Phosphorus-containing non-noble metal-based alkaline electrolytic water hydrogen production electrode and preparation method

Abstract

The application discloses a phosphorus-containing non-noble metal alkaline water electrolysis hydrogen production electrode and a preparation method thereof, and the method comprises the following steps: cleaning and surface treating a Raney nickel mesh substrate; preparing a first reaction solution containing a cobalt salt, a nickel salt, sodium dihydrogen phosphate and dimethylaminoborine, depositing the substrate in the reaction solution, drying, sintering at 400-600 DEG C, and forming a phosphorus-containing nickel-cobalt-boron inner protective layer; then preparing a second reaction solution containing a cobalt salt, a nickel salt and dimethylaminoborine, depositing the substrate with the inner protective layer in the second reaction solution, and drying to obtain an alkaline water electrolysis hydrogen production electrode with a nickel-cobalt-boron catalytic layer as the outer layer. Through the double-layer coating structure and intermediate sintering treatment, the service life of the electrode under large current density and the dynamic response ability to fluctuating power are improved, the reverse current corrosion generated in the electrolysis cell when the current is turned off can be effectively resisted, the overpotential is greatly reduced, and the electrode is suitable for industrial water electrolysis hydrogen production combined with wind energy and light energy and ordinary stable power supply.

Description

Technical Field

[0001] This invention relates to the field of electrochemical hydrogen production, and particularly to an alkaline water electrolysis hydrogen production electrode containing phosphorus and a non-precious metal and its preparation method. Background Technology

[0002] Alkaline water electrolysis for hydrogen production is one of the main technical routes for industrial hydrogen production. The performance of electrode materials directly determines the hydrogen production efficiency and operating cost. Raney nickel is widely used as a cathode substrate due to its large specific surface area and good catalytic activity. However, pure Raney nickel has problems such as rapid activity decay, poor compatibility with clean energy sources such as wind and solar power, and easy corrosion when the reverse current is greater than the forward current.

[0003] Currently, Raney nickel electrodes are mainly used in commercial alkaline water electrolysis for hydrogen production. However, Raney nickel electrodes have problems such as insufficient catalytic activity and poor stability at high current densities. In order to improve electrode performance, researchers have developed a variety of non-precious metal hydrogen evolution electrode materials, among which nickel-cobalt-boron alloys have attracted much attention due to their excellent hydrogen evolution catalytic activity.

[0004] However, existing nickel-cobalt-boron electrodes still have the following drawbacks: First, the single nickel-cobalt-boron coating has poor corrosion resistance and is easily corroded and dissolved in strongly alkaline electrolytes, resulting in a short electrode life; second, the coating has weak adhesion to the substrate, which leads to alkaline solution penetration and corrosion of the substrate, shortening the electrode life; and third, it has poor dynamic response and matching to unstable energy sources such as wind and solar power.

[0005] Therefore, developing a non-precious metal alkaline water electrolysis hydrogen production electrode with high catalytic activity, good corrosion resistance, strong adhesion to substrate, and simple preparation process has important practical significance and application value. Summary of the Invention

[0006] The main objective of this invention is to provide an alkaline water electrolysis hydrogen production electrode containing phosphorus and a non-precious metal and its preparation method. Through a double-layer coating structure and intermediate sintering treatment, the electrode's service life under high current density and dynamic response capability to fluctuating electrical energy are significantly improved, the overpotential is greatly reduced, and it does not use precious metals, resulting in low cost.

[0007] To achieve the above objectives, the present invention provides a method for preparing an alkaline water electrolysis hydrogen production electrode containing phosphorus and non-precious metals, comprising the following steps: The Raney nickel mesh substrate was ultrasonically cleaned sequentially with pure water, ethanol, and acetone. Then, the oxide layer on the surface of the Raney nickel mesh substrate was removed with nitric acid solution and sodium hydroxide solution. After drying, it was ready for use. Add cobalt salt, nickel salt, sodium succinate, sodium dihydrogen phosphate, citric acid, and dimethylaminoborane to water, stir and dissolve to prepare the first reaction solution, wherein the molar amounts of cobalt and nickel are 0.01-1 parts each, the molar amounts of phosphorus are 0.01-1 parts, and the molar amounts of boron are 0.01-1 parts. The cleaned Raney nickel mesh substrate is placed in the first reaction solution and reacted at 20-30℃ for 0.5-5 hours. After that, it is taken out, washed with pure water, and dried in an oven to obtain the inner layer precursor. The inner layer precursor is sintered at 400-600℃ and naturally cooled to room temperature to obtain a Raney nickel mesh substrate with a phosphorus-containing nickel-cobalt-boron inner protective layer on the surface. Add cobalt salt, nickel salt, sodium succinate, citric acid, and dimethylaminoborane to water, stir and dissolve to prepare a second reaction solution, wherein the molar amounts of cobalt and nickel are 0.01-1 parts each, and the molar amount of boron is 0.01-1 parts. The Raney nickel mesh substrate with an inner protective layer is placed in the second reaction solution, reacted at room temperature, removed, washed with pure water, and dried in an oven to obtain an alkaline water electrolysis hydrogen production electrode with a nickel-cobalt-boron catalytic layer on the outside.

[0008] Furthermore, the step of sintering the inner layer precursor at 400-600℃ and naturally cooling it to room temperature to obtain a Raney nickel mesh substrate with a phosphorus-containing nickel-cobalt-boron inner protective layer on the surface includes: The inner layer precursor is placed in a muffle furnace and sintered at 400℃-600℃ for 2-5 hours, then naturally cooled to room temperature with the furnace.

[0009] Furthermore, in the first reaction solution, the molar ratio of phosphorus to the total amount of cobalt and nickel is 0.3-0.7, and the molar ratio of boron to the total amount of cobalt and nickel is 0.4-0.8.

[0010] Furthermore, the step of placing the Raney nickel mesh substrate with an inner protective layer into the second reaction solution, reacting at room temperature, removing it, washing it with pure water, and drying it in an oven to obtain an alkaline water electrolysis hydrogen production electrode with a nickel-cobalt-boron catalytic layer as the outer layer includes: The Raney nickel mesh substrate with the inner protective layer is placed in the second reaction solution and reacted at room temperature of 20℃-30℃ for 0.5-5 hours. After that, it is taken out, rinsed with pure water until neutral, and dried in an oven at 70-90℃ for 0.5-1.5 hours.

[0011] Furthermore, the outer nickel-cobalt-boron catalyst layer has a sheet-like stacked structure.

[0012] Furthermore, the phosphorus source in the first reaction solution is sodium dihydrogen phosphate, and the boron source in the first and second reaction solutions is dimethylaminoborane.

[0013] Furthermore, in the first reaction solution, the molar ratio of cobalt to nickel is 0.8-1.2:1.

[0014] Furthermore, the amount of cobalt and nickel is 0.2-0.4 parts by weight.

[0015] The present invention also provides an alkaline water electrolysis hydrogen production electrode containing phosphorus and non-precious metals, which is prepared by the above-described preparation method of the alkaline water electrolysis hydrogen production electrode containing phosphorus and non-precious metals.

[0016] The present invention also provides an application of an alkaline water electrolysis hydrogen production electrode containing phosphorus and non-precious metals, wherein the above-mentioned alkaline water electrolysis hydrogen production electrode containing phosphorus and non-precious metals is used in the alkaline water electrolysis hydrogen production reaction.

[0017] The method for preparing a phosphorus-containing non-precious metal alkaline water electrolysis hydrogen production electrode provided in the above embodiments has the following beneficial effects: A dense metallurgical bonding layer is formed by sintering a phosphorus-containing nickel-cobalt-boron inner protective layer at a high temperature of 400-600℃. This layer not only prevents corrosion from strong alkaline electrolytes but also solves the problem of easy coating peeling, thus improving the long-term stability of the electrode. The outer nickel-cobalt-boron catalytic layer has a unique sheet-like stacked structure, which provides a large electrochemical active surface area and abundant catalytic active sites. It is prepared by a two-step chemical plating method, which does not require vacuum equipment or precious metal raw materials. All reagents are commonly used in industry, resulting in low production costs, good process repeatability, and suitability for large-scale industrial production. Attached Figure Description

[0018] Figure 1 This is a flowchart of a method for preparing an alkaline water electrolysis hydrogen production electrode containing phosphorus and non-precious metals, as provided in an embodiment of the present invention. Figure 2 This describes the overall morphology of the outer nickel-cobalt-boron catalyst layer sheet-like stacked structure in this invention; Figure 3 This is a fine feature of the nanosheet-like structure of the outer nickel-cobalt-boron catalytic layer in this invention; Figure 4 This describes the dense surface morphology of the inner layer after sintering of the phosphorus-containing nickel-cobalt-boron compound in this invention. Figure 5 The inner layer of the phosphorus-containing nickel-cobalt-boron composite material in this invention has a dense nanoparticle structure after sintering. Figure 6 These are the linear sweep voltammetric curves of different electrodes in the electrolyte in this invention; Figure 7 This is a comparison diagram of hydrogen evolution overpotentials of different electrodes in this invention; Figure 8 This is a table showing the long-term stability test results of different electrodes under continuous start-stop conditions in this invention; The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] Reference Figure 1 This is a schematic flowchart of a method for preparing a phosphorus-containing non-precious metal alkaline water electrolysis hydrogen production electrode proposed in this invention, including the following steps: S1. The Raney nickel mesh substrate is ultrasonically cleaned sequentially with pure water, ethanol and acetone, and then the oxide layer on the surface of the Raney nickel mesh substrate is removed with nitric acid solution and sodium hydroxide solution. After drying, it is ready for use. S2, add cobalt salt, nickel salt, sodium succinate, sodium dihydrogen phosphate, citric acid, and dimethylaminoborane to water, stir and dissolve to prepare the first reaction solution, wherein the molar amounts of cobalt and nickel are 0.01-1 parts each, the molar amounts of phosphorus are 0.01-1 parts, and the molar amounts of boron are 0.01-1 parts. S3, the cleaned Raney nickel mesh substrate is placed in the first reaction solution, reacted at 20-30℃ for 3 hours, taken out, washed with pure water, and dried in an oven to obtain the inner layer precursor; S4. The inner layer precursor is sintered at 400-600℃ and naturally cooled to room temperature to obtain a Raney nickel mesh substrate with a phosphorus-containing nickel-cobalt-boron inner layer protective layer on the surface. S5, add cobalt salt, nickel salt, sodium succinate, citric acid and dimethylaminoborane to water, stir and dissolve to prepare the second reaction solution, wherein the molar amount of cobalt and nickel is 0.01-1 parts each, and the molar amount of boron is 0.01-1 parts. S6. The Raney nickel mesh substrate with an inner protective layer is placed in the second reaction solution, reacted at room temperature, removed, washed with pure water, and dried in an oven to obtain an alkaline water electrolysis hydrogen production electrode with a nickel-cobalt-boron catalytic layer on the outside.

[0021] As described in step S1 above, the Raney nickel mesh substrate is ultrasonically cleaned sequentially in pure water, ethanol, and acetone, with each solvent requiring 10-20 minutes of ultrasonic cleaning. This removes oil, dust, and processing residues from the substrate surface. Pure water is used for initial rinsing, while ethanol and acetone are used for degreasing and oil removal to ensure a clean substrate surface. After ultrasonic cleaning, the substrate is removed and rinsed with pure water to remove any remaining organic solvents. The substrate is then chemically etched to remove the natural oxide layer and create a micro-rough structure. Specifically, the cleaned Raney nickel mesh substrate is immersed in a 3M nitric acid solution for 5-10 minutes, utilizing the strong oxidizing properties of nitric acid to dissolve the nickel oxide layer on the surface. After removal, it is rinsed with pure water and then immersed in a 1M sodium hydroxide solution for 5-10 minutes to neutralize any remaining acid and further etch the substrate surface, while also removing any potential impurities. After acid and alkali washing, the substrate is immediately and repeatedly rinsed with plenty of pure water until the pH of the rinsing solution is neutral, thoroughly removing any residual acid, alkali, and reaction products from the surface. Finally, place the cleaned substrate in an oven and dry it at 60-80℃ for 0.5-1 hour to remove moisture. The drying temperature should not be too high to avoid re-oxidation of the substrate.

[0022] As described in step S2 above, measure an appropriate amount of pure water, usually 150-250 mL, as a solvent and place it in a container. Then, add the cobalt-containing salt and the nickel-containing salt sequentially, with each salt containing 0.01-1 parts by weight. The cobalt and nickel salts act as metal ion sources, forming a nickel-cobalt alloy matrix during the reduction reaction. To ensure solution homogeneity, continuous stirring is required during the addition process to ensure complete dissolution of the salts. Add sodium succinate and citric acid to the solution. The amount of sodium succinate is usually 0.2-0.4 parts, and the amount of citric acid is 0.01-0.05 parts. Sodium succinate stabilizes the pH of the solution and regulates the release rate of metal ions; citric acid acts as a strong complexing agent, forming stable complexes with nickel and cobalt ions to control the deposition rate, thereby obtaining a uniform and dense coating. Then, sodium dihydrogen phosphate and dimethylaminoborane are added. Sodium dihydrogen phosphate provides the phosphorus source, with a molar ratio of 0.01-1 parts; dimethylaminoborane provides the boron source and also acts as a reducing agent, with a molar ratio of 0.01-1 parts. During the reaction, dimethylaminoborane decomposes and releases electrons, reducing nickel and cobalt ions to elemental metals, while simultaneously co-depositing phosphorus into the alloy to form a phosphorus-containing nickel-cobalt-boron alloy. The introduction of phosphorus improves the amorphous state and corrosion resistance of the coating. After all components are added, stirring continues until completely dissolved, yielding a clear and homogeneous first reaction solution. The pH of this reaction solution is weakly acidic to neutral due to the presence of sodium succinate and citric acid. It should be used immediately after preparation or stored in a sealed container to prevent oxidation and deactivation of the reducing agent.

[0023] As described in step S3 above, the pretreated Raney nickel mesh substrate is completely immersed in the prepared first reaction solution, and the reaction temperature is controlled at room temperature (20-30℃) for 3 hours. During the reaction, dimethylaminoborane in the first reaction solution gradually decomposes and releases electrons, reducing nickel and cobalt ions in the solution to metallic nickel and metallic cobalt. Simultaneously, phosphorus from sodium dihydrogen phosphate is co-deposited into the alloy, forming a uniform phosphorus-containing nickel-cobalt-boron alloy coating on the surface of the Raney nickel mesh substrate. Since the reaction is carried out at room temperature, the deposition rate is moderate, which is conducive to obtaining a precursor layer with uniform composition and dense structure. Only slight stirring is required during the reaction to maintain a uniform concentration of the reaction solution. After 3 hours, the substrate with the deposited layer is removed from the reaction solution and immediately rinsed repeatedly with a large amount of pure water to remove residual reaction solution, unreacted ions, decomposition products of reducing agents, and other impurities from the surface to prevent interference from impurities. Rinsing continues until the effluent is clear. After rinsing, the substrate is placed in a forced-air drying oven at 70-90℃ for 0.5-1.5 hours to remove adsorbed moisture from the substrate and the deposited layer, preventing coating cracking or substrate oxidation during high-temperature sintering. After drying, a Raney nickel mesh substrate with a phosphorus-containing nickel-cobalt-boron inner layer precursor is obtained. This precursor is not yet crystallized and remains in an amorphous or microcrystalline state, which is beneficial for sintering into a robust inner protective layer.

[0024] As described in step S4 above, the Raney nickel mesh substrate with the phosphorus-containing nickel-cobalt-boron inner layer precursor obtained in step S3 is placed in a muffle furnace for high-temperature sintering treatment at a temperature of 400-600℃, preferably 500℃. The muffle furnace is preheated to the set temperature or heated along with the furnace to ensure uniform sintering temperature. After the sample is placed in the furnace chamber, it is sintered at the target temperature for 3 hours. The sintering process is carried out in an air atmosphere. During the high-temperature sintering process, the small amount of residual moisture and organic complexing agent in the precursor is completely thermally decomposed and volatilized. Secondly, the amorphous or microcrystalline phosphorus-containing nickel-cobalt-boron alloy layer undergoes a crystallization transformation to form a dense intermetallic compound with good crystallinity. Phosphorus forms a solid solution or nickel-phosphorus compound in the alloy, while boron is dispersed, together improving the hardness and corrosion resistance of the inner protective layer. At high temperatures, interfacial diffusion and metallurgical bonding occur between the alloy layer and the Raney nickel mesh substrate, firmly anchoring the inner protective layer to the substrate surface. This overcomes the shortcomings of ordinary chemical plating layers, which rely solely on mechanical bonding and have insufficient adhesion to the substrate. After holding at high temperature for 3 hours, the muffle furnace power is turned off, allowing the sample to cool naturally to room temperature. Natural cooling avoids thermal stress caused by rapid cooling, which could lead to coating cracking or peeling. After cooling, the sample is removed, yielding a Raney nickel mesh substrate with a phosphorus-containing nickel-cobalt-boron inner protective layer. This inner protective layer is tightly bonded to the substrate, has a dense structure, and strong corrosion resistance, providing buffering and support under high current density and frequent start-stop conditions.

[0025] As described in step S5 above, using pure water as a solvent, measure 150-250 mL of pure water and place it in a container. First, add cobalt-containing salt and nickel-containing salt, with each salt containing 0.01-1 parts by weight, preferably in an equimolar ratio of 1:1. Continuously stir to completely dissolve the salts and ensure uniform dispersion of the metal ions. Add sodium succinate and citric acid to the solution, with sodium succinate containing 0.2-0.4 parts by weight and citric acid containing 0.01-0.05 parts by weight. Sodium succinate acts as a buffer and complexing agent to stabilize the pH of the reaction solution and prevent the hydrolysis and precipitation of metal ions; citric acid acts as a strong complexing agent to form stable complexes with nickel and cobalt ions, regulating the deposition rate, thereby obtaining a uniform and dense outer catalyst layer. Add dimethylaminoborane as a reducing agent and boron source, with a content of 0.01-1 parts by weight, preferably 0.2-0.4 parts by weight. During the reaction, dimethylaminoborane gradually decomposes and releases electrons, reducing nickel and cobalt ions to elemental metals. Simultaneously, boron is co-deposited into the alloy, forming a nickel-cobalt-boron ternary alloy. Since this reaction solution contains no phosphorus source, the deposited outer catalyst layer is a phosphorus-free nickel-cobalt-boron alloy, avoiding the potential negative masking effect of phosphorus on catalytic active sites and thus maintaining high catalytic activity. After all components are added, stirring continues until completely dissolved, yielding a clear and homogeneous second reaction solution. The pH of this reaction solution is weakly acidic to neutral due to the presence of sodium succinate and citric acid, requiring no additional adjustment. The second reaction solution should be prepared and used immediately to prevent dimethylaminoborane from oxidizing and becoming ineffective due to prolonged exposure to air. The prepared second reaction solution will be used to deposit the outer catalyst layer on a substrate with an inner protective layer.

[0026] As described in step S6 above, the Raney nickel mesh substrate with an inner protective layer obtained in step S4 is completely immersed in the second reaction solution prepared in step S5, and reacted at room temperature (20-30°C) for 0.5-5 hours, preferably 3 hours. During the reaction, dimethylaminoborane in the second reaction solution gradually decomposes and releases electrons, reducing nickel and cobalt ions in the solution to elemental metals. Simultaneously, boron is co-deposited, forming a uniform nickel-cobalt-boron alloy catalytic layer on the surface of the inner protective layer. Since the second reaction solution does not contain a phosphorus source, this outer catalytic layer is a phosphorus-free nickel-cobalt-boron alloy, avoiding the potential masking effect of phosphorus on catalytic active sites, thereby maintaining high hydrogen evolution catalytic activity. Unlike the inner precursor, the deposition process of the outer catalytic layer does not involve high-temperature sintering. Instead, a coating with a nanosheet-like stacked structure is formed directly through chemical plating. This sheet-like structure significantly increases the specific surface area of ​​the electrode, exposing more active sites, which is beneficial for electrolyte penetration and hydrogen desorption, thereby significantly reducing overpotential. After the reaction is complete, the substrate is removed from the second reaction solution and immediately rinsed repeatedly with pure water until neutral to thoroughly remove residual reaction solution, unreacted ions, and decomposition products of the reducing agent. The cleaned substrate is placed in a forced-air drying oven and dried at 70-90℃ for 0.5-1.5 hours to remove moisture. After natural cooling to room temperature, an alkaline water electrolysis hydrogen production electrode with a nickel-cobalt-boron catalytic layer on the outside is obtained. This electrode has a double-layer coating structure: the inner layer is a phosphorus-containing nickel-cobalt-boron protective layer, which is firmly bonded to the Raney nickel substrate through high-temperature sintering, providing corrosion resistance and anti-stripping ability; the outer layer is a phosphorus-free nickel-cobalt-boron catalytic layer with a sheet-like stacked nanostructure, providing high catalytic activity. The synergistic effect of the two layers enables the electrode to exhibit long life and excellent catalytic performance under high current density and frequent start-stop conditions.

[0027] The present invention will be specifically described below through examples.

[0028] Example 1 Take a 10cm × 10cm Raney nickel mesh substrate and ultrasonically clean it sequentially in pure water, anhydrous ethanol, and acetone for 15 minutes each. After cleaning with each solvent, rinse the surface with pure water. Immerse the cleaned Raney nickel mesh substrate in a 3M nitric acid solution for 7 minutes, then rinse with pure water until neutral. Next, immerse it in a 1M sodium hydroxide solution for 7 minutes, then rinse repeatedly with plenty of pure water until the pH of the rinsing solution is 7. Place the cleaned substrate in a forced-air drying oven and dry it at 70°C for 1 hour to remove moisture before use.

[0029] Measure 200 mL of pure water as a solvent and place it in a 500 mL beaker. While stirring continuously, add 0.2 mol of cobalt sulfate and 0.2 mol of nickel sulfate sequentially, stirring until completely dissolved. Then add 0.3 mol of sodium succinate and 0.02 mol of citric acid, and continue stirring for 10 minutes. Finally, add 0.2 mol of sodium dihydrogen phosphate and 0.24 mol of dimethylaminoborane, stirring until all components are completely dissolved, yielding a clear and homogeneous first reaction solution.

[0030] The pretreated Raney nickel mesh substrate was completely immersed in the prepared first reaction solution, and the reaction temperature was controlled at 25°C for 3 hours. No stirring was required during the reaction. After the reaction, the substrate was removed and rinsed repeatedly with plenty of pure water until the effluent was clear. The rinsed substrate was placed in a forced-air drying oven and dried at 80°C for 1 hour to obtain a Raney nickel mesh substrate with a phosphorus-containing nickel-cobalt-boron inner layer precursor attached to its surface.

[0031] The inner layer precursor was placed in a muffle furnace and heated to 500°C at a rate of 3°C per minute. After holding at this temperature for 3 hours, it was naturally cooled to room temperature with the furnace to obtain a Raney nickel mesh substrate with a phosphorus-containing nickel-cobalt-boron inner protective layer on the surface.

[0032] like Figure 4 and Figure 5 As shown, the sintered phosphorus-containing nickel-cobalt-boron inner protective layer has a dense surface without obvious cracks and pores, exhibiting a uniform nanoparticle structure. This dense structure can effectively block the penetration of strongly alkaline electrolytes and significantly improve the corrosion resistance of the electrode.

[0033] Measure 200 mL of pure water as a solvent and place it in a 500 mL beaker. While stirring continuously, add 0.2 mol of cobalt sulfate and 0.2 mol of nickel sulfate sequentially, stirring until completely dissolved. Then add 0.3 mol of sodium succinate and 0.02 mol of citric acid, and continue stirring for 10 minutes. Finally, add 0.24 mol of dimethylaminoborane and stir until all components are completely dissolved, yielding a clear and homogeneous second reaction solution.

[0034] The Raney nickel mesh substrate with an inner protective layer was completely immersed in the prepared second reaction solution, and the reaction temperature was controlled at 25°C for 3 hours. After the reaction, the substrate was removed and rinsed repeatedly with plenty of pure water until the effluent was clear. The rinsed substrate was placed in a forced-air drying oven and dried at 80°C for 1 hour to obtain the phosphorus-containing non-precious metal alkaline water electrolysis hydrogen production electrode of this embodiment.

[0035] like Figure 2 As shown, the outer nickel-cobalt-boron catalytic layer has a unique sheet-like stacked structure, with nanosheets interwoven to form a three-dimensional network structure, providing a large electrochemical active surface area and abundant catalytic active sites.

[0036] The electrochemical performance of the electrode prepared in this embodiment was tested in a standard three-electrode system, with a platinum sheet as the counter electrode, a saturated calomel electrode as the reference electrode, and a 1M KOH solution as the electrolyte.

[0037] like Figure 6 As shown, the electrode prepared in this embodiment exhibits excellent hydrogen evolution catalytic activity, and its linear sweep voltammetry curve is significantly better than that of the pure nickel electrode.

[0038] like Figure 7 As shown, at a current density of 10 mA / cm², the hydrogen evolution overpotential of the electrode in this embodiment is only 95 mV; at a current density of 100 mA / cm², the hydrogen evolution overpotential is 188 mV. In contrast, the hydrogen evolution overpotential of the pure nickel electrode under the same conditions is as high as 251 mV and 359 mV, respectively. This indicates that the hydrogen evolution catalytic activity of the electrode of the present invention is about three times that of the pure nickel electrode.

[0039] The long-term stability of the electrode prepared in this embodiment was tested using a frequent start-stop mode simulating unstable power supply conditions such as wind and solar power, with a test current density of 4000 A / m². The specific test conditions were as follows: after every 1 hour of continuous electrolysis, the external power supply was completely turned off for 1 hour, and this cycle was repeated; during the shutdown period, the electrode remained immersed in the electrolyte and kept in an open circuit state.

[0040] When the external power supply is turned off, a reverse current is spontaneously generated inside the electrolytic cell, leading to oxidation and corrosion on the cathode surface. The intermittent and fluctuating nature of renewable energy generation, such as wind and solar power, causes the electrolytic cell to frequently operate at low or zero current, thus accelerating electrode corrosion. This test accelerates the simulation of this condition to verify the actual tolerance of the electrodes to unstable power sources.

[0041] like Figure 8 As shown, the initial electrolysis voltage of the electrode in this embodiment was 2.26V. After approximately 900 start-stop cycles over 2.5 months, the electrolysis voltage only increased to 2.35V, a voltage increase of only 0.09V. In contrast, the pure Raney nickel substrate electrode, under the same test conditions, experienced a sharp increase in electrolysis voltage from 2.45V to 4.65V after only one week of operation, a voltage increase of 2.20V, resulting in complete failure.

[0042] The above results show that the electrode prepared by the present invention can effectively resist reverse current corrosion generated inside the electrolytic cell when the current is turned off, has strong adaptability to current fluctuations, and has an improved service life. At the same time, the initial electrolysis voltage of the electrode in this embodiment is significantly lower than that of the pure Raney nickel electrode, further proving that its hydrogen evolution catalytic performance has been greatly improved.

[0043] Example 2 Take a 10cm × 10cm Raney nickel mesh substrate and ultrasonically clean it sequentially in pure water, anhydrous ethanol, and acetone for 15 minutes each. After cleaning with each solvent, rinse the surface with pure water. Immerse the cleaned Raney nickel mesh substrate in a 3M nitric acid solution for 7 minutes, then rinse with pure water until neutral. Next, immerse it in a 1M sodium hydroxide solution for 7 minutes, then rinse repeatedly with plenty of pure water until the pH of the rinsing solution is 7. Place the cleaned substrate in a forced-air drying oven at 70°C for 1 hour to remove moisture before use.

[0044] Measure 200 mL of pure water as a solvent and place it in a 500 mL beaker. While stirring continuously, add 0.3 mol of cobalt sulfate and 0.3 mol of nickel sulfate in sequence, stirring until completely dissolved. Then add 0.3 mol of sodium succinate and 0.02 mol of citric acid, and continue stirring for 10 minutes. Finally, add 0.2 mol of sodium dihydrogen phosphate and 0.3 mol of dimethylaminoborane, and stir until all components are completely dissolved to obtain a clear and homogeneous first reaction solution.

[0045] In this embodiment, the elemental ratios of the first reaction solution are calculated as follows: The molar ratio of cobalt to nickel is 1:1, the molar ratio of phosphorus to the total molar ratio of cobalt and nickel is 0.2 / (0.3+0.3)≈1:3, the molar ratio of boron to the total molar ratio of cobalt and nickel is 0.3 / (0.3+0.3)=1:2, and the molar fractions of cobalt and nickel are both 0.3 parts.

[0046] The pretreated Raney nickel mesh substrate was completely immersed in the prepared first reaction solution, and the reaction temperature was controlled at 25°C for 3 hours without stirring. After the reaction, the substrate was removed and rinsed repeatedly with plenty of pure water until the effluent was clear. The rinsed substrate was then placed in a forced-air drying oven and dried at 80°C for 1 hour to obtain a Raney nickel mesh substrate with a phosphorus-containing nickel-cobalt-boron inner layer precursor attached to its surface.

[0047] The inner layer precursor was placed in a muffle furnace and heated to 500°C at a rate of 3°C per minute. After holding at this temperature for 3 hours, it was naturally cooled to room temperature with the furnace to obtain a Raney nickel mesh substrate with a phosphorus-containing nickel-cobalt-boron inner protective layer on the surface.

[0048] like Figure 4 and Figure 5 As shown, the phosphorus-containing nickel-cobalt-boron inner protective layer prepared in this embodiment also exhibits a dense, crack-free, and pore-free nanoparticle structure, which is basically consistent with the inner layer morphology of Example 1. This indicates that a high-quality inner protective layer can still be obtained under the condition of a cobalt-nickel concentration of 0.3 parts.

[0049] Measure 200 mL of pure water as a solvent and place it in a 500 mL beaker. While stirring continuously, add 0.3 mol of cobalt sulfate and 0.3 mol of nickel sulfate in sequence and stir until completely dissolved. Then add 0.3 mol of sodium succinate and 0.02 mol of citric acid and continue stirring for 10 minutes. Finally, add 0.3 mol of dimethylaminoborane and stir until all components are completely dissolved to obtain a clear and homogeneous second reaction solution.

[0050] The Raney nickel mesh substrate with an inner protective layer was completely immersed in the prepared second reaction solution, and the reaction temperature was controlled at 25°C for 3 hours. After the reaction was completed, the substrate was removed and rinsed repeatedly with a large amount of pure water until the effluent was clear. The rinsed substrate was then placed in a forced-air drying oven and dried at 80°C for 1 hour to obtain the phosphorus-containing non-precious metal alkaline water electrolysis hydrogen production electrode of this embodiment.

[0051] like Figure 3 As shown, the outer nickel-cobalt-boron catalyst layer prepared in this embodiment also has a unique sheet-like stacked structure, with the nanosheets interwoven to form a three-dimensional network structure. Compared with Example 1, the nanosheets in this embodiment are more uniform in size and more tightly stacked, providing a larger electrochemically active surface area.

[0052] The electrochemical performance of the electrode prepared in this embodiment was tested in a standard three-electrode system, with a platinum sheet as the counter electrode, a saturated calomel electrode as the reference electrode, and a 1M KOH solution as the electrolyte.

[0053] like Figure 6 As shown, the electrode prepared in this embodiment exhibits superior hydrogen evolution catalytic activity compared to that in Example 1. Its linear sweep voltammetric curve is located to the right of that in Example 1, and it has a lower hydrogen evolution overpotential at the same current density.

[0054] like Figure 7 As shown, at a current density of 10 mA / cm², the hydrogen evolution overpotential of the electrode in this embodiment is only 83 mV; at a current density of 100 mA / cm², the hydrogen evolution overpotential is 171 mV. Compared with Example 1, the overpotential of the electrode in this embodiment is reduced by 12 mV at 10 mA / cm² and by 17 mV at 100 mA / cm², further enhancing the catalytic activity. This indicates that appropriately increasing the cobalt-nickel concentration can optimize the electronic structure and morphology of the catalyst layer, thereby improving the hydrogen evolution performance.

[0055] The electrode prepared in this embodiment was subjected to long-term stability testing under the same frequent start-stop conditions of 4000 A / m² current density as in Example 1. As shown in Figure 8, the initial electrolysis voltage of the electrode in this embodiment was 2.20 V. After approximately 900 start-stop cycles over 2.5 months, the electrolysis voltage increased to 2.31 V, with a voltage increase of 0.11 V.

[0056] Compared to Example 1, the voltage increase of the electrode in this example is slightly larger, but still far superior to the 2.20V increase of the pure Raney nickel electrode. This indicates that under the condition of a cobalt-nickel concentration of 0.3 parts, the electrode can still maintain excellent resistance to internal reverse current corrosion and long-term stability. At the same time, its lower initial electrolysis voltage proves that its hydrogen evolution catalytic performance is better than that of Example 1.

[0057] In summary, this invention deposits a phosphorus-containing nickel-cobalt-boron inner layer precursor on the surface of a Raney nickel mesh substrate, followed by high-temperature sintering at 400-600℃ to form a dense protective layer with atomic-level metallurgical bonding. This effectively blocks the penetration of strongly alkaline electrolytes and improves the long-term stability of the electrode. Furthermore, a nickel-cobalt-boron catalytic layer with a unique lamellar stacked structure is deposited on the outer layer, providing an ultra-large electrochemical active surface area and abundant catalytic active sites. In a 1M KOH electrolyte at a current density of 10 mA / cm², the hydrogen evolution overpotential is as low as 83 mV, exhibiting good repeatability and low production cost, making it suitable for large-scale industrial production. This provides a high-performance, low-cost electrode solution for the widespread application of alkaline water electrolysis hydrogen production technology.

[0058] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, apparatus, article, or method that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, apparatus, article, or method. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, apparatus, article, or method that includes that element.

[0059] The above description is only a preferred 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 and drawings, 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 an alkaline water electrolysis hydrogen production electrode containing phosphorus and non-precious metals, characterized in that, Includes the following steps: The Raney nickel mesh substrate was ultrasonically cleaned sequentially with pure water, ethanol, and acetone. Then, the oxide layer on the surface of the Raney nickel mesh substrate was removed with nitric acid solution and sodium hydroxide solution. After drying, it was ready for use. A first reaction solution is prepared by adding cobalt salt, nickel salt, sodium succinate, sodium dihydrogen phosphate, citric acid, and dimethylaminoborane to water and stirring to dissolve them. The molar amounts of cobalt and nickel are 0.01-1 parts each, phosphorus is 0.01-1 part, and boron is 0.01-1 part. In the first reaction solution, the molar ratio of phosphorus to the total amount of cobalt and nickel is 0.3-0.7, and the molar ratio of boron to the total amount of cobalt and nickel is 0.4-0.

8. The phosphorus source in the first reaction solution is sodium dihydrogen phosphate. The molar ratio of cobalt to nickel in the first reaction solution is 0.8-1.2:

1. The cleaned Raney nickel mesh substrate is placed in the first reaction solution and reacted at 20-30℃ for 0.5-5 hours. After that, it is taken out, washed with pure water, and dried in an oven to obtain the inner layer precursor. The inner layer precursor is sintered at 400-600℃ and then naturally cooled to room temperature to obtain a Raney nickel mesh substrate with a phosphorus-containing nickel-cobalt-boron inner protective layer on the surface. The inner layer precursor is placed in a muffle furnace and sintered at 400-600℃ for 2-5 hours, then naturally cooled to room temperature with the furnace. A second reaction solution is prepared by adding cobalt salt, nickel salt, sodium succinate, citric acid, and dimethylaminoborane to water and stirring to dissolve them. The amount of cobalt and nickel is 0.01-1 parts each, and the amount of boron is 0.01-1 parts. The boron source in the first and second reaction solutions is dimethylaminoborane. A Raney nickel mesh substrate with an inner protective layer is placed in a second reaction solution, reacted at room temperature, removed, washed with pure water, and dried in an oven to obtain an alkaline water electrolysis hydrogen production electrode with a nickel-cobalt-boron catalytic layer on the outside. The outer nickel-cobalt-boron catalytic layer has a sheet-like stacked structure.

2. The method for preparing the phosphorus-containing non-precious metal alkaline water electrolysis hydrogen production electrode according to claim 1, characterized in that, The step of placing the Raney nickel mesh substrate with an inner protective layer into the second reaction solution, reacting at room temperature, removing it, washing it with pure water, and drying it in an oven to obtain an alkaline water electrolysis hydrogen production electrode with a nickel-cobalt-boron catalytic layer on the outside includes: The Raney nickel mesh substrate with the inner protective layer is placed in the second reaction solution and reacted at room temperature of 20℃-30℃ for 0.5-5 hours. After that, it is taken out, rinsed with pure water until neutral, and dried in an oven at 70-90℃ for 0.5-1.5 hours.

3. The method for preparing the phosphorus-containing non-precious metal alkaline water electrolysis hydrogen production electrode according to claim 1, characterized in that, The amount of cobalt and nickel is 0.2-0.4 parts by weight.

4. A phosphorus-containing non-precious metal alkaline water electrolysis hydrogen production electrode, characterized in that, It is prepared by the method for preparing an alkaline water electrolysis hydrogen production electrode containing phosphorus and non-precious metals as described in any one of claims 1-3.

5. The application of an alkaline water electrolysis hydrogen production electrode containing phosphorus and non-precious metals, characterized in that, The phosphorus-containing non-precious metal alkaline water electrolysis hydrogen production electrode as described in claim 4 is used in the alkaline water electrolysis hydrogen production reaction.

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