Nickel-based powder, hydrogen electrode for alkaline electrolysis of water, and method of preparation

Abstract

The disclosure provides a nickel-based powder, an alkaline electrolytic water hydrogen production electrode and a preparation method, and relates to the technical field of surface treatment. The preparation method of the nickel-based powder comprises the following steps: sequentially sensitizing and activating aluminum powder by means of SnCl2-HCl solution and PdCl2 solution; adding the activated aluminum powder into a target solution and performing water bath heating reaction; wherein the target solution comprises nickel sulfate, sodium citrate, citric acid, sodium hypophosphite and thiourea; performing vacuum filtration, washing and drying treatment on the product after water bath heating to obtain an intermediate nickel-based powder; placing the intermediate nickel-based powder, nickel powder raw material, wet grinding medium and forming agent in a ball mill for wet grinding mixing to obtain a mixed slurry; converting the mixed slurry into spherical agglomerated powder by means of spray granulation, and performing sintering on the spherical agglomerated powder, and then performing cooling and sieving to obtain the nickel-based powder. The disclosure can effectively inhibit the problem of performance degradation of the alkaline electrolytic water hydrogen production electrode caused by oxidation of the nickel-based coating.

Description

Technical Field

[0001] This disclosure relates to the field of surface treatment technology, and more specifically, to a nickel-based powder, an alkaline water electrolysis hydrogen production electrode, and a preparation method thereof. Background Technology

[0002] Nickel-based coatings are widely used in key electrode components of alkaline water electrolysis hydrogen production devices due to their outstanding advantages such as high catalytic activity, strong corrosion resistance, and low cost. Nickel possesses catalytic activity second only to precious metals in alkaline environments, excellent chemical stability, and significant cost advantages, making it an indispensable key material in green hydrogen energy systems.

[0003] Currently, during the preparation of nickel-based coatings, coating oxidation occurs, affecting electrode performance and lifespan.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this disclosure is to provide a nickel-based powder, an alkaline water electrolysis hydrogen production electrode, and a preparation method thereon, thereby at least to some extent overcoming the problem of electrode performance degradation caused by the oxidation of the nickel coating.

[0006] According to a first aspect of this disclosure, a method for preparing nickel-based powder is provided, comprising: sensitizing and activating aluminum powder sequentially by passing it through a SnCl2-HCl solution and a PdCl2 solution; adding the activated aluminum powder to a target solution and subjecting it to a water bath heating reaction; wherein the target solution includes nickel sulfate, sodium citrate, citric acid, sodium hypophosphite, and thiourea; subjecting the product after water bath heating to vacuum filtration, washing, and drying to obtain intermediate nickel-based powder; placing the intermediate nickel-based powder, nickel powder raw material, wet grinding media, and forming agent in a ball mill for wet grinding and mixing to obtain a mixed slurry; converting the mixed slurry into spherical agglomerated powder by spray granulation, sintering the spherical agglomerated powder, and then cooling and sieving it to obtain nickel-based powder.

[0007] Optionally, in the target solution, nickel sulfate is 200-300 g / L, sodium citrate is 30-40 g / L, citric acid is 8-10 g / L, sodium hypophosphite is 80-100 g / L, and thiourea is 3-5 g / L.

[0008] Optionally, sintering the spherical agglomerate powder includes sintering the spherical agglomerate powder at 800~1350℃ for 20~70min under a protective atmosphere.

[0009] According to a second aspect of this disclosure, a nickel-based powder is provided, prepared using any of the above-described methods for preparing nickel-based powders.

[0010] According to a third aspect of this disclosure, a method for preparing an alkaline water electrolysis hydrogen production electrode is provided, comprising: sequentially cleaning, acid-washing activation, and sandblasting roughening treatment on the surface of a hydrogen production electrode substrate to obtain a hydrogen production electrode substrate to be coated; and performing a plasma spraying operation on the hydrogen production electrode substrate to be coated using nickel-based powder to obtain an alkaline water electrolysis hydrogen production electrode; wherein the nickel-based powder is prepared using any of the above-described nickel-based powder preparation methods.

[0011] Optionally, the acid-washing and activation solution is a mixed solution of HF and HNO3, and the acid-washing and activation time is 5~10s.

[0012] Optionally, the alumina sand used for sandblasting roughening is alumina sand with a size greater than or equal to 60 mesh, the sandblasting pressure is 0.3~0.6MPa, the sandblasting distance is 100~300mm, and the sandblasting angle is 60°~90°.

[0013] Optionally, during the plasma spraying operation, ventilation is maintained and the temperature of the spraying process is monitored to control the surface temperature of the hydrogen production electrode substrate to 30~60°C.

[0014] Optionally, the process parameters for plasma spraying include: spray gun distance of 100~150mm, spray gun angle of 90°~105°, spray gun moving speed of 800~1000mm / s, powder feeding gas speed of 0.1~5r / min, hydrogen flow rate of 8~15L / min, argon flow rate of 30~50L / min, carrier gas flow rate of 0.8~5L / min, current of 500~650A, and power of 35~45kW.

[0015] According to the fourth aspect of this disclosure, an alkaline water electrolysis hydrogen production electrode is provided, which is prepared by the above-described method for preparing an alkaline water electrolysis hydrogen production electrode.

[0016] In the exemplary embodiments of this disclosure, nickel-based powder for use in alkaline water electrolysis hydrogen production electrodes is prepared by a combination of chemical preparation and mixing granulation. During the chemical preparation process, a uniform nickel coating layer is formed on the surface of aluminum powder through solution proportioning and a water bath reaction. The mixing granulation process, through the addition of nickel powder raw materials, spray granulation, and sintering, yields nickel-based spherical powder with good sphericity and flowability, while effectively controlling its oxygen content. When applied to alkaline water electrolysis hydrogen production electrodes, this process suppresses problems such as increased electrode impedance, intensified polarization, and easy damage to the coating structure caused by nickel oxide, thereby significantly improving the electrochemical performance and long-term durability of the alkaline water electrolysis hydrogen production electrode.

[0017] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0019] Figure 1 A flowchart illustrating a method for preparing nickel-based powder according to an embodiment of the present disclosure is shown.

[0020] Figure 2 A flowchart illustrating the preparation method of the alkaline water electrolysis hydrogen production electrode according to an embodiment of the present disclosure is shown.

[0021] Figure 3 The diagram schematically shows a cross-sectional SEM (Scanning Electron Microscope) image of a nickel-based coating sprayed onto the surface of the hydrogen production electrode of Embodiment 1 of this disclosure.

[0022] Figure 4 The schematic diagram shows a SEM image of the surface of the nickel-based coating sprayed onto the surface of the hydrogen production electrode of Embodiment 1 of this disclosure.

[0023] Figure 5 A schematic diagram of the energy spectrum elemental distribution of the nickel-based coating sprayed on the surface of the hydrogen production electrode of Embodiment 1 of this disclosure is shown. Detailed Implementation

[0024] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this disclosure more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a full understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced with one or more of these specific details omitted, or other methods, processes, steps, etc., can be employed. In other instances, well-known technical solutions are not shown or described in detail to avoid obscuring various aspects of this disclosure.

[0025] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. The flowcharts shown in the drawings are merely exemplary illustrations and do not necessarily include all steps. For example, some steps may be broken down, while others may be combined or partially combined; therefore, the actual order of execution may change depending on the specific circumstances.

[0026] For coatings used in alkaline water electrolysis hydrogen production electrodes, the nickel oxide present not only increases electrode impedance and exacerbates polarization, leading to increased energy consumption, but also damages the coating's structural integrity due to volume expansion and internal stress, ultimately causing powdering and flaking, significantly shortening its service life. More seriously, high-oxidation-state nickel may catalyze electrolyte decomposition, exacerbating side reactions and posing safety hazards. Therefore, effectively controlling the oxygen content of the nickel coating during plasma spraying is crucial for improving electrode performance and reliability.

[0027] To address or at least alleviate the problems described above, this disclosure provides a novel nickel-based powder, an alkaline water electrolysis hydrogen production electrode, and a preparation method thereof. Specifically, the nickel-based powder is prepared using a combination of chemical preparation and mixing granulation. By optimizing the plasma spraying process parameters, the oxidation of the nickel coating during spraying can be effectively controlled, resulting in a nickel-based coating with controllable oxygen content, a dense structure, and strong adhesion. This achieves high performance and long lifespan in the preparation of the alkaline water electrolysis hydrogen production electrode, improving the electrode's catalytic activity and durability.

[0028] Figure 1 A flowchart illustrating a method for preparing nickel-based powder according to an embodiment of the present disclosure is shown schematically. (Reference) Figure 1 The method for preparing nickel-based powder according to the present disclosure may include the following steps:

[0029] S10. The aluminum powder is sensitized and activated sequentially by passing it through SnCl2-HCl solution and PdCl2 solution.

[0030] Before step S10, the aluminum powder can be cleaned with a 5-10% NaOH solution.

[0031] S12. Add the activated aluminum powder to the target solution and perform a water bath heating reaction; wherein the target solution includes nickel sulfate, sodium citrate, citric acid, sodium hypophosphite and thiourea.

[0032] In an exemplary embodiment of this disclosure, the target solution contains 200-300 g / L nickel sulfate, 30-40 g / L sodium citrate, 8-10 g / L citric acid, 80-100 g / L sodium hypophosphite, and 3-5 g / L thiourea.

[0033] The water bath temperature is 80~90℃, and the water bath time is 60~90 minutes, with continuous stirring during the process.

[0034] Specifically, the aluminum powder processed in step S10 can be placed in a beaker containing 200-300 g / L nickel sulfate, 30-40 g / L sodium citrate, 8-10 g / L citric acid, 80-100 g / L sodium hypophosphite, and 3-5 g / L thiourea plating solution, and the pH of the solution is adjusted to 10-12.

[0035] Place the beaker in a constant temperature water bath at 80-90℃ and stir continuously for 60-90 minutes.

[0036] S14. The product heated in a water bath is subjected to vacuum filtration, washing and drying to obtain intermediate nickel-based powder.

[0037] In an exemplary embodiment of this disclosure, the product obtained in step S12 is subjected to vacuum filtration and washed alternately with anhydrous ethanol and deionized water. Then, the product is placed in a vacuum drying oven at 60-80°C for 4-6 hours to obtain intermediate nickel-based powder.

[0038] The intermediate nickel-based powder can be understood as an intermediate product in the generation of nickel-based powder for alkaline water electrolysis hydrogen production electrodes. The composition, pH value, and temperature control of the above-mentioned chemical plating solution are conducive to the formation of a uniform and dense nickel coating layer on the surface of aluminum powder, laying the foundation for the subsequent preparation of low-oxygen content coatings.

[0039] S16. The intermediate nickel-based powder, nickel powder raw material, wet grinding media and forming agent are placed in a ball mill for wet grinding and mixing to obtain a mixed slurry.

[0040] According to some embodiments of this disclosure, the above-mentioned intermediate nickel-based powder and 5-15 wt% nickel powder raw materials can be placed in a ball mill, anhydrous ethanol and deionized water can be added as wet milling media, and 2-8% polyvinyl alcohol can be added as a molding agent. The mixture can be wet-milled for at least 1 hour to obtain a mixed slurry.

[0041] S18. The mixed slurry is converted into spherical agglomerated powder by spray granulation, and the spherical agglomerated powder is sintered, cooled and sieved to obtain nickel-based powder.

[0042] For the sintering process, the spherical agglomerated powder can be sintered at 800~1350℃ for 20~70min under a protective atmosphere. Finally, after cooling and sieving, thermally sprayed spherical powder with a particle size of 15~53μm is obtained, which is the nickel-based powder subsequently applied to the alkaline water electrolysis hydrogen production electrode of this disclosure.

[0043] The granulation process and protective atmosphere sintering disclosed herein effectively control the oxygen content in the powder and obtain spherical powder with good flowability, ensuring the stability of powder feeding and the uniformity of coating quality during plasma spraying.

[0044] Figure 2 A flowchart illustrating the preparation method of the alkaline water electrolysis hydrogen production electrode according to an embodiment of this disclosure is shown schematically. (Reference) Figure 2 The preparation method of the alkaline water electrolysis hydrogen production electrode according to the present disclosure may include the following steps:

[0045] S20. The surface of the hydrogen production electrode substrate is sequentially cleaned, acid-washed for activation, and sandblasted for roughening to obtain the hydrogen production electrode substrate to be coated.

[0046] In an exemplary embodiment of this disclosure, the hydrogen production electrode substrate can be a nickel mesh electrode. After pretreatment by cleaning, acid pickling activation, and sandblasting roughening, the nickel mesh substrate can have a clean, activated, and rough surface, which can form a strong mechanical interlocking and metallurgical bond with the subsequently sprayed nickel-based coating, significantly improving the adhesion between the coating and the substrate and ensuring the long-term stability of the electrode in the water electrolysis environment.

[0047] Specifically, the pickling and activation solution is a mixture of HF and HNO3, and the pickling and activation time is 5-10 seconds. This pickling solution and short treatment time can effectively remove the oxide film on the substrate surface and achieve activation, while avoiding damage to the substrate surface caused by over-corrosion.

[0048] The alumina sand used for sandblasting roughening is 60 mesh or larger. The sandblasting pressure is 0.3~0.6MPa, the sandblasting distance is 100~300mm, and the sandblasting angle is 60°~90°. The surface roughness of the substrate after sandblasting is 2.8~3.8μm. These sandblasting parameters in this embodiment can form a uniform and moderately rough surface, significantly improving the mechanical bonding strength between the coating and the substrate, thus ensuring the preparation of functional coatings with high adhesion.

[0049] S22. A plasma spraying operation is performed on the hydrogen production electrode substrate to be sprayed using nickel-based powder to obtain an alkaline water electrolysis hydrogen production electrode.

[0050] In an exemplary embodiment of this disclosure, the nickel-based powder in this step is the nickel-based powder prepared by steps S10 to S18 described above.

[0051] According to some embodiments of this disclosure, during the plasma spraying operation, ventilation is maintained, and the temperature of the spraying process is monitored to control the surface temperature of the hydrogen production electrode substrate to 30~60°C. Controlling the substrate temperature can effectively prevent accelerated coating oxidation or substrate deformation due to overheating, and it can be considered one of the key measures for controlling the oxygen content of the coating.

[0052] The process parameters for plasma spraying include: spray gun distance of 100~150mm, spray gun angle of 90°~105°, spray gun moving speed of 800~1000mm / s, powder feeding gas speed of 0.1~5r / min, hydrogen flow rate of 8~15L / min, argon flow rate of 30~50L / min, carrier gas flow rate of 0.8~5L / min, current of 500~650A, and power of 35~45kW.

[0053] The exemplary combination of spraying parameters disclosed above ensures that the nickel-based powder is fully melted and well atomized, forming a dense and uniform coating structure. Simultaneously, minimizing heat input during the spraying process and the time particles are exposed to a high-temperature oxidizing environment helps achieve a coating with low oxygen content (2-8 wt%) and an ideal thickness (20-30 μm).

[0054] This disclosure discloses a method for preparing nickel-based spray coating powder by combining chemical preparation with mixed granulation. In the chemical preparation process, the composition, pH value, and reaction temperature of the plating solution are precisely controlled to form a uniform nickel coating layer on the surface of aluminum powder. In the mixed granulation process, metallic nickel powder is added, sintering is performed under a protective atmosphere, and a spray granulation process is combined to obtain nickel-based spherical powder with good sphericity and flowability, while effectively controlling its oxygen content. During plasma spraying, by optimizing key parameters such as spray gun distance, angle, moving speed, gas flow rate, current, and power, and strictly controlling the substrate temperature within the range of 30℃ to 60℃, a good melting state of the sprayed particles is ensured while minimizing nickel oxidation during spraying, thereby achieving precise control of the coating oxygen content (2~8 wt%). The nickel-based coating prepared by the above method has a thickness of 20~30 μm, not only with controllable oxygen content but also possessing a high specific surface area and porous structure, significantly improving the catalytic activity of the electrode and its long-term operational stability under harsh electrolysis conditions.

[0055] The beneficial effects of the solutions in the embodiments of this disclosure can include the following aspects.

[0056] In the first aspect, the embodiments of this disclosure employ a powder preparation method that combines chemical preparation with mixed granulation, and combine it with an optimized plasma spraying process to achieve precise control of the oxygen content (2~8wt%) of the nickel-based coating. This effectively suppresses problems such as increased electrode impedance, intensified polarization, and damage to the coating structure caused by nickel oxide, thereby significantly improving the electrochemical performance and long-term operational durability of the alkaline water electrolysis hydrogen production electrode.

[0057] Secondly, the embodiments of this disclosure obtain nickel-based spherical powder with good sphericity and excellent flowability through a powder preparation route that combines chemical preparation and mixing granulation. The powder has low oxygen content and uniform composition, which lays a key material foundation for the subsequent preparation of functional coatings with dense structure and uniform performance by plasma spraying.

[0058] Thirdly, the embodiments disclosed herein, through coordinated control of substrate pretreatment (acid pickling activation, sandblasting roughening) and plasma spraying process parameters (including spray gun distance, angle, moving speed, gas flow rate, electrical power, and electrode preparation temperature), achieve an ideal coating thickness of 20-30 μm while significantly suppressing overheating oxidation during the spraying process. This process has a clear process window and good repeatability, which is beneficial for large-scale production.

[0059] Fourthly, the oxygen-content-controllable nickel-based coating prepared in this embodiment has both high specific surface area and porous structure, which effectively increases the active sites for electrochemical reactions. While maintaining the cost advantage of nickel-based materials, it breaks through the bottleneck of limited working current density and insufficient catalytic activity of traditional electrodes, providing a reliable solution for the preparation of high-performance, long-life alkaline water electrolysis hydrogen production electrodes.

[0060] The scheme of Embodiment 1 of this disclosure will be described below.

[0061] Step 1: Prepare the nickel-based powder required for spraying using a combination of chemical preparation and mixing granulation.

[0062] The chemical preparation process includes: First, aluminum powder is cleaned with an 8% (w / w) NaOH solution, followed by sensitization and activation treatments using SnCl2-HCl solution and PdCl2 solution sequentially. Next, the activated aluminum powder is placed in a beaker containing a plating solution of 250 g / L nickel sulfate, 35 g / L sodium citrate, 9 g / L citric acid, 90 g / L sodium hypophosphite, and 4 g / L thiourea. The pH of the solution is adjusted to 11, and the beaker is placed in an 85°C constant temperature water bath with continuous stirring for 75 min. Then, the product is vacuum filtered, washed alternately with anhydrous ethanol and deionized water, and the resulting product is placed in a 70°C vacuum drying oven for 5 h to obtain intermediate nickel-based powder.

[0063] The mixing and granulation process includes: First, the above-mentioned intermediate nickel-based powder and 10 wt% metallic nickel powder are placed in a ball mill, with alcohol added as a wet grinding medium and 5% polyvinyl alcohol added as a forming agent. The mixture is wet-milled for 24 hours to obtain a uniform slurry. Subsequently, the slurry is converted into spherical agglomerated powder using a spray granulation process. This powder is then sintered at 1000℃ under a protective atmosphere for 45 minutes. Finally, after cooling and sieving, thermally sprayable spherical powder with a particle size of 15~53 μm is obtained. Before spraying, the obtained spherical powder is dried at 80℃ for 2 hours.

[0064] Step 2: The surface of the hydrogen generation electrode substrate is sequentially cleaned, acid-washed for activation, and sandblasted for roughening to obtain the hydrogen generation electrode substrate to be coated.

[0065] For cleaning, use alcohol ultrasonic cleaning for 15 minutes to remove surface contaminants.

[0066] For acid washing activation, a mixed solution of HF and HNO3 was used, and the acid washing time was 5 seconds, followed by rinsing with deionized water and drying.

[0067] For the sandblasting roughening treatment, 60-mesh alumina sand was used, the sandblasting pressure was 0.5MPa, the sandblasting distance was 200mm, the sandblasting angle was 90°, and the roughness of the substrate surface after sandblasting was 3.2μm.

[0068] Step 3: Use the nickel-based powder prepared in Step 1 to perform plasma spraying on the hydrogen production electrode substrate pretreated in Step 2.

[0069] Throughout the spraying process, ensure good ventilation for the hydrogen generation electrode substrate and monitor the temperature during the spraying process, keeping the substrate surface temperature at 40°C.

[0070] The spraying parameters include: spray gun distance 130mm, spray gun angle 90°, moving speed 1000mm / s, powder feeder speed 3r / min, hydrogen flow rate 9L / min, argon flow rate 40L / min, carrier gas flow rate 3.1L / min, current 580A, and power 38kW.

[0071] After the spraying is completed, turn off the equipment and remove the workpiece after it has cooled down.

[0072] refer to Figure 3 The nickel-based coating prepared in Example 1 of this disclosure is uniform, without obvious cracks, and has a thickness of approximately 25.83 μm. (Reference) Figure 4 The coating is evenly distributed and has a smooth, burr-free surface, indicating that the coating has a uniform texture and effectively controls the oxidation of the coating surface.

[0073] Figure 5 A schematic diagram of the energy dispersive spectral distribution of a nickel-based coating sprayed onto the surface of the hydrogen production electrode according to Embodiment 1 of this disclosure is shown. (Reference) Figure 5 The oxygen content of the coating is 4.12 wt%, which is low and effectively controlled.

[0074] The scheme of Embodiment 2 of this disclosure will be described below.

[0075] Step 1: Prepare the nickel-based powder required for spraying using a combination of chemical preparation and mixing granulation.

[0076] The chemical preparation process includes: First, aluminum powder is cleaned with a 5% (w / w) NaOH solution, followed by sensitization and activation treatments using SnCl2-HCl solution and PdCl2 solution sequentially. Next, the activated aluminum powder is placed in a beaker containing a plating solution of 200 g / L nickel sulfate, 30 g / L sodium citrate, 8 g / L citric acid, 80 g / L sodium hypophosphite, and 3 g / L thiourea. The pH of the solution is adjusted to 10, and the beaker is placed in an 85°C constant temperature water bath with continuous stirring for 60 min. Then, the product is vacuum filtered, washed alternately with anhydrous ethanol and deionized water, and the resulting product is placed in a 60°C vacuum drying oven for 4 h to obtain intermediate nickel-based powder.

[0077] The mixing and granulation process includes: First, the above-mentioned intermediate nickel-based powder and 5 wt% metallic nickel powder are placed in a ball mill, with alcohol added as a wet grinding medium and 2% polyvinyl alcohol added as a forming agent. The mixture is wet-milled for 24 hours to obtain a uniform slurry. Subsequently, the slurry is converted into spherical agglomerated powder using a spray granulation process. This powder is then sintered at 800°C under a protective atmosphere for 20 minutes. Finally, after cooling and sieving, thermally sprayable spherical powder with a particle size of 15~53 μm is obtained. Before spraying, the obtained spherical powder is dried at 80°C for 2 hours.

[0078] Step 2: The surface of the hydrogen generation electrode substrate is sequentially cleaned, acid-washed for activation, and sandblasted for roughening to obtain the hydrogen generation electrode substrate to be coated.

[0079] For cleaning, use alcohol ultrasonic cleaning for 15 minutes to remove surface contaminants.

[0080] For acid washing activation, a mixed solution of HF and HNO3 was used, and the acid washing time was 8 seconds, followed by rinsing with deionized water and drying.

[0081] For the sandblasting roughening treatment, 50-mesh alumina sand was used, the sandblasting pressure was 0.3MPa, the sandblasting distance was 100mm, the sandblasting angle was 60°, and the roughness of the substrate surface after sandblasting was 3.4μm.

[0082] Step 3: Use the nickel-based powder prepared in Step 1 to perform plasma spraying on the hydrogen production electrode substrate pretreated in Step 2.

[0083] Throughout the spraying process, ensure good ventilation for the hydrogen production electrode substrate and monitor the temperature during the spraying process, keeping the substrate surface temperature at 30°C.

[0084] The spraying parameters include: spray gun distance 100mm, spray gun angle 90°, moving speed 800mm / s, powder feeder speed 0.1r / min, hydrogen flow rate 5L / min, argon flow rate 30L / min, carrier gas flow rate 0.8L / min, current 500A, and power 35kW.

[0085] After the spraying is completed, turn off the equipment and remove the workpiece after it has cooled down.

[0086] The nickel-based coating prepared in Example 2 was found to have a thickness of approximately 22.66 μm and an oxygen content of 2.15 wt%.

[0087] The scheme of Embodiment 3 of this disclosure will be described below.

[0088] Step 1: Prepare the nickel-based powder required for spraying using a combination of chemical preparation and mixing granulation.

[0089] The chemical preparation process includes: First, aluminum powder is cleaned with a 10% (w / w) NaOH solution, followed by sensitization and activation treatments using SnCl2-HCl solution and PdCl2 solution. Next, the activated aluminum powder is placed in a beaker containing a plating solution of 300 g / L nickel sulfate, 40 g / L sodium citrate, 10 g / L citric acid, 100 g / L sodium hypophosphite, and 5 g / L thiourea. The pH of the solution is adjusted to 12, and the beaker is placed in an 85°C constant temperature water bath with continuous stirring for 90 min. Then, the product is vacuum filtered, washed alternately with anhydrous ethanol and deionized water, and the resulting product is placed in an 80°C vacuum drying oven for 6 h to obtain intermediate nickel-based powder.

[0090] The mixing and granulation process includes: First, the above-mentioned intermediate nickel-based powder and 15 wt% metallic nickel powder are placed in a ball mill, with alcohol added as a wet grinding medium and 8% polyvinyl alcohol added as a forming agent. The mixture is wet-milled for 24 hours to obtain a uniform slurry. Subsequently, the slurry is converted into spherical agglomerated powder using a spray granulation process. This powder is then sintered at 1350℃ under a protective atmosphere for 70 minutes. Finally, after cooling and sieving, thermally sprayable spherical powder with a particle size of 15~53 μm is obtained. Before spraying, the obtained spherical powder is dried at 80℃ for 2 hours.

[0091] Step 2: The surface of the hydrogen generation electrode substrate is sequentially cleaned, acid-washed for activation, and sandblasted for roughening to obtain the hydrogen generation electrode substrate to be coated.

[0092] For cleaning, use alcohol ultrasonic cleaning for 15 minutes to remove surface contaminants.

[0093] For acid washing activation, a mixed solution of HF and HNO3 was used, and the acid washing time was 10 seconds, followed by rinsing with deionized water and drying.

[0094] For the sandblasting roughening treatment, 40-mesh alumina sand was used, the sandblasting pressure was 0.6MPa, the sandblasting distance was 300mm, the sandblasting angle was 90°, and the roughness of the substrate surface after sandblasting was 3.8μm.

[0095] Step 3: Use the nickel-based powder prepared in Step 1 to perform plasma spraying on the hydrogen production electrode substrate pretreated in Step 2.

[0096] Throughout the spraying process, ensure good ventilation for the hydrogen production electrode substrate and monitor the temperature during the spraying process, keeping the substrate surface temperature at 60°C.

[0097] The spraying parameters include: spray gun distance 150mm, spray gun angle 105°, moving speed 1000mm / s, powder feeder speed 5r / min, hydrogen flow rate 15L / min, argon flow rate 50L / min, carrier gas flow rate 5.0L / min, current 650A, and power 45kW.

[0098] After the spraying is completed, turn off the equipment and remove the workpiece after it has cooled down.

[0099] The nickel-based coating prepared in Example 3 was found to have a thickness of approximately 24.65 μm and an oxygen content of 6.25 wt%.

[0100] The following is an explanation of Comparative Example 1 of this disclosure.

[0101] The difference between Comparative Example 1 and Example 1 is that the powder used in Comparative Example 1 is a conventional powder, that is, it was not prepared by the preparation method described above in this disclosure. The remaining operating steps are the same as in Example 1.

[0102] Testing revealed that the nickel-based coating prepared in Comparative Example 1 had a thickness of approximately 16.13 μm and an oxygen content of 12.26 wt%. This demonstrates that, compared to the results of Comparative Example 1, the present disclosure, at least based on the preparation process of nickel-based powder, can reduce the oxygen content, thereby contributing to improved performance of the alkaline water electrolysis hydrogen production electrode.

[0103] It should be noted that although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or a step may be broken down into multiple steps.

[0104] Furthermore, the above figures are merely illustrative of the processes included in the method according to exemplary embodiments of this disclosure and are not intended to be limiting. It is readily understood that the processes shown in the above figures do not indicate or limit the temporal order of these processes. Additionally, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0105] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the claims.

[0106] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A method for preparing an alkaline water electrolysis hydrogen production electrode, characterized in that, include: The surface of the hydrogen generation electrode substrate is sequentially cleaned, acid-washed for activation, and sandblasted for roughening to obtain the hydrogen generation electrode substrate to be coated. A nickel-based coating is prepared by plasma spraying the hydrogen production electrode substrate with nickel-based powder to obtain an alkaline water electrolysis hydrogen production electrode; the thickness of the nickel-based coating is 20~30μm, and the oxygen content of the nickel-based coating is 2~8wt%. During the plasma spraying process, ventilation is maintained and the temperature of the spraying process is monitored to control the surface temperature of the hydrogen production electrode substrate to 30~60℃. The process parameters for plasma spraying include: spray gun distance of 100~150mm, spray gun angle of 90°~105°, spray gun moving speed of 800~1000mm / s, powder feeding gas speed of 0.1~5r / min, hydrogen flow rate of 8~15L / min, argon flow rate of 30~50L / min, carrier gas flow rate of 0.8~5L / min, current of 500~650A, and power of 35~45kW. The method for preparing the nickel-based powder includes: Aluminum powder was sensitized and activated sequentially by passing it through SnCl2-HCl solution and PdCl2 solution. The activated aluminum powder is added to the target solution and subjected to a water bath heating reaction; wherein the target solution includes nickel sulfate, sodium citrate, citric acid, sodium hypophosphite and thiourea; The product heated in a water bath was subjected to vacuum filtration, washing, and drying to obtain intermediate nickel-based powder. The intermediate nickel-based powder, nickel powder raw material, wet grinding media and forming agent are placed in a ball mill for wet grinding and mixing to obtain a mixed slurry; The mixture slurry is converted into spherical agglomerated powder by spray granulation, and the spherical agglomerated powder is sintered, cooled and sieved to obtain nickel-based powder.

2. The preparation method according to claim 1, characterized in that, In the target solution, nickel sulfate is 200-300 g / L, sodium citrate is 30-40 g / L, citric acid is 8-10 g / L, sodium hypophosphite is 80-100 g / L, and thiourea is 3-5 g / L.

3. The preparation method according to claim 1, characterized in that, Sintering the spherical agglomerated powder includes: The spherical agglomerated powder was sintered at 800~1350℃ for 20~70 min under a protective atmosphere.

4. The preparation method according to claim 1, characterized in that, The acid-washing and activation solution is a mixture of HF and HNO3, and the acid-washing and activation time is 5~10s.

5. The preparation method according to claim 1, characterized in that, The alumina sand used for sandblasting roughening is alumina sand with a size greater than or equal to 60 mesh. The sandblasting pressure is 0.3~0.6MPa, the sandblasting distance is 100~300mm, and the sandblasting angle is 60°~90°.

6. An alkaline water electrolysis hydrogen production electrode, characterized in that, The alkaline water electrolysis hydrogen production electrode was prepared using the preparation method described in any one of claims 1 to 5.

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