Nickel-zinc hydrogen evolution electrode, preparation method thereof and electrolytic cell

Abstract

The application belongs to the technical field of hydrogen and oxygen production by water electrolysis, and particularly relates to a nickel-zinc hydrogen evolution electrode, a preparation method thereof and an electrolytic cell. The method steps are as follows: the electrode substrate is subjected to sand blasting, electrolytic oil removal, hot water washing, water washing, pickling or acid electrolysis, water washing, so as to remove the oxidation layer of the base material and roughen the surface; the nickel, zinc or alloy is loaded on the surface of the base material by spraying to obtain a hydrogen evolution electrode precursor; then, part of the zinc in the plating layer of the hydrogen evolution electrode precursor is leached out by using an activation solution, so that the hydrogen evolution electrode is prepared; or, the hydrogen evolution electrode precursor is directly assembled into the electrolytic cell, in-situ activation is carried out in the electrolytic cell in an oxygen-isolated manner, after the activation is completed, the electrolytic cell is washed in an oxygen-isolated manner and formal electrolyte is introduced, and then normal electrolysis for producing hydrogen and oxygen gas can be carried out. The electrolytic cell using the electrode has a lower cell voltage and a higher energy conversion efficiency than those of a conventional electrolytic cell.

Description

Technical Field

[0001] This invention belongs to the field of water electrolysis for hydrogen and oxygen production technology, specifically relating to a nickel-zinc hydrogen evolution electrode, its preparation method, and an electrolytic cell. Background Technology

[0002] With the large-scale development and utilization of renewable energy, the efficient conversion, storage, and utilization of energy have become critical issues that urgently need to be addressed. Alkaline water electrolysis for hydrogen production, as an important medium for realizing the large-scale storage and utilization of renewable energy, can effectively achieve energy conversion, storage, and utilization. It is a crucial technological tool for promoting the achievement of dual-carbon goals and has broad application prospects in the field of new energy.

[0003] However, the current alkaline water electrolysis hydrogen production process suffers from high energy consumption, a technical bottleneck that significantly limits its market promotion and large-scale application. Research indicates that the core key to developing high-performance alkaline water electrolysis technology lies in reducing the electrolysis voltage of the electrolysis chamber while maintaining the target current density. Specifically, reducing the overpotential of the hydrogen evolution reaction is crucial for lowering the chamber's electrolysis voltage and thus reducing overall hydrogen production energy consumption.

[0004] Currently, the commercially available method for preparing hydrogen evolution electrodes is thermal spraying. This involves spraying a coating containing nickel and aluminum onto an electrode substrate, followed by leaching some of the aluminum from the coating with a leaching solution, ultimately yielding the hydrogen evolution electrode. This method is widely accepted and used in the industry due to its high processing efficiency. However, the existing method still has significant technical drawbacks. Specifically, the uneven distribution of nickel and aluminum components in the sprayed nickel-aluminum coating results in mediocre catalytic performance of the prepared hydrogen evolution electrode, leading to higher voltage in the electrolysis chamber during electrolysis. This ultimately results in high energy consumption in the alkaline water electrolysis hydrogen production process, failing to meet the demands of large-scale, low-energy industrial hydrogen production.

[0005] CN119506932A discloses a method for preparing a hydrogen evolution electrode loaded with porous nickel. The method includes loading a nickel-zinc alloy onto a substrate via electroplating; and leaching zinc through an alkaline activating solution to obtain a porous nickel electrode. However, this method, which uses electroplating to prepare the electrode, suffers from low processing efficiency, long electroplating time of 30-60 minutes per electrode, and weak large-scale production capacity. This makes it difficult to meet the demand for efficient preparation of high-performance hydrogen evolution electrodes, resulting in high electrode costs and consequently limiting the economic viability of hydrogen production via water electrolysis.

[0006] Therefore, developing a technical solution that can solve the problem of high energy consumption in the existing technology of hydrogen production by water electrolysis, optimize the electrode preparation process, and improve the catalytic performance of the electrode has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to overcome the defects of the prior art by providing a nickel-zinc hydrogen evolution electrode, its preparation method, and an electrolytic cell.

[0008] The objective of this invention can be achieved through the following technical solutions: A method for preparing a nickel-zinc hydrogen evolution electrode includes the following steps: Surface pretreatment of the electrode substrate makes the load more reliable; A nickel-zinc composite coating is formed by loading a nickel source and a zinc source onto the electrode substrate after surface pretreatment using a thermal spraying process, thus obtaining an electrode precursor. The zinc portion in the electrode precursor is removed to obtain a nickel-zinc hydrogen evolution electrode.

[0009] Furthermore, the electrode substrate is made of a conductive material resistant to alkaline corrosion; preferably, the material of the electrode substrate is selected from stainless steel, nickel-containing alloys, or nickel; the structural form of the electrode substrate includes one or more combinations of woven mesh, stretched mesh, perforated plate, sintered porous metal powder plate, or foamed metal. The surface pretreatment includes one or more of the following processes: sandblasting, electrolysis, degreasing, hot water washing, water washing, pickling, and acid electrolysis.

[0010] Preferably, when the electrode substrate is a woven mesh, a stretched mesh, or a perforated plate, the surface pretreatment includes one or more of the following: sandblasting, electrolysis, degreasing, hot water washing, water washing, pickling, and acid electrolysis.

[0011] Preferably, when the electrode substrate is a sintered porous plate of metal powder or foam metal, the surface pretreatment method includes one or more of the following: electrolysis, degreasing, hot water washing, water washing, acid washing, and acid electrolysis.

[0012] Furthermore, the sandblasting includes: The first stage of sandblasting uses abrasive with a minimum equivalent diameter larger than the pore size of the electrode substrate to roughen the substrate surface; The second stage of sandblasting uses abrasive with a maximum equivalent diameter smaller than the aperture of the electrode substrate to perform fine cleaning on the substrate surface.

[0013] Furthermore, the minimum equivalent diameter of the abrasive used in the first stage of sandblasting is more than twice the aperture of the electrode substrate; the maximum equivalent diameter of the abrasive used in the second stage of sandblasting is less than 0.7 times the aperture of the electrode substrate; preferably, the minimum equivalent diameter of the abrasive used in the first stage of sandblasting is 5-10 times the aperture of the electrode substrate; and the maximum equivalent diameter of the abrasive used in the second stage of sandblasting is 0.5 times the aperture of the electrode substrate.

[0014] The specific sandblasting process is as follows: The electrode substrate is placed on a conveyor belt and slowly transported through the sandblasting chamber. Two sets of sandblasting heads are installed inside the chamber, with an angle between the spray directions of the two sets of heads ranging from 0° to 120°, and an angle between each head and the substrate surface ranging from 30° to 90°. The sandblasting heads reciprocate to ensure complete coverage of the substrate surface. During sandblasting, the abrasive, carried by high-pressure fluid, is ejected at high speed from the sandblasting heads, impacting the substrate surface, removing the oxide layer, and roughening the surface. The roughened substrate surface roughness Ra is 0.1–50 μm.

[0015] After sandblasting, the substrate surface is purged with high-pressure fluid to remove residual dust particles. Preferably, the high-pressure fluid is compressed air or nitrogen.

[0016] Further, the nickel source is selected from nickel wire, nickel powder, nickel-zinc alloy wire or nickel-zinc alloy powder; the zinc source is selected from zinc wire, zinc powder, nickel-zinc alloy wire or nickel-zinc alloy powder; preferably, in the nickel-zinc alloy wire or nickel-zinc alloy powder, the atomic ratio of nickel to zinc is 1:9 to 9:1.

[0017] The nickel and zinc powders require pretreatment before use. After drying to remove moisture, the nickel and zinc powders are mixed using a drum mill or ball mill. The mixed powder is then loaded into a powder feeding hopper for later use. The loading of nickel and zinc powders in the drum is controlled at 1 / 3 to 2 / 3 of the drum volume, the drum speed is 5 to 100 r / min, and the mixing time is 30 to 60 min.

[0018] The thermal spraying process is selected from plasma spraying or flame spraying; during the spraying process, the speed of nickel-zinc particles is 50~500 m / s, and the particles impact the substrate surface at high speed, forming a coating through physical bonding; specifically, plasma spraying uses a DC arc to generate plasma, and the plasma working gas is mainly argon and supplemented by hydrogen; the nickel-zinc raw material is heated to a molten or semi-molten state in the plasma flame and impacts the substrate surface at a speed of 50~500 m / s, forming a coating through physical bonding.

[0019] After the thermal spraying process is completed, the coating is further subjected to heat treatment to improve the bonding strength between the sprayed coatings or between the coating and the substrate.

[0020] The heat treatment involves heating the temperature to 400-420°C in multiple stages and holding it at that temperature for 0.5-2 hours in an inert atmosphere with an oxygen content of ≤0.5%, followed by cooling to below 50°C.

[0021] Furthermore, the thermal spraying process includes: For the first coat, the nickel-zinc mass ratio is 3:1 to 2:1, the nickel powder particle size is 100 to 150 mesh, and the zinc powder particle size is 50 to 100 mesh. For the second coat, the nickel-zinc mass ratio is 2:1 to 1:2, the nickel powder particle size is 150 to 250 mesh, and the zinc powder particle size is 100 to 200 mesh. For the third coat, the nickel-zinc mass ratio is 1:2 to 1:3, the nickel powder particle size is 250 to 350 mesh, and the zinc powder particle size is 200 to 300 mesh.

[0022] During the three-coat process, the nickel-zinc mass ratio gradually decreases and the powder particle size decreases simultaneously, forming a nickel-zinc coating with a gradual gradient in composition and particle size: the first coat uses a high nickel-zinc ratio, which can enhance the adhesion between the coating and the substrate; in subsequent coats, the nickel-zinc ratio continues to decrease, the zinc content increases and the powder particle size decreases, which is conducive to the full alloying of the nickel-zinc components and the formation of a continuously gradient porous microstructure during the subsequent activation process, thereby increasing the specific surface area and improving catalytic activity.

[0023] Furthermore, the thermal spraying process also includes surface spraying using raw materials with a high nickel-zinc ratio; the nickel-zinc mass ratio of the surface spraying load is 3:1 to 5:1, the particle size of the nickel powder is 250 to 350 mesh, the particle size of the zinc powder is 200 to 300 mesh, and the thickness of the surface spraying coating is 0.5 to 10 micrometers. This high nickel-zinc ratio surface layer can effectively protect the internal gradient coating and extend the electrode's service life.

[0024] Furthermore, the step of partially removing zinc includes immersing the electrode precursor in an activation solution for chemical dezincification, or assembling the electrode precursor into an electrolytic cell for in-situ activation under oxygen-free conditions.

[0025] The activation solution is an alkaline solution, preferably a sodium hydroxide solution with a mass fraction of 5-25% or a potassium hydroxide solution with a mass fraction of 5-30%. A zinc ion complexing agent, such as potassium sodium tartrate with a mass fraction of about 5%, may also be added to the activation solution.

[0026] The present invention also provides a hydrogen evolution electrode, which is prepared by any of the above methods and includes an electrode substrate and a nickel-zinc composite coating attached to the surface of the electrode substrate.

[0027] The present invention also provides an electrolytic cell, comprising an anode, a cathode, a diaphragm and an electrolyte, wherein the cathode is a hydrogen evolution electrode as described above.

[0028] The electrolytic cell operates at a current density of 500 A / m. 2 The operating voltage is 1.4 volts and the current density is 5000 A / m. 2 The operating voltage is 2.0 volts.

[0029] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention pretreats nickel-zinc raw materials and prepares electrode precursors with different nickel-zinc ratios using a thermal spraying process. After the zinc is partially dissolved, the resulting hydrogen evolution electrode forms a multi-level porous structure with a gradient distribution of pore size that becomes smaller closer to the surface. The powder particles near the electrode surface are finer and have a higher zinc content. After the zinc is dissolved, it forms small pores. This structure can effectively reduce the overpotential of the hydrogen evolution reaction, thereby reducing the operating voltage of the electrolyzer. The operating voltage of the electrolyzer in this invention can be controlled between 1.4 and 2.0 V. Under the same current density conditions, compared with the prior art, the cell voltage is lower and the energy conversion efficiency is higher, fundamentally solving the technical problem of high energy consumption in hydrogen production using existing hydrogen evolution electrodes.

[0030] (2) The present invention forms a nickel-rich dense layer on the surface through the final thermal spraying, which can cover and protect the fine porous structure inside, effectively inhibit the shedding of active materials, avoid the catalytic performance decay caused by the loss of active components, significantly improve the long-term operating stability and service life of the electrode, reduce the electrode replacement cost of industrial hydrogen production, and improve the value of industrial application.

[0031] (3) The present invention uses thermal spraying process to replace traditional electroplating process. Based on the specification of 2.5 square meters / piece, the processing time of the same area of ​​electrode can be shortened from 30 to 60 minutes of electroplating to 5 minutes, the processing efficiency is increased by 6 to 12 times, and the equipment investment is greatly reduced, significantly reducing the electrode preparation cost, while maintaining excellent catalytic performance. Attached Figure Description

[0032] Figure 1 This is a scanning electron microscope (SEM) image of the cross-section of the nickel-zinc hydrogen evolution electrode in Embodiment 1 of the present invention; Figure 2 The figures show the electrochemical overpotential versus current density curves for Example 1 of this invention and the commercial electrode. Detailed Implementation

[0033] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0034] Unless otherwise specified, all raw materials used in this invention are commercially available products.

[0035] Example 1 A 40-mesh nickel braided mesh was selected as the electrode substrate. The mesh is woven from nickel wire with a diameter of 0.19 mm and a pore size of 0.445 mm.

[0036] (1) Surface pretreatment The electrode substrate is placed on the conveyor belt of the sandblasting machine and transported through the sandblasting chamber. The sandblasting chamber is equipped with two sets of sandblasting heads, with a 120° angle between their spray directions and a 30° angle between the sandblasting head and the substrate surface. The sandblasting heads reciprocate to ensure complete coverage of the substrate surface.

[0037] The sandblasting process is conducted in two stages: the first stage uses abrasive grains with an equivalent diameter of 10 times the pore diameter of the substrate, and the second stage uses abrasive grains with a maximum equivalent diameter of 0.5 times the pore diameter of the substrate. The abrasive grains are ejected at high speed under the action of compressed air, impacting and removing the oxide layer on the substrate surface while simultaneously roughening the surface. After pretreatment, the macroscopic roughness of the substrate surface reaches Ra 25 μm, and the microscopic roughness reaches Ra 0.1 μm. After sandblasting, compressed air is used to blow away residual dust particles from the substrate surface.

[0038] (2) Preparation of spraying materials After drying the nickel and zinc powders separately to remove moisture, they are placed in a drum mixer for mixing. The loading amount of the mixed powder is controlled to be 1 / 3 to 2 / 3 of the drum volume, the drum speed is 5 r / min, and the mixing time is 60 min. The uniformly mixed powder is then loaded into a powder feeding hopper for later use.

[0039] (3) Plasma spraying to prepare electrode precursors A plasma thermal spraying process is used to deposit mixed powder onto a pretreated substrate. The plasma is generated using direct current, with argon as the primary working gas and hydrogen as a secondary gas. The sprayed powder is heated to a molten or semi-molten state in the plasma stream, forming particles that impact the substrate at speeds of 50–500 m / s, forming a coating through physical bonding.

[0040] The spraying process is carried out in three coats, with the specific parameters as follows: First coat: The mass ratio of nickel to zinc is 3:1, the nickel powder particle size is 100~150 mesh, the zinc powder particle size is 50~100 mesh, and the thickness of this layer is controlled to be 10μm; Second coat: The mass ratio of nickel to zinc is 2:1, the particle size of nickel powder is 150~250 mesh, the particle size of zinc powder is 100~200 mesh, and the thickness of this layer is controlled to be 10μm; The third coat: the mass ratio of nickel to zinc is 1:2, the nickel powder particle size is 250~350 mesh, the zinc powder particle size is 200~300 mesh, and the thickness of this layer is controlled to be 10μm; After spraying, the resulting coating was subjected to heat treatment: the sample was placed in an atmosphere furnace, and the atmosphere was replaced by vacuuming and purging to make the oxygen content in the furnace less than 0.5%, with the remainder being argon; the temperature was increased to 400℃ at 5℃ / min and held for 30min; then increased to 415℃ at 2℃ / min and held for 5min; then increased to 420℃ at 1℃ / min and held for 1h; finally, the temperature was cooled to below 50℃ in the furnace, and the sample was removed to obtain the electrode precursor containing nickel-zinc coating.

[0041] (4) Activation treatment The above electrode precursor was immersed in an activation solution and chemically dezincified at 80°C for 8 hours to obtain a hydrogen evolution electrode; the activation solution was a mixed aqueous solution of 25% potassium hydroxide and 5% sodium potassium tartrate.

[0042] Figure 1 This is a cross-sectional morphology diagram of the nickel-zinc hydrogen evolution electrode of Example 1. The substrate is a 40-mesh plain nickel mesh (0.19 mm wire diameter), which serves as the conductive support framework for the electrode. The outer side of the substrate is coated with a nickel-zinc coating, which is an electrode precursor layer prepared by thermal spraying. After subsequent chemical dezincification treatment, a gradient porous structure is formed, providing catalytic active sites and reaction channels for the hydrogen evolution reaction. The coating is tightly bonded to the substrate, with no obvious cracks or peeling at the interface, demonstrating good bonding strength and ensuring the long-term operational stability of the electrode.

[0043] (5) Electrolytic cell assembly and performance testing The hydrogen evolution electrode was used as the cathode and assembled with the oxygen evolution electrode, diaphragm, electrode plate, gasket, and fasteners to form a pressure filter bipolar plate electrolyzer. It was operated stably under alkaline conditions of 80℃ and operating pressure of 1.5 MPa. Different current densities were set, and the average voltage of the small chamber was measured and recorded.

[0044] Tests showed that the electrolytic cell operated at a current density of 500 A / m 2 At that time, the operating voltage was 1.4 V; at a current density of 5000 A / m 2 At that time, the operating voltage is 2.0 V.

[0045] Comparative tests were conducted on a commercial electrode (a 40-mesh plain-weave spray-coated electrode produced by Yangzhou Yufeng Special Mesh Belt Factory) under the same test conditions. This commercial electrode used only a single specification of nickel and aluminum powder, with no gradient change in coating composition, no heat treatment, and only a one-step sandblasting pretreatment. Test results showed that the electrolytic cell assembled using this commercial electrode achieved a current density of 400 A / m². 2 At that time, the operating voltage was 1.4 V; at a current density of 4000 A / m 2 At that time, the operating voltage is 2.0 V.

[0046] Figure 2 The figure shows the electrochemical overpotential-current density relationship curves of the nickel-zinc hydrogen evolution electrode of this embodiment and a commercial electrode (the reference electrode is a mercury / mercury oxide electrode). As can be seen from the figure, at the same overpotential, the current density of the electrode of this invention is significantly higher than that of the commercial electrode, indicating that under the same power consumption conditions, this invention can achieve a higher hydrogen production rate. At the same current density, the overpotential of the electrode of this invention is lower, which can significantly reduce the energy consumption of the electrolyzer and improve the energy conversion efficiency.

[0047] The comparative results show that, under the same operating voltage, the electrode of the present invention can withstand a higher current density, and its catalytic activity and energy-saving advantages are more prominent.

[0048] Example 2 A 40-mesh nickel braided mesh was selected as the electrode substrate. The mesh is woven from nickel wire with a diameter of 0.19 mm and a pore size of 0.445 mm.

[0049] (1) Surface pretreatment The electrode substrate is placed on the conveyor belt of the sandblasting machine and transported through the sandblasting chamber. The sandblasting chamber is equipped with two sets of sandblasting heads, with a 60° angle between their spray directions and the angle between the sandblasting head and the substrate surface. The sandblasting heads reciprocate to ensure complete coverage of the substrate surface.

[0050] The sandblasting process is conducted in two stages: the first stage uses abrasive grains with an equivalent diameter of 10 times the pore diameter of the substrate, and the second stage uses abrasive grains with a maximum equivalent diameter of 0.5 times the pore diameter of the substrate. The abrasive grains are ejected at high speed under the action of compressed air, impacting and removing the oxide layer on the substrate surface while simultaneously roughening the surface. After pretreatment, the macroscopic roughness of the substrate surface reaches Ra 25 μm, and the microscopic roughness reaches Ra 0.1 μm. After sandblasting, compressed air is used to blow away residual dust particles from the substrate surface.

[0051] (2) Preparation of spraying materials After drying the nickel and zinc powders separately to remove moisture, they are placed in a drum mixer for mixing. The loading amount of the mixed powder is controlled to be 1 / 3 to 2 / 3 of the drum volume, the drum speed is 60 r / min, and the mixing time is 120 min. The uniformly mixed powder is then loaded into a powder feeding hopper for later use.

[0052] (3) Plasma spraying to prepare electrode precursors A plasma thermal spraying process is used to deposit mixed powder onto a pretreated substrate. The plasma is generated using direct current, with argon as the primary working gas and hydrogen as a secondary gas. The sprayed powder is heated to a molten or semi-molten state in the plasma stream, forming particles that impact the substrate at speeds of 50–500 m / s, forming a coating through physical bonding.

[0053] The spraying process is carried out in three coats, with the specific parameters as follows: First coat: The mass ratio of nickel to zinc is 2:1, the nickel powder particle size is 100~150 mesh, the zinc powder particle size is 50~100 mesh, and the thickness of this layer is controlled to be 10μm; Second coat: The mass ratio of nickel to zinc is 1:2, the particle size of nickel powder is 150~250 mesh, the particle size of zinc powder is 100~200 mesh, and the thickness of this layer is controlled to be 10μm; The third coat: the mass ratio of nickel to zinc is 1:3, the nickel powder particle size is 250~350 mesh, the zinc powder particle size is 200~300 mesh, and the thickness of this layer is controlled to be 10μm.

[0054] After spraying, the resulting coating is heat-treated to obtain an electrode precursor containing a nickel-zinc coating. The heat treatment steps for the coating are the same as in Example 1.

[0055] (4) Activation treatment The above-mentioned electrode precursor was immersed in an activation solution and subjected to chemical dezincification treatment to obtain a hydrogen evolution electrode; the activation solution was a mixed aqueous solution of 25% potassium hydroxide and 5% sodium potassium tartrate.

[0056] (5) Electrolytic cell assembly and performance testing The hydrogen evolution electrode was used as the cathode and assembled with the oxygen evolution electrode, diaphragm, electrode plate, gasket, and fasteners to form a pressure filter bipolar plate electrolyzer. It was operated stably under alkaline conditions of 80℃ and operating pressure of 1.5 MPa. Different current densities were set, and the average voltage of the small chamber was measured and recorded.

[0057] Tests showed that the electrolytic cell operated at a current density of 520 A / m 2 At that time, the operating voltage was 1.4 V; at a current density of 5500 A / m 2 At that time, the operating voltage is 2.0 V.

[0058] Example 3 A 46-mesh nickel braided mesh was selected as the electrode substrate. The mesh is woven from nickel wire with a diameter of 0.25 mm and a pore size of 0.302 mm.

[0059] (1) Surface pretreatment The electrode substrate is placed on the conveyor belt of the sandblasting machine and transported through the sandblasting chamber. The sandblasting chamber is equipped with two sets of sandblasting heads, with a 0° angle between their spray directions and a 90° angle between the sandblasting heads and the substrate surface. The sandblasting heads reciprocate to ensure complete coverage of the substrate surface.

[0060] The sandblasting process is conducted in two stages: the first stage uses abrasive grains with an equivalent diameter of 10 times the pore diameter of the substrate, and the second stage uses abrasive grains with a maximum equivalent diameter of 0.5 times the pore diameter of the substrate. The abrasive grains are ejected at high speed under the action of compressed air, impacting and removing the oxide layer on the substrate surface while simultaneously roughening the surface. After pretreatment, the macroscopic roughness of the substrate surface reaches Ra 25 μm, and the microscopic roughness reaches Ra 0.1 μm. After sandblasting, compressed air is used to blow away residual dust particles from the substrate surface.

[0061] (2) Preparation of spraying materials After drying the nickel and zinc powders separately to remove moisture, they are placed in a drum mixer for mixing. The loading amount of the mixed powder is controlled to be 1 / 3 to 2 / 3 of the drum volume, the drum speed is 100 r / min, and the mixing time is 30 min. The uniformly mixed powder is then loaded into a powder feeding hopper for later use.

[0062] (3) Plasma spraying to prepare electrode precursors A plasma thermal spraying process is used to deposit mixed powder onto a pretreated substrate. The plasma is generated using direct current, with argon as the primary working gas and hydrogen as a secondary gas. The sprayed powder is heated to a molten or semi-molten state in the plasma stream, forming particles that impact the substrate at a speed of 100 m / s, forming a coating through physical bonding.

[0063] The spraying process is carried out in three coats, with the specific parameters as follows: First coat: The mass ratio of nickel to zinc is 2:1, the nickel powder particle size is 100~150 mesh, the zinc powder particle size is 50~100 mesh, and the thickness of this layer is controlled to be 10μm; Second coat: The mass ratio of nickel to zinc is 1:2, the particle size of nickel powder is 150~250 mesh, the particle size of zinc powder is 100~200 mesh, and the thickness of this layer is controlled to be 10μm; The third coat: the mass ratio of nickel to zinc is 1:3, the nickel powder particle size is 250~350 mesh, the zinc powder particle size is 200~300 mesh, and the thickness of this layer is controlled to be 10μm.

[0064] After spraying, the resulting coating is heat-treated to obtain an electrode precursor containing a nickel-zinc coating. The heat treatment steps for the coating are the same as in Example 1.

[0065] (4) Electrolytic cell assembly and activation treatment The obtained hydrogen evolution electrode precursor was used as the cathode and assembled with the oxygen evolution electrode, diaphragm, electrode plate, gasket, and fasteners to form a pressure filter bipolar plate electrolyzer. This electrolyzer was connected on-site to auxiliary equipment such as a gas-liquid processor, a water-alkali tank, and steam pipelines. The system was purged with nitrogen until the oxygen content was below 0.5%. An activation solution (a mixed aqueous solution of 25% potassium hydroxide and 5% sodium potassium tartrate) was prepared in the water-alkali tank and injected into the system using a pump. A circulation pump was started to circulate the activation solution, and a steam heat exchanger was activated to heat the solution. After activation, the activation solution was discharged with nitrogen, and then the operating electrolyte was injected, allowing for formal production operation. During the above activation process, the electrode did not come into contact with oxygen, ensuring high electrode activity. In-situ activation within the electrolyzer under oxygen-isolated conditions yielded an electrolyzer containing a hydrogen evolution electrode.

[0066] The electrolytic cell was stably powered on and operated under alkaline solution temperature of 80℃ and operating pressure of 1.5 MPa. Different current densities were set, and the average value of the small chamber voltage was measured and recorded.

[0067] Tests showed that the electrolytic cell operated at a current density of 600 A / m 2 At that time, the operating voltage was 1.4 V; at a current density of 7000 A / m 2 At that time, the operating voltage is 2.0 V.

[0068] Example 4 A 46-mesh 316L stainless steel woven mesh was selected as the electrode substrate. The woven mesh is made of stainless steel wire with a diameter of 0.25 mm and a mesh size of 0.302 mm.

[0069] (1) Surface pretreatment The electrode substrate is placed on the conveyor belt of the sandblasting machine and transported through the sandblasting chamber. The sandblasting chamber is equipped with two sets of sandblasting heads, with a 90° angle between their spray directions and a 45° angle between the sandblasting head and the substrate surface. The sandblasting heads reciprocate to ensure complete coverage of the substrate surface.

[0070] The sandblasting process is conducted in two stages: the first stage uses abrasive grains with an equivalent diameter of 10 times the pore diameter of the substrate, and the second stage uses abrasive grains with a maximum equivalent diameter of 0.5 times the pore diameter of the substrate. The abrasive grains are ejected at high speed under the action of compressed air, impacting and removing the oxide layer on the substrate surface while simultaneously roughening the surface. After pretreatment, the macroscopic roughness of the substrate surface reaches Ra 40 μm, and the microscopic roughness reaches Ra 0.1 μm. After sandblasting, compressed air is used to blow away residual dust particles from the substrate surface.

[0071] (2) Preparation of spraying materials After drying the nickel and zinc powders separately to remove moisture, they are placed in a drum mixer for mixing. The loading amount of the mixed powder is controlled to be 1 / 3 to 2 / 3 of the drum volume, the drum speed is 100 r / min, and the mixing time is 30 min. The uniformly mixed powder is then loaded into a powder feeding hopper for later use.

[0072] (3) Plasma spraying to prepare electrode precursors A plasma thermal spraying process is used to deposit mixed powder onto a pretreated substrate. The plasma is generated using direct current, with argon as the primary working gas and hydrogen as a secondary gas. The sprayed powder is heated to a molten or semi-molten state in the plasma stream, forming particles that impact the substrate at a speed of 100 m / s, forming a coating through physical bonding.

[0073] The spraying process is carried out in three coats, with the specific parameters as follows: First coat: The mass ratio of nickel to zinc is 2:1, the nickel powder particle size is 100~150 mesh, the zinc powder particle size is 50~100 mesh, and the thickness of this layer is controlled to be 10μm; Second coat: The mass ratio of nickel to zinc is 1:2, the particle size of nickel powder is 150~250 mesh, the particle size of zinc powder is 100~200 mesh, and the thickness of this layer is controlled to be 10μm; The third coat: the mass ratio of nickel to zinc is 1:3, the nickel powder particle size is 250~350 mesh, the zinc powder particle size is 200~300 mesh, and the thickness of this layer is controlled to be 10μm.

[0074] After spraying, the resulting coating is heat-treated to obtain an electrode precursor containing a nickel-zinc coating. The heat treatment steps for the coating are the same as in Example 1.

[0075] (4) Electrolytic cell assembly and activation treatment The assembly and activation of the electrolyzer were carried out in accordance with Example 3 to obtain an electrolyzer containing a hydrogen evolution electrode.

[0076] The electrolytic cell was stably powered on and operated under alkaline solution temperature of 80℃ and operating pressure of 1.5 MPa. Different current densities were set, and the average value of the small chamber voltage was measured and recorded.

[0077] Tests showed that the electrolytic cell operated at a current density of 640 A / m 2 At that time, the operating voltage was 1.4 V; at a current density of 6500 A / m 2 At that time, the operating voltage is 2.0 V.

[0078] Example 5 Nickel plate mesh was selected as the electrode substrate. The long pitch of the nickel plate mesh was 3 mm, the short pitch was 2 mm, the wire width was 0.5 mm, and the wire thickness was 0.5 mm.

[0079] (1) Surface pretreatment The electrode substrate is placed on the conveyor belt of the sandblasting machine and transported through the sandblasting chamber. The sandblasting chamber is equipped with two sets of sandblasting heads, with a 90° angle between their spray directions and a 45° angle between the sandblasting heads and the substrate surface. The sandblasting heads reciprocate to ensure complete coverage of the substrate surface.

[0080] The sandblasting process is conducted in two stages: the first stage uses abrasive grains with an equivalent diameter of 10 times the pore diameter of the substrate, and the second stage uses abrasive grains with a maximum equivalent diameter of 0.5 times the pore diameter of the substrate. The abrasive grains are ejected at high speed under the action of compressed air, impacting and removing the oxide layer on the substrate surface while simultaneously roughening the surface. After pretreatment, the macroscopic roughness of the substrate surface reaches Ra 40 μm, and the microscopic roughness reaches Ra 0.1 μm. After sandblasting, compressed air is used to blow away residual dust particles from the substrate surface.

[0081] (2) Preparation of spraying materials After drying the nickel and zinc powders separately to remove moisture, they are placed in a drum mixer for mixing. The loading amount of the mixed powder is controlled to be 1 / 3 to 2 / 3 of the drum volume, the drum speed is 100 r / min, and the mixing time is 30 min. The uniformly mixed powder is then loaded into a powder feeding hopper for later use.

[0082] (3) Plasma spraying to prepare electrode precursors A plasma thermal spraying process is used to deposit mixed powder onto a pretreated substrate. The plasma is generated using direct current, with argon as the primary working gas and hydrogen as a secondary gas. The sprayed powder is heated to a molten or semi-molten state in the plasma stream, forming particles that impact the substrate at a speed of 100 m / s, forming a coating through physical bonding.

[0083] The spraying process is carried out in three coats, with the specific parameters as follows: First coat: The mass ratio of nickel to zinc is 2:1, the nickel powder particle size is 100~150 mesh, the zinc powder particle size is 50~100 mesh, and the thickness of this layer is controlled to be 10μm; Second coat: The mass ratio of nickel to zinc is 1:2, the particle size of nickel powder is 150~250 mesh, the particle size of zinc powder is 100~200 mesh, and the thickness of this layer is controlled to be 10μm; The third coat: the mass ratio of nickel to zinc is 1:3, the nickel powder particle size is 250~350 mesh, the zinc powder particle size is 200~300 mesh, and the thickness of this layer is controlled to be 10μm.

[0084] After spraying, the resulting coating is heat-treated to obtain a hydrogen evolution electrode precursor containing a nickel-zinc coating. The heat treatment steps for the coating are the same as in Example 1.

[0085] (4) Electrolytic cell assembly and activation treatment The assembly and activation of the electrolyzer were carried out in accordance with Example 3 to obtain an electrolyzer containing a hydrogen evolution electrode.

[0086] The electrolytic cell was stably powered on and operated under alkaline solution temperature of 80℃ and operating pressure of 1.5 MPa. Different current densities were set, and the average value of the small chamber voltage was measured and recorded.

[0087] Tests showed that the electrolytic cell operated at a current density of 560 A / m 2 At that time, the operating voltage was 1.4 V; at a current density of 6400 A / m 2 At that time, the operating voltage is 2.0 V.

[0088] Example 6 A nickel perforated plate was selected as the electrode substrate. The nickel plate was 0.5 mm thick and had evenly distributed round holes with a diameter of 3 mm and a center-to-center distance of 5 mm.

[0089] (1) Surface pretreatment The electrode substrate is placed on the conveyor belt of the sandblasting machine and transported through the sandblasting chamber. The sandblasting chamber is equipped with two sets of sandblasting heads, with a 90° angle between their spray directions and a 45° angle between the sandblasting heads and the substrate surface. The sandblasting heads reciprocate to ensure complete coverage of the substrate surface.

[0090] The sandblasting process is conducted in two stages: the first stage uses abrasive grains with an equivalent diameter of 10 times the pore diameter of the substrate, and the second stage uses abrasive grains with a maximum equivalent diameter of 0.5 times the pore diameter of the substrate. The abrasive grains are ejected at high speed under the action of compressed air, impacting and removing the oxide layer on the substrate surface while simultaneously roughening the surface. After pretreatment, the macroscopic roughness of the substrate surface reaches Ra 40 μm, and the microscopic roughness reaches Ra 0.1 μm. After sandblasting, compressed air is used to blow away residual dust particles from the substrate surface.

[0091] (2) Preparation of spraying materials After drying the nickel and zinc powders separately to remove moisture, they are placed in a drum mixer for mixing. The loading amount of the mixed powder is controlled to be 1 / 3 to 2 / 3 of the drum volume, the drum speed is 100 r / min, and the mixing time is 30 min. The uniformly mixed powder is then loaded into a powder feeding hopper for later use.

[0092] (3) Plasma spraying to prepare electrode precursors A plasma thermal spraying process is used to deposit mixed powder onto a pretreated substrate. The plasma is generated using direct current, with argon as the primary working gas and hydrogen as a secondary gas. The sprayed powder is heated to a molten or semi-molten state in the plasma stream, forming particles that impact the substrate at a speed of 100 m / s, forming a coating through physical bonding.

[0093] The spraying process is carried out in three coats, with the specific parameters as follows: First coat: The mass ratio of nickel to zinc is 2:1, the nickel powder particle size is 100~150 mesh, the zinc powder particle size is 50~100 mesh, and the thickness of this layer is controlled to be 10μm; Second coat: The mass ratio of nickel to zinc is 1:2, the particle size of nickel powder is 150~250 mesh, the particle size of zinc powder is 100~200 mesh, and the thickness of this layer is controlled to be 10μm; The third coat: the mass ratio of nickel to zinc is 1:3, the nickel powder particle size is 250~350 mesh, the zinc powder particle size is 200~300 mesh, and the thickness of this layer is controlled to be 10μm.

[0094] After spraying, the resulting coating is heat-treated to obtain a hydrogen evolution electrode precursor containing a nickel-zinc coating. The heat treatment steps for the coating are the same as in Example 1.

[0095] (4) Electrolytic cell assembly and activation treatment The assembly and activation of the electrolyzer were carried out in accordance with Example 3 to obtain an electrolyzer containing a hydrogen evolution electrode.

[0096] The electrolytic cell was stably powered on and operated under alkaline solution temperature of 80℃ and operating pressure of 1.5 MPa. Different current densities were set, and the average value of the small chamber voltage was measured and recorded.

[0097] Tests showed that the electrolytic cell operated at a current density of 540 A / m 2 At that time, the operating voltage was 1.4 V; at a current density of 6500 A / m 2 At that time, the operating voltage is 2.0 V.

[0098] Example 7 This embodiment is basically the same as embodiment 1, except that the spraying process is divided into four passes. The first three passes are consistent with embodiment 1. The mass ratio of nickel to zinc in the fourth pass is 3:1. The nickel powder particle size is 250~350 mesh, the zinc powder particle size is 200~300 mesh, and the coating thickness of the fourth pass is 10 μm.

[0099] The electrodes prepared in this embodiment and the electrode of Example 1 were tested for ultrasonic weight loss according to the ultrasonic testing method specified in GB / T 45092 standard. The weight loss of the electrode in Example 1 was 1.8 mg / cm³. 2 In this embodiment, the electrode weight loss is 0.7 mg / cm³. 2 Therefore, it can be seen that by adding a fourth coating layer, the vibration and erosion resistance of the electrode is significantly improved in this embodiment.

[0100] Example 8 This embodiment is basically the same as embodiment 2, except that the spraying process is divided into four passes. The first three passes are consistent with embodiment 2. The mass ratio of nickel to zinc in the fourth pass is 4:1. The nickel powder particle size is 250~350 mesh, the zinc powder particle size is 200~300 mesh, and the coating thickness of the fourth pass is 5 μm.

[0101] The electrode prepared in this embodiment and the electrode in Example 2 were tested for ultrasonic weight loss according to the ultrasonic testing method specified in GB / T 45092 standard. The weight loss of the electrode in Example 2 was 1.78 mg / cm³. 2 In this embodiment, the electrode weight loss is 1.2 mg / cm³. 2 Therefore, it can be seen that by adding a fourth coating layer, the vibration and erosion resistance of the electrode is significantly improved in this embodiment.

[0102] Example 9 This embodiment is basically the same as embodiment 3, except that the spraying process is divided into four passes. The first three passes are consistent with embodiment 3. The mass ratio of nickel to zinc in the fourth pass is 4:1. The nickel powder particle size is 250~350 mesh, the zinc powder particle size is 200~300 mesh, and the coating thickness of the fourth pass is 5 μm.

[0103] The electrodes prepared in this embodiment and the electrode in Example 3 were tested for ultrasonic weight loss according to the ultrasonic testing method specified in GB / T 45092 standard. The weight loss of the electrode in Example 3 was 1.77 mg / cm³. 2 In this embodiment, the electrode weight loss is 0.8 mg / cm³. 2 Therefore, it can be seen that by adding a fourth coating layer, the vibration and erosion resistance of the electrode is significantly improved in this embodiment.

[0104] Example 10 This embodiment is basically the same as embodiment 4, except that the spraying process is divided into four passes. The first three passes are consistent with embodiment 4. The mass ratio of nickel to zinc in the fourth pass is 5:1. The nickel powder particle size is 250~350 mesh, the zinc powder particle size is 200~300 mesh, and the coating thickness of the fourth pass is 1 μm.

[0105] The electrodes prepared in this embodiment and the electrode in Example 4 were tested for ultrasonic weight loss according to the ultrasonic testing method specified in GB / T 45092 standard. The weight loss of the electrode in Example 4 was 1.75 mg / cm³. 2 In this embodiment, the electrode weight loss is 1.0 mg / cm³. 2 Therefore, it can be seen that by adding a fourth coating layer, the vibration and erosion resistance of the electrode is significantly improved in this embodiment.

[0106] Example 11 This embodiment is basically the same as embodiment 5, except that the spraying process is divided into four passes. The first three passes are consistent with embodiment 5. The mass ratio of nickel to zinc in the fourth pass is 5:1. The nickel powder particle size is 250~350 mesh, the zinc powder particle size is 200~300 mesh, and the coating thickness of the fourth pass is 1 μm.

[0107] The electrodes prepared in this embodiment and the electrode in Example 5 were tested for ultrasonic weight loss according to the ultrasonic testing method specified in GB / T 45092 standard. The weight loss of the electrode in Example 5 was 1.8 mg / cm³. 2 In this embodiment, the electrode weight loss is 1.1 mg / cm³. 2 Therefore, it can be seen that by adding a fourth coating layer, the vibration and erosion resistance of the electrode is significantly improved in this embodiment.

[0108] Example 12 This embodiment is basically the same as embodiment 6, except that the spraying process is divided into four passes. The first three passes are consistent with embodiment 6. The mass ratio of nickel to zinc in the fourth pass is 5:1. The nickel powder particle size is 250~350 mesh, the zinc powder particle size is 200~300 mesh, and the coating thickness of the fourth pass is 1 μm.

[0109] The electrodes prepared in this embodiment and the electrode in Example 6 were tested for ultrasonic weight loss according to the ultrasonic testing method specified in GB / T 45092 standard. The weight loss of the electrode in Example 6 was 1.74 mg / cm³. 2 In this embodiment, the electrode weight loss is 1.1 mg / cm³. 2 Therefore, it can be seen that by adding a fourth coating layer, the vibration and erosion resistance of the electrode is significantly improved in this embodiment.

[0110] Example 13 A nickel powder sintered porous plate was selected as the electrode substrate. The porous plate was 1 mm thick, with a porosity of 30% and an equivalent pore size of 30 μm.

[0111] (1) Surface pretreatment The electrode substrate is placed in a degreasing solution, preferably using cathode current electrolysis for degreasing, with the current density controlled at 5~10 A / dm³. 2 The electrode substrate was degreased for 10 minutes. The degreasing solution consisted of 11.5 g / L anhydrous sodium carbonate, 50 g / L sodium phosphate, 9.2 g / L sodium silicate nonahydrate, and 36 g / L potassium hydroxide. After degreasing, the electrode substrate was transferred to a 60°C hot water bath for 2 minutes, followed by a 1-minute rinse in a cold water bath. It was then placed in a 5% hydrochloric acid pickling bath for 5 minutes, and subsequently rinsed in two separate water washing baths for 2 minutes each. Finally, the electrode substrate was removed, dried with an air knife, and stored for later use.

[0112] (2) Preparation of spraying materials After drying the nickel and zinc powders separately to remove moisture, they are placed in a drum mixer for mixing. The loading amount of the mixed powder is controlled to be 1 / 3 to 2 / 3 of the drum volume, the drum speed is 100 r / min, and the mixing time is 30 min. The uniformly mixed powder is then loaded into a powder feeding hopper for later use.

[0113] (3) Plasma spraying to prepare electrode precursors A plasma thermal spraying process is used to deposit mixed powder onto a pretreated substrate. The plasma is generated using direct current, with argon as the primary working gas and hydrogen as a secondary gas. The sprayed powder is heated to a molten or semi-molten state in the plasma stream, forming particles that impact the substrate at a speed of 100 m / s, forming a coating through physical bonding.

[0114] The spraying process is carried out in four coats, with the specific parameters as follows: First coat: The mass ratio of nickel to zinc is 2:1, the nickel powder particle size is 100~150 mesh, the zinc powder particle size is 50~100 mesh, and the thickness of this layer is controlled to be 10μm; Second coat: The mass ratio of nickel to zinc is 1:2, the particle size of nickel powder is 150~250 mesh, the particle size of zinc powder is 100~200 mesh, and the thickness of this layer is controlled to be 10μm; The third coat: the mass ratio of nickel to zinc is 1:3, the particle size of nickel powder is 250~350 mesh, the particle size of zinc powder is 200~300 mesh, and the thickness of this layer is controlled to be 10μm; Fourth coat: The mass ratio of nickel to zinc is 3:1, the particle size of nickel powder is 250~350 mesh, the particle size of zinc powder is 200~300 mesh, and the thickness of the fourth coat is 10 μm.

[0115] After spraying, the resulting coating is heat-treated to obtain a hydrogen evolution electrode precursor containing a nickel-zinc coating. The heat treatment steps for the coating are the same as in Example 1.

[0116] (4) Electrolytic cell assembly and activation treatment The assembly and activation of the electrolyzer were carried out in accordance with Example 3 to obtain an electrolyzer containing a hydrogen evolution electrode.

[0117] The electrolytic cell was stably powered on and operated under alkaline solution temperature of 80℃ and operating pressure of 1.5 MPa. Different current densities were set, and the average value of the small chamber voltage was measured and recorded.

[0118] Tests showed that the electrolytic cell operated at a current density of 650 A / m 2 At that time, the operating voltage was 1.4 V; at a current density of 7300 A / m 2 At that time, the operating voltage is 2.0 V.

[0119] Example 14 Nickel foam was selected as the electrode substrate. The nickel foam thickness was 2 mm and the areal density was 400 g / m³. 2 110 PPI.

[0120] (1) Surface pretreatment The electrode substrate is placed in a degreasing solution, preferably using cathode current electrolysis for degreasing, with the current density controlled at 5~10 A / dm³. 2 The electrode substrate was degreased for 10 minutes. The degreasing solution consisted of 11.5 g / L anhydrous sodium carbonate, 50 g / L sodium phosphate, 9.2 g / L sodium silicate nonahydrate, and 36 g / L potassium hydroxide. After degreasing, the electrode substrate was transferred to a 60°C hot water bath for 2 minutes, followed by a 1-minute rinse in a cold water bath. It was then placed in a 5% hydrochloric acid pickling bath for 5 minutes, and subsequently rinsed in two separate water washing baths for 2 minutes each. Finally, the electrode substrate was removed, dried with an air knife, and stored for later use.

[0121] (2) Preparation of spraying materials After drying the nickel and zinc powders separately to remove moisture, they are placed in a drum mixer for mixing. The loading amount of the mixed powder is controlled to be 1 / 3 to 2 / 3 of the drum volume, the drum speed is 100 r / min, and the mixing time is 30 min. The uniformly mixed powder is then loaded into a powder feeding hopper for later use.

[0122] (3) Plasma spraying to prepare electrode precursors A plasma thermal spraying process is used to deposit mixed powder onto a pretreated substrate. The plasma is generated using direct current, with argon as the primary working gas and hydrogen as a secondary gas. The sprayed powder is heated to a molten or semi-molten state in the plasma stream, forming particles that impact the substrate at a speed of 100 m / s, forming a coating through physical bonding.

[0123] The spraying process is carried out in four coats, with the specific parameters as follows: First coat: The mass ratio of nickel to zinc is 2:1, the nickel powder particle size is 100~150 mesh, the zinc powder particle size is 50~100 mesh, and the thickness of this layer is controlled to be 10μm; Second coat: The mass ratio of nickel to zinc is 1:2, the particle size of nickel powder is 150~250 mesh, the particle size of zinc powder is 100~200 mesh, and the thickness of this layer is controlled to be 10μm; The third coat: the mass ratio of nickel to zinc is 1:3, the particle size of nickel powder is 250~350 mesh, the particle size of zinc powder is 200~300 mesh, and the thickness of this layer is controlled to be 10μm; Fourth coat: The mass ratio of nickel to zinc is 4:1, the nickel powder particle size is 250~350 mesh, the zinc powder particle size is 200~300 mesh, and the thickness of the fourth coat is 5 μm.

[0124] After spraying, the resulting coating is heat-treated to obtain a hydrogen evolution electrode precursor containing a nickel-zinc coating. The heat treatment steps for the coating are the same as in Example 1.

[0125] (4) Electrolytic cell assembly and activation treatment The assembly and activation of the electrolyzer were carried out in accordance with Example 3 to obtain an electrolyzer containing a hydrogen evolution electrode.

[0126] The electrolytic cell was stably powered on and operated under alkaline solution temperature of 80℃ and operating pressure of 1.5 MPa. Different current densities were set, and the average value of the small chamber voltage was measured and recorded.

[0127] Tests showed that the electrolytic cell operated at a current density of 620 A / m 2 At that time, the operating voltage was 1.4 V; at a current density of 6700 A / m 2 At that time, the operating voltage is 2.0 V.

[0128] Example 15 Nickel foam was selected as the electrode substrate. The nickel foam thickness was 2 mm and the areal density was 400 g / m³. 2 110 PPI.

[0129] (1) Surface pretreatment The electrode substrate is placed in a degreasing solution, preferably using cathode current electrolysis for degreasing, with the current density controlled at 5~10 A / dm³. 2 The electrode substrate was degreased for 10 minutes. The degreasing solution consisted of 11.5 g / L anhydrous sodium carbonate, 50 g / L sodium phosphate, 9.2 g / L sodium silicate nonahydrate, and 36 g / L potassium hydroxide. After degreasing, the electrode substrate was transferred to a 60°C hot water bath for 2 minutes, followed by a 1-minute rinse in a cold water bath. It was then placed in a 5% hydrochloric acid electrolysis tank for 1 minute of acid electrolysis at a current density of 5 A / dm³. 2 Then, the electrode substrate is transferred to two water washing tanks and washed for 2 minutes each. Finally, the electrode substrate is removed, dried by air knife, and then put into use.

[0130] (2) Preparation of spraying materials After drying the nickel and zinc powders separately to remove moisture, they are placed in a drum mixer for mixing. The loading amount of the mixed powder is controlled to be 1 / 3 to 2 / 3 of the drum volume, the drum speed is 100 r / min, and the mixing time is 30 min. The uniformly mixed powder is then loaded into a powder feeding hopper for later use.

[0131] (3) Plasma spraying to prepare electrode precursors A plasma thermal spraying process is used to deposit mixed powder onto a pretreated substrate. The plasma is generated using direct current, with argon as the primary working gas and hydrogen as a secondary gas. The sprayed powder is heated to a molten or semi-molten state in the plasma stream, forming particles that impact the substrate at a speed of 100 m / s, forming a coating through physical bonding.

[0132] The spraying process is carried out in four coats, with the specific parameters as follows: First coat: The mass ratio of nickel to zinc is 2:1, the nickel powder particle size is 100~150 mesh, the zinc powder particle size is 50~100 mesh, and the thickness of this layer is controlled to be 10μm; Second coat: The mass ratio of nickel to zinc is 1:2, the particle size of nickel powder is 150~250 mesh, the particle size of zinc powder is 100~200 mesh, and the thickness of this layer is controlled to be 10μm; The third coat: the mass ratio of nickel to zinc is 1:3, the particle size of nickel powder is 250~350 mesh, the particle size of zinc powder is 200~300 mesh, and the thickness of this layer is controlled to be 10μm; Fourth coat: The mass ratio of nickel to zinc is 5:1, the particle size of nickel powder is 250~350 mesh, the particle size of zinc powder is 200~300 mesh, and the thickness of the fourth coat is 1 μm.

[0133] After spraying, the resulting coating is heat-treated to obtain a hydrogen evolution electrode precursor containing a nickel-zinc coating. The heat treatment steps for the coating are the same as in Example 1.

[0134] (4) Electrolytic cell assembly and activation treatment The assembly and activation of the electrolyzer were carried out in accordance with Example 3 to obtain an electrolyzer containing a hydrogen evolution electrode.

[0135] The electrolytic cell was stably powered on and operated under alkaline solution temperature of 80℃ and operating pressure of 1.5 MPa. Different current densities were set, and the average value of the small chamber voltage was measured and recorded.

[0136] Tests showed that the electrolytic cell operated at a current density of 650 A / m 2 At that time, the operating voltage was 1.4 V; at a current density of 7100 A / m 2 At that time, the operating voltage is 2.0 V.

[0137] Example 16 Nickel braided mesh and nickel plate stretched mesh are combined together as the electrode substrate. The electrode substrate is 5mm thick. The braided mesh is three-dimensionally woven with a thickness of 4.8mm, and the plate stretched mesh is 0.2mm thick. The long pitch of the plate mesh is 3mm, the short pitch is 2mm, the strand width is 0.5mm, and the strand thickness is 0.2mm.

[0138] (1) Surface pretreatment The electrode substrate is placed on the conveyor belt of the sandblasting machine and transported through the sandblasting chamber. The sandblasting chamber is equipped with two sets of sandblasting heads, with a 90° angle between their spray directions and a 45° angle between the sandblasting heads and the substrate surface. The sandblasting heads reciprocate to ensure complete coverage of the substrate surface.

[0139] The sandblasting process is conducted in two stages: the first stage uses abrasive grains with an equivalent diameter of 10 times the substrate pore diameter (0.125 mm), and the second stage uses abrasive grains with a maximum equivalent diameter of 0.5 times the substrate pore diameter. The abrasive grains are ejected at high speed under the action of compressed air, impacting and removing the oxide layer on the substrate surface while simultaneously roughening the surface. After pretreatment, the macroscopic surface roughness of the substrate reaches Ra 40 μm, and the microscopic surface roughness reaches Ra 0.1 μm. After sandblasting, compressed air is used to blow away residual dust particles from the substrate surface.

[0140] The sandblasted electrode substrate is placed in a degreasing solution, preferably using cathode current electrolysis for degreasing, with the current density controlled at 5~10 A / dm³. 2 The electrode substrate was degreased for 10 minutes. The degreasing solution consisted of 11.5 g / L anhydrous sodium carbonate, 50 g / L sodium phosphate, 9.2 g / L sodium silicate nonahydrate, and 36 g / L potassium hydroxide. After degreasing, the electrode substrate was transferred to a 60°C hot water bath for 2 minutes, followed by a 1-minute rinse in a cold water bath. It was then transferred to a 5% hydrochloric acid electrolysis tank for 1 minute of acid electrolysis at a current density of 5 A / dm³. 2 Then, the electrode substrate is transferred to two water washing tanks and washed for 2 minutes each. Finally, the electrode substrate is removed, dried by air knife, and then put into use.

[0141] (2) Preparation of spraying materials After drying and removing moisture, the nickel-zinc alloy powder (the main component of the alloy is NiZn3) is placed in a powder feeding hopper for later use.

[0142] (3) Plasma spraying to prepare electrode precursors A plasma thermal spraying process is used to deposit mixed powder onto a pretreated substrate. The plasma is generated using direct current, with argon as the primary working gas and hydrogen as a secondary gas. The sprayed powder is heated to a molten or semi-molten state in the plasma stream, forming particles that impact the substrate at a velocity of 100 m / s, forming a coating through physical bonding. The coating thickness is controlled to be 30 μm.

[0143] After spraying, the resulting coating is heat-treated to obtain a hydrogen evolution electrode precursor containing a nickel-zinc coating. The heat treatment steps for the coating are the same as in Example 1.

[0144] (4) Electrolytic cell assembly and activation treatment The assembly and activation of the electrolyzer were carried out in accordance with Example 3 to obtain an electrolyzer containing a hydrogen evolution electrode.

[0145] The electrolytic cell was stably powered on and operated under alkaline solution temperature of 80℃ and operating pressure of 1.5 MPa. Different current densities were set, and the average value of the small chamber voltage was measured and recorded.

[0146] Tests showed that the electrolytic cell operated at a current density of 670 A / m 2 At that time, the operating voltage was 1.4 V; at a current density of 7500 A / m 2 At that time, the operating voltage is 2.0 V.

[0147] Example 17 Nickel braided mesh and nickel plate stretched mesh are combined together as the electrode substrate. The electrode substrate is 5mm thick. The braided mesh is three-dimensionally woven with a thickness of 4.8mm, and the plate stretched mesh is 0.2mm thick. The long pitch of the plate mesh is 3mm, the short pitch is 2mm, the strand width is 0.5mm, and the strand thickness is 0.2mm.

[0148] (1) Surface pretreatment The electrode substrate is placed on the conveyor belt of the sandblasting machine and transported through the sandblasting chamber. The sandblasting chamber is equipped with two sets of sandblasting heads, with a 90° angle between their spray directions and a 45° angle between the sandblasting heads and the substrate surface. The sandblasting heads reciprocate to ensure complete coverage of the substrate surface.

[0149] The sandblasting process is conducted in two stages: the first stage uses abrasive grains with an equivalent diameter of 10 times the pore diameter of the substrate, and the second stage uses abrasive grains with a maximum equivalent diameter of 0.5 times the pore diameter of the substrate. The abrasive grains are ejected at high speed under the action of compressed air, impacting and removing the oxide layer on the substrate surface while simultaneously roughening the surface. After pretreatment, the macroscopic roughness of the substrate surface reaches Ra 40 μm, and the microscopic roughness reaches Ra 0.1 μm. After sandblasting, compressed air is used to blow away residual dust particles from the substrate surface.

[0150] The sandblasted electrode substrate is placed in a degreasing solution, preferably using cathode current electrolysis for degreasing, with the current density controlled at 5~10 A / dm³. 2 The electrode substrate was degreased for 10 minutes. The degreasing solution consisted of 11.5 g / L anhydrous sodium carbonate, 50 g / L sodium phosphate, 9.2 g / L sodium silicate nonahydrate, and 36 g / L potassium hydroxide. After degreasing, the electrode substrate was transferred to a 60°C hot water bath for 2 minutes, followed by a 1-minute rinse in a cold water bath. It was then transferred to a 5% hydrochloric acid electrolysis tank for 1 minute of acid electrolysis at a current density of 5 A / dm³. 2 Then, the electrode substrate is transferred to two water washing tanks and washed for 2 minutes each. Finally, the electrode substrate is removed, dried by air knife, and then put into use.

[0151] (2) Preparation of electrode precursor by flame spraying The flame spraying method is adopted: the fuel is mainly methane gas with hydrogen as an auxiliary gas and oxygen as the combustion-supporting gas; the nickel-zinc alloy wire is heated to a molten or semi-molten state under the action of the flame, forming particles that impact the substrate at a speed of 80 m / s, forming a coating through physical bonding, and the coating thickness is controlled to be 30 μm.

[0152] After spraying, the resulting coating is heat-treated to obtain a hydrogen evolution electrode precursor containing a nickel-zinc coating. The heat treatment steps for the coating are the same as in Example 1.

[0153] (3) Electrolytic cell assembly and activation treatment The assembly and activation of the electrolyzer were carried out in accordance with Example 3 to obtain an electrolyzer containing a hydrogen evolution electrode.

[0154] The electrolytic cell was stably powered on and operated under alkaline solution temperature of 80℃ and operating pressure of 1.5 MPa. Different current densities were set, and the average value of the small chamber voltage was measured and recorded.

[0155] Tests showed that the electrolytic cell operated at a current density of 620 A / m 2 At that time, the operating voltage was 1.4 V; at a current density of 6500 A / m 2 At that time, the operating voltage is 2.0 V.

[0156] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a nickel-zinc hydrogen evolution electrode, characterized in that, Includes the following steps: Surface pretreatment of the electrode substrate; A nickel-zinc composite coating is formed by loading a nickel source and a zinc source onto the electrode substrate after surface pretreatment using a thermal spraying process, thus obtaining an electrode precursor. The zinc portion in the electrode precursor is removed to obtain a nickel-zinc hydrogen evolution electrode.

2. The method for preparing the nickel-zinc hydrogen evolution electrode according to claim 1, characterized in that, The surface pretreatment includes one or more of the following processes: sandblasting, electrolysis, degreasing, hot water washing, water washing, pickling, and acid electrolysis.

3. The method for preparing the nickel-zinc hydrogen evolution electrode according to claim 2, characterized in that, The sandblasting includes: The first stage of sandblasting uses abrasive with a minimum equivalent diameter larger than the pore size of the electrode substrate to roughen the substrate surface; The second stage of sandblasting uses abrasive with a maximum equivalent diameter smaller than the aperture of the electrode substrate to perform fine cleaning on the substrate surface.

4. The method for preparing the nickel-zinc hydrogen evolution electrode according to claim 3, characterized in that, The minimum equivalent diameter of the abrasive used in the first stage of sandblasting is more than twice the aperture of the electrode substrate; the maximum equivalent diameter of the abrasive used in the second stage of sandblasting is less than 0.7 times the aperture of the electrode substrate.

5. The method for preparing the nickel-zinc hydrogen evolution electrode according to claim 1, characterized in that, The nickel source is selected from nickel wire, nickel powder, nickel-zinc alloy wire, or nickel-zinc alloy powder; the zinc source is selected from zinc wire, zinc powder, nickel-zinc alloy wire, or nickel-zinc alloy powder. The thermal spraying process is selected from plasma spraying or flame spraying; The velocity of nickel-zinc particles during the spraying process is 50~500m / s; After the thermal spraying process is completed, the coating is further subjected to heat treatment.

6. The method for preparing the nickel-zinc hydrogen evolution electrode according to claim 5, characterized in that, The thermal spraying process includes: For the first coat, the nickel-zinc mass ratio is 3:1 to 2:1, the nickel powder particle size is 100 to 150 mesh, and the zinc powder particle size is 50 to 100 mesh. For the second coat, the nickel-zinc mass ratio is 2:1 to 1:2, the nickel powder particle size is 150 to 250 mesh, and the zinc powder particle size is 100 to 200 mesh. For the third coat, the nickel-zinc mass ratio is 1:2 to 1:3, the nickel powder particle size is 250 to 350 mesh, and the zinc powder particle size is 200 to 300 mesh.

7. The method for preparing the nickel-zinc hydrogen evolution electrode according to claim 6, characterized in that, The thermal spraying process also includes using raw materials with a high nickel-zinc ratio for surface spraying; the nickel-zinc mass ratio of the surface spraying load is 3:1 to 5:1, the particle size of the nickel powder is 250 to 350 mesh, the particle size of the zinc powder is 200 to 300 mesh, and the thickness of the surface spraying coating is 0.5 to 10 micrometers.

8. The method for preparing the nickel-zinc hydrogen evolution electrode according to claim 1, characterized in that, The partial zinc removal step includes immersing the electrode precursor in an activation solution for chemical zinc removal, or assembling the electrode precursor into an electrolytic cell for in-situ activation under oxygen-free conditions.

9. A hydrogen evolution electrode, characterized in that, The electrode is prepared by any one of the preparation methods described in claims 1 to 8, and includes an electrode substrate and a nickel-zinc composite coating attached to the surface of the electrode substrate.

10. An electrolytic cell, comprising an anode, a cathode, a diaphragm, and an electrolyte, characterized in that, The cathode is the hydrogen evolution electrode as described in claim 9.

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