Nitrogen-doped vertical graphene modified electrolytic hydrogen nickel net and preparation method thereof

Abstract

The invention discloses nitrogen-doped vertical graphene modified electrolytic hydrogen nickel and a preparation method thereof. The preparation method comprises the following steps: S1, activating a nickel net by adopting an acid solution; s2, heating the activated nickel net to a set temperature; s3, taking methane as a carbon source, and growing vertical graphene on the nickel net through chemical vapor deposition; and S4, performing nitrogen doping on the vertical graphene to obtain the nitrogen-doped vertical graphene modified electrolytic hydrogen nickel net. The low-cost nickel net is used as a substrate material, and the high catalytic activity of the nitrogen-doped vertical graphene is utilized, so that efficient and low-cost hydrogen production by electrolysis of water is realized. The vertical graphene grows on the nickel net through a chemical vapor deposition method, the electro-catalytic performance of the graphene is improved, and therefore the catalytic activity is improved. The problems of high cost, insufficient catalytic activity, poor electrode stability and the like in the prior art are successfully solved, and an effective solution is provided for industrial application of a water electrolysis hydrogen production technology.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen production by electrolysis of water, and in particular to a nitrogen-doped vertical graphene-modified nickel mesh for hydrogen electrolysis and a preparation method thereof. Background Art

[0002] Hydrogen production from water electrolysis is one of the key technologies to achieve sustainable energy supply. With the growing global demand for clean energy, hydrogen production from water electrolysis has attracted widespread attention as an important method of hydrogen production. The traditional process of hydrogen production from water electrolysis mainly relies on precious metal catalysts, such as platinum (Pt) and palladium (Pd), which have high catalytic activity, but their high cost limits their large-scale application. In recent years, researchers have begun to look for low-cost, high-performance non-precious metal catalysts to reduce the cost of hydrogen production from water electrolysis and improve its efficiency.

[0003] The development trend and defects of existing water electrolysis hydrogen production catalyst technology:

[0004] 1) Traditional precious metal catalysts

[0005] Main structure / principle: Traditional water electrolysis hydrogen production catalysts mainly use precious metals, such as platinum (Pt). These catalysts promote the water decomposition reaction by providing a large number of active sites, thereby improving the efficiency of water electrolysis hydrogen production.

[0006] Development trend: Although noble metal catalysts have high catalytic activity and stability, their high cost limits their feasibility in large-scale industrial applications. Therefore, researchers have begun to explore low-cost alternative materials, such as transition metals, carbon-based materials, etc.

[0007] Disadvantages: High cost, which limits large-scale application; limited resources, which is not conducive to sustainable development.

[0008] 2) Carbon-based catalysts

[0009] Main structure / principle: Carbon-based materials, such as graphene and carbon nanotubes, have become a research hotspot due to their unique two-dimensional structure and excellent electrical conductivity. These materials promote water decomposition reactions and improve the efficiency of hydrogen production by electrolysis of water by providing abundant active sites.

[0010] Development trend: Carbon-based materials have gradually become an important candidate material for hydrogen production catalysts by water electrolysis due to their low cost and abundant resources. However, carbon-based materials still face some challenges in practical applications, such as insufficient binding force with electrode materials and the need to further improve catalytic activity.

[0011] Disadvantages: Insufficient binding force affects the stability and life of the electrode; the catalytic activity is limited and needs further optimization.

[0012] 3) Nitrogen-doped graphene

[0013] Main structure / principle: Nitrogen-doped graphene introduces nitrogen atoms into graphene, which increases the active sites on its surface and improves the electrocatalytic performance. The application of nitrogen-doped graphene in hydrogen production by water electrolysis has gradually attracted attention.

[0014] Development trend: Nitrogen-doped graphene has become a research hotspot for hydrogen production from water electrolysis due to its excellent electrocatalytic activity and stability. Its catalytic performance can be further improved by optimizing the conditions of nitrogen doping.

[0015] Disadvantages: The preparation process is complicated and requires precise control of nitrogen doping conditions; the binding strength with electrode materials still needs to be improved.

[0016] Through the above analysis, it can be seen that the existing technology has problems such as high cost, insufficient binding force and limited catalytic activity in the production of hydrogen by electrolysis of water. The present invention uses nickel mesh as the base material and combines nitrogen-doped vertical graphene, which not only reduces the cost of the catalyst, but also significantly improves the efficiency and stability of hydrogen production by electrolysis of water. Summary of the invention

[0017] The technical problem to be solved by the present invention is to provide a nitrogen-doped vertical graphene-modified nickel mesh for hydrogen electrolysis and a preparation method thereof in view of the deficiencies in the above-mentioned prior art. The problem of high catalyst cost in the existing water electrolysis hydrogen production is solved, and the efficiency and stability of water electrolysis hydrogen production are improved. Specifically, it includes using nickel mesh and nitrogen-doped vertical graphene to replace traditional precious metal catalysts to reduce costs; using the excellent electrocatalytic activity of nitrogen-doped vertical graphene to improve the efficiency of water electrolysis hydrogen production; and using a specific preparation method to form a stable combination of nitrogen-doped vertical graphene and nickel mesh substrate to enhance electrode stability and service life.

[0018] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: In a first aspect of the present invention, a method for preparing a nitrogen-doped vertical graphene-modified electrolytic hydrogen nickel mesh is provided, comprising the following steps:

[0019] S1, activating the nickel mesh with an acid solution;

[0020] S2, heating the activated nickel mesh to a set temperature;

[0021] S3, using methane as a carbon source, vertical graphene was grown on a nickel mesh by chemical vapor deposition;

[0022] S4, passing ammonia gas to nitrogen-dope the vertical graphene to obtain a nitrogen-doped vertical graphene modified electrolytic hydrogen nickel network.

[0023] Preferably, step S1 specifically comprises:

[0024] The nickel mesh is immersed in an acid solution, then rinsed with deionized water, and then placed in a drying oven for drying to obtain an activated nickel mesh.

[0025] Preferably, step S1 specifically comprises:

[0026] A nickel mesh with a thickness of 0.12 mm, a mesh size of 100 and an opening rate of 14% was immersed in a dilute hydrochloric acid solution with a concentration of 0.5 mol / L for 30 minutes, then rinsed with deionized water, and then placed in a drying oven at 80°C for 2 hours to obtain an activated nickel mesh.

[0027] Preferably, step S2 specifically comprises:

[0028] The activated nickel mesh is placed in a vacuum pump, evacuated, and then the nickel mesh is electrically heated to a set temperature.

[0029] Preferably, step S2 specifically comprises:

[0030] Put the activated nickel mesh into a vacuum furnace, evacuate to 100Pa, and heat the nickel mesh to 1000-1300℃.

[0031] Preferably, step S3 specifically comprises:

[0032] Methane is introduced into a vacuum furnace, and a chemical vapor deposition reaction is carried out at 1000-1300°C for 10-14 hours to grow vertical graphene on a nickel mesh; wherein the methane pressure is 8-12 kPa and the flow rate is 18-22 L / min.

[0033] Preferably, step S3 specifically comprises:

[0034] Methane was introduced into a vacuum furnace, and a chemical vapor deposition reaction was carried out at 1200°C for 12 hours to grow vertical graphene on the nickel mesh; wherein, the methane pressure was 10 kPa and the flow rate was 20 L / min.

[0035] Preferably, step S4 is specifically:

[0036] First, cool down to 900-1100°C, evacuate to 100Pa again, switch methane to ammonia and pass it into the vacuum furnace for 2.5-3.5h to nitrogen-dope the vertical graphene; wherein, the ammonia pressure is 0.8-1.2kPa and the flow rate is 18-22L / min.

[0037] Preferably, step S4 is specifically:

[0038] First, the temperature was lowered to 1050°C, and then the vacuum was evacuated to 100Pa. The methane was switched to ammonia and introduced into the vacuum furnace for reaction for 3 hours to nitrogen-dope the vertical graphene. The ammonia pressure was 1 kPa and the flow rate was 20 L / min.

[0039] A second aspect of the present invention provides a nitrogen-doped vertical graphene-modified nickel electrolytic hydrogen mesh, which is prepared by the method as described above.

[0040] The beneficial effects of the present invention are:

[0041] The present invention provides a nitrogen-doped vertical graphene-modified electrolytic hydrogen nickel and a preparation method thereof, and the present invention has at least the following advantages:

[0042] 1. Significantly reduce catalyst costs

[0043] The present invention uses a low-cost nickel mesh as a substrate material and utilizes the high catalytic activity of nitrogen-doped vertical graphene to achieve efficient and low-cost hydrogen production by electrolysis of water. The present invention uses nickel mesh and nitrogen-doped vertical graphene as catalysts to replace traditional precious metal catalysts (such as platinum), greatly reducing the cost of hydrogen production by electrolysis of water.

[0044] 2. Improve catalytic activity

[0045] The invention grows vertical graphene on a nickel mesh by a chemical vapor deposition (CVD) method, and introduces nitrogen atoms by ammonia treatment, thereby improving the electrocatalytic performance of the graphene and thus improving the catalytic activity.

[0046] 3. Enhance electrode stability

[0047] The present invention ensures the close combination of nitrogen-doped vertical graphene and nickel mesh through a specific preparation method, forms a stable composite structure, and improves the mechanical stability and durability of the electrode. The electrode material prepared by the present invention shows excellent stability in long-term operation, extending the service life of the electrode.

[0048] 4. Optimize reaction conditions

[0049] The present invention determines the optimal reaction temperature, pressure, time and gas flow rate through detailed experimental research, ensures the high-quality growth of vertical graphene and uniform nitrogen doping, thereby optimizing the reaction conditions for hydrogen production by electrolysis of water. The present invention optimizes the reaction conditions for hydrogen production by electrolysis of water through precise control of reaction parameters, and improves the performance of the overall system.

[0050] 5. Improve energy efficiency and power density

[0051] The present invention prepares an electrode material with high catalytic activity and stability by optimizing the activation treatment, CVD growth conditions and nitrogen doping process of the nickel mesh, thereby achieving higher energy efficiency and peak power density in practical applications. The electrode material prepared by the present invention exhibits higher energy efficiency and peak power density in the process of hydrogen production by electrolysis of water, thereby improving the overall performance of the system.

[0052] 6. Extend the service life of electrodes

[0053] The present invention ensures the close combination of nitrogen-doped vertical graphene and nickel mesh by precisely controlling each step in the preparation process, forming a stable composite structure and improving the durability and reliability of the electrode. The electrode material prepared by the present invention exhibits excellent stability in long-term operation and significantly prolongs the service life of the electrode.

[0054] By combining the above technical means, the present invention successfully solves the problems of high cost, insufficient catalytic activity and poor electrode stability existing in the prior art, and provides an effective solution for the industrial application of water electrolysis hydrogen production technology. DETAILED DESCRIPTION

[0055] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0056] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0057] The test methods used in the following examples are conventional methods unless otherwise specified. The materials and reagents used in the following examples are all commercially available unless otherwise specified. In the following examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, if the manufacturer is not specified, are all conventional products that can be purchased commercially.

[0058] The present invention discloses a nitrogen-doped vertical graphene-modified nickel electrolytic hydrogen mesh, and the preparation method thereof comprises the following steps:

[0059] S1, activating the nickel mesh with an acid solution;

[0060] A nickel mesh with a thickness of 0.12 mm, a mesh size of 100 and an opening rate of 14% was immersed in a dilute hydrochloric acid solution with a concentration of 0.5 mol / L for 30 minutes, then rinsed with deionized water, and then placed in a drying oven at 80°C for 2 hours to obtain an activated nickel mesh.

[0061] The nickel mesh is activated through a specific method to remove impurities and oxides on the surface of the nickel mesh, thereby improving the surface activity of the nickel mesh and laying the foundation for the subsequent growth of vertical graphene and nitrogen doping.

[0062] S2, heating the activated nickel mesh to a set temperature;

[0063] The activated nickel mesh is placed in a vacuum pump and evacuated to below 10Pa. The nickel mesh is then electrically heated to a set temperature to provide suitable temperature conditions for subsequent chemical vapor deposition reactions.

[0064] In a preferred embodiment, the size of the nickel mesh is 200 mm*500 mm. The nickel mesh is made to reach a preset temperature in a vacuum furnace by controlling the current.

[0065] S3, using methane as a carbon source, growing vertical graphene on a nickel mesh by chemical vapor deposition; under specific temperature, pressure and flow conditions, introducing methane for chemical vapor deposition reaction, growing vertical graphene on the nickel mesh;

[0066] In a preferred embodiment, the specific steps are: introducing methane into a vacuum furnace, performing a chemical vapor deposition reaction at 1000-1300°C, more preferably at 1200°C; reacting for 10-14h, more preferably 12h, and growing vertical graphene on a nickel mesh; wherein the methane pressure is 8-12kPa and the flow rate is 15-25L / min, and more preferably, the methane pressure is 10kPa and the flow rate is 20L / min.

[0067] S4, passing ammonia gas to nitrogen-dope the vertical graphene to obtain a nitrogen-doped vertical graphene modified electrolytic hydrogen nickel mesh. First cool it down to lower the temperature a little, for example, to about 1050°C, then evacuate it again to below 10Pa, switch methane to ammonia, and nitrogen-dope the vertical graphene under specific temperature, pressure and time conditions to improve its electrocatalytic activity.

[0068] In a preferred embodiment, the specific steps are:

[0069] First cool down to 900-1100°C, evacuate to 100Pa again, switch methane to ammonia and pass it into the vacuum furnace, react for 2.5-3.5h, more preferably 3h, to nitrogen-dope the vertical graphene; wherein, the ammonia pressure is 0.8-1.2kPa, the flow rate is 15-25L / min, more preferably, the ammonia pressure is 1kPa, and the flow rate is 20L / min.

[0070] In the process of the present invention, the comprehensive relevant performance of the prepared nitrogen-doped vertical graphene-modified nickel electrolytic hydrogen network is improved by at least the following process optimization.

[0071] 1. Selection and activation of nickel mesh

[0072] The high cost of traditional precious metal catalysts limits the large-scale application of hydrogen production by water electrolysis.

[0073] The present invention selects a low-cost nickel mesh as the base material, and removes surface impurities and oxides through a specific activation treatment (such as dilute hydrochloric acid immersion), thereby improving the surface activity of the nickel mesh and creating favorable conditions for subsequent graphene growth.

[0074] 2. High-quality growth of vertical graphene

[0075] The insufficient bonding between graphene and electrode materials affects its stability and efficiency in hydrogen production by water electrolysis.

[0076] The present invention grows vertical graphene on a nickel mesh by a chemical vapor deposition (CVD) method. The temperature, pressure, gas flow rate and reaction time of the CVD reaction are precisely controlled to ensure high-quality growth of the vertical graphene, form a stable three-dimensional structure, and enhance its bonding with the nickel mesh.

[0077] 3. Optimization of nitrogen doping

[0078] The catalytic activity of graphene itself is limited and needs to be further improved to meet the needs of industrial applications.

[0079] The present invention introduces nitrogen atoms into vertical graphene by ammonia treatment, optimizes nitrogen doping conditions (such as temperature, pressure, gas flow rate and reaction time), and improves the electrocatalytic activity of graphene. Nitrogen doping can increase the active sites on the graphene surface and significantly improve its catalytic performance.

[0080] 4. Precise control of reaction parameters

[0081] Inconsistency in reaction conditions will lead to unstable performance of the prepared electrode materials.

[0082] The present invention has determined the optimal reaction parameters through detailed experimental research, including nickel mesh activation conditions, CVD growth conditions and nitrogen doping conditions. The precise control of these parameters ensures the high-quality growth and uniform nitrogen doping of vertical graphene, and improves the stability and catalytic activity of the electrode material.

[0083] 5. Comprehensive performance evaluation of electrode materials

[0084] The lack of a systematic performance evaluation method makes it difficult to fully understand the actual application effects of electrode materials.

[0085] The present invention comprehensively evaluates the performance of the prepared nitrogen-doped vertical graphene-modified nickel mesh for hydrogen electrolysis through systematic performance tests, including indicators such as catalytic activity, energy efficiency, peak power density, and stable working time. These test results provide a scientific basis for optimizing the preparation process and practical applications.

[0086] Through the optimization and improvement of the above-mentioned key technical points, the present invention successfully solves the problems of high cost, insufficient catalytic activity and poor electrode stability existing in the existing water electrolysis hydrogen production technology, and provides an effective solution for the industrial application of water electrolysis hydrogen production technology.

[0087] The above is the overall concept of the present invention, and detailed embodiments and comparative examples are provided below on the basis of the overall concept of the present invention to further illustrate the present invention.

[0088] The main raw materials and equipment involved in the following examples are described as follows:

[0089] Methane: [Xingyao Energy brand methane], purity [99.9%]. Used to provide carbon source in chemical vapor deposition process.

[0090] Nickel mesh: produced by Qina New Materials, brand [Qina-101], thickness 0.12mm, mesh number 100, porosity 14. As a base material, it provides support for the growth and nitrogen doping of vertical graphene.

[0091] Ammonia: [Ruifeng Chemical brand ammonia], purity [99.5%]. Used for nitrogen doping of vertical graphene.

[0092] Power supply: [Hua Teng Electronic Power Supply]. Provides power for the nickel net to generate heat.

[0093] Vacuum furnace: [Excellent Technology brand vacuum furnace]. Provides vacuum environment and reaction space.

[0094] Example 1

[0095] A nitrogen-doped vertical graphene-modified nickel electrolytic hydrogen mesh, the preparation method of which comprises the following steps:

[0096] S1. Activate the nickel mesh using an acid solution:

[0097] A nickel mesh with a thickness of 0.12 mm, a mesh size of 100 and an opening rate of 14% was immersed in a dilute hydrochloric acid solution with a concentration of 0.5 mol / L for 30 minutes, then repeatedly rinsed with deionized water, and then placed in a drying oven at 80°C for 2 hours to obtain an activated nickel mesh.

[0098] S2. Heat the activated nickel mesh to the set temperature:

[0099] The activated nickel mesh was placed in a vacuum furnace, and the vacuum pump was started to evacuate the furnace to 100 Pa. The nickel mesh was electrically heated to 1150°C. The size of the nickel mesh was 200mm*500mm.

[0100] S3, chemical vapor deposition (CVD) growth of vertical graphene on nickel mesh:

[0101] Methane was introduced into a vacuum furnace, and a chemical vapor deposition reaction was carried out at 1150°C for 10 hours to grow vertical graphene on the nickel mesh; wherein, the methane pressure was 8 kPa and the flow rate was 18 L / min.

[0102] S4. Cooling and switching gases for nitrogen doping:

[0103] First, the temperature was lowered to 1040°C, and then the vacuum was evacuated to 100Pa. The methane was switched to ammonia and introduced into the vacuum furnace for 2.5 hours. The vertical graphene was nitrogen-doped to obtain a nitrogen-doped vertical graphene-modified electrolytic hydrogen nickel network. The ammonia pressure was 0.8kPa and the flow rate was 18L / min.

[0104] After nitrogen doping is completed, the nitrogen-doped vertical graphene-modified electrolytic hydrogen nickel mesh is taken out from the vacuum furnace and its water electrolysis hydrogen production performance is tested to test energy efficiency, peak power density and stable working time. The test method and equipment are:

[0105] Electrochemical test: Electrochemical tests were performed using a three-electrode system, including linear sweep voltammetry (LSV), cyclic voltammetry (CV), and chronoamperometry (CA). The test equipment included an electrochemical workstation and a standard three-electrode electrolytic cell.

[0106] Physical characterization: Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the morphology and structure of the samples. X-ray diffractometer (XRD) was used to analyze the crystal structure of the samples. Raman spectrometer (Raman) was used to analyze the chemical composition and structure of the samples.

[0107] Based on Example 1, some parameters in the process were changed to form Examples 2-10, and the performance test of hydrogen production by electrolysis of water was also carried out. The parameters and test results are summarized in Table 1 below:

[0108] Table 1

[0109]

[0110] Table 1 Explanation of test results:

[0111] 1. Nickel mesh activation conditions (concentration of dilute hydrochloric acid, mol / L): Most examples use 0.5 mol / L of dilute hydrochloric acid, but in Examples 4 and 5, 0.4 mol / L and 0.6 mol / L were used, respectively, to evaluate the effect of different concentrations on the activation effect.

[0112] 2. Heating temperature (°C): Examples 2 and 3 used 1100°C and 1200°C, respectively, to evaluate the effect of temperature on graphene growth.

[0113] 3. Methane pressure (kPa): The methane pressure of Examples 1 to 10 was varied between 8 kPa and 12 kPa to find the optimal growth conditions.

[0114] 4. Reaction time (h): The reaction time of Examples 1 to 10 varied between 10 h and 14 h to evaluate the effect of time on the quality of graphene.

[0115] 5. Ammonia pressure (kPa): The ammonia pressure of Examples 1 to 10 was varied between 0.8 kPa and 1.2 kPa to evaluate the effect of nitrogen doping.

[0116] 6. Ammonia reaction time (h): The ammonia reaction time of Examples 1 to 10 varied between 2.5 h and 3.5 h to evaluate the effect of nitrogen doping time on performance.

[0117] 7. Current density (mA / cm 2 ): All embodiments use 180mA / cm 2 The current density is adjusted to maintain consistency.

[0118] 8. Energy efficiency (EE, %): Examples 5 and 10 have the highest energy efficiency, both 73%.

[0119] 9. Peak power density (mW / cm 2 The peak power density of Example 10 is the highest, which is 1330 mW / cm 2 .

[0120] 10 Stable working time (h): Example 10 has the longest stable working time, which is 10300h.

[0121] In summary, under specific experimental conditions, the electrode material of the present invention exhibits excellent catalytic activity and stability. The process in Example 10 is the relatively optimal solution, with an energy efficiency of 73% and a peak power density of 1330 mW / cm 2 , stable working time is 10300h.

[0122] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A method for preparing a nitrogen-doped vertical graphene-modified nickel mesh for electrolytic hydrogenation, characterized in that: The following steps are involved: S1, activating the nickel mesh with an acid solution; S2, heating the activated nickel mesh to a set temperature; S3, using methane as a carbon source, vertical graphene was grown on a nickel mesh by chemical vapor deposition; S4, passing ammonia gas to nitrogen-dope the vertical graphene to obtain a nitrogen-doped vertical graphene modified electrolytic hydrogen nickel network.

2. The method for preparing the nitrogen-doped vertical graphene-modified nickel mesh for electrolytic hydrogenation according to claim 1, characterized in that: Step S1 is specifically as follows: The nickel mesh is immersed in an acid solution, then rinsed with deionized water, and then placed in a drying oven for drying to obtain an activated nickel mesh.

3. The method for preparing the nitrogen-doped vertical graphene-modified nickel mesh for hydrogen electrolysis according to claim 2, characterized in that: Step S1 is specifically as follows: A nickel mesh with a thickness of 0.12 mm, a mesh size of 100 and an opening rate of 14% was immersed in a dilute hydrochloric acid solution with a concentration of 0.5 mol / L for 30 minutes, then rinsed with deionized water, and then placed in a drying oven at 80°C for 2 hours to obtain an activated nickel mesh.

4. The method for preparing the nitrogen-doped vertical graphene-modified nickel mesh for hydrogen electrolysis according to claim 1, characterized in that: Step S2 is specifically as follows: The activated nickel mesh is placed in a vacuum pump, evacuated, and then the nickel mesh is electrically heated to a set temperature.

5. The method for preparing the nitrogen-doped vertical graphene-modified nickel mesh for hydrogen electrolysis according to claim 4, characterized in that: Step S2 is specifically as follows: Put the activated nickel mesh into a vacuum furnace, evacuate to 100Pa, and heat the nickel mesh to 1000-1300℃.

6. The method for preparing the nitrogen-doped vertical graphene-modified nickel mesh for hydrogen electrolysis according to claim 1, characterized in that: Step S3 is specifically as follows: Methane is introduced into a vacuum furnace, and a chemical vapor deposition reaction is carried out at 1000-1300°C for 10-14 hours to grow vertical graphene on a nickel mesh; wherein the methane pressure is 8-12 kPa and the flow rate is 18-22 L / min.

7. The method for preparing the nitrogen-doped vertical graphene-modified nickel mesh for hydrogen electrolysis according to claim 6, characterized in that: Step S3 is specifically as follows: Methane was introduced into a vacuum furnace, and a chemical vapor deposition reaction was carried out at 1200°C for 12 hours to grow vertical graphene on the nickel mesh; wherein, the methane pressure was 10 kPa and the flow rate was 20 L / min.

8. The method for preparing the nitrogen-doped vertical graphene-modified nickel mesh for hydrogen electrolysis according to claim 1, characterized in that: Step S4 is specifically as follows: First, cool down to 900-1100°C, evacuate to 100Pa again, switch methane to ammonia and pass it into the vacuum furnace for 2.5-3.5h to nitrogen-dope the vertical graphene; wherein, the ammonia pressure is 0.8-1.2kPa and the flow rate is 18-22L / min.

9. The method for preparing the nitrogen-doped vertical graphene-modified nickel mesh for hydrogen electrolysis according to claim 8, characterized in that: Step S4 is specifically as follows: First, the temperature was lowered to 1050°C, and then the vacuum was evacuated to 100Pa. The methane was switched to ammonia and introduced into the vacuum furnace for reaction for 3 hours to nitrogen-dope the vertical graphene. The ammonia pressure was 1 kPa and the flow rate was 20 L / min.

10. A nitrogen-doped vertical graphene-modified nickel mesh for hydrogen electrolysis, characterized in that: It is prepared by the method according to any one of claims 1 to 9.

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