Nickel-iron-based alkaline water decomposition catalyst based on magnetron sputtering as well as preparation method and application of nickel-iron-based alkaline water decomposition catalyst

Abstract

The invention provides a preparation method of a nickel-iron-based alkaline water decomposition catalyst based on magnetron sputtering. The preparation method comprises the following steps: S1) pretreating a conductive substrate; (S2) a nickel-iron-based alloy layer and a carbon layer are sequentially deposited on the surface of the pretreated conductive substrate through the magnetron sputtering technology; s3) repeating the step S2) for at least one time; and S4) starting a pulsed bias power supply to carry out pulse treatment on the material obtained in the step S3), and then carrying out low-temperature annealing to obtain the ferronickel-based alkaline water decomposition catalyst. The invention further provides the nickel-iron-based alkaline water decomposition catalyst and application thereof. The prepared nickel-iron-based alkaline water decomposition catalyst has the characteristics of mechanical stability, high specific surface area and high active site density, so that the catalytic activity of the catalyst in alkaline water decomposition application is improved, and the preparation method provided by the invention is simple.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of alkaline water decomposition catalysts, in particular to a nickel-iron-based alkaline water decomposition catalyst based on magnetron sputtering, a preparation method thereof and application thereof. BACKGROUND

[0002] Hydrogen energy, as a clean energy carrier with zero carbon emissions, is considered as one of the core solutions to replace fossil fuels. Water electrolysis technology has become a research hotspot due to its environmental friendliness and sustainability, and efficient and stable electrocatalysts are the key to improving the efficiency of water electrolysis. Although traditional electrocatalysts (such as platinum and ruthenium-based materials) have excellent activity, their high cost and scarcity seriously restrict their large-scale application. In addition, non-noble metal catalysts (such as nickel-based and iron-based compounds) have low cost, but they generally face the bottleneck of insufficient activity and poor stability. How to improve the activity and durability of the catalyst while reducing the cost through material design and preparation process innovation has become a core challenge to promote the commercialization of water electrolysis technology.

[0003] The current mainstream preparation technology of alkaline water decomposition catalysts includes electrodeposition method, sol-gel method and chemical reduction method. For example, a wet chemical synthesis method of nickel-iron double metal hydroxide is disclosed in Chinese patent No. CN201910345678.9, which deposits active substances on a foam nickel substrate by co-precipitation method to form a porous catalytic layer; this method relies on the accurate proportioning of chemical reagents and step-by-step reactions, and requires high-temperature calcination (> 500℃) to remove organic templates and stabilize the crystal structure. Chinese patent No. CN202010567890.1 proposes to use a sol-gel method to prepare a porous nickel-based catalyst, using metal nitrate as a precursor, forming a gel network through hydrolysis and polycondensation, and then obtaining a porous structure through high-temperature annealing. In addition, the chemical reduction method (such as patent CN202110234567.8) deposits nanoparticles on the surface of a carbon carrier by reducing noble metal salts (such as platinum and ruthenium), but the process requires strict control of the concentration of reducing agents and reaction time.

[0004] The above-mentioned alkaline water decomposition catalysts have the following problems:

[0005] 1) Wet chemical method is prone to cause agglomeration of active substances, forming local thick films or defect regions (such as electrodeposition method), which reduces the effective specific surface area and active site density of the catalyst;

[0006] 2) The sol-gel method requires multiple steps (hydrolysis, polycondensation, drying, and calcination), and high-temperature treatment (> 500℃) significantly increases energy consumption, and grain coarsening easily occurs during calcination. In addition, the prepared catalysts have residual organic templates or low porosity, and the electronic conduction path is not smooth, which limits the conductivity and affects the overall electrochemical performance;

[0007] 3) The chemical reduction method needs to use noble metals such as platinum and ruthenium, and the cost of raw materials is high; at the same time, the synthesis of complex precursors (such as metal organic frameworks) further increases the preparation cost.

[0008] In view of the above problems, it is urgent to provide a preparation method of an alkaline water decomposition catalyst with high-precision structure regulation capability, simple process and cost advantage. SUMMARY

[0009] The technical problem solved by the present application is to provide a preparation method of a nickel-iron-based alkaline water decomposition catalyst based on magnetron sputtering, which can realize high-precision structure regulation of the catalyst material, is conducive to improving the catalytic activity, and has a simple preparation process.

[0010] Therefore, the present application provides a preparation method of a nickel-iron-based alkaline water decomposition catalyst based on magnetron sputtering, comprising the following steps:

[0011] S1) Pre-treating the conductive substrate;

[0012] S2) Depositing a nickel-iron-based alloy layer and a carbon layer on the surface of the pre-treated conductive substrate in sequence by using the magnetron sputtering technology;

[0013] S3) Repeating step S2) at least once;

[0014] S4) Turning on a pulse bias power supply to pulse process the material obtained in step S3), and then performing low-temperature annealing to obtain a nickel-iron-based alkaline water decomposition catalyst.

[0015] In some specific embodiments, after the low-temperature annealing in step S4), the method further comprises:

[0016] Plasma surface activation is performed on the surface of the material after low-temperature annealing.

[0017] In some specific embodiments, in step S1), the conductive substrate comprises a graphene conductive film, a nickel foam, a carbon cloth, or a flexible polymer;

[0018] And / or, the pre-treatment specifically comprises:

[0019] The conductive substrate is sequentially ultrasonically cleaned in acetone and ethanol, and then the surface of the substrate is blown dry with high-purity nitrogen.

[0020] In some specific embodiments, in step S2), during the deposition of the nickel-iron-based alloy layer by using the magnetron sputtering technology, the method comprises the following steps:

[0021] Placing the pre-treated conductive substrate in a magnetron sputtering chamber, evacuating the magnetron sputtering chamber to ≤5×10 -4 Pa, and then introducing argon;

[0022] The pre-processed conductive substrate is heated to 200-300℃, and the distance between the target material and the pre-processed conductive substrate is set to 5-10 cm;

[0023] The first sputtering target material is opened, and a nickel-iron-based alloy layer is deposited on the surface of the heated conductive substrate by using a first sputtering target material; the sputtering power is 200-300 W, the working pressure is 0.5-1.0 Pa, and the sputtering time is 10-15 min; the first sputtering target material includes a NiFe single target material, a NiCoFe single target material, a Pt / NiFe double target material, or a NiO / Fe3O4 double target material.

[0024] In some embodiments, in step S2, during the deposition of the carbon layer by using the magnetron sputtering technology, the following steps are included:

[0025] The first sputtering target material is closed, and a carbon layer is deposited on the surface of the deposited nickel-iron-based alloy layer by using a second sputtering target material; the sputtering power is 100-150 W, the working pressure is 0.5-1.0 Pa, and the sputtering time is 8-12 min; the second sputtering target material includes a graphite single target material, a graphene single target material, a carbon nanotube single target material, or a RuO2 / C double target material.

[0026] In some embodiments, in step S4, the frequency of the pulse treatment is 1-10 kHz, the duty cycle is 30-50%, and the bias voltage is -50--150 V; and / or, the temperature of the low-temperature annealing is 300-400℃, the time is 1-5 h, and the heating rate is 3-10℃ / min.

[0027] In some embodiments, the power of the plasma surface activation is 50-100 W, and the time is 5-10 min.

[0028] The application also provides a nickel-iron-based alkaline water splitting catalyst based on magnetron sputtering prepared by the preparation method, which includes a conductive substrate and a composite layer formed on the surface of the conductive substrate; the composite layer is a nickel-iron-based alloy layer and a carbon layer arranged in sequence, the nickel-iron-based alloy layer is formed on the surface of the conductive substrate, the number of layers of the composite layer is ≥2, and the surfaces of the nickel-iron-based alloy layer and the carbon layer both form a porous network structure.

[0029] In some embodiments, the thickness of the nickel-iron-based alloy layer is 5-10 nm, the thickness of the porous network structure is 2-5 nm, the pore size of the top carbon layer is 10-50 nm, the specific surface area is >50 m 2 / g, and the active site density is ≥1×10 19 sites / cm 3 .

[0030] The application also provides the application of the nickel-iron-based alkaline water splitting catalyst prepared by the preparation method in a hydrogen evolution electrode, an oxygen absorption electrode or a full water splitting bifunctional electrode.

[0031] The application provides a preparation method of a nickel-iron-based alkaline water splitting catalyst based on magnetron sputtering. First, an electrically conductive substrate is pretreated, then a nickel-iron-based alloy layer and a carbon layer are deposited on the surface of the pretreated electrically conductive substrate in sequence by using a magnetron sputtering technology, then the surface of the obtained material is subjected to pulse treatment by starting a pulse bias power supply, and finally low-temperature annealing is performed, thereby obtaining the nickel-iron-based alkaline water splitting catalyst. In the preparation method of the nickel-iron-based alkaline water splitting catalyst, the nickel-iron-based alloy layer-carbon layer-nickel-iron-based alloy layer-carbon layer prepared by the magnetron sputtering method can ensure that the catalyst has the characteristics of an optimized electron transport path and mechanical stability, and the pulse bias can induce the formation of a porous network structure on the surface of the nickel-iron-based alloy layer and the carbon layer, so as to improve the specific surface area and active site density of the catalyst and improve the catalytic activity of the catalyst.

[0032] Further, the preparation method of the nickel-iron-based alkaline water splitting catalyst based on magnetron sputtering provided by the application can obtain the nickel-iron-based alkaline water splitting catalyst only by magnetron sputtering, pulse bias and annealing treatment, thereby ensuring the catalytic activity of the catalyst and simplifying the preparation method. DETAILED DESCRIPTION

[0033] In order to further understand the application, the preferred embodiments of the application are described below in combination with examples, but it should be understood that the description is only for further illustrating the features and advantages of the application, and is not a limitation on the claims of the application.

[0034] In view of the demand for high-precision structure regulation, high electrochemical activity and simple preparation method of alkaline water splitting catalysts in the prior art, the application provides a preparation method of a nickel-iron-based alkaline water splitting catalyst based on magnetron sputtering. The nickel-iron-based alkaline water splitting catalyst is prepared by using a method of substrate pretreatment-nickel-iron-based alloy layer, carbon layer alternating sputtering-pulse bias treatment-low-temperature annealing. The catalyst has the characteristics of mechanical stability, high specific surface area and high active site density, thereby improving the catalytic activity of the catalyst in the application of alkaline water splitting, and the preparation method of the catalyst is simple and has low cost. Specifically, the application discloses a preparation method of a nickel-iron-based alkaline water splitting catalyst based on magnetron sputtering, which comprises the following steps:

[0035] S1) pretreating an electrically conductive substrate;

[0036] S2) depositing a nickel-iron-based alloy layer and a carbon layer on the surface of the pretreated electrically conductive substrate by using a magnetron sputtering technology;

[0037] S3) repeating step S2) at least 1 time;

[0038] S4) turning on a pulsed bias power supply to pulse the material obtained in step S3), and then performing low-temperature annealing to obtain a nickel-iron-based alkaline water-splitting catalyst.

[0039] In the preparation method of the nickel-iron-based alkaline water-splitting catalyst based on magnetron sputtering, in step S1, the conductive substrate is first pretreated. In this process, the conductive substrate is a conductive substrate well known to those skilled in the art, and examples of the conductive substrate include a graphene conductive film, a nickel foam, a carbon cloth, or a flexible polymer, wherein the flexible polymer is specifically selected from polyimide. The pretreatment is to enhance the interfacial bonding force of the conductive substrate, and the pretreatment is specifically:

[0040] The conductive substrate is sequentially ultrasonically cleaned in acetone and ethanol, and then the surface of the substrate is blown dry with high-purity nitrogen.

[0041] In the above pretreatment process, the ultrasonic cleaning time in the acetone is 3-5 min, and the ultrasonic cleaning time in the ethanol is 8-10 min.

[0042] After the conductive substrate is pretreated, in step S2, the pretreated conductive substrate is subjected to magnetron sputtering treatment to sequentially deposit a nickel-iron-based alloy layer and a carbon layer on the surface of the pretreated conductive substrate. In the above process, the pretreated conductive substrate is first fixed on a sample table in a magnetron sputtering chamber to ensure that the surface of the conductive substrate is flat and wrinkle-free. The above process is specifically:

[0043] S21) placing the pretreated conductive substrate in a magnetron sputtering chamber, and evacuating the magnetron sputtering chamber to ≤5×10 -4 Pa, and then introducing argon;

[0044] S22) heating the pretreated conductive substrate to 200-300°C, and setting the distance between the target material and the pretreated conductive substrate to 5-10 cm;

[0045] S23) turning on a magnetron power supply to deposit a nickel-iron-based alloy layer on the surface of the heated conductive substrate using a first sputtering target material; the sputtering power is 200-300 W, the working gas pressure is 0.5-1.0 Pa, and the sputtering time is 10-15 min; the first sputtering target material includes a NiFe single target material, a NiCoFe single target material, a Pt / NiFe double target material, or a NiO / Fe3O4 double target material;

[0046] S24) turn off the first sputtering target, and deposit a carbon layer on the surface on which the nickel-iron-based alloy layer is deposited by using a second sputtering target; the sputtering power is 100-150 W, the working pressure is 0.5-1.0 Pa, and the sputtering time is 8-12 min; the second sputtering target comprises a graphite single target, a graphene single target, a carbon nanotube single target, or a RuO2 / C double target.

[0047] In step S21), the purity of the argon is 99.999%, and the gas flow rate is 20-30 sccm; in step S22), the heating is to 250-280°C, and the distance between the target and the pre-processed conductive substrate is 6-8 cm to balance the sputtering uniformity and the deposition rate; in step S23), the sputtering power is 250-280 W, the working pressure is 0.7-0.9 Pa, the sputtering time is 12-14 min, and the first sputtering target is specifically a nickel-iron alloy target with a mass ratio of Ni:Fe of 3:1; in step S24), the sputtering power is 120-140 W, the working pressure is 0.7-0.9 Pa, and the sputtering time is 12-14 min, and the second sputtering target is specifically a high-purity graphite target. After the above-mentioned magnetron sputtering technology, the thickness of the nickel-iron-based alloy layer is 5-10 nm, and the thickness of the carbon layer is 2-5 nm. Specifically, the thickness of the nickel-iron-based alloy layer is 6-8 nm, and the thickness of the carbon layer is 3-4 nm.

[0048] The steps of depositing the nickel-iron-based alloy layer and the carbon layer are repeated at least once. In specific embodiments, the steps of depositing the nickel-iron-based alloy layer and the carbon layer are repeated once to obtain an alternating structure of a nickel-iron-based alloy layer-carbon layer-nickel-iron-based alloy layer-carbon layer. The nickel-iron-based alloy layer serves as a catalytic layer, and the carbon layer serves as a protective layer, which can inhibit the dissolution of catalytic elements Ni and Fe, thereby achieving the effect of optimizing the electronic transmission path and mechanical stability.

[0049] In step S4), a pulse bias power supply is turned on to perform pulse treatment on the obtained material, so as to form a porous nano-network structure on the surface of the nickel-iron-based alloy layer and the carbon layer by pulse bias induction. This is conducive to the desorption of hydrogen and oxygen generated in the electrolytic water reaction, and further exposes the catalyst active sites to the electrolyte to improve the reaction efficiency. The pore size of the above-mentioned porous nano-network structure is 10-50 nm, the specific surface area is >50 m 2 / g, and the active site density is ≥1×10 19 sites / cm 3 . The pulse treatment frequency is 1-10 kHz, the duty cycle is 30-50%, and the bias voltage is -50--150 V. Specifically, the pulse treatment frequency is 5-8 kHz, the duty cycle is 40-48%, and the bias voltage is -80--100 V.

[0050] The material obtained after pulse treatment is subjected to low-temperature annealing to eliminate sputtering internal stress, promote the ordered arrangement of the NiFe alloy lattice, and enhance the graphitization degree of the carbon layer. The low-temperature annealing temperature is 300~400℃, the time is 1~5h, and the heating rate is 3~10℃ / min. Specifically, the low-temperature annealing temperature is 350~380℃, the time is 1.5~3.5h, and the heating rate is 5~8℃ / min. The low-temperature annealing is carried out in an argon atmosphere with a gas flow rate of 50~60 sccm.

[0051] Furthermore, after low-temperature annealing, the obtained material is subjected to plasma surface activation to expose active sites and remove surface oxides; the power of plasma surface activation is 50~100W and the time is 5~10min, specifically, the power of plasma surface activation is 60~80W and the time is 6~8min.

[0052] This application also provides a nickel-iron-based alkaline water splitting catalyst prepared by the above method, comprising a conductive substrate and a composite layer formed on the surface of the conductive substrate; the composite layer is a nickel-iron-based alloy layer and a carbon layer stacked sequentially, the nickel-iron-based alloy layer is formed on the surface of the conductive substrate, the number of layers of the composite layer is ≥2, and the surfaces of the nickel-iron-based alloy layer and the carbon layer both form a porous network structure.

[0053] In the nickel-iron-based alkaline water splitting catalyst provided in this application, the nickel-iron-based alloy layer and the carbon layer are referred to as a composite layer as a whole. Multiple composite layers can be provided on the surface of the conductive substrate, that is, the number of composite layers is ≥2. The number of composite layers can be 2, 3, or 4, and those skilled in the art can make appropriate adjustments according to their needs.

[0054] This application also provides the application of nickel-iron-based alkaline water splitting catalysts in hydrogen evolution electrodes, oxygen absorption electrodes, or bifunctional electrodes for complete water splitting.

[0055] The nickel-iron-based alkaline water splitting catalyst provided in this application can be used in various catalytic scenarios such as alkaline / acidic water splitting, seawater electrolysis, and CO2 reduction.

[0056] To further understand the present invention, the preparation method of the nickel-iron-based alkaline water splitting catalyst based on magnetron sputtering provided by the present invention will be described in detail below with reference to the embodiments. The scope of protection of the present invention is not limited by the following embodiments.

[0057] Example

[0058] 1) Matrix selection and pretreatment

[0059] Matrix material: A 0.2 mm thick graphene conductive matrix was selected;

[0060] Pretreatment process: Immerse the graphene conductive substrate in acetone and ultrasonically clean for 5 minutes to remove surface grease; then transfer it to ethanol and continue ultrasonic cleaning for 10 minutes to remove residual organic matter; then use high-purity nitrogen to dry the substrate surface to avoid moisture residue;

[0061] Installation: Fix the pretreated substrate onto the sample stage of the magnetron sputtering chamber, ensuring a smooth and wrinkle-free surface;

[0062] 2) Target configuration

[0063] Metal target: Nickel-iron alloy target (Ni:Fe mass ratio 3:1, purity ≥99.99%).

[0064] Non-metallic target: High-purity graphite target (purity ≥ 99.95%);

[0065] Target-substrate distance adjustment: Set the distance between the target and the substrate to 6cm to balance sputtering uniformity and deposition rate;

[0066] 3) Equipment debugging

[0067] Vacuum system: Evacuate the sputtering chamber to a vacuum level ≤5×10⁻⁶. -4 Pa;

[0068] Gas flow control: Connect the argon gas (99.999% purity) pipeline and calibrate the flow meter to 20~30 sccm;

[0069] Temperature control: Turn on the substrate heating module and set the initial temperature to 200℃;

[0070] 4) Sputtering parameter settings

[0071] Metal target sputtering:

[0072] Sputtering power: 250W (DC power supply);

[0073] Working pressure: 0.7 Pa (argon flow rate 25 sccm);

[0074] Matrix temperature: 250℃;

[0075] Sputtering time: 10 min / layer;

[0076] Carbon target sputtering:

[0077] Sputtering power: 120W (RF power supply);

[0078] Other parameters are the same as those for the metal target;

[0079] 5) Alternating sputtering of multi-layered structure deposition:

[0080] After the above preparations are completed, a NiFe alloy layer and a carbon layer are sequentially deposited on the surface of the pretreated substrate using magnetron sputtering technology, and the process is repeated twice.

[0081] First layer: Deposited NiFe alloy layer (approximately 8nm thick);

[0082] Second layer: Deposited carbon layer (approximately 3nm thick);

[0083] Third layer: Deposited NiFe alloy layer (approximately 8nm thick);

[0084] Fourth layer: Deposited carbon layer (approximately 3 nm thick);

[0085] 6) Pulse bias application:

[0086] The material obtained in step 5) is pulsed by turning on the pulse bias power supply. The frequency is set to 5kHz, the duty cycle to 40%, and the bias voltage to -100V. This induces the formation of a porous nano-network structure (pore size of about 30nm) on the surface of both the NiFe alloy layer and the carbon layer.

[0087] 7) Low-temperature annealing

[0088] The material obtained in step 6) was subjected to low-temperature annealing at 350℃ (argon atmosphere, flow rate 50 sccm) for 1.5 hours, with a heating rate of 5℃ / min.

[0089] 8) Plasma surface activation

[0090] The material obtained in step 7) was subjected to plasma surface activation at a power of 80W for 5 minutes.

[0091] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0092] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1.A method for preparing a nickel-iron-based alkaline water splitting catalyst based on magnetron sputtering, comprising the following steps: S1) pretreating a conductive substrate; S2) depositing a nickel-iron-based alloy layer and a carbon layer on the surface of the pretreated conductive substrate in sequence by using a magnetron sputtering technology; S3) repeating step S2) at least once; S4) performing pulse treatment on the material obtained in step S3) by using a pulse bias power supply, and then performing low-temperature annealing to obtain a nickel-iron-based alkaline water splitting catalyst. In step S4), after the low-temperature annealing, the following step is further included: performing plasma surface activation on the surface of the material after the low-temperature annealing. In step S1), the conductive substrate comprises a graphene conductive film, a nickel foam, a carbon cloth, or a flexible polymer; and / or, the pretreatment specifically comprises: ultrasonic cleaning the conductive substrate in acetone and ethanol in sequence, and then blowing the surface of the substrate dry with high-purity nitrogen. In step S2), during the process of depositing the nickel-iron-based alloy layer by using the magnetron sputtering technology, the following steps are included: heating the pretreated conductive substrate to 200-300℃, and setting the distance between the target material and the pretreated conductive substrate to 5-10 cm; turning on a magnetron power supply to deposit a nickel-iron-based alloy layer on the surface of the heated conductive substrate by using a first sputtering target material; the sputtering power is 200-300 W, the working pressure is 0.5-1.0 Pa, and the sputtering time is 10-15 min; and the first sputtering target material comprises a NiFe single target material, a NiCoFe single target material, a Pt / NiFe double target material, or a NiO / Fe3O4 double target material. In step S2), during the process of depositing the carbon layer by using the magnetron sputtering technology, the following steps are included: turning off the first sputtering target material, and depositing a carbon layer on the surface on which the nickel-iron-based alloy layer is deposited by using a second sputtering target material; the sputtering power is 100-150 W, the working pressure is 0.5-1.0 Pa, and the sputtering time is 8-12 min; and the second sputtering target material comprises a graphite single target material, a graphene single target material, a carbon nanotube single target material, or a RuO2 / C double target material. In step S4), the frequency of the pulse treatment is 1-10 kHz, the duty cycle is 30-50%, and the bias voltage is -50--150 V; and / or, the temperature of the low-temperature annealing is 300-400℃, the time is 1-5 h, and the temperature rising rate is 3-10℃ / min. The power of the plasma surface activation is 50-100 W, and the time is 5-10 min. 8.A nickel-iron-based alkaline water splitting catalyst based on magnetron sputtering, prepared by the preparation method of claim 1, comprising a conductive substrate and a composite layer formed on the surface of the conductive substrate; the composite layer comprises a nickel-iron-based alloy layer and a carbon layer arranged in sequence, the nickel-iron-based alloy layer is formed on the surface of the conductive substrate, the number of layers of the composite layer is ≥2, and the surfaces of the nickel-iron-based alloy layer and the carbon layer both form a porous network structure. 10.The nickel-iron-based alkaline water splitting catalyst prepared by the preparation method of any one of claims 1-7 or any one of claims 8-9, and application of the nickel-iron-based alkaline water splitting catalyst in a hydrogen evolution electrode, an oxygen absorption electrode, or a full water splitting double-function electrode. ​ ​ ​ ​ 2. The production method according to claim 1, characterized by, ​ ​ 3. The production method according to claim 1, characterized by, ​ ​ ​ 4. The production method according to claim 1 or 2, characterized by, ​ The pre-processed conductive substrate is placed in a magnetron sputtering chamber, which is evacuated to < 5 x 10 -4 Pa, and argon gas is introduced again; ​ ​ 5. The preparation method according to claim 4, characterized in that, ​ ​ 6. The production method according to claim 1 or 2, characterized by, ​ 7. The preparation method according to claim 2, characterized in that, ​ ​ 9. The nickel-iron-based alkaline water-splitting catalyst according to claim 8, characterized in that, The thickness of the nickel-iron-based alloy layer is 5-10 nm, the thickness of the carbon layer is 2-5 nm, the pore size of the porous network structure is 10-50 nm, the specific surface area is >50 m 2 / g, and the active site density is ≥1×10 19 sites / cm 3 . ​