Preparation method of catalyst based on synergy of porous nickel framework structure, electrodeposition and electroactivation

Abstract

The application discloses a catalyst preparation method based on Raney nickel porous framework structure cooperation electrodeposition and electroactivation, adopts mechanical heat treatment technology to form a nickel-aluminum alloy layer on the surface of a nickel mesh, carries out chemical activation treatment in an alkali solution, selectively dissolves aluminum elements, and thus constructs a Raney nickel porous framework structure; then, a nickel-iron-molybdenum-copper multi-metal active catalytic layer is constructed on the surface of the nickel mesh through an electrodeposition technology; finally, the obtained nickel-based catalyst is placed in a phosphorus-containing alkaline electrolyte to carry out electroactivation treatment, in-situ structure reconstruction and surface chemical state transformation of the multi-metal active catalytic layer on the surface of the nickel mesh are induced, and the electrode catalytic performance is further improved, and the nickel-based catalyst has great application potential in the field of alkaline electrolytic water hydrogen production.

Description

Technical Field

[0001] This invention relates to the field of water electrolysis catalyst technology, and in particular to a method for preparing a catalyst based on the synergistic electrodeposition and electroactivation of a Raney nickel porous framework structure. Background Technology

[0002] Alkaline water electrolysis for hydrogen production is currently the most commercially viable method for producing green hydrogen, and electrode materials are one of the core components determining its hydrogen production efficiency, energy consumption, and cost. Developing efficient, stable, and economically viable non-precious metal electrode catalysts, especially transition metal electrode catalysts, has become a research hotspot in the field of alkaline water electrolysis.

[0003] However, pure nickel has a limited number of intrinsic catalytic active sites, resulting in poor hydrogen evolution and oxygen evolution performance. This makes it difficult to meet the high-efficiency operation requirements of water electrolysis for hydrogen production under high current densities. Furthermore, optimizing the substrate structure or controlling the surface elemental composition often fails to balance high catalytic activity with long-term operational stability, especially under high current density and strongly alkaline corrosive environments, where the catalyst layer is prone to detachment, leading to significant performance degradation. For example, the Raney nickel electrode, which has been industrially applied, still has certain limitations. Its performance degrades significantly under high current densities, and its catalytic ability for the oxygen evolution reaction is poor, making it difficult to use as a bifunctional electrode for both the cathode and anode in alkaline washing water electrolysis. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A method for preparing a catalyst based on a Raney nickel porous framework structure through synergistic electrodeposition and electroactivation is provided, comprising the following steps:

[0006] S1. Pre-treat the nickel mesh substrate to remove the oxide layer and impurities on the surface of the nickel mesh substrate.

[0007] S2. Mix aluminum powder and nickel powder in a mass ratio of 1:1, and add 0.1wt%-5wt% ammonium chloride to the mixture. Then, evenly cover the mixture onto the dried nickel mesh substrate. Next, place the nickel mesh substrate into a tube furnace and heat treat it under argon protection at a temperature of 500℃-1000℃ for 0.5h-5h. After the heat treatment, allow it to cool naturally and brush off any residual aluminum and nickel powder from the surface of the nickel mesh to obtain the nickel-aluminum alloy layer.

[0008] S3. Immerse the nickel-aluminum alloy layer nickel mesh in an alkaline solution and chemically activate it at room temperature for 5-15 hours. Then, remove the nickel-aluminum alloy layer nickel mesh and immerse it in a fresh alkaline solution. Heat it to 50-100°C and chemically activate it for 0.5-5 hours to form a Raney nickel porous framework structure on its surface. After removing it, rinse it clean and vacuum dry it to obtain a porous framework structure Raney nickel.

[0009] S4. Dissolve nickel sulfate, ferric sulfate, copper sulfate, and ammonium molybdate in sodium sulfate electrolyte and adjust the pH to 3.0 (±0.2). Stir thoroughly until completely dissolved to prepare an electrodeposition solution with the following concentrations: sodium sulfate 0.05M-1M, nickel sulfate 0.05M-1M, ferric sulfate 1mM-100mM, copper sulfate 1mM-100mM, and ammonium molybdate 1mM-100mM. Place the nickel mesh obtained in step S3 into the electrodeposition solution and use it as the working electrode for constant potential electrodeposition to form a multi-metal active catalytic layer on the surface of the nickel mesh. After electrodeposition, rinse the nickel mesh clean and allow it to air dry.

[0010] S5. The electrodeposited nickel mesh is placed in a phosphorus-containing alkaline electrolyte for constant potential activation treatment to induce in-situ structural reconstruction and surface chemical state transformation of the multi-metal active catalytic layer on the surface of the nickel mesh; after electroactivation, it is thoroughly rinsed and naturally dried to obtain a nickel-based catalyst.

[0011] In a preferred embodiment of the present invention, in step S1, the nickel mesh substrate is a single-sided or double-sided sandblasted nickel mesh.

[0012] In a preferred embodiment of the present invention, in step S1, the pretreatment of the nickel mesh substrate includes ultrasonic cleaning in acetone, hydrochloric acid and deionized water in sequence, with the number of cycles being 1-3, and then drying in a vacuum oven.

[0013] In a preferred embodiment of the present invention, in step S1, the concentration of hydrochloric acid used in the pretreatment is 0.1M-6M; the ultrasonic cleaning time of the nickel mesh substrate in acetone, hydrochloric acid and deionized water is 5min-30min.

[0014] In a preferred embodiment of the present invention, in step S2, the particle size of aluminum powder is 20μm to 100μm, and the particle size of nickel powder is 20μm to 100μm.

[0015] In a preferred embodiment of the present invention, in step S3, the two alkaline solutions used for soaking the nickel-aluminum alloy layer nickel mesh are the same, using a sodium hydroxide or potassium hydroxide solution with a concentration of 1M-5M.

[0016] In a preferred embodiment of the present invention, in step S4, the acid used to adjust the pH is dilute sulfuric acid, dilute hydrochloric acid, or boric acid.

[0017] In a preferred embodiment of the present invention, in step S4, the constant potential electrodeposition on the porous framework Raney nickel surface is performed by applying a negative potential with a potential magnitude of 1V-10V, a deposition time of 5min-60min, and a temperature of 10℃-70℃.

[0018] In a preferred embodiment of the present invention, in step S5, the phosphorus-containing alkaline electrolyte is a mixed solution of potassium hydroxide and sodium dihydrogen phosphate, wherein the concentration of potassium hydroxide in the mixed solution is 1M~8M and the concentration of sodium dihydrogen phosphate is 0.01M~3M.

[0019] In a preferred embodiment of the present invention, in step S5, during constant potential activation, the electrodeposited nickel-based catalyst is used as the anode and the nickel photocell is used as the cathode. The applied activation potential is 1V~10V, the activation time is 1min~200min, and the activation process is carried out by water bath heating with the temperature set at 40℃-100℃.

[0020] The beneficial effects of this invention are as follows: by mechanically heat-treating a nickel-aluminum alloy and then chemically activating it, a Raney nickel porous framework structure is constructed. Based on this, electrodeposition and electro-activation are carried out to obtain a nickel-based catalyst that combines the high specific surface area of ​​the porous framework structure, the high catalytic activity of the multi-metal components, and excellent long-term operational stability. It can be used as a bifunctional electrode to simultaneously catalyze hydrogen evolution and oxygen evolution reactions, significantly reducing the production cost of anode and cathode electrode catalysts. It has good application prospects in the alkaline water electrolysis hydrogen production industry. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0022] Figure 1 These are the hydrogen evolution overpotential test results of the nickel-based catalysts in the embodiments and comparative examples of this invention;

[0023] Figure 2 These are the oxygen evolution overpotential test results of the nickel-based catalysts in the embodiments and comparative examples of this invention;

[0024] Figure 3 These are the results of the on-tank stability test of the nickel-based catalyst prepared in Example 2 of the present invention. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In recent years, those skilled in the art have attempted to further prepare multi-metal catalytic layers on the surface of Raney nickel porous frameworks via electrodeposition, such as depositing nickel-molybdenum or nickel-iron alloy layers, in order to combine the high specific surface area of ​​the porous framework structure with the high catalytic activity of the multi-metal components. However, existing preparation methods still suffer from problems such as limited interfacial bonding strength between electrodeposition and the Raney nickel structure, and difficulty in achieving precise control over the microstructure and surface chemical state of the electrode catalytic layer after electrodeposition.

[0027] The embodiments of the present invention include:

[0028] A catalyst preparation method based on Raney nickel porous framework structure synergistic electrodeposition and electroactivation effectively integrates the construction of high specific surface area porous framework structure, strong anchoring and loading of multi-metal active catalyst layer, and fine control of the chemical state of catalyst layer surface. The steps include:

[0029] S1. Pre-treat the nickel mesh substrate to remove the oxide layer and impurities on the surface of the nickel mesh substrate.

[0030] Furthermore, the nickel mesh substrate is a single-sided or double-sided sandblasted nickel mesh.

[0031] Furthermore, the pretreatment of the nickel mesh substrate includes ultrasonic cleaning in acetone, hydrochloric acid and deionized water in sequence, with the number of cycles being 1-3. After cleaning, it is placed in a vacuum oven for drying.

[0032] In some embodiments of this application, the concentration of hydrochloric acid used during pretreatment is 0.1M-6M.

[0033] In some embodiments of this application, the ultrasonic cleaning time of the nickel mesh substrate in acetone, hydrochloric acid and deionized water is 5 min to 30 min.

[0034] S2. A nickel-aluminum alloy layer is formed on the surface of the nickel mesh using mechanical heat treatment technology.

[0035] Aluminum powder (purity ≥99.5%) and nickel powder (purity ≥99.5%) are mixed at a mass ratio of 1:1, and 0.1wt%-5wt% ammonium chloride is added. The mixture is then evenly spread on a dried nickel mesh substrate. The nickel mesh substrate is then placed in a tube furnace and heat-treated under argon protection at a temperature of 500℃-1000℃ for 0.5h-5h. After the heat treatment, the mixture is allowed to cool naturally, and any residual aluminum and nickel powder on the surface of the nickel mesh is brushed off to obtain the nickel-aluminum alloy layer.

[0036] Furthermore, the particle size of the aluminum powder is 20μm to 100μm, and the particle size of the nickel powder is 20μm to 100μm.

[0037] S3. Immerse the nickel mesh with the nickel-aluminum alloy layer in an alkaline solution and perform chemical activation treatment at room temperature for 5-15 hours. Then, remove the nickel mesh with the nickel-aluminum alloy layer and immerse it in a fresh alkaline solution (the same as the previous one). Heat the solution at 50-100°C for 0.5-5 hours. Through the chemical activation treatment with the alkaline solution, aluminum is selectively dissolved, thereby constructing a porous framework structure for Raney nickel. After removing the nickel mesh, rinse it repeatedly with deionized water and vacuum dry it to obtain a porous framework structure for Raney nickel.

[0038] Furthermore, the alkaline solution used is a sodium hydroxide or potassium hydroxide solution with a concentration of 1M-5M.

[0039] S4. Construct a nickel-iron-molybdenum-copper multi-metal active catalytic layer on the surface of a nickel mesh using electrodeposition technology.

[0040] S4.1 Dissolve nickel sulfate, ferric sulfate, copper sulfate, and ammonium molybdate in sodium sulfate electrolyte, and adjust the pH to 2.8-3.2 with acid. Stir thoroughly until completely dissolved to prepare an electrodeposition solution with the following concentrations: sodium sulfate 0.05M-1M, nickel sulfate 0.05M-1M, ferric sulfate 1mM-100mM, copper sulfate 1mM-100mM, and ammonium molybdate 1mM-100mM.

[0041] Furthermore, the acid used to adjust the pH is dilute sulfuric acid, dilute hydrochloric acid, or boric acid.

[0042] S4.2 Using the prepared porous framework Raney nickel as the working electrode, a platinum sheet as the counter electrode, and an Ag / AgCl electrode as the reference electrode, constant potential electrodeposition is performed to form a multi-metal active catalytic layer on the surface of the nickel mesh. After deposition, the nickel mesh is rinsed with deionized water and allowed to dry naturally.

[0043] Furthermore, the constant potential electrodeposition on the porous framework Raney nickel surface involves applying a negative potential with a magnitude of 1V-10V, a deposition time of 5min-60min, and a temperature of 10℃-70℃.

[0044] S5. The electrodeposited nickel-based catalyst is placed in a phosphorus-containing alkaline electrolyte for constant potential activation treatment to induce in-situ structural reconstruction and surface chemical state transformation of the multi-metal active catalyst layer on the nickel mesh surface, thereby further improving its electrode catalytic performance; after electroactivation, it is thoroughly rinsed with deionized water and naturally dried.

[0045] Furthermore, the phosphorus-containing alkaline electrolyte is a mixed solution of potassium hydroxide and sodium dihydrogen phosphate, wherein the concentration of potassium hydroxide in the mixed solution is 1M~8M and the concentration of sodium dihydrogen phosphate is 0.01M~3M.

[0046] Furthermore, during constant potential activation, the electrodeposited nickel-based catalyst is used as the anode and the nickel photocell as the cathode. The applied activation potential is 1V~10V, the activation time is 1min~200min, and the activation process is carried out by water bath heating with the temperature set at 40℃-100℃.

[0047] In the catalyst preparation method of this application, a nickel-aluminum alloy is first prepared by mechanical heat treatment, which is combined with chemical activation to create a porous framework structure, thereby increasing the electrochemical specific surface area and providing abundant active binding sites for subsequent multi-metal deposition.

[0048] Traditional Raney nickel, obtained by dissolving aluminum to create a porous structure, often suffers from numerous structural weaknesses, impacting lifespan and limiting the active surface area. This application addresses this by electrodepositing multiple metals onto a substrate surface to create a nickel-iron-molybdenum-copper (NiFeMoCo) multi-metal active catalytic layer. This process strengthens the porous framework and increases the active surface area, resulting in a robust bond between the NiFeMoCo multi-metal active catalytic layer and the porous nickel mesh substrate. Furthermore, the introduction of other metal elements synergistically enhances hydrogen and oxygen evolution performance, increases catalytic active sites, and significantly improves the long-term stability of the active catalytic layer, mitigating its tendency to detach under high current densities. The uniform distribution of copper within the multi-metal layer provides synergistic electronic interactions, optimizing charge transfer and adsorption energy at active sites, promoting hydrogen and oxygen evolution reactions in water electrolysis, and further optimizing the increased active sites on the nickel mesh surface.

[0049] Finally, under phosphorus-containing conditions, the surface multi-metal catalytic layer is electrochemically reconstructed through electroactivation treatment. Phosphorus is doped into the lattice of other metals on the surface, further changing the surface electronic structure, directionally regulating the oxidation state and hydroxylation degree of the electrode catalyst surface, improving catalytic activity, and inhibiting the excessive growth of nickel hydroxide film from affecting surface active sites, thus forming a stable surface active layer.

[0050] Example 1

[0051] The double-sided sandblasted nickel mesh substrate was ultrasonically cleaned in acetone, 6M hydrochloric acid and deionized water in sequence for 10 minutes each time, and the cleaning was repeated 3 times. After cleaning, it was placed in a vacuum oven at 60°C and dried for more than 2 hours. Aluminum powder (purity ≥99.5%, particle size 20μm~50μm) and nickel powder (purity ≥99.5%, particle size 20μm~50μm) were mixed in a 1:1 mass ratio, and 1wt% ammonium chloride was added. The mixture was then evenly spread on a dried nickel mesh substrate and placed in a tube furnace for heat treatment under argon protection at 600℃ for 3 hours. After the heat treatment, the mixture was allowed to cool naturally. The nickel mesh was then removed and the residual aluminum and nickel powder on the surface was brushed off. The mesh was then immersed in a 3M sodium hydroxide solution and treated at room temperature for 8 hours. The solution was replaced with a fresh 3M sodium hydroxide solution, and the mesh was then heated in a water bath to 80℃ for 2 hours to selectively dissolve aluminum elements from the surface of the nickel mesh, forming a Raney nickel porous framework structure. The mesh was then removed, rinsed repeatedly with deionized water, and vacuum dried at 60℃. An electrodeposition solution containing nickel sulfate, ferric sulfate, copper sulfate, and ammonium molybdate was prepared. These compounds were dissolved in a sodium sulfate electrolyte, and the pH was adjusted to 3.0 (±0.2) with boric acid. The solution was stirred thoroughly until completely dissolved. The concentrations of sodium sulfate, nickel sulfate, ferric sulfate, copper sulfate, and ammonium molybdate were all 0.1 M, 10 mM, 15 mM, and 15 mM, respectively. The prepared porous framework Raney nickel electrode was used as the working electrode, a platinum sheet as the counter electrode, and an Ag / AgCl electrode as the reference electrode. A constant potential electrodeposition was performed with a negative potential of 1 V applied for 20 min in a water bath at 30 °C. After deposition, the electrodeposited nickel-based electrode was rinsed with deionized water and allowed to air dry. The electrodeposited nickel-based electrode was then used as the anode, and a nickel plating mesh as the cathode, and constant potential activation was performed in a phosphorus-containing alkaline electrolyte. The phosphorus-containing alkaline electrolyte is a potassium hydroxide solution with added sodium dihydrogen phosphate. The concentration of potassium hydroxide is 1M and the concentration of sodium dihydrogen phosphate is 0.05M. The applied activation potential is 3V and the activation time is 30min. The activation process is carried out by water bath heating at 50℃. After electroactivation, the catalyst is thoroughly rinsed with deionized water and allowed to dry naturally, thus completing the preparation of the nickel-based catalyst.

[0052] The hydrogen evolution and oxygen evolution performance of the nickel-based catalyst prepared in Example 1 is as follows: Figure 1 , 2 As shown, the nickel-based catalyst exhibits a current density of 500 mA / cm² at 80°C and 30% KOH. 2 The hydrogen evolution overpotential was 163 mV and the oxygen evolution overpotential was 279 mV. Compared with the traditional porous framework Raney nickel (Comparative Example 1), the hydrogen evolution performance was improved by 93 mV and the oxygen evolution performance was improved by 172 mV. Compared with the nickel-based catalyst prepared by electrodeposition and electroactivation (Comparative Example 2), the hydrogen evolution performance was improved by 38 mV and the oxygen evolution performance was improved by 96 mV.

[0053] Example 2

[0054] The double-sided sandblasted nickel mesh substrate was ultrasonically cleaned in acetone, 6M hydrochloric acid and deionized water in sequence for 10 minutes each time, and the cleaning was repeated 3 times. After cleaning, it was placed in a vacuum oven at 60°C and dried for more than 2 hours. Aluminum powder (purity ≥99.5%, particle size 20μm~50μm) and nickel powder (purity ≥99.5%, particle size 20μm~50μm) were mixed in a 1:1 mass ratio, and 1wt% ammonium chloride was added. The mixture was then evenly spread on a dried nickel mesh substrate and placed in a tube furnace for heat treatment under argon protection at 650℃ for 2.5h. After the heat treatment, the mixture was allowed to cool naturally. The nickel mesh was then removed and the residual aluminum and nickel powder on the surface was brushed off. The mesh was then immersed in a 3M sodium hydroxide solution and treated at room temperature for 8h. The solution was replaced with a fresh 3M sodium hydroxide solution, and the mesh was then heated in a water bath to 80℃ for 2h to selectively dissolve aluminum elements from the surface of the nickel mesh, forming a Raney nickel porous framework structure. The mesh was then removed, rinsed repeatedly with deionized water, and vacuum dried at 60℃. An electrodeposition solution containing nickel sulfate, ferric sulfate, copper sulfate, and ammonium molybdate was prepared. These compounds were dissolved in a sodium sulfate electrolyte, and boric acid was added to adjust the pH to 3.0 (±0.2). The solution was stirred thoroughly until completely dissolved. The concentration of the sodium sulfate electrolyte was 0.1 M, the concentration of the added nickel sulfate was 0.2 M, the concentration of the added ferric sulfate was 15 mM, the concentration of the added copper sulfate was 20 mM, and the concentration of the added ammonium molybdate was 20 mM. The prepared porous framework Raney nickel electrode was used as the working electrode, a platinum sheet as the counter electrode, and an Ag / AgCl electrode as the reference electrode. A constant potential electrodeposition was performed with a negative potential of 2 V applied for 15 min in a water bath at 40 °C. After deposition, the electrodeposited nickel-based electrode was rinsed with deionized water and allowed to air dry. The electrodeposited nickel-based electrode was used as the anode, and a nickel plating mesh as the cathode, and constant potential activation was performed in a phosphorus-containing alkaline electrolyte. The phosphorus-containing alkaline electrolyte is a potassium hydroxide solution with added sodium dihydrogen phosphate. The concentration of potassium hydroxide is 3M and the concentration of sodium dihydrogen phosphate is 0.1M. The applied activation potential is 4V and the activation time is 20min. The activation process is carried out by water bath heating at 60℃. After electroactivation, the solution is thoroughly rinsed with deionized water and allowed to dry naturally to complete the preparation of the nickel-based catalyst.

[0055] The hydrogen evolution and oxygen evolution performance of the nickel-based catalyst prepared in Example 2 is as follows: Figure 1 , 2 As shown, the nickel-based catalyst exhibits a current density of 500 mA / cm² at 80°C and 30% KOH. 2The hydrogen evolution overpotential was 112 mV and the oxygen evolution overpotential was 219 mV. Compared with the traditional porous framework Raney nickel (Comparative Example 1), the hydrogen evolution performance was improved by 144 mV and the oxygen evolution performance was improved by 232 mV. Compared with the nickel-based catalyst prepared by electrodeposition and electroactivation (Comparative Example 2), the hydrogen evolution performance was improved by 89 mV and the oxygen evolution performance was improved by 156 mV.

[0056] The on-tank stability test of the nickel-based catalyst prepared in Example 2 is as follows: Figure 3 As shown, the prepared nickel-based catalyst was tested in a 0.3 standard cubic meter electrolyzer at a current density of 4000 A / m. 2 The test temperature was 85℃, and the average cell voltage remained stable at around 1.75V. After 500 hours of testing, its performance did not degrade, demonstrating good long-term operational stability.

[0057] Example 3

[0058] The double-sided sandblasted nickel mesh substrate was ultrasonically cleaned in acetone, 6M hydrochloric acid and deionized water in sequence for 10 minutes each time, and the cleaning was repeated 3 times. After cleaning, it was placed in a vacuum oven at 60°C and dried for more than 2 hours. Aluminum powder (purity ≥99.5%, particle size 20μm~50μm) and nickel powder (purity ≥99.5%, particle size 20μm~50μm) were mixed in a 1:1 mass ratio, and 1wt% ammonium chloride was added. The mixture was then evenly spread on a dried nickel mesh substrate and placed in a tube furnace for heat treatment under argon protection at 700℃ for 2 hours. After the heat treatment, the mixture was allowed to cool naturally. The nickel mesh was then removed and the residual aluminum and nickel powder on the surface was brushed off. The mesh was then immersed in a 3M sodium hydroxide solution and treated at room temperature for 8 hours. The solution was replaced with a fresh 3M sodium hydroxide solution, and the mesh was then heated in a water bath to 80℃ for 2 hours to selectively dissolve aluminum elements from the surface of the nickel mesh, forming a Raney nickel porous framework structure. The mesh was then removed, rinsed repeatedly with deionized water, and vacuum dried at 60℃. An electrodeposition solution containing nickel sulfate, ferric sulfate, copper sulfate, and ammonium molybdate was prepared. These components were dissolved in a sodium sulfate electrolyte, and boric acid was added to adjust the pH to 3.0 (±0.2). The solution was stirred thoroughly until completely dissolved. The concentration of the sodium sulfate electrolyte was 0.1 M, the concentration of the added nickel sulfate was 0.3 M, the concentration of the added ferric sulfate was 20 mM, the concentration of the added copper sulfate was 25 mM, and the concentration of the added ammonium molybdate was 25 mM. The prepared porous framework Raney nickel electrode was used as the working electrode, a platinum sheet as the counter electrode, and an Ag / AgCl electrode as the reference electrode. A constant potential electrodeposition was performed with a negative potential of 3 V applied for 10 min in a water bath at 50 °C. After deposition, the electrodeposited nickel-based electrode was rinsed with deionized water and allowed to air dry. The electrodeposited nickel-based electrode was used as the anode, and a nickel plating mesh as the cathode, and constant potential activation was performed in a phosphorus-containing alkaline electrolyte. The phosphorus-containing alkaline electrolyte was prepared by adding sodium dihydrogen phosphate to a potassium hydroxide solution. The concentration of potassium hydroxide was 6M and the concentration of sodium dihydrogen phosphate was 0.2M. The applied activation potential was 5V and the activation time was 10min. The activation process was carried out by water bath heating at 70℃. After electroactivation, the solution was thoroughly rinsed with deionized water and allowed to dry naturally to complete the preparation of the nickel-based catalyst.

[0059] The hydrogen evolution and oxygen evolution performance of the nickel-based catalyst prepared in Example 3 is as follows: Figure 1 , 2 As shown, the nickel-based catalyst exhibits a current density of 500 mA / cm² at 80°C and 30% KOH. 2 The hydrogen evolution overpotential was 148 mV and the oxygen evolution overpotential was 248 mV. Compared with the traditional porous framework Raney nickel (Comparative Example 1), the hydrogen evolution performance was improved by 108 mV and the oxygen evolution performance was improved by 203 mV. Compared with the nickel-based catalyst prepared by electrodeposition and electroactivation (Comparative Example 2), the hydrogen evolution performance was improved by 53 mV and the oxygen evolution performance was improved by 127 mV.

[0060] Comparative Example 1

[0061] The double-sided sandblasted nickel mesh substrate was ultrasonically cleaned in acetone, 6M hydrochloric acid and deionized water in sequence for 10 minutes each time, and the cleaning was repeated 3 times. After cleaning, it was placed in a vacuum oven at 60°C and dried for more than 2 hours. Aluminum powder (purity ≥99.5%, particle size 20μm~50μm) and nickel powder (purity ≥99.5%, particle size 20μm~50μm) were mixed in a 1:1 mass ratio, and 1wt% ammonium chloride was added. The mixture was then evenly spread on a dried nickel mesh substrate and placed in a tube furnace for heat treatment under argon protection at 650℃ for 2.5h. After the heat treatment, the mixture was allowed to cool naturally. The nickel mesh was then removed and the residual aluminum and nickel powder on the surface was brushed off. The mesh was then immersed in a 3M sodium hydroxide solution and treated at room temperature for 8h. The solution was replaced with a fresh 3M sodium hydroxide solution and the mesh was heated in a water bath to 80℃ for 2h to selectively dissolve aluminum elements from the surface of the nickel mesh, forming a Raney nickel porous framework structure. The mesh was then removed, rinsed repeatedly with deionized water, and vacuum dried at 60℃.

[0062] The hydrogen evolution and oxygen evolution performance of the nickel-based catalyst prepared in Comparative Example 1 is as follows: Figure 1 , 2 As shown, the nickel-based catalyst exhibits a current density of 500 mA / cm² at 80°C and 30% KOH. 2 The hydrogen evolution overpotential is 256 mV, and the oxygen evolution overpotential is 451 mV.

[0063] Comparative Example 2

[0064] The double-sided sandblasted nickel mesh substrate was ultrasonically cleaned sequentially in acetone, 6M hydrochloric acid, and deionized water for 10 minutes each time, repeated three times. After cleaning, it was dried in a vacuum oven at 60℃ for at least 2 hours. An electrodeposition solution containing nickel sulfate, ferric sulfate, copper sulfate, and ammonium molybdate was prepared. These components were dissolved in sodium sulfate electrolyte, and boric acid was added to adjust the pH to 3.0 (±0.2). The solution was stirred thoroughly until completely dissolved. The concentration of the sodium sulfate electrolyte was 0.1M, the added nickel sulfate concentration was 0.2M, the ferric sulfate concentration was 15mM, the copper sulfate concentration was 20mM, and the ammonium molybdate concentration was 20mM. Using the pretreated double-sided sandblasted nickel mesh as the working electrode, a platinum sheet as the counter electrode, and an Ag / AgCl electrode as the reference electrode, constant potential electrodeposition was performed. A negative potential of 2V was applied, the deposition time was 15 minutes, and the water bath heating temperature was 40℃. After deposition, the substrate was rinsed with deionized water and allowed to air dry. The electrodeposited nickel-based electrode was used as the anode, and the nickel photocell as the cathode. Constant potential activation was performed in a phosphorus-containing alkaline electrolyte. The phosphorus-containing alkaline electrolyte consisted of potassium hydroxide solution with added sodium dihydrogen phosphate (3M potassium hydroxide, 0.1M sodium dihydrogen phosphate). The applied activation potential was 4V, and the activation time was 20 minutes. The activation process was carried out in a water bath at 60℃. After electroactivation, the catalyst was thoroughly rinsed with deionized water and allowed to air dry, thus completing the preparation of the nickel-based catalyst.

[0065] The hydrogen evolution and oxygen evolution performance of the nickel-based catalyst prepared in Comparative Example 2 is as follows: Figure 1 , 2 As shown, the nickel-based catalyst exhibits a current density of 500 mA / cm² at 80°C and 30% KOH. 2 The hydrogen evolution overpotential is 201 mV, and the oxygen evolution overpotential is 375 mV.

[0066] The beneficial effects of this invention's catalyst preparation method based on the synergistic electrodeposition and electroactivation of a Raney nickel porous framework structure are as follows: By mechanically and thermally treating a nickel-aluminum alloy followed by chemical activation, a Raney nickel porous framework structure is constructed. Electrodeposition and electroactivation are then performed on this structure to obtain a nickel-based catalyst that possesses the high specific surface area of ​​a porous framework structure, the high catalytic activity of multiple metal components, and excellent long-term operational stability. This catalyst can be used as a bifunctional electrode for simultaneously catalyzing hydrogen evolution and oxygen evolution reactions, significantly reducing the production cost of anode and cathode electrode catalysts. It has promising application prospects in the alkaline water electrolysis hydrogen production industry.

[0067] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing a catalyst based on the synergistic electrodeposition and electroactivation of a Raney nickel porous framework structure, characterized in that the steps include... include: S1. Pre-treat the nickel mesh substrate to remove the oxide layer and impurities on the surface of the nickel mesh substrate; S2. Mix aluminum powder and nickel powder in a mass ratio of 1:1, and add 0.1wt%-5wt% ammonium chloride. Then, evenly cover the mixture onto the dried nickel mesh substrate. Then, put the nickel mesh substrate into a tube furnace and heat treat it under argon protection at a temperature of 500℃-1000℃ for 0.5h-5h. After the heat treatment, allow it to cool naturally and brush off any residual aluminum and nickel powder from the surface of the nickel mesh to obtain the nickel-aluminum alloy layer. S3. Immerse the nickel-aluminum alloy layer nickel mesh in an alkaline solution and chemically activate it at room temperature for 5-15 hours. Then, remove the nickel-aluminum alloy layer nickel mesh and immerse it in a fresh alkaline solution. Heat it to 50℃-100℃ and chemically activate it for 0.5-5 hours to form a Raney nickel porous framework structure on its surface. After removing it, rinse it clean and vacuum dry it to obtain a porous framework structure Raney nickel. S4. Dissolve nickel sulfate, ferric sulfate, copper sulfate, and ammonium molybdate in sodium sulfate electrolyte and adjust the pH to 2.8-3.

2. Stir thoroughly until completely dissolved to prepare an electrodeposition solution with the following concentrations: sodium sulfate 0.05M-1M, nickel sulfate 0.05M-1M, ferric sulfate 1mM-100mM, copper sulfate 1mM-100mM, and ammonium molybdate 1mM-100mM. Place the nickel mesh obtained in step S3 into the electrodeposition solution and use it as the working electrode for constant potential electrodeposition to form a multi-metal active catalytic layer on the surface of the nickel mesh. After electrodeposition, rinse the nickel mesh clean and allow it to air dry. S5. The electrodeposited nickel mesh is placed in a phosphorus-containing alkaline electrolyte for constant potential activation treatment to induce in-situ structural reconstruction and surface chemical state transformation of the multi-metal active catalytic layer on the surface of the nickel mesh; after electroactivation, it is thoroughly rinsed and naturally dried to obtain a nickel-based catalyst.

2. The catalyst preparation method based on the synergistic electrodeposition and electroactivation of Raney nickel porous framework structure according to claim 1, characterized in that, In step S1, the nickel mesh substrate is a single-sided or double-sided sandblasted nickel mesh.

3. The catalyst preparation method based on the synergistic electrodeposition and electroactivation of Raney nickel porous framework structure according to claim 1, characterized in that, In step S1, the pretreatment of the nickel mesh substrate includes ultrasonic cleaning in acetone, hydrochloric acid and deionized water in sequence, with the number of cycles being 1-3. After cleaning, the substrate is placed in a vacuum oven for drying.

4. The catalyst preparation method based on the synergistic electrodeposition and electroactivation of Raney nickel porous framework structure according to claim 1, characterized in that, In step S1, the concentration of hydrochloric acid used in the pretreatment is 0.1M-6M; the ultrasonic cleaning time of the nickel mesh substrate in acetone, hydrochloric acid and deionized water is 5min-30min.

5. The catalyst preparation method based on the synergistic electrodeposition and electroactivation of Raney nickel porous framework structure according to claim 1, characterized in that, In step S2, the particle size of aluminum powder is 20μm to 100μm, and the particle size of nickel powder is 20μm to 100μm.

6. The catalyst preparation method based on the synergistic electrodeposition and electroactivation of Raney nickel porous framework structure according to claim 1, characterized in that, In step S3, the two alkaline solutions used to soak the nickel-aluminum alloy layer nickel mesh are the same, using sodium hydroxide or potassium hydroxide solutions with a concentration of 1M-5M.

7. The catalyst preparation method based on the synergistic electrodeposition and electroactivation of Raney nickel porous framework structure according to claim 1, characterized in that, In step S4, the acid used to adjust the pH is dilute sulfuric acid, dilute hydrochloric acid, or boric acid.

8. The method for preparing a catalyst based on the synergistic electrodeposition and electroactivation of a Raney nickel porous framework structure according to claim 1, characterized in that, In step S4, the constant potential electrodeposition on the porous framework Raney nickel surface is performed by applying a negative potential with a magnitude of 1V-10V, a deposition time of 5min-60min, and a temperature of 10℃-70℃.

9. The method for preparing a catalyst based on the synergistic electrodeposition and electroactivation of a Raney nickel porous framework structure according to claim 1, characterized in that, In step S5, the phosphorus-containing alkaline electrolyte is a mixed solution of potassium hydroxide and sodium dihydrogen phosphate, wherein the concentration of potassium hydroxide in the mixed solution is 1M~8M and the concentration of sodium dihydrogen phosphate is 0.01M~3M.

10. The method for preparing a catalyst based on the synergistic electrodeposition and electroactivation of a Raney nickel porous framework structure according to claim 1, characterized in that, In step S5, during constant potential activation, the electrodeposited nickel-based catalyst is used as the anode and the nickel photocell is used as the cathode. The applied activation potential is 1V~10V, the activation time is 1min~200min, and the activation process is carried out by water bath heating with the temperature set at 40℃-100℃.

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