Preparation method of catalytic electrode based on Ni-Cr bottom layer enhancement and Ni-W heterojunction

Abstract

The invention discloses a preparation method of a catalytic electrode based on Ni-Cr bottom layer enhancement and Ni-W heterojunction. The preparation method comprises the steps of pretreatment, plasma spraying, electro-deposition, annealing treatment, electrochemical activation and the like. Through the mode, according to the preparation method of the catalytic electrode based on Ni-Cr bottom layer enhancement and Ni-W heterojunction, the compact Ni-Cr alloy layer is formed on the surface of the nickel net substrate through plasma spraying, so that the adhesive force and the conductivity of the substrate are improved; a Ni-W heterojunction structure is constructed through electrochemical deposition and heat treatment, and a stable active phase is formed through alkaline electrolyte activation treatment, so that the electrode has the characteristics of firm interface bonding, efficient electron conduction, excellent chemical stability and the like, and shows relatively low overpotential and good durability in electrocatalytic reactions such as water electrolysis and the like; the method is suitable for various electrochemical reaction systems.

Description

Technical Field

[0001] This invention relates to the field of materials engineering technology, and in particular to a method for preparing a Ni-Cr-based underlayer reinforced and Ni-W heterojunction catalytic electrode. Background Technology

[0002] With the development of electrochemical energy conversion technologies such as water electrolysis for hydrogen production, oxygen electrolysis, and fuel cells, efficient, stable, and cost-effective electrocatalytic materials have become a research focus. Nickel-based materials are widely used in alkaline electrocatalytic systems due to their abundant resources, good conductivity, and low cost. However, pure nickel materials are prone to surface oxidation during long-term reactions, leading to reduced catalytic activity and insufficient structural stability. By introducing transition metals such as tungsten, iron, and molybdenum to form alloys or heterostructures, the electronic structure can be effectively adjusted, and the distribution of reactive sites can be improved, thereby enhancing catalytic performance.

[0003] While existing Ni-W alloy catalytic electrodes exhibit certain synergistic effects, the bonding force between their deposited layers and the substrate is weak, making them prone to delamination or activity degradation during prolonged operation, thus limiting practical applications. Furthermore, the lack of stable means to regulate the interface structure results in insufficient electron transport and reaction site utilization. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A method for preparing a Ni-Cr substrate-enhanced and Ni-W heterojunction catalytic electrode is provided, comprising the following steps: S1. Pretreatment of the substrate;

[0006] Preparation of S2.Ni-Cr alloy spray coating:

[0007] A Ni-Cr alloy layer was uniformly deposited on the pretreated substrate surface using a plasma spraying process. The spraying material was Ni-Cr alloy powder with a nickel content of 90–95 wt% and a Cr content of 5–10 wt%, and the Ni-Cr alloy layer thickness was 10–20 μm. After completion, the substrate was naturally cooled to room temperature. The resulting Ni-Cr alloy layer was tightly bonded to the substrate and had a dense and smooth surface, which facilitated the adhesion of subsequent deposition.

[0008] S3.Ni-W co-deposition electrolyte preparation:

[0009] Add NiSO4·6H2O, Na2WO4·2H2O, and complexing agent Na3C6H5O7·2H2O to deionized water, such that the concentrations of NiSO4·6H2O, Na2WO4·2H2O, and the complexing agent are all 0.01-0.1 mol / L. The complexing agent may include Na3C6H5O7·2H2O or EDTA. Adjust the pH of the mixed solution to 8.5–9.0 and stir for 15–20 minutes until the solution is clear and homogeneous to form a deposition electrolyte.

[0010] S4.Ni-W heterojunction electrochemical deposition:

[0011] A substrate coated with a Ni-Cr alloy layer was used as the working electrode and placed in a deposition electrolyte to construct a three-electrode system. Magnetic stirring was turned on, and constant potential deposition was performed at 40°C. The potential of the working electrode was -0.8 to -1.5V (vsHg / HgO) to form a dense Ni-W heterostructure precursor layer on the Ni-Cr alloy layer. After deposition, the substrate was removed, rinsed, and dried.

[0012] S5. Annealing treatment:

[0013] The electrochemically deposited substrate was placed in a quartz boat and sent into the heating zone of a tube furnace. After the air was purged from the tube furnace, a mixture of argon and hydrogen with a volume ratio of 95:5 was introduced and the total flow rate was maintained at 100 mL / min. The tube furnace was heated to 400 °C at a rate of 5 °C / min, and then held at that temperature for 1 hour before being allowed to cool naturally. This heat treatment was used to allow Ni and W to diffuse and interact at the interface, thereby forming a stable Ni-W heterojunction structure.

[0014] S6. Electrochemical activation:

[0015] A three-electrode system was constructed in an activated electrolyte, with the annealed substrate serving as the working electrode. Cyclic voltammetric activation was performed, with the working electrode potential ranging from -0.5 to 0.5 V (vsHg / HgO), to obtain a Ni-W heterojunction catalytic electrode with an active phase on its surface.

[0016] In a preferred embodiment of the present invention, the pretreatment step S1 includes: first rinsing the nickel mesh substrate with deionized water to remove dust; then ultrasonically cleaning the substrate in acetone and anhydrous ethanol for 5 minutes each to remove oil and organic impurities; subsequently immersing the nickel mesh substrate in a 0.1-3 mol / L hydrochloric acid solution for 10 minutes to remove the surface oxide layer; immediately rinsing with a large amount of deionized water until neutral, and rinsing with anhydrous ethanol to remove moisture; finally drying the substrate in an 80°C vacuum oven and cooling it for later use.

[0017] In a preferred embodiment of the present invention, in step S2, the working gas used for spraying is a mixture of argon and hydrogen with a volume ratio of 4:1, with a total flow rate of 40L / min, the spraying current is controlled at 500A to 600A, and the spraying distance is about 100mm.

[0018] In a preferred embodiment of the present invention, in step S3, concentrated ammonia is added dropwise to adjust the pH of the deposition electrolyte.

[0019] In a preferred embodiment of the present invention, in step S3, the deposited electrolyte is left to stand at room temperature for later use or preheated in a water bath at 40°C for later use.

[0020] In a preferred embodiment of the present invention, in step S4, the three-electrode system uses Hg / HgO as the reference electrode and a platinum sheet as the counter electrode, with an electrode spacing of approximately 2 cm.

[0021] In a preferred embodiment of the present invention, in step S4, the constant potential deposition time is 10-30 minutes.

[0022] In a preferred embodiment of the present invention, in step S4, the substrate after deposition is thoroughly rinsed with deionized water and ethanol, and then dried at 60°C for 30 minutes.

[0023] In a preferred embodiment of the present invention, in step S6, the activation electrolyte is a 1.0 mol / L KOH solution, the platinum sheet is the counter electrode in the three-electrode system, and Hg / HgO is the reference electrode in the three-electrode system.

[0024] In a preferred embodiment of the present invention, in step S6, the scan rate of the cyclic voltammetric activation treatment is 50 mV / s, and the cycle is 10 times; the activated electrode is rinsed with deionized water and dried.

[0025] The beneficial effects of this invention are as follows: By forming a dense Ni-Cr alloy layer on the surface of a nickel mesh substrate using plasma spraying, the adhesion and conductivity of the substrate are improved; by constructing a Ni-W heterojunction structure through electrochemical deposition and heat treatment, and by activating it with an alkaline electrolyte, a stable active phase is formed, which makes the electrode have the characteristics of strong interfacial bonding, high electronic conduction efficiency and excellent chemical stability. It exhibits low overpotential and good durability in electrocatalytic reactions such as water electrolysis, and is suitable for a variety of electrochemical reaction systems. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0027] Figure 1 This is a material morphology diagram obtained after plasma spraying in Embodiment 1 of the present invention;

[0028] Figure 2 This is a microscopic image of the material morphology obtained after plasma spraying in Example 1 of the present invention;

[0029] Figure 3 This is the final catalyst morphology diagram obtained in Example 1 of the present invention;

[0030] Figure 4 This is a microscopic morphology diagram of the catalyst finally obtained in Example 1 of the present invention. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Please see Figure 1-4 The embodiments of the present invention include:

[0033] A method for preparing a Ni-Cr-based underlayer reinforced and Ni-W heterojunction catalytic electrode involves introducing a Ni-Cr alloy layer with high bonding strength and corrosion resistance as a supporting underlayer on a nickel mesh substrate via plasma spraying. A stable Ni-W heterojunction structure is then constructed through electrochemical co-deposition and heat treatment, resulting in a stable interface and strong bonding. This significantly improves catalytic activity and durability, making it suitable for various electrocatalytic reactions.

[0034] The specific steps are as follows:

[0035] (1) Substrate pretreatment

[0036] Take twill woven nickel mesh (10×10cm) 2 First, rinse with deionized water to remove dust, then ultrasonically clean in acetone and anhydrous ethanol for 5 minutes each to remove oil and organic impurities. Next, immerse the nickel mesh in 0.1-3 mol / L hydrochloric acid solution for 10 minutes to remove the surface oxide layer. Immediately after immersion, rinse with plenty of deionized water until neutral, and then rinse with anhydrous ethanol to remove moisture. Finally, dry in an 80℃ vacuum oven for about 10 minutes and cool for later use.

[0037] (2) Preparation of Ni-Cr alloy spray coating

[0038] A Ni-Cr alloy layer was deposited on the pretreated nickel mesh using a plasma spraying process. The spraying material was Ni-Cr alloy powder with a nickel content of 90–95 wt%. The working gas of the spraying device was a mixture of argon and hydrogen (volume ratio 4:1) with a total flow rate of 40 L / min. The spraying current was controlled at 500 A to 600 A, and the spraying distance was about 100 mm.

[0039] A 10–20 μm thick Ni-Cr alloy coating is uniformly deposited by repeated spraying; after completion, the sample is allowed to cool naturally to room temperature.

[0040] The formed Ni-Cr layer is tightly bonded to the nickel mesh substrate and has a dense and smooth surface, providing a good adhesion basis for subsequent deposition.

[0041] (3) Preparation of Ni-W co-deposition electrolyte

[0042] Add 100 mL of deionized water to a 250 mL beaker, and dissolve a certain amount of NiSO4·6H2O and Na2WO4·2H2O sequentially. Add a small amount of Na3C6H5O7·2H2O (sodium citrate) as a complexing agent. Adjust the pH to 8.5–9.0 by adding concentrated ammonia dropwise, and stir for 15–20 minutes until the solution is clear and homogeneous. The resulting solution can be left to stand at room temperature or preheated in a 40°C water bath before use.

[0043] (4) Electrochemical deposition of Ni-W heterojunction layer

[0044] A nickel mesh coated with Ni-Cr alloy was fixed to an electrode holder as the working electrode and placed in an electrolytic cell containing the aforementioned electrolyte to assemble a three-electrode system: Hg / HgO as the reference electrode and a platinum sheet as the counter electrode, with an electrode spacing of approximately 2 cm. Magnetic stirring was turned on (approximately 300 rpm), and deposition was carried out at a constant potential of −1.0 V (vs Hg / HgO) for 15 minutes at 40°C. After deposition, the power was turned off, the sample was removed, thoroughly rinsed with deionized water and ethanol, and dried at 60°C for 30 minutes. The resulting surface exhibited a grayish-silver metallic luster, forming a dense Ni-W heterostructure precursor layer.

[0045] (5) Annealing treatment

[0046] The dried sample was placed in a quartz boat and placed in the heating zone of a tube furnace. High-purity argon gas (100 mL / min) was first introduced for 15 minutes to purge air, then switched to a mixed gas of Ar / H2 = 95 / 5, maintaining a total flow rate of 100 mL / min. The temperature was increased to 400 °C at a rate of 5 °C / min, held at that temperature for 1 hour, and then allowed to cool naturally. This heat treatment process promotes elemental diffusion and interaction between Ni and W at the interface, forming a stable Ni-W heterojunction structure.

[0047] (6) Electrochemical activation

[0048] The annealed electrodes were assembled into a three-electrode system (Ni-W electrode as the working electrode, platinum sheet as the counter electrode, and Hg / HgO as the reference electrode) in a 1.0 mol / L KOH solution and subjected to cyclic voltammetry activation treatment. The potential range was −0.5 V to 0.5 V (vs Hg / HgO), the scan rate was 50 mV / s, and the cycle was 10 times. After activation, the electrodes were rinsed with deionized water and dried to obtain a Ni-W heterojunction catalytic electrode with an active phase on its surface.

[0049] Example 1

[0050] Methods for fabricating low-load Ni–W heterojunction electrodes include:

[0051] (1) Substrate pretreatment

[0052] Take a size of 10×10cm 2 The twill-woven nickel mesh was ultrasonically cleaned sequentially with deionized water, acetone, and anhydrous ethanol for 5 minutes each to remove impurities and oil. The mesh was then immersed in a 1 mol / L hydrochloric acid solution for 10 minutes to remove the surface oxide layer. After removal, it was immediately rinsed with plenty of deionized water until neutral, then rinsed with anhydrous ethanol to remove moisture, and finally dried in an 80°C vacuum oven for 10 minutes and cooled for later use.

[0053] (2) Preparation of Ni-Cr alloy spray coating

[0054] Atmospheric plasma spraying was employed. Ni-Cr alloy powder with a Ni content of approximately 92 wt% was selected. The Ar / H2 mixed gas volume ratio was 4:1, the total flow rate was 40 L / min, the spraying current was 550 A, and the spraying distance was 100 mm. Multiple reciprocating spraying processes were used to form an alloy layer approximately 15 μm thick. The coating was then allowed to cool naturally to room temperature.

[0055] (3) Ni-W co-deposition electrolyte preparation

[0056] Add 100 mL of deionized water to a 250 mL beaker to dissolve NiSO4·6H2O (25 g / L) and Na2WO4·2H2O (15 g / L), and simultaneously add Na3C6H5O7·2H2O (10 g / L) as a complexing agent. Adjust the pH to 8.8 with concentrated ammonia and stir for 20 minutes until the solution becomes clear.

[0057] (4) Electrochemical deposition of Ni–W heterojunction layer

[0058] A nickel mesh coated with a Ni-Cr layer was used as the working electrode, Hg / HgO as the reference electrode, and platinum sheets as the counter electrode, spaced 2 cm apart. Deposition was performed at a constant potential of −1.0 V (vs. Hg / HgO) for 15 minutes at 40°C with magnetic stirring at 300 rpm. After deposition, the surface was rinsed with deionized water and ethanol, and dried at 60°C for 30 minutes to obtain a grayish-silver Ni-W layer.

[0059] (5) Annealing treatment

[0060] The sample was placed in a tube furnace and an Ar / H2 (95 / 5) mixed gas was introduced (100 mL / min). The temperature was increased to 400 °C at 5 °C / min and held for 1 hour, followed by natural cooling to room temperature. A stable Ni-W heterojunction structure was formed through interfacial element diffusion.

[0061] (6) Electrochemical activation

[0062] A three-electrode system was constructed in a 1 mol / L KOH solution (Ni-W as the working electrode, platinum sheet as the counter electrode, and Hg / HgO as the reference electrode). The potential range was −0.2 V to 0.6 V (vs Hg / HgO), the scan rate was 50 mV / s, and the cycle was 10 times. After activation, the electrode surface exhibited a highly active Ni–W phase.

[0063] Example 2

[0064] Method for fabricating high-load Ni-W heterojunction electrodes:

[0065] (1) Substrate pretreatment

[0066] Select 10×10cm 2 The nickel mesh was cleaned following the same steps as in Example 1, except that the concentration of the pickling solution was adjusted to 3 mol / L hydrochloric acid to enhance the removal of the surface oxide layer. It was then washed with water until neutral, rinsed with ethanol, and vacuum-dried at 80°C for 10 minutes.

[0067] (2) Preparation of Ni-Cr alloy spray coating

[0068] The spraying material was Ni-Cr alloy powder with a Ni content of 95wt%, and the argon-hydrogen gas volume ratio was 4:1 with a total flow rate of 45L / min. The spraying current was 600A, the distance was 100mm, and repeated spraying was used to form a 20μm thick alloy layer, which was then cooled and set aside.

[0069] (3) Ni–W co-deposited electrolyte

[0070] Dissolve NiSO4·6H2O (30 g / L), Na2WO4·2H2O (20 g / L), and Na3C6H5O7·2H2O (15 g / L) in 100 mL of deionized water. Adjust the pH to 8.5, stir for 15 minutes, and then preheat in a 40 °C water bath.

[0071] (4) Electrochemical deposition

[0072] The three-electrode system was deposited at a constant potential of −1.1V (vsHg / HgO) at 40°C for 20 minutes with a stirring speed of 350 rpm. After rinsing, it was dried at 60°C for 30 minutes.

[0073] (5) Annealing treatment

[0074] An Ar / H2 (95 / 5) mixed gas was introduced (100 mL / min), and the temperature was increased to 450 °C at a rate of 5 °C / min and held for 1 h. After annealing, the sample surface was smooth and dense, and the alloy layer and Ni–W layer were well bonded.

[0075] (6) Electrochemical activation

[0076] Using the same method as in Example 1, cyclic voltammetry was performed 10 times in 1 mol / L KOH (−0.2 V to 0.6 V, 50 mV / s). The resulting electrode exhibited a higher electrochemical active area and excellent hydrogen evolution performance.

[0077] In Example 1, the Ni-Cr alloy layer formed by plasma spraying alone exhibits a uniform and dense granular structure, with a coating morphology showing good continuity. Magnified observation reveals that its microscopic surface layer consists of interconnected fine particles, forming a certain degree of interconnected pores. This porous and uniformly distributed characteristic is beneficial for the adhesion and interfacial bonding of subsequent electrochemically deposited layers.

[0078] After Ni-W co-deposition and annealing, the electrode surface morphology undergoes significant changes. The original micropores of the sprayed coating are partially filled and reconstructed by the new deposited phase, forming a finer surface structure. Numerous new particulate materials are observed on the post-deposition sample surface, which are rougher and have significantly smaller pore sizes, exhibiting a coexistence of layered and micro / nano particles. This structural reconstruction significantly increases the surface area, exposing more active sites, thus constructing a Ni-W heterojunction catalytic surface with high interfacial activity, providing a structural basis for excellent electrocatalytic performance.

[0079] Table 1 shows the overpotential comparison of the catalytic hydrogen evolution reaction and oxygen evolution reaction of the synthesized materials and comparative samples in Example 2.

[0080] Sample Name <![CDATA[HER(@3000A / m 2 )]]> <![CDATA[OER(@3000A / m 2 )]]> <![CDATA[HER(@5000A / m 2 )]]> <![CDATA[OER(@5000A / m 2 )]]> Ni-W heterogeneous and Ni-Cr alloy catalysts -170.2mV 291.3mV -227.2mV 237.6mV Ni-Cr alloy catalyst -216.7mV 237.7mV -257.3mV 279.9mV Nickel mesh substrate -285.4mV 315.3mV -277.2mV 317.6mV

[0081] To systematically evaluate the electrochemical performance of the prepared electrodes, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) polarization tests were performed on untreated nickel mesh substrates, samples treated only with Ni-Cr spraying, and samples prepared by Ni-Cr spraying and Ni-W co-deposition coupling processes. The results showed that the catalytic activity of the sprayed sample was improved compared to the original substrate, but a higher overpotential was still required at the same current density. In contrast, the sample treated by the coupling process exhibited a significantly reduced overpotential and a higher current response, demonstrating excellent electrochemical activity.

[0082] Further interfacial contact resistance testing revealed that the samples prepared by Ni-Cr spraying and Ni-W co-deposition coupling processes had the lowest interfacial resistance, significantly lower than that of the samples prepared by spraying alone and the untreated samples. This indicates that the formation of the Ni-Cr / Ni-W heterostructure effectively improved the electron transport path and reduced the interfacial energy barrier.

[0083] In summary, the coupled spraying and electrodeposition process constructs a multi-level micro / nano structure and a stable heterogeneous interface on the electrode surface, thereby optimizing charge transport and the adsorption-desorption process of reaction intermediates, and significantly improving the overall electrocatalytic performance.

[0084] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing a Ni-Cr-based underlayer reinforced and Ni-W heterojunction catalytic electrode, characterized in that the steps include... include: S1. Pre-treat the substrate; Preparation of S2.Ni-Cr alloy spray coating: A Ni-Cr alloy layer was uniformly deposited on the pretreated substrate surface using a plasma spraying process. The spraying material was Ni-Cr alloy powder with a nickel content of 90–95 wt% and a Cr content of 5–10 wt%, and the Ni-Cr alloy layer thickness was 10–20 μm. After completion, the substrate was naturally cooled to room temperature. The resulting Ni-Cr alloy layer was tightly bonded to the substrate and had a dense and smooth surface, which facilitated the adhesion of subsequent deposition. S3.Ni-W co-deposition electrolyte preparation: Add NiSO4·6H2O, Na2WO4·2H2O, and complexing agent Na3C6H5O7·2H2O to deionized water, such that the concentrations of NiSO4·6H2O, Na2WO4·2H2O, and the complexing agent are all 0.01-0.1 mol / L. The complexing agent may include Na3C6H5O7·2H2O or EDTA. Adjust the pH of the mixed solution to 8.5–9.0 and stir for 15–20 minutes until the solution is clear and homogeneous to form a deposition electrolyte. S4.Ni-W heterojunction electrochemical deposition: A substrate coated with a Ni-Cr alloy layer was used as the working electrode and placed in a deposition electrolyte to construct a three-electrode system. Magnetic stirring was turned on, and constant potential deposition was carried out at 40°C. The potential of the working electrode was -0.8 to -1.5V to form a dense Ni-W heterostructure precursor layer on the Ni-Cr alloy layer. After deposition, the substrate is removed, rinsed, and dried. S5. Annealing treatment: The electrochemically deposited substrate was placed in a quartz boat and sent into the heating zone of a tube furnace. After the air was purged from the tube furnace, a mixture of argon and hydrogen with a volume ratio of 95:5 was introduced and the total flow rate was maintained at 100 mL / min. The tube furnace was heated to 400 °C at a rate of 5 °C / min, and then held at that temperature for 1 hour before being allowed to cool naturally. This heat treatment was used to allow Ni and W to diffuse and interact at the interface, thereby forming a stable Ni-W heterojunction structure. S6. Electrochemical activation: A three-electrode system was constructed in an activated electrolyte, with the annealed substrate serving as the working electrode. Cyclic voltammetric activation was performed, with the working electrode potential ranging from -0.5 to 0.5 V, to obtain a Ni-W heterojunction catalytic electrode with an active phase on its surface.

2. The method for preparing a Ni-Cr-based underlayer reinforced and Ni-W heterojunction catalytic electrode according to claim 1, characterized in that, In step S1, the pretreatment steps include: first rinsing the nickel mesh substrate with deionized water to remove dust; then ultrasonically cleaning the substrate in acetone and anhydrous ethanol for 5 minutes each to remove oil and organic impurities; subsequently immersing the nickel mesh substrate in 0.1-3 mol / L hydrochloric acid solution for 10 minutes to remove the surface oxide layer; immediately rinsing with plenty of deionized water until neutral, and rinsing with anhydrous ethanol to remove moisture; finally drying the substrate in an 80℃ vacuum oven and cooling it for later use.

3. The method for preparing a Ni-Cr-based underlayer reinforced and Ni-W heterojunction catalytic electrode according to claim 1, characterized in that, In step S2, the working gas used for spraying is a mixture of argon and hydrogen with a volume ratio of 4:1, with a total flow rate of 40 L / min, the spraying current is controlled at 500 A to 600 A, and the spraying distance is about 100 mm.

4. The method for preparing a Ni-Cr-based underlayer reinforced and Ni-W heterojunction catalytic electrode according to claim 1, characterized in that, In step S3, concentrated ammonia is added dropwise to adjust the pH of the deposition electrolyte.

5. The method for preparing a Ni-Cr-based underlayer reinforced and Ni-W heterojunction catalytic electrode according to claim 1, characterized in that, In step S3, the deposited electrolyte is left to stand at room temperature for later use or preheated in a 40°C water bath for later use.

6. The method for preparing a Ni-Cr-based underlayer reinforced and Ni-W heterojunction catalytic electrode according to claim 1, characterized in that, In step S4, the three-electrode system uses Hg / HgO as the reference electrode and a platinum sheet as the counter electrode, with an electrode spacing of approximately 2 cm.

7. The method for preparing a Ni-Cr-based underlayer reinforced and Ni-W heterojunction catalytic electrode according to claim 1, characterized in that, In step S4, the constant potential deposition time is 10-30 minutes.

8. The method for preparing a Ni-Cr-based underlayer reinforced and Ni-W heterojunction catalytic electrode according to claim 1, characterized in that, In step S4, the substrate after deposition is thoroughly rinsed with deionized water and ethanol, and then dried at 60°C for 30 minutes.

9. The method for preparing a Ni-Cr-based underlayer reinforced and Ni-W heterojunction catalytic electrode according to claim 1, characterized in that, In step S6, the activation electrolyte is a 1.0 mol / L KOH solution, the platinum sheet is the counter electrode in the three-electrode system, and Hg / HgO is the reference electrode in the three-electrode system.

10. The method for preparing a Ni-Cr-based underlayer reinforced and Ni-W heterojunction catalytic electrode according to claim 1, characterized in that, In step S6, the scan rate of the cyclic voltammetric activation treatment is 50 mV / s, and the cycle is 10 times; the activated electrode is rinsed with deionized water and dried.

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