Alkaline hydrogen production electrode and preparation method thereof

Abstract

The invention belongs to the field of electrode materials, and particularly relates to an alkaline hydrogen production electrode and a preparation method thereof.The alkaline hydrogen production electrode comprises an electrode substrate and a catalyst loaded on the electrode substrate; the catalyst comprises the following components: Ni, Fe, Mo, Cr and Mn, the molar percentage of Mo is 5-15%, and the total molar percentage of Fe and Mo is 35%. By alloying, introducing Mo and controlling the content of Fe and Mo, the catalytic activity is enhanced, compared with existing binary Raney nickel, the catalytic activity is higher, the HER reaction overpotential can be effectively reduced, so that the energy consumption of an electrolytic bath is reduced, and the corrosion resistance of an electrode can be enhanced through Cr and Mn.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of electrode materials, and particularly relates to an alkaline hydrogen production electrode and a preparation method thereof. BACKGROUND

[0002] With the rapid growth of wind power and photovoltaic new energy installations, the importance of new energy power consumption has begun to stand out. Hydrogen, as an important chemical raw material and energy carrier, is currently mostly produced from coal and chemical by-products, which produces a large amount of carbon emissions. Green hydrogen production can solve the above two problems at the same time. The current mainstream green hydrogen production method is still water electrolysis. Unlike the stable operation condition of traditional electrolytic cells, green hydrogen production has strong volatility, and the electrolytic cell needs to be powered by the source. Frequent start-stop and working condition fluctuations of the electrolytic cell are not friendly to the electrode which directly affects the performance of the electrolytic cell. The reverse current caused by the start-stop of the electrolytic cell will cause rapid decay of the electrode, which is difficult to meet the demand of large-scale hydrogen production.

[0003] The current electrode for alkaline water electrolysis hydrogen production is mainly a nickel-aluminum binary catalyst. However, the performance of the nickel-aluminum binary catalyst has been difficult to meet the increasing performance requirements of the electrolytic cell. The multi-element alloy electrode such as nickel-molybdenum-aluminum ternary electrode has a rapid performance decay due to intermetallic potential corrosion and other problems.

[0004] In summary, the existing alkaline water electrolysis hydrogen production electrode material still has significant deficiencies in dealing with the complexity of green power volatility, frequent start-stop and reverse current, and it is urgent to develop a new electrode material with high catalytic activity and excellent electrochemical stability to meet the needs of large-scale development of green hydrogen production technology. SUMMARY

[0005] The technical problem to be solved by the present application is to provide an alkaline hydrogen production electrode and a preparation method thereof, which have high catalytic activity and excellent electrochemical stability.

[0006] In a first aspect, the present application provides an alkaline hydrogen production electrode, comprising: an electrode substrate and a catalyst loaded on the electrode substrate. The catalyst comprises the following components: Ni, Fe, Mo, Cr, and Mn, wherein the molar percentage of Mo is 5-15%, and the total molar percentage of Fe and Mo is 35%.

[0007] Optionally, the molar ratio of Ni, Fe, Mo, Cr, and Mn in the catalyst is 10:5:2:2:1.

[0008] Optionally, the catalyst surface has a nitrided layer.

[0009] Optionally, the thickness of the nitrided layer is 40-50 microns.

[0010] Optionally, the surface layer of the catalyst has a nitrogen content of 25%, and gradually decreases to a nitrogen content of 5% from outside to inside in three gradients.

[0011] Optionally, the thickness of the catalyst is 40-60 microns.

[0012] Optionally, the material of the electrode substrate comprises one of nickel mesh, nickel foam, and carbon paper.

[0013] In a second aspect, the application provides a preparation method of an alkaline hydrogen production electrode, comprising the following steps: S1. Weighing Ni, Fe, Mo, Cr, and Mn powders, melting in an inert gas atmosphere, and obtaining a catalyst powder after atomization, wherein the molar percentage of Mo powder is 5-15%; S2. Loading the catalyst powder on an electrode substrate, and then performing vacuum annealing treatment.

[0014] Optionally, in the step S1, the particle size of the Ni, Fe, Mo, Cr, and Mn powders is 45-75 microns.

[0015] Optionally, the parameters of the melting are as follows: vacuum degree ≤10 -3 Pa, and current 1600-2200 A.

[0016] Optionally, the parameters of the vacuum annealing treatment are as follows: treatment temperature 700-900℃, and treatment time 2-6 hours.

[0017] Optionally, the application provides a preparation method of an alkaline hydrogen production electrode, further comprising: S3. performing surface plasma nitriding treatment, and the steps of the surface plasma nitriding treatment are as follows: S3.1. placing the electrode in a vacuum chamber, and vacuumizing to 4x10 -3 Pa-6x10 -3 Pa, and introducing argon to 90-110 Pa; applying a negative bias to generate plasma, heating to 350-450℃ at a heating rate of 5-15℃ / min, introducing hydrogen for activation to remove oxides on the surface of the electrode; and then starting to introduce nitrogen for nitriding; The nitriding is divided into three stages: First stage: time 0.1-1 hour, temperature 460-550℃, volume ratio of nitrogen to hydrogen 3.5-4.5:1, gas pressure 200-400 Pa, and voltage 650-850 V; Second stage: time 1-3 hours, temperature 500-650℃, volume ratio of nitrogen to hydrogen 2.5-1.5:1, gas pressure 400-600 Pa, and voltage 550-650 V; The third stage: time 1h~2h, temperature 550℃~680℃, volume ratio of nitrogen to hydrogen 0.5~1.5:1, gas pressure 700Pa~900Pa, voltage 350V~450V; A surface layer with a nitrogen content of 25% is formed on the surface of the catalyst, and the nitrogen content gradually decreases to 5% from the outside to the inside in three gradients.

[0018] The beneficial effects of the present application are: The alkaline hydrogen production electrode provided in the first aspect of the present application enhances the catalytic activity by alloying and introducing Mo and controlling the contents of Fe and Mo. Compared with the existing binary Raney nickel, the catalytic activity is higher, which can effectively reduce the HER reaction overpotential, thereby reducing the energy consumption of the electrolytic cell, and Cr and Mn can enhance the corrosion resistance of the electrode.

[0019] The preparation method of the alkaline hydrogen production electrode provided in the second aspect of the present application forms a multi-element alloy catalyst by introducing an appropriate amount of Mo (5~15%) and compounding Fe, Cr and Mn. Mo promotes water dissociation, Fe and Mn optimize the electronic structure, Cr improves corrosion resistance, enhances intrinsic catalytic activity, and reduces hydrogen evolution overpotential. Vacuum annealing is used to enhance the metallurgical bonding of the powder and the substrate, improve the electrical conductivity and interface stability, and construct a multi-layer structure with high nitrogen (25%) on the surface and decreasing to 5% in the inner layer. High-activity Ni-N / Mo-N sites are formed, and stress is relieved, which inhibits and peels off the gradient nitriding layer, which has high activity and long service life, and adapts to green electricity fluctuations and frequent start-stop conditions. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below with examples. It should be understood that the specific examples described herein are only used to explain the present application and not to limit the present application.

[0021] In the first aspect, the present application provides an alkaline hydrogen production electrode, comprising: an electrode substrate and a catalyst loaded on the electrode substrate; The catalyst comprises the following components: Ni, Fe, Mo, Cr and Mn, wherein the molar percentage of Mo is 5~15%, and the total molar percentage of Fe and Mo is 35%.

[0022] The alkaline hydrogen production electrode provided in the first aspect of the present application enhances the catalytic activity by alloying and introducing Mo and controlling the contents of Fe and Mo. Compared with the existing binary Raney nickel, the catalytic activity is higher, which can effectively reduce the HER reaction overpotential, thereby reducing the energy consumption of the electrolytic cell, and Cr and Mn can enhance the corrosion resistance of the electrode.

[0023] In a possible implementation, the molar ratio of Ni, Fe, Mo, Cr, and Mn in the catalyst is 10:5:2:2:1. This technical solution further improves the catalytic activity of the catalyst and reduces the overpotential of the HER reaction and the energy consumption of the electrolytic cell.

[0024] In a possible implementation, the catalyst surface has a nitrided layer. By introducing nitrogen elements on the catalyst surface to form metal nitrides, the electronic structure and surface chemical properties of the material are changed. The electronegativity of nitrogen atoms is higher than that of metal atoms. After the formation of metal nitrides, electrons will be attracted from metal atoms, causing the center of the metal d band to move up, enhancing the adsorption capacity of reaction intermediates (such as ), thereby significantly improving the intrinsic catalytic activity of the hydrogen evolution reaction (HER). Nitrides (such as Ni3N and Mo2N) have metal-like electrical conductivity, which can effectively reduce the charge transfer resistance at the electrode / electrolyte interface, improve the current response speed, adapt to green power fluctuation conditions, and inhibit the damage of impurity ions to the electrode while ensuring the ion conduction of OH - , thereby prolonging the service life of the electrode.

[0025] In a possible implementation, the thickness of the nitrided layer is 40-50 microns. Accurately controlling the thickness of the nitrided layer in the range of 40-50 microns is an optimized result considering the catalytic activity, stability, and process feasibility. This thickness range can provide sufficient catalytic active surface area and the ability of bulk phase to participate in the reaction, avoiding the problems of insufficient active sites and corrosion of the substrate caused by the penetration of the electrolyte due to the thinness (<40 microns). A thickness of ≥40 microns can form a continuous and dense nitride layer, effectively blocking the inward diffusion of OH - ions and water molecules, preventing the corrosion of the substrate metal, and prolonging the service life of the electrode. If the nitrided layer is too thick (50 microns), it may lead to increased internal stress, easy cracking or peeling, longer charge transport path, increased resistance, and higher preparation cost and energy consumption. Therefore, 40-50 microns is the “golden range” that balances performance and reliability.

[0026] In a possible implementation, the surface layer of the catalyst has a nitrogen content of 25%, which gradually decreases to a nitrogen content of 5% from the outside to the inside. Specifically, this scheme realizes the synergistic optimization of catalytic activity and stability by constructing a multi-layer structure with a surface layer nitrogen content of 25% and a gradient decrease from the outside to the inside to 5%. High nitrogen doping in the surface layer significantly regulates the electronic structure of Ni, Mo, and other metals, reduces the electron density of the d orbit, optimizes the hydrogen adsorption free energy (ΔG ), forming a large number of Ni-N and Mo-N active sites, improving the kinetics of the hydrogen evolution reaction; at the same time, it promotes the formation of a hydrophilic oxide layer and accelerates the adsorption and dissociation of water molecules (Volmer step). The gradient distribution of nitrogen content effectively alleviates the thermal stress and lattice mismatch between the nitride layer and the substrate, inhibits cracking and spalling, and enhances interfacial bonding; it also achieves a smooth energy band transition, reduces the charge transfer barrier, improves conductivity, and slows down nitrogen diffusion to maintain long-term structural stability. The inner layer retains a 5% nitrogen content to enhance the metallurgical bonding between the nitride layer and the substrate, anchor the active layer, and maintain the conductivity and mechanical strength of the substrate. This gradient structure combines high activity, strong durability, and anti-fluctuation capabilities, making it suitable for high-efficiency alkaline hydrogen production electrodes under complex working conditions.

[0027] In one possible implementation, the catalyst thickness is 40μm to 60μm. This thickness range ensures sufficient active site density and reaction depth in the catalyst layer, increasing the electrochemical surface area and thus enhancing the catalytic current density of the hydrogen evolution reaction (HER). Furthermore, this thickness forms a continuous and dense active layer, effectively blocking alkaline electrolyte corrosion on the metal substrate (such as nickel mesh), inhibiting substrate oxidation and corrosion, and extending electrode life. A thickness of 40μm to 60μm also balances the electron conduction path and mass transfer efficiency: too thin (<40μm) can easily lead to incomplete coverage and poor durability; too thick (60μm) increases internal resistance and mass transfer resistance, potentially causing cracking, flaking, or hindering reactant diffusion. Furthermore, this thickness range facilitates the establishment of a stable thermal field and composition gradient during the preparation process, supporting the implementation of structures such as gradient nitrogen doping, and improving the mechanical and electrochemical stability of the electrode under frequent start-stop and current fluctuations.

[0028] In one possible implementation, the electrode substrate material includes one of nickel mesh, nickel foam, and carbon paper. Among these materials, nickel mesh and nickel foam offer high conductivity and a three-dimensional pore structure, which facilitates catalyst loading, mass transfer, and electron transport. They also match the nickel-based catalyst composition and provide a stable interface. Carbon paper is corrosion-resistant, lightweight, and has uniform pores, reducing weight and increasing flexibility. All three materials effectively support the catalyst layer, ensuring structural and performance stability during long-term operation and frequent starts and stops.

[0029] In a second aspect, the present application provides a method for preparing an alkaline hydrogen production electrode, comprising the following steps: S1. Weigh Ni, Fe, Mo, Cr, and Mn powders, smelt them in an inert gas atmosphere, and atomize them to obtain catalyst powder, wherein the molar percentage of Mo powder is 5-15%; S2. The catalyst powder is loaded on the electrode substrate and then subjected to vacuum annealing treatment.

[0030] The preparation method of the alkaline hydrogen production electrode provided in the second aspect of the application is as follows: a proper amount of Mo (5-15 mol%) is introduced and combined with Fe, Cr and Mn to form a multi-element alloy catalyst, Mo promotes water dissociation, Fe and Mn optimize the electronic structure, Cr improves corrosion resistance, improves intrinsic catalytic activity, and reduces hydrogen evolution overpotential; vacuum annealing is further performed to strengthen the metallurgical bonding between the powder and the substrate, improve the electrical conductivity and the interface stability; a multi-layer structure with high nitrogen (25%) on the surface and gradually decreasing to 5% in the inner layer is constructed by gradient nitriding, high-activity Ni-N / Mo-N sites are formed, and stress is relieved, which inhibits and peels off the gradient nitriding layer, and the gradient nitriding layer has high activity and long service life, and is suitable for green electricity fluctuation and frequent start-stop working conditions.

[0031] In one possible implementation, in the S1 step, the particle size of the Ni, Fe, Mo, Cr and Mn powders is 45-75 μm. Specifically, the particle size of the Ni, Fe, Mo, Cr and Mn powders is controlled to be 45-75 μm, which can maintain good fluidity and mixing uniformity during melting and atomization, and is conducive to forming a multi-element alloy powder with uniform composition; during loading and vacuum annealing, the moderate particle size helps to realize dense packing, promote the metallurgical bonding between the particles and the substrate, and improve the interface stability; at the same time, it provides a uniform diffusion channel for subsequent gradient nitriding, which is conducive to forming a gradient nitriding layer with continuous structure and controllable nitrogen content distribution. This particle size range avoids the problems of easy agglomeration and oxidation of too fine powder, small specific surface area of too coarse powder, and poor adhesion of rough coating, and can obtain a high-density, low-porosity catalyst layer, improve the electrical conductivity and mechanical strength, ensure the nitriding quality, enhance the catalytic activity and long-term durability of the electrode, and is suitable for large-scale preparation processes such as spraying and pressing, which is stable in process and conducive to industrial application.

[0032] In one possible implementation, the parameters of melting are as follows: vacuum degree ≤10 -3 Pa, current 1600 A-2200 A. Specifically, the vacuum degree is ≤10 -3The melting in a high vacuum environment of Pa can effectively reduce the interference of impurity gases such as oxygen, nitrogen and water vapor, inhibit the oxidation and inclusion of metal powders such as Ni, Fe, Mo, Cr and Mn at high temperatures, ensure the purity and uniformity of the alloy composition, and avoid the generation of inactive oxide phases that affect the catalytic performance. At the same time, high vacuum helps to remove gas and volatile impurities in the melt, improving the density of the alloy. Arc or induction melting with a high current of 1600A-2200A can provide sufficient heat energy in a short time, allowing the rapid and uniform melting of various metal powders, promoting full diffusion and alloying between elements, and forming a multi-element alloy with uniform structure and stable composition (such as Ni-Fe-Mo-Cr-Mn). This current range takes into account the melting efficiency and temperature controllability, avoiding incomplete fusion and composition segregation caused by too low current, or local overheating, element volatilization and increased energy consumption caused by too high current. This combination of melting parameters ensures high purity, high uniformity and good metallurgical quality of the alloy powder, laying a material foundation for subsequent atomization, catalyst loading and gradient nitriding, and is conducive to improving the catalytic activity and stability of the final electrode.

[0033] In one possible implementation, the parameters of the vacuum annealing process are: a treatment temperature of 700-900°C and a treatment time of 2-6h. For example, the treatment temperature can be 700°C, 750°C, 800°C, 850°C, 900°C, or any other typical but non-limiting point value or interval value between any two point values. The treatment time can be 2h, 3h, 4h, 5h, 6h, or any other typical but non-limiting point value or interval value between any two point values. In this case, annealing in a vacuum environment can effectively prevent the oxidation of the catalyst powder and the substrate at high temperatures, keeping the material surface clean and the composition stable. A temperature range of 700-900°C is sufficient to activate atomic diffusion, promote interfacial atomic diffusion between catalyst particles and between the catalyst and the substrate, form a good metallurgical bond, and significantly enhance the adhesion of the coating and the interface conductivity. At the same time, this temperature range can eliminate internal stress generated during melting, atomization and loading of the powder, improve lattice integrity, reduce defect density, and improve the crystallinity and electronic conductivity of the material. Controlling the annealing time to 2-6 hours ensures sufficient thermal activation and structural relaxation, while avoiding excessive grain growth or element segregation caused by long-term processing. This process helps to build a stable, low-resistance, high-bonding-strength electrode structure, providing a guarantee for subsequent surface plasma nitriding treatment and long-term stable operation of the electrode under high current density and frequent start-stop working conditions.

[0034] In one possible implementation, the application provides a method for preparing an alkaline hydrogen production electrode, further comprising: S3, performing surface plasma nitriding treatment, and the steps of surface plasma nitriding treatment are as follows: The electrode is placed in a vacuum chamber, and the vacuum degree is extracted to 4x10 -3Pa~6×10 -3 Pa, introduce argon to 90Pa~110Pa; apply negative bias to generate plasma, heat to 350℃~450℃, and heat up at a rate of 5~15℃ / min. Introduce hydrogen for activation to remove oxides on the electrode surface; then start introducing nitrogen for nitriding.

[0035] For example, the vacuum degree can be drawn to 4×10 -3 Pa, 5×10 -3 Pa, 6×10 -3 Pa, etc., typical but non-restrictive arbitrary point values ​​or interval values ​​between any two point values; the introduction of argon gas can reach 90Pa, 100Pa, 105Pa, 110Pa, etc., typical but non-restrictive arbitrary point values ​​or interval values ​​between any two point values; the temperature can be raised to 350℃, 400℃, 450℃, etc., typical but non-restrictive arbitrary point values ​​or interval values ​​between any two point values.

[0036] Nitriding is divided into 3 stages: Stage 1: time 0.1h~1h, temperature 460℃~550℃, volume ratio of nitrogen to hydrogen 3.5~4.5:1, pressure 200Pa~400Pa, voltage 650V~850V; The second stage: time 1h~3h, temperature 500℃~650℃, volume ratio of nitrogen to hydrogen 2.5~1.5:1, pressure 400Pa~600Pa, voltage 550V~650V; The third stage: time 1h~2h, temperature 550℃~680℃, volume ratio of nitrogen to hydrogen 0.5~1.5:1, pressure 700Pa~900Pa, voltage 350V~450V; A surface nitrogen content of 25% is formed on the catalyst surface, which is divided into three nitrided layers from the outside to the inside, with a nitrogen content gradually decreasing to 5%.

[0037] Exemplarily, the time of the first-stage nitriding can be 0.1 h, 0.5 h, 0.8 h, 1 h, etc. typical but non-limiting any point value or interval value between any two point values; the temperature can be 460°C, 480°C, 500°C, 520°C, 550°C, etc. typical but non-limiting any point value or interval value between any two point values; the volume ratio of nitrogen to hydrogen can be 3.5:1, 4:1, 4.5:1, etc. typical but non-limiting any point value or interval value between any two point values; the gas pressure can be 200 Pa, 250 Pa, 300 Pa, 350 Pa, 400 Pa, etc. typical but non-limiting any point value or interval value between any two point values; the voltage can be 650 V, 700 V, 750 V, 800 V, 850 V, etc. typical but non-limiting any point value or interval value between any two point values. In this case, by low temperature combined with high nitrogen partial pressure and high voltage, a large number of nitrogen ions are promoted to be injected at high speed in the surface layer under a strong electric field, and a surface layer with high nitrogen content (25%) is quickly formed, and a high-activity catalytic region is constructed.

[0038] Exemplarily, the time of the second-stage nitriding can be 1 h, 2 h, 3 h, etc. typical but non-limiting any point value or interval value between any two point values; the temperature can be 500°C, 580°C, 600°C, 650°C, etc. typical but non-limiting any point value or interval value between any two point values; the volume ratio of nitrogen to hydrogen can be 2.5:1, 2:1, 1.5:1, etc. typical but non-limiting any point value or interval value between any two point values; the gas pressure can be 400 Pa, 450 Pa, 500 Pa, 550 Pa, 600 Pa, etc. typical but non-limiting any point value or interval value between any two point values; the voltage can be 550 V, 600 V, 620 V, 650 V, etc. typical but non-limiting any point value or interval value between any two point values. In this case, by increasing the temperature and reducing the voltage, the nitrogen ion injection rate is slowed down, and thermal diffusion is mainly used to make the surface layer nitrogen atoms slowly diffuse inward, forming an intermediate transition zone with nitrogen content from high to low, and relieving stress concentration.

[0039] For example, the time of the third stage nitriding can be 1 h, 1.5 h, 2 h, etc. typical but non-limiting any point value or interval value between any two point values; the temperature can be 550℃, 600℃, 650℃, 680℃, etc. typical but non-limiting any point value or interval value between any two point values; the volume ratio of nitrogen to hydrogen can be 0.5:1, 1:1, 1.5:1, etc. typical but non-limiting any point value or interval value between any two point values; the gas pressure can be 700Pa, 750Pa, 800Pa, 850Pa, 900Pa, etc. typical but non-limiting any point value or interval value between any two point values; the voltage can be 350V, 400V, 450V, etc. typical but non-limiting any point value or interval value between any two point values. In this case, further temperature rise enhances the ability of body phase diffusion, and nitrogen element penetrates deeply in the direction of the substrate, while low voltage reduces the surface nitrogen supersaturation, forming a multi-layer structure with decreasing nitrogen content from the surface to the inside (25%→5%), which improves the bonding force and structural stability.

[0040] The whole process controls the penetration and diffusion dynamics of nitrogen through temperature gradient, gas pressure increment, nitrogen-hydrogen ratio decrement, and voltage reduction, to realize a high-performance gradient nitriding layer with continuous transition of composition, stress, and energy band, which takes into account high activity and long life.

[0041] To enable the above-mentioned implementation details and operations of the present application to be clearly understood by those skilled in the art, and to embody the significant performance of the alkaline hydrogen production electrode and its preparation method, the following examples are used to illustrate the above technical solutions. Example 1

[0042] Preparation of the alkaline hydrogen production electrode: S1, according to the mole percentage, Ni 50%, Fe 25%, Mo 10%, Cr 10%, Mn 5% powder, in an argon atmosphere, vacuum degree ≤10 -3 Pa, current 2000A smelting, after atomization to get catalyst powder; S2, the catalyst powder is loaded on the foamed nickel by plasma spraying, and then vacuum annealing treatment is carried out, the treatment temperature is 800℃, and the treatment time is 4h; S3, surface plasma nitriding treatment: put the electrode into the vacuum cavity, vacuum degree to 5×10 -3 Pa, pass argon to 100Pa, apply negative bias to generate plasma, heat to 400℃, heating rate 10℃ / min, then pass hydrogen for activation, remove the oxide on the surface of the electrode; The nitriding is divided into three stages:

[0043] Foamed nickel: porosity 95%, thickness 1 mm; the obtained electrode thickness 50 um, surface layer nitrogen content 25%, inner layer gradually reduced to 5%, performance: 5000 A / m 2 , HER overpotential 248 mV, HER overpotential 258 mV after 1000 CV, 30% KOH, 60℃, 600W ultrasonic weight loss rate 0.93%.

[0044] At a high current density of 5000 A / m², only 248 mV overpotential is required to drive the hydrogen evolution reaction (HER), indicating that the electrode material has extremely high intrinsic catalytic activity. The HER overpotential only increases by 10 mV (from 248 mV to 258 mV) after 1000 CV cycles, indicating that the catalytic active sites of the electrode remain stable during repeated redox cycles, and the electrochemical durability is excellent.

[0045] Comparative Example 1 Preparation of alkaline hydrogen production electrode: According to the mole percentage, Ni 50%, Fe 30%, Mo 10%, Cr 10% powder; the rest is the same as Example 1; Foamed nickel: porosity 95%, thickness 1 mm; the obtained electrode thickness 50 um, performance: 5000 A / m 2 , HER overpotential 281 mV, HER overpotential 324 mV after 1000 CV, 30% KOH, 60℃, 600W ultrasonic weight loss rate 1.53%.

[0046] It is shown that without the addition of Mn element, the electrode has a higher ultrasonic weight loss rate in an alkaline environment and a larger decay rate after cycling.

[0047] Comparative Example 2 Preparation of alkaline hydrogen production electrode: According to the mole percentage, Ni 50%, Fe 30%, Mo 5%, Cr 10%, Mn 5% powder; the rest is the same as Example 1; Foamed nickel: porosity 95%, thickness 1 mm; the obtained electrode thickness 50 um, performance: 5000 A / m 2 , HER overpotential 263 mV, HER overpotential 281 mV after 1000 CV, 30% KOH, 60℃, 600W ultrasonic weight loss rate 0.95%.

[0048] It is shown that when the Mo element is added less, the synergistic effect between NiMo intermetallic is weak, and the electrode catalytic activity is relatively poor.

[0049] Comparative Example 3 Preparation of alkaline hydrogen production electrode: Take Ni 50%, Fe 15%, Mo 20%, Cr 10%, Mn 5% powder according to mole percentage; the rest is the same as example 1; Foamed nickel: porosity 95%, thickness 1mm; the obtained electrode thickness is 50um, and the performance is 5000A / m 2 , HER overpotential 243mV, HER overpotential 295mV after 1000 times CV, 30% KOH, 60℃, 600W ultrasonic weight loss rate 1.03%.

[0050] It is shown that the electrode stability is poor when Mo element is added more. Example 2

[0051] Preparation of alkaline hydrogen production electrode: Take Ni 50%, Fe 25%, Mo 10%, Cr 10%, Mn 5% powder according to mole percentage; no surface plasma nitriding treatment, the rest is the same as example 1; Foamed nickel: porosity 95%, thickness 1mm; the obtained electrode thickness is 50um, and the performance is 5000A / m 2 , HER overpotential 251mV, HER overpotential 282mV after 1000 times CV, 30% KOH, 60℃, 600W ultrasonic weight loss rate 1.25%.

[0052] It is shown that the electrode stability is affected without surface plasma nitriding treatment.

[0053] Comparative example 4 Preparation of alkaline hydrogen production electrode: The surface plasma nitriding treatment method is different, and the rest is the same as example 1; The surface plasma nitriding treatment method is as follows: Foamed nickel: porosity 95%, thickness 1mm; the obtained electrode thickness is 50um, and the performance is 5000A / m 2 , HER overpotential 259mV, HER overpotential 297mV after 1000 times CV, 30% KOH, 60℃, 600W ultrasonic weight loss rate 1.24%.

[0054] It is shown that the N content of the nitrided layer surface layer needs to be controlled at about 20%-30%, and the lower N content of the surface layer cannot effectively protect.

[0055] Comparative example 5 Preparation of alkaline hydrogen production electrode: The surface plasma nitriding treatment method is different, and the rest is the same as example 1; The surface plasma nitriding treatment method is as follows: Foamed nickel: porosity 95%, thickness 1mm; the obtained electrode thickness 50um, surface layer nitrogen content 40%, performance 5000A / m 2 , HER overpotential 275mV, HER overpotential 302mV after 1000 times CV, 30% KOH, 60℃, 600W ultrasonic weight loss rate 0.89%.

[0056] It is shown that the surface layer N content of the nitrided layer needs to be controlled at about 20%-30%, and the surface layer nitrogen content is too high, which affects the contact of the electrolyte with the internal active sites.

[0057] Comparative Example 6 Preparation of alkaline hydrogen production electrode: The surface plasma nitriding treatment method is different, and the rest is the same as in Example 1. The surface plasma nitriding treatment method is as follows: Foamed nickel: porosity 95%, thickness 1mm; the obtained electrode thickness 50um, surface layer nitrogen content 25%, deep layer nitrogen content 15%, performance: 5000A / m 2 , HER overpotential 256mV, HER overpotential 276mV after 1000 times CV, 30% KOH, 60℃, 600W ultrasonic weight loss rate 0.89%.

[0058] It is shown that the deep layer nitrogen content is too high, and the porosity is low, which also affects the contact of the electrolyte, reduces the activity, and the deep layer nitrogen content should be controlled at about 5%.

[0059] By comparing Example 1 with Comparative Examples 1-3, by introducing an appropriate amount of Mo (5-15%) and compounding Fe, Cr and Mn, a multi-alloy catalyst is formed, the synergistic effect between Ni / Mo is enhanced, and the electrode catalytic activity is improved. By comparing Example 2 with Comparative Examples 4-6, the gradient nitriding scheme improves the stability of the electrode.

[0060] Those skilled in the art should understand that the discussion of any of the above examples is only exemplary and is not intended to suggest that the scope of protection of the present application is limited to these examples; under the idea of the present application, the above examples or technical features in different examples can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of one or more embodiments of the present application as described above. In order to be brief, they are not provided in detail.

[0061] It is intended that the embodiments of the application herein disclosed meet all the written requirements of the patent statutes and come within the judicial doctrines of equivalents and will not be construed to be limited to the embodiments shown and described and by the keeping within the spirit and scope of the embodiments of the application.

Claims

1. An alkaline hydrogen production electrode, characterized in that include: an electrode substrate and a catalyst supported on the electrode substrate; The catalyst comprises the following components: Ni, Fe, Mo, Cr, and Mn, wherein the molar percentage of Mo is 5-15%, and the total molar percentage of Fe and Mo is 35%.

2. The alkaline hydrogen production electrode according to claim 1, characterized in that The molar ratio of Ni, Fe, Mo, Cr and Mn in the catalyst is 10:5:2:2:

1.

3. The alkaline hydrogen production electrode according to claim 1 or 2, characterized in that: The catalyst surface has a nitride layer.

4. The alkaline hydrogen production electrode according to claim 3, characterized in that The thickness of the nitride layer is 40 μm to 50 μm.

5. The alkaline hydrogen production electrode according to claim 4, characterized in that The surface nitrogen content of the catalyst is 25%, which is divided into three gradients from the outside to the inside and gradually decreases to 5%.

6. The alkaline hydrogen production electrode according to any one of claims 1, 2, 4 and 5, characterized in that: The thickness of the catalyst is 40-60 μm; And / or, the material of the electrode substrate includes one of nickel mesh, nickel foam, and carbon paper.

7. A method for preparing an alkaline hydrogen production electrode, characterized in that: The following steps are involved: S1. Weigh Ni, Fe, Mo, Cr, and Mn powders, smelt them in an inert gas atmosphere, and atomize them to obtain catalyst powder, wherein the molar percentage of Mo powder is 5-15%, and the total molar percentage of Fe and Mo is 35%; S2. The catalyst powder is loaded on the electrode substrate and then subjected to vacuum annealing treatment.

8. The method for preparing the alkaline hydrogen production electrode according to claim 7, wherein: In step S1, the particle size of Ni, Fe, Mo, Cr, and Mn powders is 45 μm to 75 μm.

9. The method for preparing the alkaline hydrogen production electrode according to claim 7, wherein: The melting parameters are: vacuum degree ≤ 10 -3 Pa, current 1600A~2200A; And / or, the parameters of the vacuum annealing treatment are: treatment temperature of 700° C. to 900° C., and treatment time of 2 h to 6 h.

10. The method for preparing an alkaline hydrogen production electrode according to any one of claims 7 to 9, characterized in that: Also includes: S3, performing surface plasma nitriding treatment, the steps of the surface plasma nitriding treatment are as follows: Place the electrode in a vacuum chamber and pump the vacuum to 4×10 -3 Pa~6×10 -3 Pa, introduce argon gas to 90Pa~110Pa; Apply negative bias voltage to generate plasma, heat up to 350℃~450℃, and increase the temperature by 5~15℃ / min. Then, introduce hydrogen to activate and remove oxides on the electrode surface. Then, introduce nitrogen to perform nitridation. Nitriding is divided into 3 stages: Stage 1: time 0.1h~1h, temperature 460℃~550℃, volume ratio of nitrogen to hydrogen 3.5~4.5:1, pressure 200Pa~400Pa, voltage 650V~850V; The second stage: time 1h~3h, temperature 500℃~650℃, volume ratio of nitrogen to hydrogen 2.5~1.5:1, pressure 400Pa~600Pa, voltage 550V~650V; The third stage: time 1h~2h, temperature 550℃~680℃, volume ratio of nitrogen to hydrogen 0.5~1.5:1, pressure 700Pa~900Pa, voltage 350V~450V; A surface nitrogen content of 25% is formed on the catalyst surface, which is divided into three nitrided layers from the outside to the inside, with a nitrogen content gradually decreasing to 5%.

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