Electrode with adjustable component structure and preparation method and application thereof

Abstract

The invention relates to an electrode with an adjustable component structure and a preparation method and application thereof. The method comprises the following steps: mixing and ball-milling high-catalysis powder and active corrosion powder to obtain mixed powder; the high catalytic powder is one or more of Ni powder, Fe powder, Co powder and Mo powder, and the active corrosion powder is one or more of Al powder, Zn powder and Mg powder; depositing the mixed powder on the surface of a pretreated substrate by utilizing a directional energy deposition process to obtain a deposited electrode; carrying out heat treatment on the deposition electrode in an inert atmosphere and / or a reducing atmosphere to obtain a heat treatment electrode; and performing electrochemical corrosion on the heat treatment electrode by taking alkali liquor as electrolyte to prepare the electrode with an adjustable component structure. According to the method, additive manufacturing (directional energy deposition) and subtractive manufacturing (electrochemical corrosion) are combined, the components and the microstructure of the prepared electrode can be accurately regulated and controlled, and the prepared electrode is excellent in catalytic hydrogen evolution performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalysis, and particularly relates to an electrode with adjustable composition and structure, a preparation method thereof, and an application thereof. Background Art

[0002] Hydrogen energy is a sustainable and environmentally friendly energy source. Electrolyzing water to produce hydrogen under alkaline conditions can use non-precious metals as electrodes, which has more cost advantages and is the most mature and competitive electrolytic water method in industry.

[0003] Currently, the mainstream green hydrogen electrolyzers are mainly alkaline tanks, and their electrodes are prepared by spraying nickel-aluminum alloy powder on the surface of nickel mesh and then activating it. This material has good plasticity, which helps to improve the bonding force between the spray coating and the substrate. However, it still faces the following problems: (1) During the preparation of nickel-aluminum alloy powder, due to the significant difference in melting points between nickel and aluminum, the powder-making process must be strictly controlled. The ratio of nickel and aluminum not only affects the phase transition temperature but also the stability of the alloy phase. Certain specific ratios may lead to an abnormally high phase transition temperature, which is difficult to achieve due to cost and equipment limitations. Similarly, when preparing various binary alloy systems composed of elements with high melting points and high catalytic activities such as Co, Mo, Fe, etc. and elements with active corrosion such as Mg, Zn, etc., similar challenges will also be encountered; (2) The activation process generally requires soaking in alkaline solution for 24 - 30 hours, which greatly increases the production cycle; (3) The composition and microstructure of the electrode cannot be adjusted during the preparation process; (4) The hydrogen evolution potential of this electrode is high and the current density is low; resulting in the continuous high operation cost of hydrogen production, which hinders the expansion of the hydrogen energy industry and its commercialization process in downstream fields.

[0004] Therefore, it is highly necessary to provide a preparation method for large-scale and rapid preparation of high-performance electrodes with adjustable composition and structure to solve one or more of the above existing technical problems. Summary of the Invention

[0005] In order to solve one or more technical problems existing in the prior art, the present invention provides an electrode with adjustable composition and structure, a preparation method thereof, and an application thereof. The present invention can efficiently achieve precise control of the composition and microstructure of the electrode. The electrode prepared by the present invention has excellent catalytic hydrogen evolution performance, low hydrogen evolution potential, high current density, and extremely good electrode stability.

[0006] The present invention provides a preparation method for an electrode with adjustable composition and structure in the first aspect. The method comprises the following steps:

[0007] S1. Mix and ball-mill high-catalytic powder and active-corrosion powder to obtain mixed powder; the high-catalytic powder is one or more of Ni powder, Fe powder, Co powder, and Mo powder, and the active-corrosion powder is one or more of Al powder, Zn powder, and Mg powder;

[0008] S2. Use the directed energy deposition process to deposit the mixed powder onto the surface of the pretreated substrate to obtain a deposited electrode;

[0009] S3. Under an inert atmosphere and / or a reducing atmosphere, heat-treat the deposited electrode to obtain a heat-treated electrode;

[0010] S4. Using an alkaline solution as the electrolyte, electrochemically corrode the heat-treated electrode to produce an electrode with adjustable composition and structure.

[0011] Preferably, in step S1: Mix the highly catalytic powder with the active corrosion powder, add anhydrous ethanol and perform vacuum treatment, then ball mill and dry to obtain the mixed powder; the mass ratio of the highly catalytic powder to the active corrosion powder is (5 - 9):(1 - 5); and / or a catalytic aid is further added to the mixed powder, and the catalytic aid is composed of molybdenum disulfide nanosheets and nickel phosphide powder in a mass ratio of (1 - 2):1, and the dosage of the catalytic aid is 3 - 5% of the mass of the highly catalytic powder.

[0012] Preferably, in step S2: The directed energy deposition process is one or more of a laser cladding process, a plasma spraying process, and a cold spraying process.

[0013] Preferably, the directed energy deposition process is a plasma spraying process, and the parameters of the plasma spraying process are: the argon gas flow rate is 44 - 50 nlpm, the hydrogen gas flow rate is 0.6 - 0.8 nlpm, the carrier gas flow rate is 2 - 4 nlpm, the spray gun power is 27 - 35 kW, the spraying distance is 120 - 130 mm, the spraying angle is 45 - 50°, the powder feeding rate is 3.6 - 4.0 r / min, the spraying times are 3 - 5 times, the spraying thickness is 130 - 150 μm, and after plasma spraying, the loading amount of the mixed powder on the surface of the pretreated substrate is 250 - 320 g / m 2 ; or the directed energy deposition process is a cold spraying process, and the parameters of the cold spraying process are: the cold spraying temperature is 350 - 400 °C, the cold spraying distance is 90 - 120 mm, the cold spraying pressure is 4 - 6 MPa, and the powder feeding gas is nitrogen.

[0014] Preferably, in step S2: The substrate is one or more of stainless steel, titanium alloy, and nickel-based materials; and / or the pretreatment includes one or more of activation treatment, sandblasting roughening treatment, and electrochemical anodic oxidation treatment.

[0015] Preferably, in step S3: the heat treatment is to rise from room temperature to 250 - 280°C at a heating rate of 3 - 5°C / min, hold for 1 - 3 h, then rise to 400 - 450°C at a heating rate of 3 - 5°C / min, and hold for 3 - 5 h.

[0016] Preferably, in step S4, electrochemical corrosion is carried out with the heat treatment electrode as the working electrode, a platinum electrode as the counter electrode, and a Hg / HgO electrode as the reference electrode; and / or in step S4, the parameters for electrochemical corrosion are: the electrolyte is a KOH solution with a concentration of 1 mol / L and / or a NaOH solution with a concentration of 1 mol / L, the electrochemical corrosion temperature is 20 - 30°C. When the active corrosion powder is Al powder, the electrochemical corrosion potential is -1.6 - -2.3 V relative to the standard hydrogen electrode, and the electrochemical corrosion time is 2 - 4 h. When the active corrosion powder is Zn powder, the electrochemical corrosion potential is -1.2 - -1.3 V relative to the standard hydrogen electrode, and the electrochemical corrosion time is 8 - 10 h. When the active corrosion powder is Mg powder, the electrochemical corrosion potential is -1.5 - -1.6 V relative to the standard hydrogen electrode, and the electrochemical corrosion time is 5 - 7 h.

[0017] Preferably, sodium fluoride and / or ammonium fluoride are further added to the electrolyte, and the concentration of sodium fluoride and / or ammonium fluoride in the electrolyte is 0.1 - 0.3 mol / L.

[0018] In a second aspect, the present invention provides an electrode with adjustable composition and structure prepared by the preparation method described in the first aspect of the present invention.

[0019] In a third aspect, the present invention provides the application of the electrode with adjustable composition and structure prepared by the preparation method described in the first aspect of the present invention in the field of hydrogen evolution, or the application of the preparation method described in the first aspect of the present invention in the field of hydrogen evolution.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] (1) The present invention combines additive manufacturing (directed energy deposition) and subtractive manufacturing (electrochemical corrosion). Additive manufacturing provides flexibility for the preparation of electrode materials and can accurately control the layer-by-layer deposition of components; subtractive manufacturing adjusts the electrode porosity and pore size by regulating the electrochemical corrosion parameters to form a specific structure, and finally efficiently realizes the precise control of the composition and microstructure of the prepared electrode.

[0022] (2) The steps of the present invention are simple, without the need for alloying. The types and proportions of raw material components are adjustable. In the present invention, high-catalytic powder and active corrosion powder are mixed and ball-milled, and the proportions of the two types of metals in the obtained mixed powder can be adjusted arbitrarily. Through ball-milling, the preparation of high-melting-point metal powder with the same proportion as that in alloy powder can be achieved. Then, by combining additive manufacturing and electrochemical corrosion subtractive manufacturing, large-scale and rapid preparation of electrodes with the same proportion of high-melting-point metal powder components can be realized, with high preparation efficiency and suitable for large-scale production processes. Moreover, compared with alloy powder, the hydrogen evolution effect of the electrode finally prepared from the mixed powder obtained by ball-milling in the present invention is more excellent.

[0023] (3) The electrode obtained by using the preparation method of the present invention has a catalytic electrode coating with a rough and porous structure, and a micron-nano scale multi-level three-dimensional pore structure with adjustable pore diameters, which is beneficial to increasing the catalytic active surface area of the electrode and improving the mass transfer of reactants, can significantly improve the hydrogen evolution reaction efficiency, and can reach an ampere-level current density. The electrode prepared by the present invention has excellent catalytic hydrogen evolution performance, low hydrogen evolution potential, high current density, and excellent electrode stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments and comparative examples will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the scope of the present invention.

[0025] Figure 1 It is a cross-sectional scanning electron micrograph of the electrode prepared in Example 1 of the present invention;

[0026] Figure 2 It is a polarization curve graph of different electrodes prepared in Example 1, Comparative Example 1, and Comparative Example 2 of the present invention; in the figure, the abscissa Potential represents potential, and the ordinate Current Density represents current density;

[0027] Figure 3 It is a chronopotentiometry curve graph of the electrode prepared in Example 1 of the present invention; in the figure, the abscissa Duration of stability represents the stable duration, and the ordinate Potential represents potential. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] In a first aspect, the present invention provides a method for preparing an electrode with adjustable composition and structure, the method comprising the following steps:

[0030] S1. Mix and ball-mill a high-catalytic powder and an active corrosion powder to obtain a mixed powder; the high-catalytic powder is one or more of nickel (Ni) powder, iron (Fe) powder, cobalt (Co) powder, and molybdenum (Mo) powder, and the active corrosion powder is one or more of aluminum (Al) powder, zinc (Zn) powder, and magnesium (Mg) powder;

[0031] S2. Use a directed energy deposition process to deposit the mixed powder onto the surface of a pretreated substrate to obtain a deposited electrode;

[0032] S3. Heat-treat the deposited electrode in an inert atmosphere and / or a reducing atmosphere to obtain a heat-treated electrode;

[0033] S4. Use an alkaline solution as an electrolyte to electrochemically corrode the heat-treated electrode to prepare an electrode with adjustable composition and structure (also denoted as a high-performance electrode with adjustable composition and structure); in the present invention, the electrode includes a substrate and a coating (metal catalytic coating) formed on the substrate.

[0034] The process of preparing an electrode with adjustable composition and structure in the present invention is as follows: by step S1, the required metal powders are ball-milled and mixed evenly to prepare for the subsequent preparation of the metal catalytic layer; in step S2, additive manufacturing is carried out using directed energy deposition, and the mixed powder is deposited onto the surface of the pretreated substrate as required, and then heat-treated in step S3 to further improve the bonding strength between the catalytic coating and the substrate, effectively preventing the shedding of the catalytic layer during the reaction process, greatly improving the stability of the obtained electrode, obtaining a catalytic layer containing high-catalytic elements and active corrosion elements, and finally, in step S4, electrochemically corroding to remove the active corrosion powder by subtractive manufacturing, and finally obtaining an electrode (high-performance electrode) containing a micron-nano scale multi-level three-dimensional pore structure and a specific composition, with high stability and good catalytic performance of the electrode.

[0035] The steps of the present invention are simple, without alloying, and the types and proportions of the raw material components are adjustable. In the present invention, the high-catalytic powder and the active corrosion powder are mixed and ball-milled, and the proportions of the two types of metals in the obtained mixed powder can be adjusted arbitrarily. By ball-milling, the preparation of the high-melting-point metal powder proportion powder in the alloy powder can be achieved. By combining additive manufacturing and subtractive manufacturing by electrochemical corrosion, the large-scale and rapid preparation of electrodes with the same proportion of high-melting-point metal powder components can be realized;

[0036] The composition and microstructure of the electrode prepared by the present invention can be precisely controlled.

[0037] In the present invention, the selected combination methods of the mixed powder are preferably 12 types as follows, as shown in Table 1 below.

[0038] Table 1: Mixing method of mixed powder

[0039]

[0040] According to some preferred embodiments, in step S1: Mix the highly catalytic powder with the active corrosion powder, add absolute ethanol and perform vacuum treatment, then ball mill and dry to obtain the mixed powder; in the present invention, adding absolute ethanol and performing vacuum treatment can ensure uniform mixing of materials and avoid oxidation, promote heat transfer and dissipation, reduce powder agglomeration, and make the powder particles evenly dispersed; in the present invention, the drying temperature is, for example, 80 - 90 °C; specifically, for example, mix the highly catalytic powder and the active corrosion powder according to a specific particle size distribution and mass percentage, add absolute ethanol and perform vacuum treatment, then ball mill and dry to obtain the mixed powder; in some specific embodiments, the mass ratio of the highly catalytic powder to the active corrosion powder is (5 - 9):(1 - 5).

[0041] According to some preferred embodiments, the highly catalytic powder is Ni powder, the particle size of the Ni powder is 15 - 53 μm, the active corrosion powder is Al powder, the particle size of the Al powder is 40 - 50 μm, and the sphericity is ≥0.97. The Ni powder and the Al powder are mixed according to 50 - 90% by mass percentage and 10 - 50% by mass percentage respectively; the machine used for ball milling is an XQM - planetary ball mill. In the present invention, preferably, the particle size distribution D50 of the ball - milled mixed powder is 15 - 30 μm, preferably 20 - 30 μm; in the mixed powder, the mass proportion of the highly catalytic powder is 50 - 90%, and the mass proportion of the active corrosion powder is 10 - 50%.

[0042] According to some preferred embodiments, a catalytic additive is further added to the mixed powder. The catalytic additive is composed of molybdenum disulfide nanosheets (MoS 2 nanosheets) and nickel phosphide powder (Ni 2 P powder) in a mass ratio of (1 - 2):1, and the dosage of the catalytic additive is 3 - 5% of the mass of the highly catalytic powder; the present invention does not specifically limit the sources of the molybdenum disulfide nanosheets and the nickel phosphide powder, and products that can be directly purchased or products synthesized by existing methods can be used; in the present invention, the particle size of the nickel phosphide powder is, for example, 10 - 50 μm; in the present invention, it is preferred to add an appropriate amount of the catalytic additive composed of molybdenum disulfide nanosheets and nickel phosphide powder to the mixed powder, which helps to improve the hydrogen evolution performance of the finally prepared electrode. The possible reason is that MoS 2 nanosheets, due to their large specific surface area and abundant lattice defects, can provide more active sites, thus helping to improve the catalytic efficiency and reaction efficiency of the electrode, Ni2 NiP powder can effectively reduce the energy barrier of the reaction and improve the electrochemical activity of the electrode in the catalytic hydrogen evolution reaction, and can effectively promote the generation of hydrogen in the hydrogen evolution reaction. By combining with MoS 2 nanosheets, a synergistic effect can be exerted to optimize the kinetics of the hydrogen evolution reaction. MoS 2 nanosheets provide abundant active sites, while Ni 2 P powder reduces the overpotential of the reaction through its strong catalytic ability, and the micron particles of Ni 2 P can form a good electron conductive network with MoS 2 nanosheets, improving the conductivity of the entire electrode and promoting the rapid transfer of electrons in the hydrogen evolution reaction. The combined action of the two can significantly improve the catalytic hydrogen evolution performance of the electrode; in the present invention, preferably, the dosage of the catalytic assistant is 3-5% of the mass of the high catalytic powder, which ensures that MoS 2 nanosheets and Ni 2 P powder can exert a good catalytic effect without affecting the overall structure and stability of the electrode. If too much catalytic assistant is added, it may instead affect the catalytic effect and the performance of the electrode; in the present invention, preferably, the mass ratio of molybdenum disulfide nanosheets (MoS 2 nanosheets) to nickel phosphide powder (Ni 2 P powder) is (1-2):1. This is obtained by comprehensively considering the balance between the synergistic effect and catalytic efficiency of the two in the present invention. This ratio can maximize the advantages of the two and can maximize the catalytic hydrogen evolution effect. Compared with the single addition of molybdenum disulfide nanosheets, molybdenum disulfide nanoflakes or nickel phosphide powder, the catalytic assistant adopted in the present invention can enable the electrode to exhibit better catalytic hydrogen evolution performance in the catalytic reaction; in addition, the present invention finds that the molybdenum disulfide nanosheets adopted in the present invention are more conducive to improving the hydrogen evolution effect of the electrode compared with molybdenum disulfide nanoflakes. The possible reason is that the planar structure of the molybdenum disulfide nanosheets can effectively expose more active sites, especially the edge sites. These active sites are beneficial to the adsorption and conversion of reactants on the electrode surface, thereby being beneficial to improving the catalytic efficiency of the hydrogen evolution reaction. And the two-dimensional structure of the molybdenum disulfide nanosheets helps to reduce the electron transport resistance inside the material, further enhancing the rate and efficiency of the catalytic reaction. This helps to improve its catalytic activity in the hydrogen evolution reaction. Molybdenum disulfide nanosheets can provide more reaction sites and better electron conductivity, which also helps to jointly optimize the electron transport and reaction mechanism with nickel phosphide powder. Compared with molybdenum disulfide nanoflakes, the combination of molybdenum disulfide nanosheets and nickel phosphide powder can better promote the synergistic catalytic effect.

[0043] According to some preferred embodiments, in step S2: the directed energy deposition process is one or more of laser cladding process, plasma spraying process, and cold spraying process; in the present invention, the mixed powder is deposited layer by layer onto the surface of the pretreated substrate through the directed energy deposition (DED) process; the directed energy deposition (DED) process is an additive manufacturing process, which provides flexibility for the preparation of electrode materials and can precisely control the layer-by-layer deposition of components.

[0044] According to some preferred embodiments, the directed energy deposition process is the plasma spraying process, and the parameters of the plasma spraying process are: the argon gas flow rate is 44 - 50 nlpm (i.e., NLPM), the hydrogen gas flow rate is 0.6 - 0.8 nlpm, the carrier gas flow rate is 2 - 4 nlpm, the spray gun power is 27 - 35 kW, the spraying distance is 120 - 130 mm, the spraying angle is 45 - 50°, the powder feeding rate is 3.6 - 4.0 r / min, the spraying times are 3 - 5 times, and the spraying thickness is 130 - 150 μm. After plasma spraying, the loading amount of the mixed powder on the surface of the pretreated substrate is 250 - 320 g / m 2 ; in the present invention, the argon gas and hydrogen gas are working gases, and the carrier gas is argon, which is used to transport the mixed powder into the spray gun; in the present invention, by reasonably controlling the plasma spraying parameters, the oxygen content in the surface coating of the deposited electrode can be effectively reduced, and the catalytic hydrogen evolution performance of the finally prepared electrode can be improved. In particular, by controlling parameters such as argon, hydrogen flow rates, spraying power, spraying distance, and spraying angle, the introduction of oxygen can be reduced, and the denseness and uniformity of the coating can be ensured. If the spraying parameters are inappropriate, it will lead to problems such as too high oxygen content in the coating, formation of non-uniform coatings, and decline in catalytic performance; in the present invention, it is preferably to control the oxygen mass percentage content of the surface coating of the deposited electrode to be not more than 5.5%; and if the spraying parameters are inappropriate, it will also lead to problems such as insufficient bonding strength of the sprayed coating and coating peeling off.

[0045] According to some preferred embodiments, the directed energy deposition process is the cold spraying process, and the parameters of the cold spraying process are: the cold spraying temperature is 350 - 400 °C, the cold spraying distance is 90 - 120 mm, the cold spraying pressure is 4 - 6 MPa, and the powder feeding gas is nitrogen.

[0046] According to some preferred embodiments, in step S2: the substrate is one or more of stainless steel, titanium alloy, and nickel-based materials; in some specific embodiments, for example, the substrate is a 40-mesh 316 stainless steel mesh.

[0047] According to some preferred embodiments, the pretreatment includes one or more of activation treatment, sandblasting roughening treatment, and electrochemical anodic oxidation treatment; the present invention does not make specific limitations on the activation treatment, sandblasting roughening treatment, and electrochemical anodic oxidation treatment, and those skilled in the art can make conventional selections; in some specific embodiments, the preparation of the pretreated substrate includes, for example: ① Activation treatment: First, ultrasonically clean the substrate in acetone for 20 min, then repeatedly wash it with ethanol, then place it in 4 mol / L hydrochloric acid and ultrasonically clean it for 10 min, then let it stand for 15 min, and finally repeatedly wash it with distilled water to remove the oxide layer on the metal surface, and store it in a vacuum drying oven after natural air drying for later use; ② Sandblasting roughening treatment: Use 36-mesh white corundum as the abrasive material to perform sandblasting roughening treatment on the substrate after activation treatment. The number of sandblasting times is 1-3 times, the spraying angle is 45°, and the sandblasting treatment covers the front side or both the front and back sides of the electrode substrate. The process parameters are: the nozzle diameter is 8 mm, the pressure of compressed air during sandblasting is set at 0.6 MPa, and the direct distance between the spray gun and the substrate is controlled at 180-220 mm. After sandblasting, the surface finish R a = 3.2-6.3 μm; ③ Electrochemical anodic oxidation treatment: Use the electrolyte to perform an electrolytic reaction on the substrate after sandblasting roughening treatment. Among them, the electrolyte is any one of sulfuric acid solution, carboxylic acid solution, and oxalic acid solution, such as a sulfuric acid solution (sulfuric acid aqueous solution) with a concentration of 15 wt%. During this process, surface impurities are removed by applying current, which is beneficial to further improving the adhesion between the pretreated substrate and the subsequent coating.

[0048] According to some preferred embodiments, in step S3: the heat treatment is to rise from room temperature to 250 - 280°C at a heating rate of 3 - 5°C / min, hold for 1 - 3 h, then rise to 400 - 450°C at a heating rate of 3 - 5°C / min, and hold for 3 - 5 h; in the present invention, room temperature (ambient temperature) refers to, for example, room temperature of 15 - 35°C; in the present invention, preferably when performing the heat treatment, the gas to be introduced into the tubular furnace is argon with a volume percentage content of 90 vt% and hydrogen with a volume percentage content of 10 vt% to prevent oxidation of the sprayed mixed powder coating. Before the heat treatment, the substrate sprayed with the mixed powder needs to be cut into square thin mesh pieces of 10 mm × 10 mm in size, ultrasonically cleaned in absolute ethanol for 5 min to effectively remove dirt and impurities attached to the surface, and then placed in the tubular furnace for heat treatment; the first heat treatment rises from room temperature to 250 - 280°C at a heating rate of 3 - 5°C / min and holds for 1 - 3 h to remove the residual stress inside the coating, and then the second heat treatment raises the temperature to 400 - 450°C and holds for 3 - 5 h, which helps to refine the precipitated phase and homogenize the internal structure of the coating, improve the corrosion resistance of the material, and then slowly cool to room temperature at a cooling rate of 3 - 5°C / min to control the pore distribution and structural stability in the electrode; the heat treatment process in the present invention can better optimize the catalytic hydrogen evolution performance of the electrode, reduce the formation of oxides, maintain the porous structure of the coating, inhibit grain coarsening, and also helps to save energy and reduce production costs compared with the heat treatment above 700°C.

[0049] According to some preferred embodiments, in step S4, electrochemical corrosion is carried out with the heat-treated electrode as the working electrode, a platinum electrode as the counter electrode, and Hg / HgO (mercury / mercuric oxide) as the reference electrode; and / or in step S4, the parameters for electrochemical corrosion are: the electrolyte (electrochemical corrosion solution) is a KOH solution with a concentration of 1 mol / L and / or a NaOH solution with a concentration of 1 mol / L, the electrochemical corrosion temperature is 20 - 30°C. When the active corrosion powder is Al powder, the electrochemical corrosion potential is -1.6 - -2.3 V relative to the standard hydrogen electrode, and the electrochemical corrosion time is 2 - 4 h. When the active corrosion powder is Zn powder, the electrochemical corrosion potential is -1.2 - -1.3 V relative to the standard hydrogen electrode, and the electrochemical corrosion time is 8 - 10 h. When the active corrosion powder is Mg powder, the electrochemical corrosion potential is -1.5 - -1.6 V relative to the standard hydrogen electrode, and the electrochemical corrosion time is 5 - 7 h; in the present invention, the KOH solution refers to an aqueous KOH solution, and the NaOH solution refers to an aqueous NaOH solution.

[0050] In the present invention, through electrochemical corrosion, active corrosion components can be removed, and a catalytic layer with specific components and pore structures can be formed on the surface of the substrate. Moreover, the present invention discovers that corrosion parameters such as the corrosion potential and time of the electrochemical corrosion need to be determined according to the material components and deposited structures during the additive manufacturing process. For different active corrosion powders, appropriate electrochemical corrosion parameters need to be adopted in order to obtain a multi-level three-dimensional pore structure containing micron-nano levels and an electrode (high-performance electrode) containing specific components, so that the electrode has high stability and good catalytic performance. If the electrochemical corrosion parameters are not matched with the active corrosion powder, it may lead to incomplete formation of the pore structure, and it is impossible to obtain a multi-level three-dimensional pore structure containing micron-nano levels. In addition, too long or too short electrochemical corrosion time may also result in too thick or too dense pore structures, losing the gradient structure of the multi-level pores, making the specific surface area of the electrode not large enough and affecting its catalytic performance. Furthermore, if the electrochemical corrosion parameters are not appropriate, the corrosion may become uneven, resulting in local over-corrosion or under-corrosion on the electrode surface, thereby affecting the stability and catalytic performance of the electrode.

[0051] In the present invention, electrochemical corrosion is a subtractive manufacturing process. By controlling the electrochemical corrosion parameters according to different active corrosion powders, the pore size and pore diameter of the electrode can be adjusted to form a catalytic layer with adjustable composition and structure, making the electrode composition and microstructure more precise and adjustable. In addition, the advantage of using the electrochemical corrosion process in the present invention is that after electrochemical subtractive manufacturing, hydrogen evolution can be directly carried out under this condition, reducing the production cycle.

[0052] According to some preferred embodiments, sodium fluoride and / or ammonium fluoride are further added to the electrolyte, and the concentration of sodium fluoride and / or ammonium fluoride in the electrochemical corrosion solution is 0.1 - 0.3 mol / L. For example, in some specific embodiments, the electrolyte is composed of a KOH solution and sodium fluoride, and the preparation of the electrolyte is as follows: sodium fluoride is added to a KOH solution with a concentration of 1 mol / L to obtain an electrolyte, so that the concentration of sodium fluoride in the electrolyte is 0.1 - 0.3 mol / L; or the electrolyte is composed of a KOH solution and ammonium fluoride, and the preparation of the electrolyte is as follows: ammonium fluoride is added to a KOH solution with a concentration of 1 mol / L to obtain an electrolyte, so that the concentration of ammonium fluoride in the electrolyte is 0.1 - 0.3 mol / L; or the electrolyte is composed of a NaOH solution and sodium fluoride, and the preparation of the electrolyte is as follows: sodium fluoride is added to a NaOH solution with a concentration of 1 mol / L to obtain an electrolyte, so that the concentration of sodium fluoride in the electrolyte is 0.1 - 0.3 mol / L; or the electrolyte is composed of a NaOH solution and ammonium fluoride, and the preparation of the electrolyte is as follows: ammonium fluoride is added to a NaOH solution with a concentration of 1 mol / L to obtain an electrolyte, so that the concentration of ammonium fluoride in the electrolyte is 0.1 - 0.3 mol / L.

[0053] In the present invention, it is preferred to further add a suitable concentration of sodium fluoride and / or ammonium fluoride to the electrolyte, which is beneficial to further improving the hydrogen evolution catalytic performance of the prepared electrode. The possible reason is that adding a suitable concentration of sodium fluoride and / or ammonium fluoride to the electrolyte can react with the metal surface during the electrochemical corrosion process to form a fluoride layer. This structure can modify the metal surface, promote the formation of a more uniform and fine microporous structure on the electrode surface, optimize the distribution of catalytic active sites on the electrode surface and the permeability of the electrolyte. This modification helps to improve the catalytic activity on the electrode surface, reduce the overpotential on the electrode surface, thus making the hydrogen evolution reaction more efficient and further enhancing the hydrogen evolution catalytic performance of the electrode. Moreover, the addition of sodium fluoride and / or ammonium fluoride may also promote the local dissolution of the metal surface during the electrochemical corrosion process to form a hierarchical pore structure. This hierarchical pore structure not only increases the specific surface area but also helps the contact between the electrolyte and the electrode surface, enabling the hydrogen evolution reaction to proceed more effectively. In addition, through the interaction with the metal surface, fluoride ions can change the electronic structure of the electrode surface, reduce the energy barrier of the hydrogen evolution reaction, and thus accelerate the evolution of hydrogen.

[0054] In the second aspect, the present invention provides an electrode with adjustable composition and structure prepared by the preparation method described in the first aspect of the present invention. The electrode obtained by the present invention includes a substrate and a metal catalytic coating on the surface of the substrate. The metal catalytic coating contains a micron-nano hierarchical three-dimensional pore structure, which has high catalytic activity, a large specific surface area, good reactant mass transfer effect, and high catalytic hydrogen evolution activity and can reach an ampere-level current density in alkaline water electrolysis for hydrogen production. The electrode prepared by the present invention has excellent hydrogen evolution catalytic performance, a low hydrogen evolution potential, a high current density, and excellent electrode stability.

[0055] In the third aspect, the present invention provides the application of the electrode with adjustable composition and structure prepared by the preparation method described in the first aspect of the present invention in the field of hydrogen evolution or the application of the preparation method described in the first aspect of the present invention in the field of hydrogen evolution. When preparing the electrode by the preparation method of the present invention, since the last step is an electrochemical corrosion step and belongs to an electrochemical reaction environment, the preparation method described in the first aspect of the present invention can also directly carry out hydrogen evolution work under this condition and be applied in the field of hydrogen evolution. That is, after the electrochemical corrosion to obtain the electrode with adjustable composition and structure, the obtained electrode with adjustable composition and structure can directly carry out hydrogen evolution work under the same electrochemical corrosion conditions and be applied in the field of hydrogen evolution.

[0056] The present invention will be further described by way of examples below, but the protection scope of the present invention is not limited to these embodiments.

[0057] Example 1

[0058] A preparation method of an electrode with adjustable composition and structure includes the following steps:

[0059] S1. Take 200 g of nickel powder and 50 g of aluminum powder, with a ball-to-material ratio of 1:1. Add 100 g of absolute ethanol to submerge the ball-milling beads and the powder, and then evacuate. Conduct mixed ball-milling in a planetary ball mill at a rotation speed of 250 r / min for 8 h. After the mixed ball-milling is completed, the powder is vacuum-dried in a vacuum drying oven at 80 °C and stored in the vacuum drying oven for later use, obtaining a mixed powder with a D50 particle size of 25 μm.

[0060] S2. Take a 316 stainless steel mesh with plain weave, a wire diameter of 0.15 mm ± 0.01 mm, 40 meshes, and a thickness of 0.25 mm. First, ultrasonically clean it in an acetone solution for 20 min, and then repeatedly wash it with ethanol to remove lipid impurities on the surface of the metal (316 stainless steel mesh). Then, place the 316 stainless steel mesh in a hydrochloric acid solution (HCl aqueous solution) with a concentration of 4 mol / L for 10 min, then let it stand for 15 min, and repeatedly wash it with distilled water to remove the oxide layer on the metal surface, obtaining an activated 316 stainless steel mesh substrate. After natural air drying, it is stored in a vacuum drying oven for later use. Subsequently, use 36-mesh white corundum as the abrasive material, and use a 304 stainless steel ring with a diameter of 20 cm as a fixture to clamp the activated 316 stainless steel mesh substrate between two 304 stainless steel rings for fixation, and conduct sandblasting on both the front and back sides of the activated 316 stainless steel mesh substrate for 3 times each. Among them, the nozzle diameter is 8 mm, the sandblasting compressed air pressure is 0.6 MPa, the spraying spacing is 180 mm, and the surface finish after sandblasting is R a = 3.2 μm, obtaining a sandblasted and roughened 316 stainless steel mesh substrate; then, through the application of an electric current, conduct electrochemical anodic oxidation treatment on the 316 stainless steel mesh substrate in a sulfuric acid solution (sulfuric acid aqueous solution) with a concentration of 15 wt% to remove surface impurities, obtaining a pre-treated substrate (pre-treated substrate); deposit the mixed powder on the surface of the pre-treated substrate by plasma spraying process. During plasma spraying, the argon gas flow rate is 44 nlpm, the hydrogen gas flow rate is 0.6 nlpm, the carrier gas (argon) flow rate is 2 nlpm, the arc voltage (spraying voltage) is 48 V, the arc current (spraying current) is 650 A, the spray gun power is 31 kW, the spraying spacing is 120 mm, the spraying angle is 45°, the powder feeding rate is 3.6 r / min, the spraying times are 4 times, and the thickness of the sprayed coating is 130 μm. When the loading amount of the mixed powder on the surface of the pre-treated substrate is 290 g / m 2 stop plasma spraying to obtain a deposited electrode. Among them, the oxygen mass percentage content of the coating on the surface of the deposited electrode is 5.20%, the nickel mass percentage content is 80.58%, and the aluminum mass percentage content is 14.22%.

[0061] S3. Cut the 316 stainless steel mesh (deposition electrode) sprayed with nickel-aluminum mixed powder into square thin mesh pieces with a size of 10 mm × 10 mm. Ultrasonically clean it in absolute ethanol for 5 min to effectively remove the dirt and impurities attached to the surface, and then put it into a tube furnace for heat treatment. During heat treatment, a mixed gas of 90 vt% argon and 10 vt% hydrogen is introduced into the tube furnace. It is heated from room temperature of 25 °C to 250 °C at a heating rate of 5 °C / min and held for 1 h, then heated to 400 °C at a heating rate of 5 °C / min and held for 3 h, and then slowly cooled to room temperature of 25 °C at a cooling rate of 3 °C / min to obtain a heat-treated electrode.

[0062] S4. Using a KOH solution with a concentration of 1 mol / L as the electrolyte, using the heat-treated electrode as the working electrode, a platinum electrode as the counter electrode, and Hg / HgO as the reference electrode, at 25 °C, make the electrochemical corrosion potential -1.9 V relative to the standard hydrogen electrode, and the electrochemical corrosion time is 3 h, thus obtaining an electrode with adjustable composition and structure.

[0063] Example 2

[0064] A preparation method of an electrode with adjustable composition and structure, other contents are the same as those in Example 1, the difference is that the raw materials are 225 g of nickel powder and 25 g of aluminum powder.

[0065] Example 3

[0066] A preparation method of an electrode with adjustable composition and structure, other contents are the same as those in Example 1, the difference is that the raw materials are 125 g of nickel powder and 125 g of aluminum powder.

[0067] Example 4

[0068] A preparation method of an electrode with adjustable composition and structure, other contents are the same as those in Example 1, the difference is that in step S2, the plasma spraying process is replaced by the cold spraying process. The parameters of the cold spraying process are: cold spraying temperature 380 °C, cold spraying distance 100 mm, cold spraying pressure 5 MPa, and the powder feeding gas is nitrogen.

[0069] Example 5

[0070] A preparation method of an electrode with adjustable composition and structure, other contents are the same as those in Example 1, the difference is that the nickel powder is replaced by Co powder and the aluminum powder is replaced by Mg powder. At the same time, in step S4, make the electrochemical corrosion potential -1.5 V relative to the standard hydrogen electrode, and the electrochemical corrosion time is 6 h, thus obtaining an electrode with adjustable composition and structure.

[0071] Example 6

[0072] A preparation method of an electrode with adjustable composition and structure, other contents are the same as those in Example 1, the difference is that nickel powder is replaced by Mo powder, aluminum powder is replaced by Zn powder, and at the same time, in step S4, the electrochemical corrosion potential is -1.2V relative to the standard hydrogen electrode, and the electrochemical corrosion time is 8h, thus obtaining an electrode with adjustable composition and structure.

[0073] Example 7

[0074] A preparation method of an electrode with adjustable composition and structure, other contents are the same as those in Example 1, the difference is that in step S1, 200g of nickel powder, 50g of aluminum powder, 4.8g of molybdenum disulfide nanosheets and 3.2g of nickel phosphide powder are used, with a ball-to-material ratio of 1:1, and 100g of absolute ethanol is added to immerse the ball milling beads and the powder and vacuumize, and the mixture is ball milled at a speed of 250r / min for 8h in a planetary ball mill. The powder after the completion of the ball milling is vacuum dried at 80°C in a vacuum drying oven, and after drying, it is stored in the vacuum drying oven for standby, obtaining a mixed powder with a particle size D50 of 25μm.

[0075] Example 8

[0076] A preparation method of an electrode with adjustable composition and structure, other contents are the same as those in Example 1, the difference is that in step S1, 200g of nickel powder, 50g of aluminum powder, 8g of molybdenum disulfide nanosheets are used, with a ball-to-material ratio of 1:1, and 100g of absolute ethanol is added to immerse the ball milling beads and the powder and vacuumize, and the mixture is ball milled at a speed of 250r / min for 8h in a planetary ball mill. The powder after the completion of the ball milling is vacuum dried at 80°C in a vacuum drying oven, and after drying, it is stored in the vacuum drying oven for standby, obtaining a mixed powder with a particle size D50 of 25μm.

[0077] Example 9

[0078] A preparation method of an electrode with adjustable composition and structure, other contents are the same as those in Example 1, the difference is that in step S1, 200g of nickel powder, 50g of aluminum powder, 8g of nickel phosphide powder are used, with a ball-to-material ratio of 1:1, and 100g of absolute ethanol is added to immerse the ball milling beads and the powder and vacuumize, and the mixture is ball milled at a speed of 250r / min for 8h in a planetary ball mill. The powder after the completion of the ball milling is vacuum dried at 80°C in a vacuum drying oven, and after drying, it is stored in the vacuum drying oven for standby, obtaining a mixed powder with a particle size D50 of 25μm.

[0079] Example 10

[0080] A preparation method of an electrode with adjustable composition structure, the other contents are the same as those in Example 1, the difference is that in step S4, the electrolyte used is obtained by adding sodium fluoride to a KOH solution with a concentration of 1 mol / L, and the concentration of sodium fluoride in the electrolyte is 0.2 mol / L.

[0081] Example 11

[0082] A preparation method of an electrode with adjustable composition structure, the other contents are the same as those in Example 1, the difference is that in step S1, 200 g of nickel powder, 50 g of aluminum powder, 4.8 g of molybdenum disulfide nanosheets and 3.2 g of nickel phosphide powder are used, with a ball-to-material ratio of 1:1, and 100 g of absolute ethanol is added to immerse the ball milling beads and the powder and vacuumize. The mixture is ball milled at a speed of 250 r / min for 8 h in a planetary ball mill. The powder after the completion of the ball milling is vacuum dried at 80 °C in a vacuum drying oven and stored in the vacuum drying oven for standby, obtaining a mixed powder with a D50 particle size of 25 μm; in step S4, the electrolyte used is obtained by adding sodium fluoride to a KOH solution with a concentration of 1 mol / L, and the concentration of sodium fluoride in the electrolyte is 0.2 mol / L.

[0083] Example 12

[0084] A preparation method of an electrode with adjustable composition structure, the other contents are the same as those in Example 1, the difference is that in step S4, the electrochemical corrosion potential is -1.5 V relative to the standard hydrogen electrode, and the electrochemical corrosion time is 6 h.

[0085] Example 13

[0086] A preparation method of an electrode with adjustable composition structure, the other contents are the same as those in Example 1, the difference is that in step S4, the electrochemical corrosion potential is -2.5 V relative to the standard hydrogen electrode, and the electrochemical corrosion time is 1.5 h.

[0087] Example 14

[0088] A preparation method of an electrode with adjustable composition structure, the other contents are the same as those in Example 1, the difference is that in step S3, during the heat treatment, a mixed gas of 90 vt% argon and 10 vt% hydrogen is introduced into the tubular furnace, and the temperature is raised from room temperature 25 °C to 760 °C at a heating rate of 5 °C / min and held for 30 min, and then slowly cooled to room temperature 25 °C at a cooling rate of 3 °C / min to obtain a heat-treated electrode.

[0089] Comparative Example 1

[0090] A preparation method of an electrode, the other contents are the same as those in Example 1, the difference is that the preparation method of the mixed powder in step S1 is to obtain it by gas atomization of 80% by mass of Ni powder and 20% of Al powder in a mixed gas atomization.

[0091] Comparative Example 2

[0092] A preparation method of an electrode, the other contents are the same as those in Example 1, the difference is that step S4 is replaced by: using a chemical corrosion method to remove the active corrosion components, the chemical corrosion solution is composed of KOH, potassium sodium tartrate and water, the mass percentage of KOH contained in the chemical corrosion solution is 30wt%, the mass percentage of potassium sodium tartrate contained is 10wt%, soak in the chemical corrosion solution at 90 °C for 1 h, take it out and place it in a 1mol / L KOH solution for 24 h, then wash and air dry.

[0093] Comparative Example 3

[0094] A preparation method of an electrode, the other contents are the same as those in Example 1, the difference is that the preparation method of the mixed powder in step S1 is to obtain it by gas atomization of 80% by mass of Ni powder and 20% of Al powder in a mixed gas atomization; in step S2, the substrate used is a nickel mesh with a wire diameter of 0.15mm ± 0.01mm.

[0095] Comparative Example 4

[0096] This comparative example provides a strongly corrosion-resistant hydrogen evolution electrode material as the electrode with reference to Example 2 of CN118461047A.

[0097] Comparative Example 5

[0098] A preparation method of an electrode, the other contents are the same as those in Example 1, the difference is that the preparation method of the mixed powder is to obtain it by gas atomization of 90% by mass of Ni powder and 10% by mass of Al powder in a mixed gas atomization.

[0099] Comparative Example 6

[0100] A preparation method of an electrode, the other contents are the same as those in Example 1, the difference is that the preparation method of the mixed powder is to obtain it by gas atomization of 50% by mass of Ni powder and 50% by mass of Al powder in a mixed gas atomization.

[0101] Testing and Evaluation

[0102] Test the relevant indicators and performance of the electrode obtained in Example 1, including:

[0103] Microscopic morphology: The cross-sectional morphology of the electrode prepared in Example 1 was tested using a ZEISS Sigma300 scanning electron microscope, and its scanning electron microscope (SEM) photograph is as shown in Figure 1 shown.

[0104] Catalytic hydrogen evolution performance test: After preparing the electrodes according to the methods in Example 1, Comparative Example 1, and Comparative Example 2, directly enter the hydrogen evolution stage, and use the linear potential sweep test method to test the performance of the prepared electrodes; a three-electrode system is used during the test: the above-mentioned electrode is the working electrode, the platinum electrode is the counter electrode, and Hg / HgO is the reference electrode. The electrolyte is a KOH solution with a concentration of 1 mol / L, and its catalytic hydrogen evolution performance is tested on an electrochemical workstation (CS350H). The scanning rate is 5 mV / s, and the scanning range is 0 to -1 V (relative to the standard hydrogen electrode). The test results correspond to Figure 2 ; It can also be seen from the Figure 2 results that when the current density is -300 mA / cm 2 , the hydrogen evolution potential (overpotential) of the electrode in Example 1 is measured to be -0.333 V, the hydrogen evolution potential (overpotential) of the electrode in Comparative Example 1 is -0.661 V, and the hydrogen evolution potential (overpotential) of the electrode in Comparative Example 2 is -0.45 V.

[0105] Stability test: Using a three-electrode system, with the high-performance electrode with adjustable composition and structure prepared in Example 1 as the working electrode, the platinum electrode as the counter electrode, and Hg / HgO as the reference electrode, and the electrolyte being a KOH solution with a concentration of 1 mol / L, on an electrochemical workstation (CS350H), the chronopotentiometry curve of continuous electrolysis for 200 h at a current density of -1000 mA / cm 2 is measured to characterize the stability of the electrode. The test results correspond to Figure 3 ; As Figure 3 can be seen, the electrode prepared in Example 1 of the present invention has high stability.

[0106] To test the catalytic hydrogen evolution performance of the electrodes obtained in different examples and comparative examples, the steps are as follows:

[0107] The test system is a three-electrode system. The electrodes prepared in different examples or comparative examples are used as the working electrode, the Pt electrode is the counter electrode, Hg / HgO is the reference electrode, the electrolyte is a 1 mol / L KOH solution, and the temperature is room temperature (25 - 35 °C). The hydrogen evolution electrode (without IR compensation) and the measured maximum current density at -3 kA / m 2 are tested, and the results are shown in Table 2.

[0108] Table 2: Test results of the catalytic hydrogen evolution performance of different electrodes

[0109]

[0110]

[0111] In the present invention, the lower the absolute value of the hydrogen evolution potential, the lower the hydrogen evolution potential; the higher the absolute value of the maximum current density, the greater the maximum current density, and the more excellent the catalytic hydrogen evolution performance of the corresponding electrode.

[0112] As can be seen from Table 2, the method of removing the active corrosion components is better for electrochemical corrosion reduction manufacturing than chemical corrosion. Moreover, hydrogen evolution can occur after electrolysis, the process is simple, the hydrogen evolution performance is more excellent, and an ampere-level current density can be achieved. Comparing Comparative Example 1 and Comparative Example 3, it can be seen that when using different spraying substrates, the nickel mesh has better performance than the 316 stainless steel mesh. The reason is that the nickel mesh has catalytic characteristics. Compared with the preparation of mixed powder by ball milling, the alloy powder prepared by gas atomization powder preparation method requires a complex alloying process, and its catalytic performance is significantly reduced compared with the powder mixed by a ball mill.

[0113] The parts not detailed in the present invention are well-known technologies to those skilled in the art.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the above embodiments have been described in detail, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the above embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an electrode with adjustable composition and structure, characterized in that: The method comprises the following steps: S1. Mixing high catalytic powder and active corrosion powder by ball milling to obtain mixed powder; the high catalytic powder is one or more of Ni powder, Fe powder, Co powder and Mo powder, and the active corrosion powder is one or more of Al powder, Zn powder and Mg powder; S2. Depositing the mixed powder onto the pretreated substrate surface using a directed energy deposition process to obtain a deposited electrode; S3, heat-treating the deposited electrode under an inert atmosphere and / or a reducing atmosphere to obtain a heat-treated electrode; S4. Using alkaline solution as electrolyte, electrochemically corrode the heat-treated electrode to obtain an electrode with adjustable composition and structure.

2. The preparation method according to claim 1, characterized in that: In step S1: The high catalytic powder and the active corrosion powder are mixed, anhydrous ethanol is added, and vacuum treatment is performed, followed by ball milling and drying to obtain the mixed powder; The mass ratio of the high catalytic powder to the active corrosion powder is (5-9):(1-5); and / or A catalytic aid is also added to the mixed powder. The catalytic aid is composed of molybdenum disulfide nanosheets and nickel phosphide powder in a mass ratio of (1-2):

1. The amount of the catalytic aid is 3-5% of the mass of the high catalytic powder.

3. The preparation method according to claim 1, characterized in that: In step S2: The directed energy deposition process is one or more of a laser cladding process, a plasma spraying process, and a cold spraying process.

4. The preparation method according to claim 3, characterized in that : The directed energy deposition process is a plasma spraying process, and the parameters of the plasma spraying process are: argon gas flow rate of 44-50nlpm, hydrogen gas flow rate of 0.6-0.8nlpm, carrier gas flow rate of 2-4nlpm, spray gun power of 27-35kW, spraying spacing of 120-130mm, spraying angle of 45-50°, powder feeding rate of 3.6-4.0r / min, spraying times of 3-5 times, spraying thickness of 130-150μm, and after plasma spraying, the loading amount of the mixed powder on the surface of the pretreated substrate is 250-320g / m 2 ;or The directed energy deposition process is a cold spray process, and the parameters of the cold spray process are: cold spray temperature is 350-400° C., cold spray distance is 90-120 mm, cold spray pressure is 4-6 MPa, and powder feeding gas is nitrogen.

5. The preparation method according to claim 1, characterized in that: In step S2: The substrate is one or more of stainless steel, titanium alloy, and nickel-based materials; and / or The pretreatment includes one or more of activation treatment, sandblasting roughening treatment, and electrochemical anodizing treatment.

6. The preparation method according to claim 1, characterized in that: In step S3: The heat treatment is to increase the temperature from room temperature to 250-280°C at a heating rate of 3-5°C / min, and keep the temperature for 1-3h, then increase the temperature to 400-450°C at a heating rate of 3-5°C / min, and keep the temperature for 3-5h.

7. The preparation method according to claim 1, characterized in that: In step S4, electrochemical corrosion is performed using the heat-treated electrode as a working electrode, the platinum electrode as a counter electrode, and Hg / HgO as a reference electrode; and / or In step S4, the parameters for electrochemical corrosion are: the electrolyte is a KOH solution with a concentration of 1 mol / L and / or a NaOH solution with a concentration of 1 mol / L, the electrochemical corrosion temperature is 20-30°C, when the active corrosion powder is Al powder, the electrochemical corrosion potential is -1.6-2.3V relative to the standard hydrogen electrode, and the electrochemical corrosion time is 2-4h, when the active corrosion powder is Zn powder, the electrochemical corrosion potential is -1.2-1.3V relative to the standard hydrogen electrode, and the electrochemical corrosion time is 8-10h, when the active corrosion powder is Mg powder, the electrochemical corrosion potential is -1.5-1.6V relative to the standard hydrogen electrode, and the electrochemical corrosion time is 5-7h.

8. The preparation method according to claim 1, characterized in that: Sodium fluoride and / or ammonium fluoride are also added to the electrolyte, and the concentration of sodium fluoride and / or ammonium fluoride in the electrolyte is 0.1-0.3 mol / L.

9. An electrode with adjustable composition and structure obtained by the preparation method according to any one of claims 1 to 8.

10. Use of an electrode with adjustable composition and structure prepared by the preparation method according to any one of claims 1 to 8 in the field of hydrogen evolution or use of the preparation method according to any one of claims 1 to 8 in the field of hydrogen evolution.

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