A self-supporting non-noble metal ni-re alloy electrocatalytic hydrogen evolution electrode

Abstract

The application discloses a self-supporting non-noble metal Ni-Re alloy electrocatalytic hydrogen evolution electrode and a preparation method and application thereof, and belongs to the technical field of electrocatalytic hydrogen evolution. In the application, the Re-Ni alloy hemispheres are self-supported on the surface of a nickel base, which is conducive to improving the electrocatalytic hydrogen evolution stability; the monomer microstructure of the hemispheres is conducive to improving the active area of the electrode surface and increasing the reaction active sites; the co-electrodeposition of rhenium and nickel can realize the uniform mixing of the two at the atomic level, which is conducive to generating synergistic effects to improve the electrocatalytic hydrogen evolution activity; the rich microcracks on the surface are conducive to eliminating the stress on the alloy surface and further providing additional reaction sites, and are conducive to improving the hydrogen evolution stability and activity. The electrode can control the hydrogen evolution overpotential to be between 190 mV and 500 mV under an industrial current density of 100 mA·cm ‑2 -500 mA·cm ‑2 .

Description

Technical Field

[0001] This invention belongs to the field of electrocatalytic hydrogen evolution technology, specifically relating to a self-supporting non-noble metal Ni-Re alloy electrocatalytic hydrogen evolution electrode, its preparation method, and its application. Background Technology

[0002] Hydrogen energy is a clean and sustainable energy source with advantages such as high energy density, zero carbon emissions, and abundant reserves, making it an effective alternative to traditional fossil fuels. Among various hydrogen production methods, water electrolysis can utilize intermittent green electricity from photovoltaic / wind power generation as input energy, and is considered one of the most promising new energy sources. To improve efficiency, industrial water electrolysis for hydrogen production is often carried out under acidic or alkaline conditions. However, under acidic conditions, the oxygen evolution reaction requires the use of iridium / ruthenium, and the hydrogen evolution reaction relies on platinum and other precious metals as catalysts. The scarcity of precious metals limits the large-scale use of water electrolysis in acidic systems. Compared to acidic systems, water electrolysis under alkaline conditions can use non-precious metals as electrodes, offering a greater cost advantage and making it the most mature and competitive water electrolysis method in industry. For example, non-precious metal nickel-based catalysts, including Raney nickel, Ni-WP, Ni-S alloys, and Ni-Mo alloys, are all used industrially. NanoRes., 2016, 9: 28-46 ).

[0003] Although hydrogen production by water electrolysis under alkaline conditions has been widely adopted in industry, the following problems still urgently need to be addressed: 1) Slow reaction kinetics. Compared to acidic systems, the H+ in the electrolyte... + 1) The concentration is 2-3 orders of magnitude lower, resulting in slower hydrogen evolution kinetics; 2) The catalytic activity of non-precious metals needs to be improved. The catalytic activity and stability of nickel-based non-precious metal hydrogen evolution are still significantly lower than those of precious metals, resulting in higher costs for hydrogen production through water electrolysis.

[0004] The modification of commercially available nickel-based non-noble metal electrodes to further enhance their catalytic activity has been extensively studied, and the overall strategy includes the following three aspects: 1) The catalytic hydrogen evolution kinetics can be enhanced by introducing a second phase, such as metal oxides or another electrocatalytic hydrogen evolution catalyst, onto the nickel substrate surface to trigger a synergistic effect. For example, "A nickel / vanadium oxide hydrogen evolution electrode and its preparation method and application (CN 110424023A)" enhances hydrogen evolution kinetics by introducing V2O3 onto the surface of nickel foam; "A self-supporting nickel-yttrium oxide electrocatalytic hydrogen evolution electrode and its preparation method and application (CN 113774419 A)" improves the catalytic hydrogen evolution activity of the nickel-based electrode by generating Y2O3 in situ on a nickel substrate; and "A nickel oxide-supported sulfur and phosphorus-doped graphene composite electrocatalyst and its preparation method (CN 109876833 A)" obtains a highly active electrocatalytic hydrogen evolution powder catalyst by supporting nickel oxide on sulfur and phosphorus-doped graphene.

[0005] 2) The surface electronic structure of the nickel-based substrate can be adjusted by introducing non-metallic elements such as S, P, B, C, and Se to improve the catalytic hydrogen evolution activity. For example, "A method for preparing a chemically plated nickel-boron alloy hydrogen evolution electrode (CN 111378987 B)" enhances hydrogen evolution activity by generating borides on the nickel substrate surface; "A method for preparing a non-noble metal Ni-Mo-PB high-efficiency electrocatalytic hydrogen evolution electrode (CN 113584517 A)" enhances hydrogen evolution activity by generating phosphides on the nickel substrate surface; "An integrated NiSe@Ni3Se2 / NF composite electrode material and preparation method for electrocatalytic hydrogen evolution electrode (CN 115807242 A)" enhances hydrogen evolution performance by generating selenides on the surface of a foamed nickel substrate; and "A molybdenum-nickel composite carbonitride electrocatalytic hydrogen evolution electrode and its preparation and application (CN 108195906 A)" enhances hydrogen evolution activity by generating carbides / nitrides, etc. 3) Enhancing catalytic hydrogen evolution activity by forming an alloy coating on the nickel substrate surface. For example, in "An Electrocatalytic Hydrogen Evolution Electrode and Its Preparation Method (CN 115369436 A)," a nickel-cobalt alloy coating is formed on the nickel substrate surface to strengthen surface hydrogen evolution activity. (Reference...) NanoRes., 2016, 9: 28-46 The article also reviews how nickel can be alloyed with molybdenum and tungsten to improve its catalytic hydrogen evolution activity. Although the activity of nickel-based catalysts has been significantly improved, the following issues still need to be addressed to further enhance their catalytic activity and stability: 1) Insufficient stability of the surface active layer. In-situ generation or coating of non-metallic oxides, non-metallic compounds, etc., on the nickel substrate can significantly increase the surface reaction area. However, the newly generated catalytic active layer and the metal substrate are still two different phases with vastly different properties, resulting in insufficient stability under the intense scouring of hydrogen bubbles at industrial-grade high current densities. This is especially true for powdered catalysts such as oxides and carbonaceous materials coated on the substrate surface, where detachment is more severe under industrial-grade high current conditions; 2) Stability is largely lost through the generation of alloyed coatings on the surface. However, alloyed coatings generated on the metal substrate surface often have a smooth surface and lack micro / nano structures, resulting in insufficient effective active reaction area and higher overpotentials at the same apparent current density under service conditions. Furthermore, the compositional difference between the alloyed coating and the substrate creates mechanical stress at the interface, which somewhat degrades the mechanical stability of the electrode. Summary of the Invention

[0006] To address the problems of high overpotential and insufficient stability of modified active reaction layers in existing alkaline nickel-based electrocatalytic hydrogen evolution electrodes, this invention proposes a self-supporting non-noble metal Ni-Re alloy electrocatalytic hydrogen evolution electrode and its preparation method.

[0007] The first objective of this invention is to provide a non-noble metal Ni-Re alloy electrocatalytic hydrogen evolution electrode. This electrode has a higher hydrogen evolution specific surface area and provides more active sites compared to conventional alloy electrodes, resulting in a lower hydrogen evolution overpotential. Furthermore, the incorporation of rhenium enhances the hydrogen evolution activity of the nickel-based electrode. In addition, the Ni-Re coating is formed in situ, without obvious interfaces, and exhibits strong coating stability. Moreover, the unique micro / nano structure on the surface of the Ni-Re alloy electrode reduces surface tension, facilitating the removal of hydrogen bubbles. Under alkaline conditions, at 100 mA·cm⁻¹… -2 ~500mA·cm -2 At industrial-grade current densities, the hydrogen evolution overpotential is only between 190mV and 500mV.

[0008] The second objective of this invention is to provide a method for preparing a non-precious metal Ni-Re alloy electrocatalytic hydrogen evolution electrode. This method uses readily available raw materials, is simple to implement, and is easy to scale up for mass production.

[0009] To achieve the above objectives, the following technical solution was adopted: To achieve the first objective, "providing a non-noble metal Ni-Re alloy electrocatalytic hydrogen evolution electrode," a tightly packed hemispherical Ni-Re alloy body is formed on a nickel substrate surface. The size of each hemispherical alloy body is controlled to be 10-15 μm, with adjacent Ni-Re alloy hemispheres bonded together. The Re content in the alloy body is between 40% and 80%, and the alloy body surface has abundant microcracks with a crack depth of less than 100 nm. Through the above-mentioned microstructure control of surface composition, the content described in the first objective is achieved.

[0010] The second objective, "to provide a method for preparing a non-precious metal Ni-Re alloy electrocatalytic hydrogen evolution electrode," includes two aspects: 1) a method for controlling the surface composition and microstructure to enhance the reactive surface area. Using a nickel substrate as the initial electrode, a Ni-Re alloy electrode is obtained through electrodeposition. This is achieved by strictly controlling the pH of the electroplating solution to 3.5 ± 0.2, and by adding citric acid and sodium dodecyl sulfate as surfactants while strictly controlling their absolute concentrations. Furthermore, the composition of the alloy coating can be controlled by adjusting the electrodeposition time and the relative content of nickel and rhenium species in the plating solution; 2) coating stability adjustment. Using nickel as one of the substrate elements in the coating eliminates stress at the interface between the coating and the substrate. Additionally, a simple subsequent heat treatment eliminates internal stress and enhances the interdiffusion between Ni and Re atoms at the interface, eliminating the interface layer and significantly improving the mechanical stability between the coating and the substrate.

[0011] The above technical solution is further detailed below: A self-supporting non-noble metal Ni-Re alloy electrocatalytic hydrogen evolution electrode and its preparation method are characterized in that: the surface of the nickel substrate is composed of a closely packed hemispherical Ni-Re alloy body; the size of a single hemispherical alloy body is 10~15μm, and adjacent Ni-Re alloy hemispheres are bonded to each other; the Re content in the alloy body is between 40% and 80%; the surface of the alloy body has abundant microcracks with a crack depth of less than 100nm. The preparation method includes the following steps: 1) Substrate pretreatment. First, the nickel substrate was ultrasonically cleaned in anhydrous ethanol for more than 6 min, then ultrasonically cleaned in 1 mol / L hydrochloric acid for more than 30 min, and finally ultrasonically cleaned in ultrapure water for more than 6 min.

[0012] 2) Electrolyte preparation. Add nickel and rhenium sources to ultrapure water. Simultaneously add citric acid and dodecyl sulfate. Sodium sulfate is used as a surfactant. After complete dissolution, 0.2 mol / L NaOH solution is added dropwise to adjust the pH value, which is strictly controlled to be 3.5, with fluctuations within 0.2.

[0013] 3) Electrodeposition of hemispherical alloy bodies. A pretreated nickel substrate is used as the cathode, and platinum metal is used as the anode. The solution temperature was adjusted to 65°C, and the current density was 50 mA·cm⁻¹. -2 ~60 mA·cm -2 Deposition under the specified conditions for 30-60 minutes.

[0014] 1) Post-treatment. After electrodeposition, the cathode was ultrasonically cleaned in 0.5 mol / L hydrochloric acid for 10 min, then... Then, under a nitrogen protective gas flow, the temperature was first maintained at 100℃ for 120 min, then increased to 1000℃ and maintained for 60 min, and finally cooled to room temperature to obtain a self-supporting non-precious metal Ni-Re alloy high-efficiency electrocatalytic hydrogen evolution electrode.

[0015] Optionally, the nickel substrate mentioned in step 1) is one of nickel sheet, nickel mesh, or nickel foam.

[0016] Optionally, the nickel source in step 2) is one of nickel aminosulfonate, nickel nitrate, and nickel chloride, and the rhenium source is one of ammonium rhenium, potassium rhenium, and sodium rhenium.

[0017] Optionally, the amount of nickel source added is based on Ni 2+ The concentration of rhenium source is calculated as 5 mmol / L to 500 mmol / L, and the amount of rhenium added is based on ReO4. - The concentration ranges from 5 mmol / L to 500 mmol / L. The amount of citric acid added is strictly controlled at 450 mmol / L, and the amount of sodium dodecyl sulfate added is strictly controlled at 0.1 g / L.

[0018] Optionally, the electrocatalytic hydrogen evolution electrode is suitable for NaOH or KOH alkaline electrolyte systems with an electrolyte concentration of 0.1 mol / L to 6 mol / L, at 100 mA·cm⁻¹. -2 ~500mA·cm -2 At industrial-grade current densities, the hydrogen evolution overpotential is between 190mV and 500mV.

[0019] In the modification and improvement of traditional nickel-based non-precious metal electrocatalytic hydrogen evolution electrodes, it is difficult to achieve a balance between stability and high activity. Forming an active layer on the nickel substrate surface, either in situ or ex-situ, often results in rich micro / nano structures, significantly increasing the specific surface area and active sites compared to a flat surface, while also exhibiting higher catalytic activity than the substrate itself. However, the significant differences and non-integral nature between the substrate and the active layer often make it difficult to guarantee long-term stability, especially in the harsh bubble-flushing environment of industrial current densities. On the other hand, alloying the nickel substrate surface can ensure strong stability, but the flat alloy surface has a limited specific surface area, making it difficult to provide more active reaction sites.

[0020] Compared with existing methods for modifying non-precious metal nickel-based electrocatalytic hydrogen evolution electrodes, this invention achieves a balance between stability and high activity in nickel-based non-precious metal modified electrodes. Its beneficial effects are detailed below: 1) The number of reactive sites on the electrode surface is significantly increased compared to flat alloy electrodes. The alloy electrode surface provided by this invention is composed of hemispherical particles arranged in a way that adjacent hemispheres are bonded together. Theoretically, its specific surface area can be increased by 60% compared to flat alloy electrodes, thus providing more reactive sites; 2) The composition control of the coating and the post-treatment process further improve the stability of the coating. The surface alloy composition contains the base element nickel, which can reduce the stress between the electrode surface and the substrate. Furthermore, the abundant microcracks on the surface can further release the internal stress caused by the compositional difference between the substrate and the surface layer, thereby improving mechanical stability. In addition, subsequent heat treatment can not only promote atomic diffusion at the interface between the surface alloy coating and the substrate, further forming an integrated structure and improving the overall stability of the electrode, but also remove volatile rhenium oxides generated by surface oxidation through volatilization, further improving the service stability of the electrode; 3) The introduction of Re element can enhance the intrinsic hydrogen evolution activity of the electrode. Introducing highly reactive Re elements into the coating can reduce the hydrogen evolution overpotential of the electrode and improve its activity. The electrocatalytic hydrogen evolution electrode provided by this method can operate under alkaline conditions at 100 mA·cm⁻¹. -2 ~500mA·cm -2 Under industrial-grade current density, the hydrogen evolution overpotential remains between 190mV and 500mV after more than 5000 hours of continuous service. Attached Figure Description

[0021] Figure 1 Cross-sectional view of the Ni-Re alloy electrode in Example 1; (a) Optical photograph; (b, c) Cross-sectional electron microscope images; (d) Re elemental distribution map; (e) Ni elemental distribution map; Figure 2 This is a front view of the Ni-Re alloy electrode in Example 1; Figure 3 The diagram shows the micro / nano structure of the Ni-Re alloy electrode in Example 1; (a) a schematic diagram of the Ni-Re alloy coating structure; (b) the surface area of ​​a flat surface with dimensions of 4a*4a (top) and the surface area of ​​a Ni-Re alloy surface of the same size (bottom); Figure 4 Comparison of hydrogen evolution polarization curves for Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3; Figure 5 Example 4 uses nickel foam as a substrate and an industrial-grade current density of 100 mA·cm⁻¹. -2 Timing potential curves after 5000 hours of service under certain conditions. Detailed Implementation

[0022] To make the above-mentioned features and advantages of the present invention more apparent and understandable, specific embodiments are described below in detail. Unless otherwise specified, the methods of the present invention are conventional methods in the art.

[0023] Example 1 Using a nickel mesh as a substrate, the plating solution was first ultrasonically cleaned in anhydrous ethanol for 8 min, then ultrasonically cleaned in 1 mol / L hydrochloric acid for 35 min, and finally ultrasonically cleaned in ultrapure water for 8 min. The plating bath composition was as follows: nickel sulfamate concentration of 300 mmol / L, ammonium perlite concentration of 30 mmol / L, citric acid and sodium dodecyl sulfate added at 450 mmol / L and 0.1 g / L respectively, with a pH of 3.5 ± 0.2. The treated nickel mesh was used as the cathode, platinum sheet as the anode, and the plating bath temperature was 65℃. The plating temperature was maintained at 60 mA·cm⁻¹. -2 Deposition was performed at the current density for 30 min. The nickel mesh was then removed and ultrasonically cleaned in 0.5 mol / L hydrochloric acid for 10 min. It was then held at 100℃ for 120 min under a nitrogen protective gas flow, followed by heating to 1000℃ and holding for 60 min. Finally, it was cooled to room temperature to obtain a self-supporting non-noble metal Ni-Re alloy high-efficiency electrocatalytic hydrogen evolution electrode. The electrode surface has a rhenium content of 60%, is composed of hemispherical Ni-Re alloy bodies with dimensions of 10 μm to 15 μm, and exhibits abundant surface microcracks with a depth of approximately 90 nm.

[0024] The electrode was placed in a 1 mol / L NaOH solution as an electrocatalytic hydrogen evolution electrode at 300 mA·cm⁻¹. -2At current density, the hydrogen evolution overpotential is 280mV after 1000 hours of service, and the coating on the electrode surface remains stable after 2000 hours of service.

[0025] Example 2 Using nickel sheets as the substrate, the plating solution was first ultrasonically cleaned in anhydrous ethanol for 10 min, then ultrasonically cleaned in 1 mol / L hydrochloric acid for 40 min, and finally ultrasonically cleaned in ultrapure water for 10 min. The plating bath composition was as follows: nickel nitrate concentration of 5 mmol / L, potassium permanganate concentration of 5 mmol / L, citric acid and sodium dodecyl sulfate added at 450 mmol / L and 0.1 g / L respectively, with a pH of 3.5 ± 0.2. The treated nickel sheet was used as the cathode, and the plating bath as the anode. The plating bath temperature was 65℃, and the concentration was maintained at 50 mA·cm⁻¹. -2 Deposition was performed at a current density for 60 min. The nickel sheet was then removed and ultrasonically cleaned in 0.5 mol / L hydrochloric acid for 10 min. It was then held at 100℃ for 120 min under a nitrogen atmosphere, followed by a rise to 1000℃ and holding for 60 min. Finally, it was cooled to room temperature to obtain a self-supporting non-precious metal Ni-Re alloy high-efficiency electrocatalytic hydrogen evolution electrode. The electrode surface has a rhenium content of 80%, is composed of hemispherical Ni-Re alloy bodies with dimensions of 10 μm to 15 μm, and exhibits abundant surface microcracks with a depth of approximately 60 nm.

[0026] The electrode was placed in a 0.1 mol / L KOH solution as an electrocatalytic hydrogen evolution electrode at 200 mA·cm⁻¹. -2 At the current density, the hydrogen evolution overpotential is 230mV after 1000 hours of service, and the coating on the electrode surface remains stable after 5000 hours of service.

[0027] Example 3 Using nickel foam as a substrate, the plating solution was first ultrasonically cleaned in anhydrous ethanol for 15 min, then ultrasonically cleaned in 1 mol / L hydrochloric acid for 35 min, and finally ultrasonically cleaned in ultrapure water for 15 min. The plating bath composition was as follows: nickel chloride concentration of 500 mmol / L, sodium perlite concentration of 500 mmol / L, citric acid and sodium dodecyl sulfate added at 450 mmol / L and 0.1 g / L respectively, with a pH of 3.5 ± 0.2. The treated nickel foam was used as the cathode, platinum sheet as the anode, and the plating bath temperature was 65℃. The plating temperature was maintained at 50 mA·cm⁻¹. -2Deposition was performed at a current density for 30 min. The nickel foam was then removed and ultrasonically cleaned in 0.5 mol / L hydrochloric acid for 10 min. It was then held at 100 °C for 120 min under a nitrogen atmosphere, followed by a rise to 1000 °C and holding for 60 min. Finally, it was cooled to room temperature to obtain a self-supporting non-noble metal Ni-Re alloy high-efficiency electrocatalytic hydrogen evolution electrode. The electrode surface has a rhenium content of 40%, is composed of hemispherical Ni-Re alloy bodies with dimensions of 10 μm to 15 μm, and exhibits abundant surface microcracks with a depth of approximately 50 nm.

[0028] The electrode was used as an electrocatalytic hydrogen evolution electrode in a 6 mol / L NaOH solution at 500 mA·cm⁻¹. -2 At current density, the hydrogen evolution overpotential is 500mV after 1000 hours of service, and the coating on the electrode surface remains stable after 2000 hours of service.

[0029] Example 4 Using nickel foam as a substrate, the plating solution was first ultrasonically cleaned in anhydrous ethanol for 15 min, then ultrasonically cleaned in 1 mol / L hydrochloric acid for 35 min, and finally ultrasonically cleaned in ultrapure water for 15 min. The plating bath composition was as follows: nickel aminosulfonate concentration of 400 mmol / L, ammonium rheniumate concentration of 50 mmol / L, citric acid and sodium dodecyl sulfate added at 450 mmol / L and 0.1 g / L respectively, with a pH of 3.5 ± 0.2. The treated nickel foam was used as the cathode, platinum sheet as the anode, and the plating bath temperature was 65℃. The plating temperature was maintained at 55 mA·cm⁻¹. -2 Deposition was performed at a current density for 40 min. The nickel foam was then removed and ultrasonically cleaned in 0.5 mol / L hydrochloric acid for 10 min. It was then held at 100 °C for 120 min under a nitrogen atmosphere, followed by a rise to 1000 °C and holding for 60 min. Finally, it was cooled to room temperature to obtain a self-supporting non-noble metal Ni-Re alloy high-efficiency electrocatalytic hydrogen evolution electrode. The electrode surface has a rhenium content of 60%, is composed of hemispherical Ni-Re alloy bodies with dimensions of 10 μm to 15 μm, and exhibits abundant surface microcracks with a depth of approximately 30 nm.

[0030] The electrode was placed in a 1 mol / L NaOH solution as an electrocatalytic hydrogen evolution electrode at 100 mA·cm⁻¹. -2 At current density, the hydrogen evolution overpotential is 190mV after 1000 hours of service, and the coating on the electrode surface remains stable after 2000 hours of service.

[0031] Comparative Example 1 A commercially available 20% Pt / C hydrogen evolution catalyst was used. 5% Nafion solution was added and dispersed in alcohol. The resulting slurry was then magnetically stirred and coated onto a nickel foam substrate. This slurry was then used as an electrocatalytic hydrogen evolution electrode in a 1 mol / L NaOH solution at 100 mA·cm⁻¹. -2 At the current density, the hydrogen evolution overpotential is 242mV after 1000 hours of service, and the catalyst layer on the electrode surface has fallen off after 2000 hours of service.

[0032] Comparative Example 2 Commercially available nickel foam was first ultrasonically cleaned in anhydrous ethanol for 15 min, then ultrasonically cleaned in 1 mol / L hydrochloric acid for 35 min, and finally ultrasonically cleaned in ultrapure water for 15 min. After pretreatment, it was used as an electrocatalytic hydrogen evolution electrode in 1 mol / L NaOH solution at 100 mA·cm⁻¹. -2 At the current density, the hydrogen evolution overpotential is 600 mV after 1000 hours of service, and the electrode surface remains stable after 2000 hours of service.

[0033] Comparative Example 3 Using nickel foam as a substrate, the plating solution was first ultrasonically cleaned in anhydrous ethanol for 15 min, then ultrasonically cleaned in 1 mol / L hydrochloric acid for 35 min, and finally ultrasonically cleaned in ultrapure water for 15 min. The plating bath composition was as follows: ammonium rhenium oxide concentration of 500 mmol / L, citric acid and sodium dodecyl sulfate added at 450 mmol / L and 0.1 g / L respectively, with a pH of 3.5 ± 0.2. The treated nickel foam was used as the cathode, platinum sheet as the anode, and the plating bath temperature was 65℃, at 50 mA·cm⁻¹. -2 Deposition was performed at a current density for 30 min. The nickel foam was then removed and ultrasonically cleaned in 0.5 mol / L hydrochloric acid for 10 min. It was then held at 100℃ for 120 min under a nitrogen protective gas flow, followed by a rise to 1000℃ and holding for 60 min. Finally, it was cooled to room temperature to obtain a self-supporting pure Re metal-coated electrode. The electrode surface coating lacked hemispherical micro / nano structures, was uneven, and exhibited localized flaking.

[0034] The electrode was placed in a 1 mol / L NaOH solution as an electrocatalytic hydrogen evolution electrode at 100 mA·cm⁻¹. -2 At the current density, the hydrogen evolution overpotential is 260mV after 1000 hours of service, and the coating on the electrode surface has peeled off after 2000 hours of service.

[0035] Figure 1The images show a cross-sectional view of the Ni-Re alloy electrode in Example 1; (a) optical photograph; (b, c) cross-sectional electron microscope images; (d) Re elemental distribution map; (e) Ni elemental distribution map. Through image observation, it can be clearly seen that the electrode surface is composed of hemispherical particles with an ordered structure, and adjacent hemispheres are bonded together. Furthermore, comparative images show that nickel and rhenium are relatively uniformly distributed on the electrode surface.

[0036] Figure 2 This is a front view of the Ni-Re alloy electrode in Example 1. Through image analysis, it can be observed that the electrode surface exhibits a micro-nano structure, and its morphology distribution can be understood in detail.

[0037] Figure 3 The diagram shows the micro / nano structure of the Ni-Re alloy electrode in Example 1; (a) a schematic diagram of the Ni-Re alloy coating structure; (b) the surface area of ​​a flat surface with dimensions of 4a*4a (top) and the surface area of ​​a Ni-Re alloy surface of the same size (bottom). Through the analysis of the schematic diagram, it is clearly shown that the surface area of ​​the alloy electrode is effectively improved after modification.

[0038] Figure 4 The hydrogen evolution polarization curves of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 are compared. Through image observation, it can be clearly seen that the hydrogen evolution performance of the alloy electrode is effectively improved after modification.

[0039] Figure 5 Example 4 uses nickel foam as a substrate and an industrial-grade current density of 100 mA·cm⁻¹. -2 The time-potential curves after 5000 hours of service under certain conditions clearly show that alloying the nickel substrate surface ensures strong stability.

[0040] For those skilled in the art, various corresponding changes and modifications can be made based on the above technical solutions and concepts, and all such changes and modifications should be included within the protection scope of the claims of this invention.

Claims

1. A self-supporting non-noble metal Ni-Re alloy electrocatalytic hydrogen evolution electrode, characterized in that: The nickel substrate surface is composed of closely packed hemispherical Ni-Re alloy bodies; the size of a single hemispherical alloy body is 10~15μm, and adjacent Ni-Re alloy bodies are bonded to each other; the mass content of Re in the alloy body is 40%~80%; the surface of the alloy body has abundant microcracks with a crack depth of less than 100nm.

2. A method for preparing a self-supporting non-noble metal Ni-Re alloy electrocatalytic hydrogen evolution electrode as described in claim 1, characterized in that: Includes the following steps: (1) Substrate pretreatment: First, the nickel substrate was ultrasonically cleaned in anhydrous ethanol for more than 6 min, then ultrasonically cleaned in 1 mol / L hydrochloric acid for more than 30 min, and finally ultrasonically cleaned in ultrapure water for more than 6 min. (2) Electrolyte preparation: Add nickel source and rhenium source to ultrapure water, and add citric acid and sodium dodecyl sulfate as surfactants. After they are completely dissolved, add 0.2 mol / L NaOH solution to adjust the pH value to 3.5 ± 0.

2. (3) Electrodeposition of hemispherical alloy body: The pretreated nickel substrate was used as the cathode and platinum metal as the anode. The electrolyte temperature was controlled at 65℃ and the current density was 50 mA·cm. -2 ~60 mA·cm -2 Deposition under the specified conditions for 30-60 minutes; (4) Post-treatment: After electrodeposition, the cathode was ultrasonically cleaned in 0.5 mol / L hydrochloric acid for 10 min, and then kept at 100℃ for 120 min under nitrogen protection, and then heated to 1000℃ and kept for 60 min. It was then naturally cooled to room temperature to obtain the self-supporting non-precious metal Ni-Re alloy electrocatalytic hydrogen evolution electrode.

3. The method according to claim 2, characterized in that: The nickel substrate is one of nickel sheet, nickel mesh, or nickel foam; the nickel source is one of nickel sulfamate, nickel nitrate, or nickel chloride; and the rhenium source is one of ammonium rhenium, potassium rhenium, or sodium rhenium.

4. The method according to claim 2, characterized in that: The concentration of the nickel source in the electrolyte is based on Ni 2+ The concentration of the rhenium source is calculated as 5 mmol / L to 500 mmol / L, expressed as ReO4. - The concentrations are calculated to be 5 mmol / L to 500 mmol / L, citric acid concentration is 450 mmol / L, and sodium dodecyl sulfate concentration is 0.1 g / L.

5. The application of a self-supporting non-noble metal Ni-Re alloy electrocatalytic hydrogen evolution electrode as described in claim 1, or a self-supporting non-noble metal Ni-Re alloy electrocatalytic hydrogen evolution electrode prepared by the method described in any one of claims 2-4, characterized in that: The electrocatalytic hydrogen evolution electrode is suitable for NaOH or KOH alkaline electrolyte systems with an electrolyte concentration of 0.1 mol / L to 6 mol / L, at 100 mA·cm⁻¹. -2 ~500mA·cm -2 At industrial-grade current densities, the hydrogen evolution overpotential is 190mV~500mV.

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