Preparation method and application of nickel-iron-chromium catalytic electrode

Abstract

The invention discloses a preparation method and application of a nickel-iron-chromium catalytic electrode. The preparation method comprises the following steps: mixing a nickel salt solution, an iron salt solution, a chromium salt solution and an additive, and adjusting the pH value to obtain an electroplating solution; putting a first pure nickel material serving as a cathode and a second pure nickel material serving as an anode into the electroplating solution, and performing pulse electrodeposition on the first pure nickel material to obtain a NiFeCr substrate; the NiFeCr substrate is used as a working electrode, saturated calomel is used as a reference electrode, a light nickel net is used as a counter electrode, sulfuric acid is used as an electrolyte, anodic oxidation is conducted on the NiFeCr substrate, and a NiFeCr-A substrate with a Ni / Fe-Cr2O3 passivation layer on the surface is obtained; the method comprises the following steps: by taking a NiFeCr-A substrate as a working electrode, saturated calomel as a reference electrode, a light nickel net as a counter electrode and potassium hydroxide as an electrolyte, carrying out alkaline electrochemical etching on the NiFeCr-A substrate, so that Cr < 3 + > is leached, Ni and Fe are oxidized and react with OH <-> to form a NiFe-OOH layer, thereby obtaining the nickel-iron-chromium catalytic electrode. According to the preparation method, the problem of uncontrolled leaching of elements in the multi-metal system reconstruction process can be avoided, and the stability of the nickel-iron-chromium catalytic electrode is ensured.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrogen production by alkaline electrolysis of water, and particularly relates to a preparation method and application of a nickel-iron-chromium catalytic electrode. BACKGROUND

[0002] Hydrogen production by water electrolysis is a key technology for realizing renewable energy storage and carbon neutralization. However, as a half-reaction in the process of water electrolysis, the oxygen evolution reaction (OER) is a core bottleneck that restricts the industrial application of water electrolysis technology due to its slow kinetics and high energy consumption. At present, although noble metal-based catalysts (such as IrO2 and RuO2) have excellent OER catalytic activity, their reserves are scarce, the cost is high, and the stability is poor at an industrial current density (> 500 mA / cm2), which makes it difficult to meet the demand of large-scale application.

[0003] Non-noble metal-based catalysts, especially nickel-iron-based oxyhydroxides, are considered as the most potential substitutes for OER catalysts due to their low cost, adjustable electronic structure, and suitable adsorption energy for OER intermediates. However, the oxyhydroxide itself has semiconductor properties and poor conductivity, which affects the efficiency of electron transmission. In addition, under an industrial high current density, non-noble metal catalysts are prone to nanoparticle agglomeration, phase separation, and irreversible leaching of active components, which leads to rapid decay of catalytic activity and limits its application.

[0004] In recent years, in-situ electrochemical reconstruction based on multi-metal alloy precursors is considered as an effective strategy for preparing OER catalysts with high activity and stability. This strategy exposes rich catalytically active sites and optimizes the surface reactivity through the reconstruction process. However, uncontrolled leaching of elements (such as Fe 3+ ) in the multi-metal system during the reconstruction process leads to rapid decline of the activity of nickel-iron oxyhydroxide and poor stability, which restricts the development of large-scale hydrogen production in industry.

[0005] The information disclosed in this BACKGROUND section is only for the purpose of increasing the understanding of the background of the application and should not be taken as an acknowledgment or any form of suggestion that this information forms prior art that is publicly known in the field. SUMMARY

[0006] The purpose of the present application is to provide a preparation method of a nickel-iron-chromium catalytic electrode, which can avoid the problem of uncontrolled leaching of elements in the reconstruction process of a multi-metal system and ensure the stability of the nickel-iron-chromium catalytic electrode.

[0007] To achieve the above objectives, a specific embodiment of the present invention provides a method for preparing a nickel-iron-chromium catalytic electrode, comprising: mixing a nickel salt solution, an iron salt solution, a chromium salt solution, and additives uniformly and adjusting the pH to 1.5 to 3 to obtain an electroplating solution; placing a first pure nickel material as the cathode and a second pure nickel material as the anode into the electroplating solution, and performing pulse electrodeposition on the first pure nickel material to obtain a NiFeCr substrate; using the NiFeCr substrate as the working electrode, saturated calomel as the reference electrode, a bright nickel mesh as the counter electrode, and sulfuric acid as the electrolyte, anolyzing the NiFeCr substrate, such that Ni and Fe on the surface of the NiFeCr substrate dissolve first, and Cr is subsequently exposed and oxidized, to obtain a NiFeCr-A substrate with a Ni / Fe-Cr2O3 passivation layer on the surface; using the NiFeCr-A substrate as the working electrode, saturated calomel as the reference electrode, a bright nickel mesh as the counter electrode, and potassium hydroxide as the electrolyte, performing alkaline electrochemical etching on the NiFeCr-A substrate, such that the Ni / Fe-Cr2O3 passivation layer dissociates, and Cr is oxidized. 3+ During leaching, Ni and Fe are oxidized to higher oxidation states and react with OH groups. - The reaction forms a NiFe-OOH layer, yielding a nickel-iron-chromium catalytic electrode.

[0008] In one or more embodiments of the present invention, the peak current density of the pulse electrodeposition is 10 to 15 A / dm². 2 The duty cycle is 30 to 50%; the frequency is 10 to 40 Hz.

[0009] In one or more embodiments of the present invention, the current density of the anodizing is 300 mA / cm² to 500 mA / cm²; the anodizing time is 200 s to 300 s.

[0010] In one or more embodiments of the present invention, the current density of the alkaline electrochemical etching is from 600 mA / cm² to 1200 mA / cm²; and the time of the alkaline electrochemical etching is from 4 h to 6 h.

[0011] In one or more embodiments of the present invention, the concentration of the nickel salt solution is 180 to 240 g / L; and / or, the nickel salt solution is selected from one or more of nickel sulfate hexahydrate and nickel chloride hexahydrate.

[0012] In one or more embodiments of the present invention, the concentration of the iron salt solution is 10 to 40 g / L; and / or, the iron salt solution is selected from one or more of ferrous sulfate heptahydrate and ferrous chloride tetrahydrate.

[0013] In one or more embodiments of the present application, the chromium salt solution has a concentration of 30 to 40 g / L; and / or, the chromium salt solution is selected from one or more of chromium chloride hexahydrate and chromium sulfate hexahydrate.

[0014] In one or more embodiments of the present application, the additive includes boric acid with a concentration of 25 to 35 g / L, citric acid with a concentration of 10 to 20 g / L, sodium citrate with a concentration of 15 to 25 g / L, sodium dodecyl sulfate with a concentration of 0.06 to 0.1 g / L, ascorbic acid with a concentration of 5 to 8 g / L, and saccharin with a concentration of 3 to 5 g / L.

[0015] Another specific embodiment of the present application provides a nickel-iron-chromium catalytic electrode prepared by the preparation method of any one of the above embodiments.

[0016] Still another specific embodiment of the present application provides an application of the above nickel-iron-chromium catalytic electrode in the field of hydrogen production by alkaline electrolysis of water.

[0017] Compared with the prior art, the preparation method of the nickel-iron-chromium catalytic electrode of the present application realizes controllable reconstruction and component regulation of the surface of the nickel-iron-chromium catalytic electrode through selective removal of Cr and step-by-step electrochemical etching, effectively solves the problem of uncontrolled leaching of elements in the reconstruction process of the multi-metal system by using the dual role of chromium elements (stabilizer and sacrificial template), and ensures the long-term stability of the surface of the nickel-iron-chromium catalytic electrode. Further, the nickel-iron-chromium catalytic electrode prepared by the method has a NiFe-OOH@Ni / Fe-Cr2O3@NiFeCr structure, and the structure has a synergistic enhancement effect. Among them, Ni / Fe-Cr2O3 as the core provides mechanical support and an electron transport channel, NiFe-OOH as the shell provides abundant active sites, and the NiFeCr substrate ensures the strong interaction between the catalytic layer and the substrate, and the three synergistically improve the electron transport efficiency, ion diffusion rate and catalytic reaction kinetics. In addition, the electrodeposition process in the method is simple and convenient to operate, the voltage of the electroplating device is low, and the running life is long, which is suitable for large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creating laborious work.

[0019] Figure 1 The flow chart of the preparation method of the nickel-iron-chromium catalytic electrode in an embodiment of the present application;

[0020] Figure 2The graphs show the OER performance of the nickel-iron-chromium catalytic electrode and the commercial catalyst (IrO2 oxygen evolution catalytic electrode) in Examples 1-3 of this invention.

[0021] Figure 3 This is a graph showing the stability test of the nickel-iron-based oxygen evolution catalytic electrode in Example 1 of this invention;

[0022] Figure 4 The polarization curves are for the nickel-iron-chromium catalytic electrodes of Example 3 and Comparative Example 1 of the present invention. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solutions in this disclosure, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this disclosure.

[0024] like Figure 1 As shown, a method for preparing a nickel-iron-chromium catalytic electrode in one embodiment of the present invention includes steps S1-S4.

[0025] Step S1: Mix the nickel salt solution, iron salt solution, chromium salt solution and additives evenly and adjust the pH to 1.5 to 3 to obtain the electroplating solution.

[0026] Specifically, in step S1, the nickel salt solution, iron salt solution, chromium salt solution, and additives are mixed evenly and the pH is adjusted to 1.5 to 3 using sulfuric acid and ammonia to obtain the electroplating solution.

[0027] The nickel salt solution serves as the nickel source, with a concentration of 180 to 240 g / L. The nickel salt solution is selected from one or more of nickel sulfate hexahydrate and nickel chloride hexahydrate. Preferably, the nickel salt solution is a combination of nickel sulfate hexahydrate and nickel chloride hexahydrate.

[0028] The iron salt solution, being an iron salt, has a concentration of 10 to 40 g / L. The iron salt solution is selected from one or more of ferrous sulfate heptahydrate and ferrous chloride tetrahydrate. Preferably, the iron salt solution is ferrous sulfate heptahydrate.

[0029] The chromium salt solution, as a chromium salt, has a concentration of 30 to 40 g / L. The chromium salt solution is selected from one or more of chromium chloride hexahydrate and chromium sulfate hexahydrate. Preferably, the nickel salt solution is chromium chloride hexahydrate.

[0030] In an embodiment, the additive comprises boric acid with a concentration of 25 to 35 g / L, citric acid with a concentration of 10 to 20 g / L, sodium citrate with a concentration of 15 to 25 g / L, sodium dodecyl sulfate with a concentration of 0.06 to 0.1 g / L, ascorbic acid with a concentration of 5 to 8 g / L, and saccharin with a concentration of 3 to 5 g / L.

[0031] Ascorbic acid is used as an antioxidant to ensure the stability of the electroplating solution. Saccharin is used as a stress modifier to make the plating layer (catalytic layer) more uniform. Boric acid is used as a buffer to maintain the pH stability of the electroplating solution. Citric acid and sodium citrate can form stable complexes with Fe 3+ , Cr 3+ , and other easily hydrolyzed ions in the electroplating solution to prevent the formation of Fe(OH)3 and other precipitates, thereby improving the stability of the plating solution. Sodium dodecyl sulfate is used as a brightener to make the plating layer surface smoother and brighter.

[0032] Step S2: placing the first pure nickel material as the cathode and the second pure nickel material as the anode into the electroplating solution, and performing pulse electrodeposition on the first pure nickel material to obtain a NiFeCr substrate.

[0033] Specifically, in step S2, the prepared electroplating solution is transferred into an electroplating tank to build an electrodeposition device. The first pure nickel material as the cathode and the second pure nickel material as the anode are placed into the electroplating solution, and then the first pure nickel material as the cathode is subjected to pulse electrodeposition using an electrochemical working to obtain a NiFeCr substrate.

[0034] The peak current density, duty cycle, and frequency are the key factors to control the composition, microstructure, and final catalytic performance of the catalytic layer alloy. Preferably, the peak current density of the pulse electrodeposition is 10 to 15 A / dm 2 ; the duty cycle is 30 to 50%; and the frequency is 10 to 40 Hz.

[0035] In an embodiment, the first pure nickel material and the second pure nickel material can be one of a nickel foam and a nickel mesh. Preferably, the size of the anode is larger than that of the cathode to ensure uniform cathode current density and obtain high-quality plating layer; reduce the anode current density to prevent anode passivation or abnormal dissolution, and reduce side reactions to maintain the stability of the electrolyte.

[0036] In an embodiment, the first pure nickel material can be pretreated before use. Specifically, the first pure nickel material as the cathode is sequentially subjected to water bath ultrasonic cleaning with ethanol and pure water for 10-15 min to remove oil, and then is immersed in 3 M hydrochloric acid for 5 to 10 min to remove impurities. After washing with pure water, the first pure nickel material is blown dry or oven dried and weighed, and then is immersed in 3 M hydrochloric acid for 10 to 15 s before use and washed with pure water.

[0037] Step S3: Anodic oxidation of the NiFeCr substrate to obtain a NiFeCr-A substrate with a Ni / Fe-Cr2O3 passivation layer on the surface of the substrate.

[0038] Specifically, in step S3, the step is acid electrochemical etching. The NiFeCr substrate is used as the working electrode (anode), saturated mercury is used as the reference electrode, and the light nickel mesh is used as the counter electrode. The 0.5-0.8 M sulfuric acid is used as the electrolyte. The NiFeCr substrate is anodically oxidized, and the Ni and Fe with high electrochemical activity on the surface of the NiFeCr substrate are selectively dissolved first, so that the Cr is exposed and oxidized. Thus, a NiFeCr-A substrate with a Ni / Fe-Cr2O3 passivation layer on the surface of the substrate is obtained.

[0039] The anodic oxidation current density and time directly affect the structure, thickness, specific surface area, and stability of the Ni / Fe-Cr2O3 passivation layer generated on the NiFeCr substrate. In an embodiment, the anodic oxidation current density is 300-500 mA / cm2, and the anodic oxidation time is 200-300 s.

[0040] Step S4: Alkaline electrochemical etching of the NiFeCr-A substrate to obtain a nickel-iron-chromium catalytic electrode. 3+ Leaching, oxidation of Ni and Fe to high valence state and reaction with OH - to form a NiFe-OOH layer, thereby obtaining a nickel-iron-chromium catalytic electrode.

[0041] Specifically, in step S4, the step is alkaline electrochemical etching. The NiFeCr-A substrate is used as the working electrode, saturated mercury is used as the reference electrode, and the light nickel mesh is used as the counter electrode. The 1-1.5 M potassium hydroxide is used as the electrolyte. The NiFeCr-A substrate is subjected to alkaline electrochemical etching (electrochemical reconstruction), so that the Ni / Fe-Cr2O3 passivation layer is gradually dissociated, the Cr 3+ slowly leaches, and Ni and Fe are further oxidized to high valence state and react with OH - to form a NiFe-OOH layer rich in hydroxyl groups and high activity, thereby obtaining a nickel-iron-chromium catalytic electrode.

[0042] The current density and time affect the etching degree, structure, composition transformation and final electrochemical active area of the surface of the catalytic layer. Therefore, in an embodiment, the current density of the alkaline electrochemical etching is 600 mA / cm2 to 1200 mA / cm2. The time of the alkaline electrochemical etching is 4 h to 6 h.

[0043] Steps S2-S4 first prepare a NiFeCr layer on the surface of the cathode, and then gradually dissolve Cr in the NiFeCr layer by anodic oxidation in step S3 and alkaline electrochemical etching in step S4, to finally form a nickel-iron-chromium electrode with a NiFe-OOH@Ni / Fe-Cr2O3@NiFeCr structure on the surface of the cathode. The NiFe-OOH@Ni / Fe-Cr2O3@NiFeCr structure has a synergistic enhancement effect. Among them, the Ni / Fe-Cr2O3 as the inner core provides mechanical support and an electron transport channel, the NiFe-OOH as the outer shell provides abundant active sites, and the NiFeCr as the base ensures the strong interaction between the catalytic layer and the base, thereby synergistically improving the electron transport efficiency, ion diffusion rate and catalytic reaction kinetics.

[0044] The application will be further described below in conjunction with specific examples and comparative examples.

[0045] Example 1

[0046] Step S1: accurately weigh 30 g / L of ferrous sulfate heptahydrate, 170 g / L of nickel sulfate hexahydrate, 35 g / L of nickel chloride hexahydrate, 30 g / L of chromium chloride hexahydrate, 30 g / L of boric acid, 15 g / L of citric acid, 20 g / L of sodium citrate, 0.06 g / L of sodium dodecyl sulfate, 6 g / L of ascorbic acid, and 4 g / L of saccharin, stir to dissolve, and mix uniformly. Adjust the pH of the solution with sulfuric acid and ammonia water to keep it at 3.

[0047] Step S2: transfer the prepared electroplating solution to an electroplating tank, place a nickel mesh as the cathode and a stretched nickel mesh as the anode into the electroplating solution, build an electrodeposition device, and use a blue electrochemical workstation to perform pulse electrodeposition on the cathode with a peak current density of 10 A / dm 2 , a duty cycle of 30%, and a frequency of 20 Hz. After electroplating, wash and dry to obtain a NiFeCr base.

[0048] Step S3: use the NiFeCr base as the working electrode (anode), saturated mercury as the reference electrode, a light nickel mesh as the counter electrode, and 0.5 M H2SO4 as the electrolyte, and anodically oxidize the NiFeCr base at a current density of 500 mA / cm2 for 200 s. Obtain a NiFeCr-A base.

[0049] Step S4: Using NiFeCr-A as the working electrode (anode), saturated calomel as the reference electrode, a bright nickel mesh as the counter electrode, and 1 M KOH as the electrolyte, the NiFeCr-A substrate was subjected to alkaline electrochemical etching for 4 h at a current density of 1200 mA / cm² to obtain a nickel-iron-chromium catalytic electrode.

[0050] Example 2

[0051] The difference from Example 1 is that: Step S3: Anodize the NiFeCr substrate for 300 s at a current density of 300 mA / cm².

[0052] Example 3

[0053] The difference from Example 1 is that: Step S4: Alkaline electrochemical etching of NiFeCr-A substrate at a current density of 600 mA / cm² for 6 h.

[0054] Comparative Example 1

[0055] Accurately weigh 30 g / L ferrous sulfate heptahydrate, 170 g / L nickel sulfate hexahydrate, 35 g / L nickel chloride hexahydrate, 30 g / L chromium chloride hexahydrate, 30 g / L boric acid, 15 g / L citric acid, 20 g / L sodium citrate, 0.06 g / L sodium dodecyl sulfate, 6 g / L ascorbic acid, and 4 g / L saccharin. Stir until dissolved and mixed thoroughly. Adjust the pH of the solution to 3 using sulfuric acid and ammonia.

[0056] The prepared electroplating solution was transferred to the electroplating tank. A nickel mesh (cathode) and a stretched nickel mesh (anode) were placed in the solution. An electrodeposition apparatus was assembled, and pulse electrodeposition was performed using a Blue Electric electrochemical workstation with a peak current density of 10 A / dm³. 2 The duty cycle was 30% and the frequency was 20 Hz. After electroplating, the electrode was cleaned and dried to obtain a nickel-iron-chromium catalytic electrode.

[0057] The oxygen evolution reaction (OER) performance of the nickel-iron-chromium catalytic electrodes prepared in Examples 1-3 and the commercial catalyst (IrO2 oxygen evolution catalytic electrode) was tested using a biological electrochemical workstation. Specifically, the OER was conducted at 80 °C with a bright nickel mesh as the counter electrode, saturated calomel as the reference electrode, the nickel-iron-chromium catalytic electrodes prepared in Examples 1-3 and the commercial catalyst as the working electrodes, and 3 M KOH solution as the electrolyte solution.

[0058] like Figure 2 As shown, the nickel-iron-chromium catalytic electrodes prepared in Examples 1-3 are tested at an industrial current density of 500 mA / cm². 2The overpotential is only 261 mV. In comparison, the overpotential of the commercial catalyst is 367 mV at the same current density. Therefore, the nickel-iron-chromium catalytic electrode prepared in Example 1-3 has a lower overpotential and higher catalytic activity.

[0059] The nickel-iron-chromium catalytic electrode prepared in Example 1 was subjected to stability test. Specifically, the test temperature was 80 ℃, and the electrolyte was a 30 wt% KOH solution. The current density was 6000 A / m 2 for 1000 h. As shown in FIG. 6, the nickel-iron-based oxygen evolution catalytic electrode prepared in Example 1 did not decay in performance after 1000 h of testing, and had better stability. Figure 3

[0060] The nickel-iron-chromium catalytic electrodes prepared in Example 3 and Comparative Example 1 were subjected to OER performance test using a Biological electrochemical workstation. Specifically, the light nickel mesh was used as the counter electrode, the saturated calomel electrode was used as the reference electrode, the nickel-iron-chromium catalytic electrodes prepared in Example 3 and Comparative Example 1 were used as the working electrode (anode), and the 3 M KOH solution was used as the electrolyte solution. The anodic polarization curve of the nickel-iron-chromium catalytic electrodes prepared in Example 3 and Comparative Example 1 was obtained by linear voltammetry scanning. As shown in FIG. 7, the nickel-iron-chromium catalytic electrode prepared in Example 3 after two-step etching reconstruction has a lower overpotential than the untreated nickel-iron-chromium catalytic electrode in Comparative Example 1 at the same current density, thereby having better activity and stability. Figure 4

[0061] Another embodiment of the present application provides a nickel-iron-chromium catalytic electrode prepared by the preparation method of any one of the above embodiments.

[0062] Still another embodiment of the present application provides an application of the above nickel-iron-chromium catalytic electrode in the field of hydrogen production by alkaline electrolysis of water.

[0063] ​​In summary, the preparation method of the nickel-iron-chromium catalytic electrode of the present application realizes controllable reconstruction and component regulation of the surface of the nickel-iron-chromium catalytic electrode by selective removal of Cr and step-by-step electrochemical etching, effectively solves the problem of uncontrolled leaching of elements in the reconstruction process of the multi-metal system by using the dual role of chromium elements (stabilizer and sacrificial template), and ensures the long-term stability of the surface of the nickel-iron-chromium catalytic electrode. Further, the nickel-iron-chromium catalytic electrode prepared by the method has a NiFe-OOH@Ni / Fe-Cr2O3@NiFeCr structure, and the structure has a synergistic enhancement effect. Among them, Ni / Fe-Cr2O3 as the core provides mechanical support and an electron transport channel, NiFe-OOH as the shell provides abundant active sites, and the NiFeCr substrate ensures the strong interaction of the catalytic layer and the substrate, and the three synergistically improve the electron transport efficiency, ion diffusion rate and catalytic reaction kinetics. In addition, the electrodeposition process in the method is simple and convenient to operate, the voltage of the electroplating device is low, and the running life is long, which is suitable for large-scale production.

[0064] It is apparent to those skilled in the art that the present disclosure is not limited to the details of the foregoing exemplary embodiments, and that the present disclosure can be implemented in other particular forms without departing from the spirit or essential characteristics of the present disclosure. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, and the scope of the present disclosure is defined by the appended claims rather than the foregoing description, and it is intended to include all changes falling within the meaning and range of equivalents of the essential elements of the claims. Any reference signs in the claims should not be considered as limiting the claims involved.

[0065] In addition, it should be understood that, although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A method for preparing a nickel iron chromium catalytic electrode, characterized in that, Comprising: mixing a nickel salt solution, an iron salt solution and a chromium salt solution and an additive uniformly and adjusting pH to 1.5-3 to obtain an electroplating solution; putting a first pure nickel material as a cathode and a second pure nickel material as an anode into the electroplating solution, carrying out pulse electrodeposition on the first pure nickel material to obtain a NiFeCr substrate; taking the NiFeCr substrate as a working electrode, saturated mercury as a reference electrode, a light nickel mesh as a counter electrode and sulfuric acid as an electrolyte, carrying out anodic oxidation on the NiFeCr substrate so that Ni and Fe on the surface of the NiFeCr substrate are dissolved first, Cr is exposed and oxidized later to obtain a NiFeCr-A substrate with a Ni / Fe-Cr2O3 passivation layer on the surface; With the NiFeCr-A substrate as the working electrode, saturated mercury as the reference electrode, light nickel mesh as the counter electrode, and potassium hydroxide as the electrolyte, the NiFeCr-A substrate is subjected to alkaline electrochemical etching, so that the Ni / Fe-Cr2O3 passivation layer is dissociated, Cr 3+ is leached out, Ni and Fe are oxidized to high valence states and react with OH - to form a NiFe-OOH catalytic layer, thereby obtaining a nickel-iron-chromium catalytic electrode.

2. The method for preparing a nickel iron chromium catalytic electrode according to claim 1, characterized in that, The peak current density of the pulse electrodeposition is 10 to 15 A / dm 2 ; the duty cycle is 30 to 50%; and the frequency is 10 to 40 Hz.

3. The method for preparing a nickel iron chromium catalytic electrode according to claim 1, characterized in that, the current density of the anodic oxidation is 300-500 mA / cm2; and the time of the anodic oxidation is 200-300 s.

4. The method for preparing a nickel iron chromium catalytic electrode according to claim 1, characterized in that, the current density of the alkaline electrochemical etching is 600-1200 mA / cm2; and the time of the alkaline electrochemical etching is 4-6 h.

5. The method of claim 1, wherein the nickel iron chromium catalytic electrode is prepared by the steps of: the concentration of the nickel salt solution is 180-240 g / L; and / or the nickel salt solution is selected from one or more of nickel sulfate hexahydrate and nickel chloride hexahydrate.

6. The method of claim 1, wherein the nickel iron chromium catalytic electrode is prepared by the steps of: the concentration of the iron salt solution is 10-40 g / L; and / or the iron salt solution is selected from one or more of ferrous sulfate heptahydrate and ferrous chloride tetrahydrate.

7. The method of claim 1, wherein the nickel iron chromium catalytic electrode is prepared by the steps of: the concentration of the chromium salt solution is 30-40 g / L; and / or the chromium salt solution is selected from one or more of chromium chloride hexahydrate and chromium sulfate hexahydrate.

8. The method of claim 1, wherein the nickel iron chromium catalytic electrode is prepared by the steps of: the additive comprises boric acid with a concentration of 25-35 g / L, citric acid with a concentration of 10-20 g / L, sodium citrate with a concentration of 15-25 g / L, sodium dodecyl sulfate with a concentration of 0.06-0.1 g / L, ascorbic acid with a concentration of 5-8 g / L and saccharin with a concentration of 3-5 g / L. 9.A nickel iron chromium catalytic electrode prepared by the preparation method of any one of claims 1-8. 10.Use of the nickel iron chromium catalytic electrode of claim 9 in the field of alkaline electrolytic water hydrogen production.

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