A method for large-scale preparation of a nanowire array electrode

Abstract

The present invention discloses a method for large-scale preparation of an electrolyzed water hydrogen evolution array electrode material, belonging to the technical field of preparation of electrolyzed water hydrogen evolution electrode materials. The preparation of the nanowire array electrode can be completed in three steps: lay the nickel foam flat in a petri dish with a magnet at the bottom, ensure that the nickel foam is within the magnetic field coverage range, pour the nickel-containing solution obtained by a chemical reaction at a certain temperature into it, and obtain a nanowire array electrode after standing for a period of time under the physical action of the magnetic field. By separating the reduction reaction from the growth of the nickel nanowire array, the present invention realizes the treatment of nickel foams of different sizes, different shapes, and different quantities.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen production and energy storage by electrolyzing water, and particularly relates to a method for large-scale preparation of a nickel-based nanowire array electrode for electrolyzing water. Background Art

[0002] Nowadays, with the increasing energy demand and the inevitable depletion of fossil fuels, people have to search for new clean energy sources and seek effective new methods for extracting energy. Hydrogen energy has naturally come into people's view. Hydrogen production by electrolyzing water is the most favored hydrogen production method, and currently, the most common industrial method is to electrolyze water under alkaline electrolyte conditions. Among them, the most important issue is the large-scale production of the hydrogen evolution electrode. The hydrogen evolution electrode that can be industrialized must have a simple preparation method and excellent performance. Currently, noble metal catalyst hydrogen evolution electrode materials are still the most advanced catalysts, which can respectively achieve lower overpotentials for HER and OER. However, the high cost and scarce content of noble metals limit their large-scale development and utilization. People then turn their attention to transition metals. Metal nickel has a high conductivity. Due to its rich reserves in the earth, high stability, corrosion resistance, and excellent performance in electrocatalytic aspects, it has attracted wide attention. To make nickel shine in the hydrogen evolution electrode material, a special structure is needed to provide more active sites to promote the cathodic hydrogen evolution reaction. The nanowire array structure of nickel fully meets these requirements, but the method of growing nickel nanowire arrays under magnetic field conditions cannot achieve large-scale production. Summary of the Invention

[0003] To solve the problems in the background art, the present invention provides a method for large-scale preparation of a nanowire array electrode to solve the problems of inability to process nickel foam on a large scale and inability to process large-sized nickel foam in industry.

[0004] The specific steps are as follows:

[0005] Step 1: Pretreat the nickel foam.

[0006] Put the cut nickel foam into a hydrochloric acid solution and etch it under ultrasonic conditions for 15 minutes. After etching, put it into deionized water and clean the nickel foam under ultrasonic conditions to wash away the residual hydrochloric acid solution on the surface of the nickel foam. Repeat the cleaning process three times, and then put it into an anhydrous ethanol solution and clean the nickel foam under ultrasonic conditions to obtain the treated nickel foam. The area of the nickel foam is 1×1 cm 2 ~40×40 cm 2 , and the concentration of the hydrochloric acid solution is 3M.

[0007] Step 2: Prepare a nanowire solution containing nickel.

[0008] Nickel chloride hexahydrate (NiCl2·6H2O) powder and sodium citrate powder are added to deionized water, stirred to dissolve the solid powder, and potassium chloroplatinate solution is added dropwise after dissolution, and stirred for 3 to 5 minutes to obtain solution A. A hydrazine hydrate solution of the same volume and a certain concentration is added to another beaker to obtain solution B. Potassium hydroxide solution is continuously added dropwise to adjust the pH of solution A and solution B to 12.5 to obtain a suitable alkaline environment. After preheating solution A and solution B at 80°C for 5 minutes, solution A will become a green colloidal fluid. Solution A and solution B are directly mixed evenly and then transferred to an oil bath environment at 80°C. After mechanical stirring, heating and stirring for a period of time, a solution containing nickel nanoparticles for growing nanowires, i.e., a nanowire solution containing nickel, is obtained.

[0009] In the solution A, NiCl2·6H2O is 3mmol, sodium citrate is 1.125mmol, deionized water is 30mL, and the concentration of potassium chloroplatinate solution is 4mgmL -1 , the dosage is 2 drops.

[0010] The concentration of hydrazine hydrate in solution B is 0.38 mol / L -1 , the concentration of potassium hydroxide solution is 6 molL -1 .

[0011] Step 3: Prepare nickel nanowire array electrode material (Ni NWs / NF).

[0012] The treated nickel foam is spread on the bottom of the watch glass, and is located in the middle of the watch glass as far as possible. A magnet is placed under the watch glass, and the upper surface area of the magnet is larger than the area of the treated nickel foam. The solution containing nickel nanowires is poured into the watch glass, and the magnet is placed in the grid plate of the plate. The solution is poured into the grid plate of the large watch glass, and the watch glass is covered with plastic wrap. The entire watch glass is in a room temperature environment. After being placed for half an hour, it can be clearly observed that the solution in the watch glass changes from a black turbid liquid to a clear light green solution, and there is an obvious black flocculent solid at the bottom of the watch glass. The entire nickel foam also turns black, and the nickel nanowire array electrode material (Ni NWs / NF) is obtained.

[0013] The size and shape of the plate and the watch glass are adjustable, and the size and shape of the grid plate cells in the watch glass are also adjustable, so that multiple nickel foams of different shapes and sizes can be processed at the same time.

[0014] The material of the plate can be plastic, ceramic, or wood, and the size of the plate is 1×1m 2 ~10×10m 2 , various shapes, such as round, square, regular hexagon and triangle.

[0015] The size of the watch glass is 1×1 m 2 ~10×10 m 2 and it has various shapes, which can be circular, square, regular hexagon, or triangular. The material is a transparent material, such as glass, which is convenient for observing the solution phenomenon.

[0016] The overall size of the grid plate is the same as the size of the plate, and the size of the unit cell is 1×1 cm 2 ~40×40 cm 2 and the materials are plastic, ceramic, and wood.

[0017] Beneficial effects:

[0018] (1) Separating the reduction reaction process from the growth process on nickel foam solves the drawback that the original steps cannot be industrially scaled up.

[0019] (2) The present invention can process nickel foams of different sizes, shapes, and quantities simultaneously, enabling the production of batch electrode materials and the production of large-area electrode materials.

[0020] (3) Compared with electroplating, it has no drawback of polluting the environment with electroplating solution, and the experiment can be completed in only three steps, meeting the requirements of large-scale production.

[0021] (4) The reduction reaction is carried out under oil bath conditions. Instead of ordinary magnetic stirring, mechanical stirring is adopted to prevent the influence of magnetism on the nickel solution, so that the reaction can proceed smoothly at 80°C. Description of the drawings

[0022] Figure 1 is a schematic diagram of the entire hydrogen evolution electrode preparation device;

[0023] Figure 2 is a schematic diagram of a circular glass watch glass with a small grid plate cell size Figure Ⅰ ;

[0024] Figure 3 is a schematic diagram of a circular glass watch glass with a small grid plate cell size Figure Ⅱ ;

[0025] Figure 4 is a schematic diagram of a circular glass watch glass with a small grid plate cell size Figure Ⅲ ;

[0026] Figure 5 is a schematic diagram of a circular glass watch glass with a large grid plate cell size Figure Ⅰ ;

[0027] Figure 6 is a schematic diagram of a circular glass watch glass with a large grid plate cell size Figure Ⅱ ;

[0028] Figure 7 Schematic diagram of a circular glass petri dish with a large grid plate cell size Figure Ⅲ ;

[0029] Figure 8 Schematic diagram of a square glass petri dish with a small grid plate cell size Figure Ⅰ ;

[0030] Figure 9 Schematic diagram of a square glass petri dish with a small grid plate cell size Figure Ⅱ ;

[0031] Figure 10 Schematic diagram of a square glass petri dish with a small grid plate cell size Figure Ⅲ ;

[0032] Figure 11 Schematic diagram of a small regular hexagonal glass plate with a small grid plate cell size Figure Ⅰ ;

[0033] Figure 12 Schematic diagram of a small regular hexagonal glass plate with a small grid plate cell size Figure Ⅱ ;

[0034] Figure 13 Schematic diagram of a small regular hexagonal glass plate with a small grid plate cell size Figure Ⅲ ;

[0035] Figure 14 Simulation of the growth process of nanowires in the cell Figure Ⅰ ;

[0036] Figure 15 Simulation of the growth process of nanowires in the cell Figure Ⅱ ;

[0037] Figure 16 Simulation of the growth process of nanowires in the cell Figure Ⅲ ;

[0038] Figure 17 Large area sample image obtained;

[0039] Figure 18A SEM of the obtained Ni NWs / NF electrode material Figure Ⅰ ;

[0040] Figure 18B SEM of the obtained Ni NWs / NF electrode material Figure Ⅱ ;

[0041] Figure 19 XRD pattern of the obtained Ni NWs / NF electrode material;

[0042] Figure 20It is a comparison diagram of LSV curves of the obtained Ni NWs / NF electrode material and commercial nickel foam;

[0043] Figure 21 It is a comparison diagram of overpotentials of the obtained Ni NWs / NF electrode material and commercial nickel foam;

[0044] Figure 22 It is a comparison diagram of electrochemical impedance of the obtained Ni NWs / NF electrode material and commercial nickel foam;

[0045] Figure 23 It is a stability test diagram of the obtained Ni NWs / NF electrode material;

[0046] Figure 24 It is a flow chart of the present invention. Specific embodiments

[0047] To make the present invention clearer and more understandable, the following is a further description of the large-scale production method in the present invention through examples of the preparation process and the accompanying drawings of the nickel-based nanowire array with commercial nickel foam as the substrate.

[0048] A large-scale preparation method of an electrolytic water hydrogen evolution electrode material, in which the reduction reaction is carried out smoothly under oil bath conditions. After the reaction ends, a solution containing nickel is obtained, which is poured into a surface dish grid plate with nickel foam placed at the bottom and a magnet placed below, and left to stand at room temperature for a period of time to obtain a nickel nanowire array hydrogen evolution electrode material. The size and shape of the plate and the surface dish can be adjusted, and at the same time, the size and shape of the grid cells in the surface dish can also be adjusted, so that nickel foams of different sizes and shapes can be processed.

[0049] Its step flow is as Figure 24 shown:

[0050] Step 1: Pretreat the nickel foam.

[0051] Put the cut nickel foam into hydrochloric acid solution and etch it under ultrasonic conditions for 15 minutes. After the etching is completed, put it into deionized water and clean the nickel foam under ultrasonic conditions to wash away the residual hydrochloric acid solution on the surface of the nickel foam. The cleaning process is repeated three times, and then put it into absolute ethanol solution and clean the nickel foam under ultrasonic conditions to obtain the treated nickel foam. The area of the nickel foam is 1×1 cm 2 ~40×40 cm 2 , and the concentration of the hydrochloric acid solution is 3M.

[0052] Step 2: Prepare a nickel nanowire solution containing nickel.

[0053] Nickel chloride hexahydrate (NiCl2·6H2O) powder and sodium citrate powder are added to deionized water, stirred to dissolve the solid powder, and potassium chloroplatinate solution is added dropwise after dissolution, and stirred for 3 to 5 minutes to obtain solution A. A hydrazine hydrate solution of the same volume and a certain concentration is added to another beaker to obtain solution B. Potassium hydroxide solution is continuously added dropwise to adjust the pH of solution A and solution B to 12.5 to obtain a suitable alkaline environment. After preheating solution A and solution B at 80°C for 5 minutes, solution A will become a green colloidal fluid. Solution A and solution B are directly mixed evenly and then transferred to an oil bath environment at 80°C. After mechanical stirring, heating and stirring for a period of time, a solution containing nickel nanoparticles for growing nanowires, i.e., a nanowire solution containing nickel, is obtained.

[0054] The solution A contains 3 mmol of NiCl2·6H2O, 1.125 mmol of sodium citrate, 30 mL of deionized water, and 4 mg mL of potassium chloroplatinate solution. -1 , the dosage is 2 drops.

[0055] The concentration of hydrazine hydrate in solution B is 0.38 mol L -1 The concentration of potassium hydroxide solution is 6 mol L -1 .

[0056] Step 3: Prepare nickel nanowire array electrode material (Ni NWs / NF).

[0057] The treated nickel foam is spread on the bottom of the watch glass, and is located in the middle of the watch glass as far as possible. A magnet is placed under the watch glass, and the upper surface area of the magnet is larger than the area of the treated nickel foam. The solution containing nickel nanowires is poured into the watch glass, and the magnet is placed in the grid plate of the plate. The solution is poured into the grid plate of the large watch glass, and the watch glass is covered with plastic wrap. The entire watch glass is in a room temperature environment. After being placed for half an hour, it can be clearly observed that the solution in the watch glass changes from a black turbid liquid to a clear light green solution, and there is an obvious black flocculent solid at the bottom of the watch glass. The entire nickel foam also turns black, and the nickel nanowire array electrode material (Ni NWs / NF) is obtained.

[0058] The size and shape of the plate and the watch glass are adjustable, and the size and shape of the grid plate cells in the watch glass are also adjustable, so that multiple nickel foams of different shapes and sizes can be processed at the same time.

[0059] The material of the plate can be plastic, ceramic, or wood, and the size of the plate is 1×1m 2 ~10×10m 2 , various shapes, such as round, square, regular hexagon and triangle.

[0060] The size of the watch glass is 1×1 m 2 ~10×10 m 2 and it has various shapes, which can be circular, square, regular hexagon, or triangular. The material is a transparent material, such as glass, for convenient observation of solution phenomena.

[0061] The overall size of the grid plate is the same as the size of the plate, and the size of the grid cell is 1×1 cm 2 ~40×40 cm 2 and the materials are plastic, ceramic, or wood.

[0062] Example 1

[0063] According to Figures 11 - 13 shown;

[0064] (1) Pretreatment of commercial nickel foam

[0065] Put commercial nickel foam (NF) with a size of 2×3 cm 2 into 3M HCl solution and etch it under ultrasonic conditions for 15 minutes. After etching, put it into deionized water and clean it under ultrasonic conditions to wash away the residual hydrochloric acid solution on the surface. The cleaning process is repeated 3 times, and then put it into absolute ethanol solution and clean it under ultrasonic conditions to obtain the treated nickel foam.

[0066] (2) Magnet region

[0067] Magnet size: The cross-section is a square of 5×5 cm 2 and the height is 1 cm. It is placed flat on the table.

[0068] (3) Nanowire growth region

[0069] Use a watch glass to statically grow nanowires: The cross-section of the watch glass is a circle with a radius of 2.5 cm and the height is 1 cm. It is used to place the pretreated nickel foam.

[0070] (4) Reaction process

[0071] Add 3 mmol of nickel chloride hexahydrate (NiCl2·6H2O) powder medicine and 1.125 mmol of sodium citrate powder to 30 mL of deionized water. At the same time, add 2 drops of potassium chloroplatinate solution and mix well under ultrasonic conditions. Wait until the powder is completely dissolved to obtain solution A. Add 30 mL of a 0.38 mol L-1 hydrazine hydrate solution to another beaker to obtain solution B. Use 6 M potassium hydroxide solution to adjust the pH of A and solution B to 12.5. As potassium hydroxide is continuously added, white flocculants will appear in solution A. After stirring, the solution will change from green transparent to light green transparent. There is no obvious change in solution B. After preheating solutions A and B at 80 °C for 5 minutes, solution A will become a green colloidal fluid. After directly mixing solutions A and B evenly, transfer them to an 80 °C oil bath environment and use mechanical stirring. After heating and stirring for 20 minutes, a solution containing nickel nanowires is obtained.

[0072] Add 20 mL of the solution to a petri dish containing nickel foam. After filling it up, let it stand for 30 minutes to obtain a nickel-based nanowire array structure electrode material.

[0073] Example 2

[0074] According to Figures 2 - 4 as shown:

[0075] (1) Pretreatment of commercial nickel foam

[0076] Put commercial nickel foam (NF) with a size of 2×3 cm 2 into 3 M HCl solution and etch it under ultrasonic conditions for 15 minutes. After etching, put it into deionized water and clean it under ultrasonic conditions to wash away the residual hydrochloric acid solution on the surface. Repeat the cleaning process 3 times, and then put it into absolute ethanol solution and clean it under ultrasonic conditions to obtain the treated nickel foam.

[0077] (2) Magnet region

[0078] Use a circular ceramic plate with a diameter of 1 m. The overall grille plate is circular with a diameter of 1 m. The cell size of the grille plate is 3×3 cm 2 , with an overall height of 1 cm and a magnet installed inside. The overall device is easy to assemble, meets the need for reactions at any time and place, and can use common commercially available magnets that meet the size for reactions.

[0079] (3) Nanowire growth region

[0080] Grow nanowires using a petri dish: Use a circular glass petri dish with a diameter of 1 m and a height of 1 cm, with a cell size of 3×3 cm inside 2, The overall is a circular grid plate with a diameter of 1m and a height of 1cm, used for placing pretreated nickel foam. There is also a circular grid plate with a diameter of 3cm for the circular cells and an overall diameter of 1m and a height of 1cm, used for placing nickel foam of different shapes.

[0081] (4) Reaction process

[0082] Add 0.4mol of nickel chloride hexahydrate (NiCl2·6H2O) powder medicine and 0.15mol of sodium citrate powder to 4L of deionized water. After magnetic stirring until the solid is dissolved, add 25mL of potassium chloroplatinate solution, mix evenly, and stir for 3 minutes to obtain solution A. Add 4L of hydrazine hydrate solution with a concentration of 0.38mol / L -1 to another beaker to obtain solution B. Use 6M potassium hydroxide solution to adjust the pH of solution A and solution B to 12.5. As potassium hydroxide is continuously added, white flocculates will appear in solution A, and after stirring, the solution will change from green transparent to light green transparent. There is no obvious change in solution B. After preheating solution A and solution B at 80°C for 5 minutes, solution A will become a green colloidal fluid. After directly mixing solution A and solution B evenly, transfer them to an 80°C oil bath environment, use mechanical stirring, heat and stir for 20 minutes to obtain a solution containing nickel nanowires.

[0083] Add the solution to a petri dish containing nickel foam, and let it stand for 30 minutes after filling to obtain a nickel-based nanowire array structure electrode material.

[0084] Example 3

[0085] According to Figures 5 - 7 shown;

[0086] (1) Pretreatment of commercial nickel foam

[0087] Put commercial nickel foam (NF) with a size of 20×10cm 2 into 3M HCl solution and etch it under ultrasonic conditions for 15 minutes. After etching, put it into deionized water and clean it under ultrasonic conditions to wash away the residual hydrochloric acid solution on the surface. Repeat the cleaning process 3 times, and then put it into absolute ethanol solution and clean it under ultrasonic conditions to obtain the treated nickel foam.

[0088] (2) Magnet area

[0089] Use a circular ceramic plate with a diameter of 1m. The overall grid plate is circular with a diameter of 1m. The grid plate cell size is 40×40cm 2 , with an overall height of 1cm and a magnet installed inside. The overall device is easy to assemble, meets the need for reactions at any time and place, and can use common commercially available magnets of suitable sizes for reactions.

[0090] (3) Nanowire growth region

[0091] Growing nanowires using a petri dish: Use a circular glass petri dish with a diameter of 1 m and a height of 1 cm, with cell size 40×40 cm 2 and an overall circular grid plate with a diameter of 1 m and a height of 1 cm for placing pretreated nickel foam. There is also a circular grid plate with a cell diameter of 40 cm and an overall circular grid plate with a diameter of 1 m and a height of 1 cm for placing nickel foam of different shapes.

[0092] (4) Reaction process

[0093] Add 0.4 mol of nickel chloride hexahydrate (NiCl2·6H2O) powder medicine and 0.15 mol of sodium citrate powder to 4 L of deionized water. After magnetic stirring until the solid dissolves, add 25 mL of potassium chloroplatinate solution, mix well, and stir for 3 minutes to obtain solution A. Add 4 L of hydrazine hydrate solution with a concentration of 0.38 mol L -1 to another beaker to obtain solution B. Use 6 M potassium hydroxide solution to adjust the pH of A and solution B to 12.5. As potassium hydroxide is continuously added, white flocs will appear in solution A, and after stirring, the solution will change from green transparent to light green transparent. There is no obvious change in solution B. After preheating solution A and solution B at 80 °C for 5 minutes, solution A will become a green colloidal fluid. After directly mixing solution A and solution B evenly, transfer them to an 80 °C oil bath environment, use mechanical stirring, heat and stir for 20 minutes to obtain a solution containing nickel nanowires.

[0094] Add the solution to the petri dish containing nickel foam. After filling it up, let it stand for 30 minutes to obtain a nickel-based nanowire array structure electrode material.

[0095] Example 4

[0096] According to Figures 8 - 10 as shown:

[0097] (1) Pretreatment of commercial nickel foam

[0098] Put commercial nickel foam (NF) with a size of 20×10 cm 2 into 3 M HCl solution and etch it under ultrasonic conditions for 15 minutes. After etching, use deionized water and clean it under ultrasonic conditions to wash away the residual hydrochloric acid solution on the surface. Repeat the cleaning process 3 times, and then put it into absolute ethanol solution and clean it under ultrasonic conditions to obtain the treated nickel foam.

[0099] (2) Magnet region

[0100] Use a magnet with a size of 1×1 m 2The square ceramic plate has an overall size of 1×1m for the grille plate. 2 The grille plate is square with a cell size of 3×3cm. 2 It has an overall height of 1cm and contains magnets inside, and common commercially available magnets of suitable size can be used for the reaction.

[0101] (3) Nanowire growth area

[0102] Growing nanowires using a petri dish: Use a square glass petri dish with a cross-section of 1×1m 2 and a height of 1cm, with cell size of 3×3cm inside 2 and a square grille plate with a cross-section of 1×1m 2 and a height of 1cm, used to place the pretreated nickel foam. There is also a square grille plate with a circular cell diameter of 3cm and an overall cross-section of 1×1m 2 and a height of 1cm, used to place nickel foam of different shapes.

[0103] (4) Reaction process

[0104] Add 0.4mol of nickel chloride hexahydrate (NiCl2·6H2O) powder medicine and 0.15mol of sodium citrate powder to 4L of deionized water. After magnetic stirring until the solid dissolves, add 25mL of potassium chloroplatinate solution, mix well, and stir for 3 minutes to obtain solution A. Add 4L of hydrazine hydrate solution with a concentration of 0.38mol L -1 to another beaker to obtain solution B. Use 6M potassium hydroxide solution to adjust the pH of A and solution B to 12.5. As potassium hydroxide is continuously added, white flocs will appear in solution A, and after stirring, the solution will change from green transparent to light green transparent. There is no obvious change in solution B. After preheating solution A and solution B at 80°C for 5 minutes, solution A will become a green colloidal fluid. After directly mixing solution A and solution B evenly and transferring them to an 80°C oil bath environment, use mechanical stirring, heat and stir for 20 minutes to obtain a solution containing nickel nanowires.

[0105] Add the solution to the petri dish containing nickel foam, fill it up and let it stand for 30 minutes to obtain the nickel-based nanowire array structure electrode material.

[0106] Example 5

[0107] According to Figures 1 - 24 as shown:

[0108] (1) Pretreatment of commercial nickel foam

[0109] The nickel foam with a size of 2×3cm 2The commercial nickel foam (NF) is placed in a 3M HCl solution and etched under ultrasonic conditions for 15 minutes. After etching, it is placed in deionized water and cleaned under ultrasonic conditions to wash away the residual hydrochloric acid solution on the surface. The cleaning process is repeated 3 times, and then it is placed in an anhydrous ethanol solution and cleaned under ultrasonic conditions to obtain the treated nickel foam.

[0110] (2) Magnet region

[0111] Use a regular hexagonal ceramic plate with a side length of 1 m. The overall grille plate is regular hexagonal with a side length of 1 m, and the cell size of the grille plate is 3×3 cm 2 , with an overall height of 1 cm and containing a magnet inside. Common commercially available magnets that meet the size requirements can be used for the reaction.

[0112] (3) Nanowire growth region

[0113] Use a petri dish to grow nanowires: Use a regular hexagonal glass petri dish with a side length of 1 m and a height of 1 cm, with a cell size of 3×3 cm inside 2 and an overall regular hexagonal grille plate with a side length of 1 m and a height of 1 cm, which is used to place the pretreated nickel foam. There is also a regular hexagonal grille plate with a circular cell diameter of 3 cm, an overall side length of 1 m, and a height of 1 cm, which is used to place nickel foams of different shapes. The overall structure is as Figures 11 - 13 shown.

[0114] (4) Reaction process

[0115] The growth process simulation diagram of the entire nanowire array structure is as Figure 1 shown. The nanowire growth region is above, and the magnet placement region is below. There are only two ways and two steps to complete the whole process. By Figures 2 - 13 analyzing the nanowire growth region, we can conclude that the nanowire growth method in this patent can simultaneously process the preparation process of hundreds of nickel nanowire array electrode materials. This patent can also process commercial nickel foams of different sizes, as small as 1×1 cm 2 , and as large as 40×40 cm 2 . The obtained nickel foam samples can all be used to prepare hydrogen evolution electrodes with a nickel nanowire array structure. Figure 17 is the obtained 20×10 cm 2 sample. From this, it can be seen that the method of the present invention for large-scale production of electrode materials can be fully applied to the industrial environment.

[0116] As Figures 14 - 16As shown, Example 1 simulates the reaction process in a single cell. The nickel-based nanowire array structure electrode material obtained in Example 1 is subjected to physical characterization and electrochemical testing. By performing a scanning electron microscope test (SEM) on the obtained nickel-based nanowire array structure electrode material, Figures 18A - 18B , it can be clearly seen in the picture that the nanowires grow densely, and these nanowires provide a large number of active sites for the reaction. And Figure 19 shows the results of X-ray powder diffraction testing (XRD). By comparing the peaks, it can be concluded that only nickel elements are present on the surface of the material. This shows that nickel nanowires can also be grown by separating the reduction reaction from the growth under the magnetic field. Figure 20 , Figure 21 and Figure 22 show the excellent electrochemically hydrogen evolution performance of the obtained nickel nanowire electrode material. At a current density of 10 mA cm -2 , the overpotential is only 71 mV, which is much lower than that of commercial nickel foam. By comparing the impedance, it can be seen that the charge transfer resistance of the nickel nanowire array is significantly reduced. Figure 23 shows the stability of this material. In summary, it can be concluded that the large-scale method for preparing the nickel nanowire electrode material of the present invention is feasible.

[0117] The above are only specific embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. It should be noted that for those of ordinary skill in the art, improvements and refinements made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. A method for large-scale preparation of a nanowire array electrode, characterized in that, It includes the following steps: Step 1: Pretreat the nickel foam; Put the cut nickel foam into hydrochloric acid solution and etch it under ultrasonic conditions for 15 minutes. After the etching is completed, put it into deionized water and clean the nickel foam under ultrasonic conditions to wash away the residual hydrochloric acid solution on the surface of the nickel foam. Repeat the cleaning process three times. Then put it into anhydrous ethanol solution and clean the nickel foam under ultrasonic conditions to obtain the treated foam; the area of the nickel foam is 1×1 cm 2 ~40×40 cm 2 , and the concentration of the hydrochloric acid solution is 3 M; Step 2: Prepare a nanowire solution containing nickel; Add nickel chloride hexahydrate powder medicine and sodium citrate powder to deionized water, stir to dissolve the solid powder. After dissolution, add potassium chloroplatinate solution dropwise, and then stir for 3 - 5 minutes to obtain solution A. Add a hydrazine hydrate solution with a certain concentration and the same volume to another beaker to obtain solution B. Use the method of continuously dropping potassium hydroxide solution to adjust the pH of solution A and solution B to 12.5 to obtain a suitable alkaline environment. After preheating solution A and solution B at 80 °C for 5 minutes, solution A will become a green colloidal fluid. After directly mixing solution A and solution B evenly, transfer them to an 80 °C oil bath environment, use mechanical stirring, heat and stir for a period of time to obtain a solution containing nickel nanoparticles for growing nanowires, that is, a nickel-containing nanowire solution; where in solution A, NiCl₂·6H₂O is 3 mmol, sodium citrate is 1.125 mmol, deionized water is 30 mL, the concentration of potassium chloroplatinate solution is 4 mg / mL -1 , and the dosage is 2 drops. The concentration of hydrazine hydrate in solution B is 0.38 mol / L -1 , and the concentration of potassium hydroxide solution is 6 mol / L -1； Step 3: Prepare the nanowire array electrode material Ni NWs / NF of nickel; Lay the treated nickel foam flat at the middle position at the bottom of the petri dish. Place a magnet under the petri dish. The upper surface area of the magnet is larger than the area of the treated nickel foam. Pour the solution containing nickel nanowires into the petri dish. The magnet is placed inside the grid plate of the plate. The solution is poured into the grid plate of the large petri dish. Wrap the petri dish with plastic wrap. The whole petri dish is in a normal temperature environment. Let it stand for half an hour. When the solution in the petri dish changes from a black turbid liquid to a clear light green solution, and there are obvious black flocculent solids at the bottom of the petri dish, and the whole nickel foam also turns black, at this time, the nanowire array electrode material Ni NWs / NF of nickel is obtained.

2. The large-scale preparation method of a nanowire array electrode according to claim 1, wherein, Step 3 further includes that the material of the plate is any one of plastic, ceramic, and wood, and the size of the plate is 1×1 m 2 ~10×10 m 2 , and the shape is any one of circular, square, regular hexagon, and triangle; The size of the watch glass is 1×1 m 2 ~10×10 m 2 , and the shape is any one of circular, square, regular hexagon, and triangle, and the material is a transparent material; The overall size of the grid plate is the same as the size of the plate, and the size of the cell is 1×1 cm 2 ~40×40 cm 2 , and the material is any one of plastic, ceramic, and wood

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