Preparation method of hydrogen production multilayer alloy mesh electrode by alkaline electrolysis water and multilayer alloy mesh electrode

Abstract

The application relates to a preparation method of a hydrogen production multilayer alloy mesh electrode of alkaline electrolytic water and the multilayer alloy mesh electrode. In the preparation method, alloy electrode mesh material selection is first performed, then the alloy electrode mesh is etched, the alloy electrode mesh is used as an anode, an inert electrode is used as a cathode, 0.5-5M acid liquid is used for electrochemical etching, a pure nickel mesh with a mesh number of 80-200 is used as a first layer, alloy electrode meshes after 40-80 mesh and 20-40 mesh etching are used as second and third layers respectively, and the second and third layers are stacked in sequence, vacuum sintering is carried out at 800-1400 DEG C for 2-5 hours, and finally stirring and drying treatment are carried out in a polyethylene imine aqueous solution. Compared with the prior art, the electrode obtained by the application has the advantages of low cost, high catalytic activity, fast bubble release, strong durability and stability and the like, effectively solves many problems of the existing alkaline water hydrogen production electrode, has a wide application prospect in the field of alkaline electrolytic water hydrogen production, can significantly improve the water electrolysis efficiency, and is beneficial to large-scale industrial production.

Description

Technical Field

[0001] This invention relates to an alkaline water electrolysis hydrogen production electrode, and more particularly to a method for preparing an alkaline water electrolysis hydrogen production multilayer alloy mesh electrode and the multilayer alloy mesh electrode. Background Technology

[0002] With the growth of global energy demand and the environmental problems caused by fossil fuel use, the search for clean and renewable energy conversion technologies has become particularly important. Hydrogen, as a clean energy carrier, can be used for fuel cell power generation and transportation, promoting the development of the hydrogen economy. Hydrogen production through water electrolysis can be combined with renewable energy sources such as wind and solar power, converting these energy sources into hydrogen that is easy to store and transport. Alkaline water electrolysis is currently the most mature and commercially viable technology for hydrogen production. Improving the efficiency of the water electrolysis electrode is a key research focus, and developing novel electrodes to reduce energy consumption and increase hydrogen production rates is of great significance.

[0003] Traditional electrode materials, especially those using precious metals such as platinum and iridium as catalysts, are expensive, limiting their economic viability in large-scale industrial applications. Currently, nickel mesh electrodes are mainly used in industry, with pure nickel mesh at the anode and Raney nickel-coated mesh at the cathode. However, this type of electrode still presents many problems in practical applications.

[0004] First, the catalytic activity of a single-layer nickel mesh is insufficient. The slow kinetics of the four-electron oxygen evolution reaction (OER) at the anode severely limit oxygen production. The single-layer nickel mesh mainly relies on the intrinsic catalytic activity of nickel for the OER, which has limited activity, a small active area, and few catalytic sites.

[0005] Secondly, the single-layer nickel mesh structure is too simple, resulting in poor bubble removal performance. Hydrogen and oxygen generated at the anode and cathode during water electrolysis need to be rapidly removed from the electrode surface and discharged with the alkaline solution to ensure good contact and reaction between the alkaline solution and the electrode. The poor bubble removal performance of the smooth surface of the single-layer nickel mesh leads to gas accumulation on the electrode surface. Increased bubbles between the solution and electrode increase ohmic impedance, resulting in higher voltage and increased energy consumption; bubbles covering active sites on the electrode surface reduce electrolysis efficiency; excessive bubble accumulation can also lead to increased pressure on both sides, increasing the risk of gas crosstalk.

[0006] Furthermore, the Raney nickel-coated cathode electrode exhibits poor durability and stability. While Raney nickel coating improves hydrogen evolution performance to some extent, it also leads to a decrease in mechanical stability and contact properties. The contact between the coated Raney nickel catalyst and the membrane side deteriorates, increasing contact resistance, and excessive assembly pressure may even cause membrane perforation. After a period of operation, the Raney nickel electrode will experience powder shedding, resulting in a decline in the overall performance of the electrolyzer.

[0007] In summary, existing nickel mesh electrodes have many shortcomings in terms of catalytic activity, bubble removal structure, and durability, which limit the rapid development of industrial alkaline water hydrogen production technology. Given this situation, there is an urgent need for a new type of electrode that can improve intrinsic activity while optimizing the bubble removal structure, increasing mechanical strength and durability, and achieving efficient water electrolysis for hydrogen production. Summary of the Invention

[0008] To address the problems of poor catalytic activity, slow bubble removal, and insufficient durability and stability of existing alkaline water hydrogen production electrodes, this invention designs a novel water electrolysis electrode. This electrode includes the selection of the substrate, the design and matching of the multilayer mesh structure, and the subsequent optimization treatment of the electrode, which can significantly improve the above-mentioned problems of existing single-layer nickel mesh electrodes.

[0009] The objective of this invention can be achieved through the following technical solutions:

[0010] The first aspect of this invention provides a method for preparing a multilayer alloy mesh electrode for alkaline water electrolysis to produce hydrogen, comprising the following steps:

[0011] S1: Selection of alloy electrode mesh material: Select a nickel-iron alloy electrode mesh with a mass ratio of 50%-95% nickel and 5%-50% iron as the anode alloy mesh, or select a nickel-molybdenum alloy mesh with a mass ratio of 60%-95% nickel and 5%-40% molybdenum as the cathode alloy electrode mesh.

[0012] S2: Electrode mesh etching: Using the alloy electrode mesh obtained in S1 as the anode and the inert electrode as the cathode, electrochemical etching is performed with 0.5-5M acid solution to obtain the etched alloy electrode mesh.

[0013] S3: After stacking pure nickel mesh with a mesh size of 80-200 as the first layer, alloy electrode mesh with a mesh size of 40-80 as the second layer, and alloy electrode mesh with a mesh size of 20-40 as the third layer, the layers are vacuum sintered at 800-1400℃ for 2-5 hours to obtain multilayer alloy mesh electrodes.

[0014] S4: Hydrophilic and gas-repellent layer coating: The sintered multilayer alloy mesh electrode is placed in a polyethyleneimine aqueous solution, stirred, and dried to obtain the alkaline water electrolysis hydrogen production multilayer alloy mesh electrode product.

[0015] Furthermore, in S2, the acid solution includes hydrochloric acid or other acids, which are used to prevent impurities from forming on the electrode surface during the etching process and covering the active sites.

[0016] Furthermore, in S2, the inert electrode is a platinum sheet electrode, and dual cathodes are provided on both sides of the anode alloy mesh to ensure the uniformity of etching on the electrode surface.

[0017] Furthermore, in S2, during the electrode mesh etching process, the etching temperature is controlled at 20-30℃, and the current density is between 10-60 mA / cm². 2 When the current density is between 2 and 10 A, the etching time is 20-60 minutes. When the current density is between 2 and 10 A, the etching time is 3-10 seconds, thereby controlling the surface morphology of the electrode.

[0018] Furthermore, in S3, the wire diameter of the pure nickel mesh in the first layer is smaller than that of the alloy electrode mesh in the second layer, and the mesh density of the pure nickel mesh in the first layer is greater than that of the alloy electrode mesh in the second layer, so as to facilitate the adaptation to the diaphragm and the gas discharge.

[0019] Furthermore, in S3, the wire diameter of the alloy electrode mesh in the second layer is smaller than that in the third layer, and the mesh density of the alloy electrode mesh in the second layer is greater than that in the third layer, thus achieving a gradual transition in structural characteristics from the inner layer to the outer layer, which facilitates gas discharge.

[0020] Furthermore, in S3, during the vacuum sintering process, the sintering atmosphere is an inert gas atmosphere to prevent the electrode material from oxidizing at high temperatures and to promote the fusion between the electrode mesh layers.

[0021] Furthermore, in S3, the mass concentration of polyethyleneimine in the aqueous solution of polyethyleneimine is 2%-5%;

[0022] In S3, the multilayer alloy mesh electrode obtained after sintering is stirred in a polyethyleneimine aqueous solution for 1-3 hours.

[0023] Further, in S4, the drying process includes: baking at 100-120°C for 10 minutes, then crosslinking polyethyleneimine with a 1 wt% glutaraldehyde aqueous solution for 1 minute, and finally freeze-drying for 10 minutes. The resulting hydrophilic and gas-repellent layer has a mesh structure. The pore size and distribution of the mesh structure are adapted to the electrode mesh structure to synergistically promote the rapid detachment of bubbles.

[0024] A second aspect of the present invention provides an alkaline water electrolysis hydrogen production multilayer alloy mesh electrode prepared by the above-described preparation method.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] Firstly, in terms of electrode material selection, nickel-iron alloy mesh with a specific mass ratio is selected as the anode and nickel-molybdenum alloy mesh as the cathode. These transition metal alloy materials are low in cost, suitable for large-scale production, and their activity stability is effectively improved compared with traditional materials. They can provide a good catalytic basis for the water electrolysis reaction, significantly reduce production costs, and ensure the long-term efficient operation of the electrodes.

[0027] Secondly, in the electrode etching step, by precisely controlling the electrochemical etching conditions, including acid concentration, current density, and etching time, the surface roughness and the number of active sites on the electrode were successfully increased. This not only greatly improved the catalytic performance of the electrode, enabling the electrolysis reaction to proceed more efficiently, but also optimized the bubble removal structure on the electrode surface, effectively solving the problem of slow bubble removal in traditional electrodes, reducing the increased solution impedance caused by bubble adhesion, and further improving electrolysis efficiency.

[0028] Furthermore, the unique three-layer electrode mesh structure design and processing played a crucial role. The first layer, an 80-200 mesh pure nickel mesh, tightly adheres to the porous membrane, preventing puncture and the resulting serious risk of hydrogen-oxygen cross-contamination, thus ensuring the safety and stability of the electrolysis process. The second and third layers are etched alloy electrode meshes of 40-80 mesh and 20-40 mesh, respectively. With decreasing mesh size and appropriately varying wire diameter from the inside out, they form a denser inner layer and a looser outer layer. This structure increases the solution-electrode contact area, providing ample reaction space for the electrolysis reaction. Simultaneously, the large mesh structure of the outer layer facilitates rapid gas escape, effectively improving bubble removal performance. Moreover, the three layers are firmly bonded through high-temperature vacuum sintering, resulting in overall mechanical stability far superior to traditional single-layer nickel meshes. This allows the electrode to withstand alkaline impacts during electrolysis and operate stably, significantly extending its service life.

[0029] Finally, the hydrophilic and gas-repellent layer coating step involves treating the multilayer alloy mesh electrode with an aqueous solution of polyethyleneimine to form a mesh-like hydrophilic and gas-repellent layer on the electrode surface. This layer works synergistically with the electrode mesh structure to further promote the rapid detachment of bubbles from the electrode surface, significantly reducing the solution impedance caused by bubble aggregation. This ensures that the entire electrode system maintains high efficiency throughout the water electrolysis process, further enhancing the overall performance of the electrode of this invention in alkaline water electrolysis for hydrogen production, and providing solid technical support and guarantee for large-scale industrial applications. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the multilayer alloy mesh assembly in Embodiment 1 of the present invention. The innermost layer is a 100-mesh nickel mesh, the middle layer is a 40-mesh nickel-iron alloy mesh, and the outermost layer is a 20-mesh nickel-iron alloy mesh.

[0031] Figure 2 Figure 3 Images of the front and back of a multilayer alloy mesh sintered together (not of this embodiment, for illustrative purposes only);

[0032] Figure 4 This is a scanning electron microscope image of the surface of the alloy mesh without etching treatment in Example 1 of the present invention;

[0033] Figure 5This is a scanning electron microscope image of the surface of the 40-mesh nickel-iron alloy mesh in the intermediate layer of Embodiment 1 of the present invention after etching.

[0034] Figure 6 This is a scanning electron microscope image of the surface of the outer 20-mesh nickel-iron alloy mesh after etching, as shown in Embodiment 1 of the present invention.

[0035] Figure 7 The diagram shows the oxygen evolution current-voltage curves of the multilayer electrode mesh in Embodiment 1 of the present invention and a common single-layer 40-mesh nickel mesh. Detailed Implementation

[0036] Overall, this invention is mainly achieved through the following technical solutions: First, alkaline water electrolysis anode or cathode electrode materials are selected, preferably transition metals with good catalytic performance for the oxygen evolution reaction, due to their advantages of low cost, suitability for large-scale production, and good activity stability; then, the electrode mesh is etched to increase the surface roughness and the number of active sites, optimizing the bubble removal structure on the electrode surface; multiple layers of treated electrode meshes with different mesh sizes are stacked and then sintered together to enhance the catalytic performance, bubble removal performance, and durability stability of the electrode; finally, a hydrophilic and gas-repellent polymer coating is applied to effectively help bubble removal.

[0037] (1) Selection of electrode mesh:

[0038] Electrode mesh material:

[0039] The preferred anode material is nickel-iron alloy mesh, in which nickel is the main element, accounting for 50%-95% by mass, and iron is the minor element, accounting for 5%-50% by mass.

[0040] The preferred cathode material is a nickel-molybdenum alloy mesh, in which nickel is the main element, accounting for 60%-95% by mass, and molybdenum is the minor element, accounting for 5%-40% by mass.

[0041] ②Electrode mesh structure ：

[0042] The electrode designed in this invention consists of a three-layer electrode mesh, with each of the three parts performing a corresponding function.

[0043] The first layer of pure nickel mesh has a mesh count of 80-200, which is characterized by a relatively dense mesh, a small wire diameter, and a high degree of smoothness and flatness.

[0044] The second layer of alloy mesh has a mesh count of 40-80, medium mesh size, and is similar to that of currently commercially available nickel mesh, with a moderate wire diameter.

[0045] The third layer of alloy mesh has a mesh count of 20-40, sparse mesh openings, and relatively large wire diameter.

[0046] The main reason for choosing alloy materials as the electrode alloy mesh substrate is that relevant literature shows that transition metals are excellent materials for hydrogen production by water electrolysis, and that the synergistic effect of two or more metals can achieve better electrolysis performance. That is, nickel-based alloys with nickel as the main element can achieve better catalytic performance than pure nickel, such as nickel-iron alloys, which are also cheaper than pure nickel.

[0047] The three-layer alloy mesh structure can provide a larger solution-electrode contact area, effectively improving electrolysis efficiency. At the same time, the mesh count of the alloy mesh decreases from the inner porous membrane to the outer current plate side.

[0048] The inner layer, near the membrane, uses a high-mesh pure nickel mesh. This mesh ensures perfect adhesion between the electrode and the porous membrane. The high mesh size and small wire diameter also effectively prevent the porous membrane from being punctured by the electrode mesh, thus avoiding serious problems such as hydrogen-oxygen cross-contamination. The middle layer uses an alloy mesh with a moderate mesh size, similar to commercial nickel mesh, providing the main catalytic activity and improving electrolysis efficiency. The alloy mesh offers superior performance compared to pure nickel mesh, and also boasts higher mechanical strength and durability. The outer layer uses a sparse alloy mesh with larger pores and a larger wire diameter, providing a flow channel-like function similar to that of an electrolytic cell, facilitating rapid gas discharge during surface electrolysis gas generation.

[0049] (2) Electrode mesh etching process:

[0050] Preparation of electrode mesh material and etching solution:

[0051] Select the intermediate and outer alloy meshes for etching (the inner layer does not need to be etched). Prepare 0.5-5M hydrochloric acid (or other acid solution) as the etching solution. Using acid solution for etching can effectively prevent impurities from being generated on the electrode surface during the etching process and cover the active sites.

[0052] Electrochemical etching:

[0053] The alloy mesh is immersed in the prepared etching solution, serving as the anode and an inert electrode (such as a platinum sheet electrode) as the cathode. A dual cathode setup is used, placed on either side of the anode alloy mesh to ensure uniform etching of the electrode surfaces.

[0054] A constant-current electrochemical etching method was used to control the current density and guide the generation of different morphologies. The current density was 10-60 mA / cm². 2 When the current density is between 2 and 10 A, the etching time should be controlled to be 20-60 minutes; when the current density is between 2 and 10 A, the etching time should be 3-10 seconds.

[0055] The etching temperature is around room temperature, 20-30℃. Ensure good ventilation in the surrounding environment during etching.

[0056] (3) Sintering of three-layer electrode mesh:

[0057] After etching the alloy mesh, the inner nickel mesh needs to be sintered with the middle and outer alloy meshes. These three layers of electrode mesh are stacked sequentially in descending order of mesh size, forming a multi-layered electrode mesh structure with a denser inner layer and a looser outer layer. This multi-layered mesh is then placed in a vacuum sintering furnace for sintering. Specific sintering conditions are: temperature controlled at 800-1400℃, sintering time of 2-5 hours. Through vacuum sintering, the surfaces of the three electrode meshes slightly melt and adhere together at high temperature, forming a unified structure.

[0058] The function of this electrode mesh structure is as follows: the inner high-mesh nickel mesh adheres tightly to the porous membrane, reducing contact resistance and preventing membrane puncture that could lead to hydrogen-oxygen cross-contamination; the middle etched electrode layer effectively increases the active surface area, exposing more active sites, and compared to easily detached sprayed or deposited catalysts, the high active area obtained by this method is more stable and durable, suitable for large-scale industrial production. The outer sparse alloy mesh surface is etched with stripes that are more conducive to gas escape, reducing the adsorption force for bubble escape. The ingenious combination of these three electrode mesh layers results in superior electrolysis performance.

[0059] (4) Hydrophilic and air-repellent layer covering:

[0060] To obtain better bubble removal performance, the multilayer electrode mesh obtained in step (3) is further subjected to hydrophilic and gas-repellent treatment. Polyethyleneimine (PEI) has good hydrophilic and gas-repellent properties, which can effectively help bubbles to escape quickly from the electrode surface and prevent the increase in solution resistance caused by the large accumulation of bubbles.

[0061] The multilayer electrode mesh was placed in a 2%-5% (w / w) aqueous solution of polyethyleneimine and gently stirred for 1-3 hours.

[0062] After removing it, bake it at 100-120℃ for about 10 minutes to obtain better adhesion between the polyethyleneimine and the substrate;

[0063] Crosslinking polyethyleneimine with a 1 wt% aqueous solution of glutaraldehyde for 1 min results in a Schiff base condensation reaction (as shown below).

[0064] R-CHO+R′-NH2→RC=NR′+H2O

[0065] Finally, freeze-dry for 10 minutes and then remove.

[0066] A multilayer network covered with a layer of mesh-like polyethyleneimine is obtained, which can quickly expel bubbles while possessing excellent electrolytic performance.

[0067] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Any preparation methods, materials, structures, or compositional ratios not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0068] Example 1

[0069] (1) Selection of multilayer alloy mesh

[0070] Substrate material (this embodiment uses the anode electrode mesh of water electrolysis as an example):

[0071] The first layer is a 100-mesh nickel mesh;

[0072] The second layer is a 40-mesh nickel-iron alloy mesh, in which the mass ratio of nickel to iron alloy mesh components is 80% nickel and 20% iron.

[0073] The third layer is a 20-mesh nickel-iron alloy mesh, in which the mass ratio of nickel to iron alloy mesh is 80% nickel and 20% iron.

[0074] All dimensions are 2cm*2cm;

[0075] Etching solution: Prepare 1M and 3M dilute hydrochloric acid solutions;

[0076] Figure 1 This is a schematic diagram of the multilayer alloy mesh assembly in Embodiment 1 of the present invention. The innermost layer is a 100-mesh nickel mesh, the middle layer is a 40-mesh nickel-iron alloy mesh, and the outermost layer is a 20-mesh nickel-iron alloy mesh. Figure 2 Figure 3 Images of the front and back of a multilayer alloy mesh sintered together (not of this embodiment, for illustrative purposes only).

[0077] (2) Alloy mesh etching

[0078] Preprocessing:

[0079] First, perform simple pretreatment on the alloy mesh materials, namely, use 1M hydrochloric acid to ultrasonically clean the alloy mesh (40 mesh and 20 mesh), then rinse with deionized water, and then use anhydrous ethanol to ultrasonically clean the alloy mesh for 15 minutes. After air drying, etching can begin.

[0080] Etching process:

[0081] Etching treatment of the second layer of 40-mesh nickel-iron alloy mesh:

[0082] The nickel-iron alloy mesh was immersed in 3M hydrochloric acid for 24 hours to create certain etching sites. Then it was taken out and ultrasonically cleaned with deionized water for 10 minutes, and then air-dried for later use.

[0083] Two platinum sheet electrodes, each 2cm x 2cm in size, are used as cathodes, and a nickel-iron alloy mesh is used as anode. The electrodes are immersed in 1M hydrochloric acid etching solution. The nickel-iron alloy mesh anode is placed between the two cathodes to ensure that the three electrodes are facing each other and at the same distance, in order to ensure the uniformity of the etching effect.

[0084] Configure a constant current power supply, with the current density set to 5A / cm². 2 The etching time is 10 seconds.

[0085] During the electrochemical etching process, a constant temperature water bath device is used to ensure that the temperature of the etching solution is 20-30℃;

[0086] After etching, remove the nickel-iron alloy mesh, rinse off the etching solution with deionized water, and air dry. The resulting alloy mesh surface morphology is as follows. Figure 5 As shown.

[0087] Etching treatment of the third layer of 20-mesh nickel-iron alloy mesh:

[0088] Two platinum sheet electrodes, each 2cm x 2cm in size, are used as cathodes, and a nickel-iron alloy mesh is used as anode. The electrodes are immersed in 1M hydrochloric acid etching solution. The nickel-iron alloy mesh anode is placed between the two cathodes to ensure that the three electrodes are facing each other and at the same distance, in order to ensure the uniformity of the etching effect.

[0089] Configure a constant current power supply, set the current density to 20mA / cm, and the etching time to 30min.

[0090] During the electrochemical etching process, a constant temperature water bath device is used to ensure that the temperature of the etching solution is 20-30℃;

[0091] After etching, remove the nickel-iron alloy mesh, rinse off the etching solution with deionized water, and air dry. The resulting alloy mesh surface morphology is as follows. Figure 6 As shown.

[0092] (3) Sintering treatment

[0093] The nickel mesh and two layers of etched nickel-iron alloy mesh were stacked face to face, and the three layers of electrodes were rapidly sintered as a whole. The sintering temperature was set at 1100℃ and the sintering time was 3 hours. Then the temperature was slowly lowered and solidified.

[0094] This sintering condition is suitable for the three-layer electrode mesh structure of this component. It can cause the contact parts of the three-layer electrode mesh to melt slightly under high temperature conditions and then firmly bond together with each other when cooled to form an integral electrode structure.

[0095] (4) Hydrophilic and air-repellent layer covering:

[0096] Cover both sides of the multilayer electrode mesh with raw material tape (the two sides of the electrode mesh are in contact with the porous membrane and the electrode plate respectively. In order to obtain good contact performance, it is not necessary to cover it with a hydrophilic and gas-repellent layer), and put it into a 3wt% polyethyleneimine aqueous solution and stir gently for 2 hours.

[0097] After removing it from the oven, bake it in an oven at 100°C for 10 minutes to ensure good adhesion between the polyethyleneimine and the substrate;

[0098] Crosslinking polyethyleneimine with a 1 wt% aqueous solution of glutaraldehyde for 1 min forms a mesh-like hydrophilic and gas-repellent layer on the surface of the electrode grid.

[0099] After drying for 10 minutes, it can be removed.

[0100] A multilayer network covered with a layer of mesh-like polyethyleneimine is obtained, which can quickly expel bubbles while possessing excellent electrolytic performance.

[0101] Through the above steps, a multilayer electrode network with an etched structure and a hydrophilic and gas-repellent layer, and with optimized materials, can be obtained.

[0102] (5) Electrode performance characterization:

[0103] Scanning electron microscopy (SEM) characterization:

[0104] The surface morphology of the nickel-iron alloy mesh electrode was observed using SEM, and its microstructure and surface roughness were analyzed, such as... Figure 4 , Figure 5 , Figure 6 As shown.

[0105] Linear sweep voltammetry (LSV) test:

[0106] LSV tests were performed on an electrochemical workstation using 1M KOH solution as the electrolyte. The test range was 0V to 2V (relative to a standard hydrogen electrode), and the scan rate was 10mV / s. The LSV curves showed that the electrode of this invention exhibited a low oxygen evolution overpotential during water electrolysis, demonstrating excellent catalytic activity. Figure 7 As shown.

[0107] Verification and explanation for this embodiment:

[0108] The above embodiments yielded a three-layer alloy mesh with excellent performance:

[0109] The inner layer is a smooth and dense nickel mesh, which facilitates good contact with the diaphragm, maintains good conductivity, and helps reduce impedance caused by contact.

[0110] The intermediate layer is an etched 40-mesh nickel-iron alloy mesh, such as... Figure 5As shown, its surface has a regular pitted structure, which can effectively increase the active surface area of ​​the electrode, compared to the smooth surface of the original alloy mesh. Figure 4 It is more conducive to improving electrolysis efficiency;

[0111] The outer layer is an etched 20-mesh nickel-iron alloy mesh, such as... Figure 6 As shown, the prismatic structure on the surface can effectively reduce the adhesion force of the bubbles, help the generated bubbles to quickly detach from the electrode surface, reduce the coverage time of the bubbles on the active sites, and reduce the solution resistance increased due to the bubbles.

[0112] The sintering step firmly bonds the three-layer electrode mesh, and the etching process provides a more stable surface structure compared to traditional deposition methods. This is the key reason why in-situ etching is superior to external catalysts "accumulating" on the surface of the electrode mesh. After etching, the original material composition and optimized structure are maintained, while catalysts loaded by deposition and other methods obviously do not have this kind of firmness and stability.

[0113] Finally, the hydrophilic and gas-repellent layer is applied to further enhance the overall hydrophilic and gas-repellent properties of the electrode network, helping the electrode catalytic sites to have good contact and reaction with the solution, while also quickly expelling the generated bubbles, thereby improving the electrolysis efficiency. The oxygen evolution performance tested by the three electrodes also confirms the significant improvement of the electrode in Example 1 of this invention in terms of oxygen evolution performance in water electrolysis.

[0114] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing a hydrogen-producing multilayer alloy mesh electrode for alkaline electrolysis of water, characterized by, The method comprises the following steps: S1: alloy electrode mesh material selection: select a nickel-iron alloy electrode mesh with a mass ratio of nickel 50%-95% and iron 5%-50% as the anode alloy mesh; S2: electrode mesh etching: using the alloy electrode mesh obtained in S1 as the anode and an inert electrode as the cathode, electrochemical etching is performed with 0.5-5M acid solution to obtain the etched alloy electrode mesh; S3: pure nickel mesh with a mesh number of 80-200 is used as the first layer, 40-80 mesh etched alloy electrode mesh is used as the second layer, and 20-40 mesh etched alloy electrode mesh is used as the third layer, which are stacked in sequence, vacuum sintering is performed at 800-1400℃ for 2-5 hours, the three layers of mesh are fused and cooled and solidified to be tightly combined, and a multilayer alloy mesh electrode is obtained; S4: hydrophilic and air-repellent layer covering: the multilayer alloy mesh electrode obtained after sintering is placed in a polyethylene imine aqueous solution for stirring and drying to obtain an alkaline electrolytic water hydrogen production multilayer alloy mesh electrode product; In S4, the drying comprises baking at 100-120℃ for 10 minutes, then crosslinking the polyethylene imine with 1wt% glutaraldehyde aqueous solution for 1 minute, and finally freeze-drying for 10 minutes, the hydrophilic and air-repellent layer has a mesh structure, the mesh structure has a pore size and distribution that are matched with the electrode mesh structure to synergistically promote the rapid separation of bubbles.

2. The method of claim 1, wherein the method further comprises the step of: In S2, the acid solution is a hydrochloric acid solution comprising hydrochloric acid, and the acid solution is used to prevent impurities from covering active sites on the electrode surface during etching. ​ 3. The method of claim 1, wherein the method further comprises the step of: In S2, the inert electrode is a platinum sheet electrode, and double cathodes are arranged on both sides of the anode alloy mesh to ensure the uniformity of the electrode surface etching. ​ 4. The method of claim 1, wherein the method further comprises the step of: 4-1) annealing the multi-layered alloy mesh electrode at a temperature of 300- 400 °C for 1-3 hours in a vacuum or in an inert gas atmosphere. In S2, the etching temperature is controlled at 20-30℃ during the etching of the electrode mesh, and the current density is at 10-60 mA / cm 2 When the current density is at 2-10 A, the etching time is 3-10 seconds, so as to control the surface morphology of the electrode.

5. The method for preparing an alkaline water electrolysis hydrogen production multilayer alloy mesh electrode according to claim 1, characterized in that, In S3, the wire diameter of the pure nickel mesh in the first layer is smaller than that of the alloy electrode mesh in the second layer, and the mesh hole density of the pure nickel mesh in the first layer is greater than that of the alloy electrode mesh in the second layer, so as to facilitate the adaptation with the diaphragm and the gas discharge.

6. The method of claim 1, wherein the method further comprises: In S3, the wire diameter of the alloy electrode mesh in the second layer is smaller than that of the alloy electrode mesh in the third layer, and the mesh hole density of the alloy electrode mesh in the second layer is greater than that of the alloy electrode mesh in the third layer, so as to realize the gradual transition of the structural characteristics from the inner layer to the outer layer and facilitate the gas discharge.

7. The method for preparing an alkaline water electrolysis hydrogen production multilayer alloy mesh electrode according to claim 1, characterized in that, In S3, during the vacuum sintering process, the sintering atmosphere is an inert gas atmosphere to prevent the electrode material from being oxidized at high temperature and promote the fusion between the electrode meshes in different layers.

8. The method for preparing an alkaline water electrolysis hydrogen production multilayer alloy mesh electrode according to claim 1, characterized in that, In S3, the mass concentration of polyethylene imine in the polyethylene imine aqueous solution is 2%-5%; In S3, the stirring time of the multilayer alloy mesh electrode obtained after sintering in the polyethylene imine aqueous solution is 1h-3h.

9. An alkaline electrolytic water hydrogen production multilayer alloy mesh electrode prepared by the method of any one of claims 1-8.

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