were clamped together with electrode clips and used as working electrodes, while the Hg / HgO (1 mol / L KOH) electrode was used as the reference electrode. The area of the electrode was 2 × 2 cm². 2 A platinum sheet was used as the counter electrode, and a saturated KOH (1 mol / L) aqueous solution was used as the electrolyte. The constructed three-electrode system was connected to an electrochemical workstation, and the same constant voltage was applied for 50 hours of time-current testing on both catalysts. The applied constant voltage was -0.15V (compared to the reversible hydrogen electrode). Figure 8 The time-current curves of Co@P3NCFs and Pt / C catalysts for hydrogen evolution through water electrolysis are shown in the figure. As can be seen from the figure, after 50 hours of testing, Co@P3NCFs only showed a current decay of about 3.73%, indicating that it has good stability in the HER reaction.
[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A method for preparing a nitrogen-phosphorus co-doped cobalt metal catalyst, characterized in that: Includes the following steps: (1) Dissolve the nitrogen-containing polymer and phosphoric acid together in an organic solvent to obtain a mixture; (2) Add cobalt salt to the mixture to obtain a precursor solution; (3) Electrospinning the precursor solution to obtain a precursor membrane; (4) The precursor film was heated and kept warm in a nitrogen atmosphere to obtain a nitrogen-phosphorus co-doped cobalt metal catalyst. In step (1), the nitrogen-containing polymer is polyvinylpyrrolidone, and the concentration of polyvinylpyrrolidone in the mixture is 80~120g / L; In step (2), the cobalt salt is cobalt acetate tetrahydrate, and the concentration of the cobalt salt in the precursor solution is 0.15~0.20 mol / L.
2. The method for preparing a nitrogen-phosphorus co-doped cobalt metal catalyst according to claim 1, characterized in that: In step (1), the organic solvent is N,N-dimethylformamide, and the volume ratio of phosphoric acid to N,N-dimethylformamide is 0~4:
60.
3. The method for preparing a nitrogen-phosphorus co-doped cobalt metal catalyst according to claim 1, characterized in that: In step (3), the electrospinning process is as follows: In an environment with constant air humidity, the precursor solution is ejected from the spinneret at a constant thrust rate and runs under the action of an external constant high voltage electric field. Due to the electric field force, it is stretched and split, and at the same time, the organic solvent evaporates rapidly. Subsequently, the jet is deposited on the receiver and solidified into a precursor film.
4. The method for preparing a nitrogen-phosphorus co-doped cobalt metal catalyst according to claim 3, characterized in that: In step (3), the air humidity index is 60~70%, the pushing speed is 0.0001~0.0005mm / s, and the voltage is 15~20kV.
5. The method for preparing a nitrogen-phosphorus co-doped cobalt metal catalyst according to claim 1, characterized in that: In step (4), the heating temperature is 850~950℃ and the holding time is 2~3h.
6. A nitrogen-phosphorus co-doped cobalt metal catalyst, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 7.
7. The application of the nitrogen-phosphorus co-doped cobalt metal catalyst according to claim 6, characterized in that: Application of nitrogen-phosphorus co-doped cobalt metal catalysts in water electrolysis reaction.