A nickel-molybdenum alloy self-supporting electrode and a preparation method and application thereof
By constructing a macroporous array of nickel-molybdenum alloy self-supporting electrodes, the problem of bubble blockage in traditional nickel-molybdenum alloy electrodes under high current density was solved, achieving efficient electrochemical catalytic performance and hydrogen production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ANHUI UNIV
- Filing Date
- 2023-04-12
- Publication Date
- 2026-07-24
AI Technical Summary
Traditional nickel-molybdenum alloy electrodes are prone to blockage by air bubbles at high current densities, leading to a significant decrease in electrochemical performance and affecting the hydrogen production rate.
Opal structures were constructed by self-assembly of silica nanospheres as electrodeposition templates, and nickel-molybdenum thin films were grown by electrochemical deposition to prepare macroporous array nickel-molybdenum alloy self-supporting electrodes, forming a three-dimensional ordered porous structure.
It improves the electrochemical performance of the electrode at high current densities, provides a fast ion and electron diffusion channel, enhances the enrichment of active sites and mass transfer efficiency, ensures the removal of gaseous products, and achieves efficient hydrogen evolution.
Smart Images
Figure CN116145172B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrocatalytic electrode preparation technology, specifically to a nickel-molybdenum alloy self-supporting electrode, its preparation method, and its application. Background Technology
[0002] Hydrogen, as a renewable and clean energy source, boasts advantages such as being pollution-free and having high energy density, far surpassing other fossil fuels and holding significant potential in the energy market. Electrochemical water splitting can produce clean, sustainable, and high-purity hydrogen. Nickel-molybdenum alloys are widely used as electrodes in catalytic hydrogen production processes via water electrolysis due to their low cost, ease of production, excellent mechanical properties, stability, and corrosion resistance. However, traditional nickel-molybdenum alloy electrodes perform well at low current densities, but at high current densities, the generated bubbles easily clog the active reaction sites, leading to a significant decrease in electrochemical performance and severely impacting hydrogen production rates. Improving the electrochemical performance of electrodes at high current densities has become a pressing challenge. Summary of the Invention
[0003] The purpose of this invention is to provide a nickel-molybdenum alloy self-supporting electrode, its preparation method, and its application. It constructs an opal structure by self-assembly of silica nanospheres as an electrodeposition template, and uses electrochemical deposition to grow a nickel-molybdenum thin film to construct a macroporous array nickel-molybdenum alloy self-supporting electrode.
[0004] In one aspect of the present invention, a method for preparing a nickel-molybdenum alloy self-supporting electrode is provided. According to an embodiment of the present invention, the method includes the following steps: self-assembling silica nanospheres on a nickel foam substrate to form a silica nanosphere electrodeposition template; using a mixed aqueous solution of sodium citrate hydrate, nickel sulfate hexahydrate, and sodium molybdate dihydrate as the electrolyte for electrodeposition of the nickel-molybdenum alloy; and preparing a size-controllable nickel-molybdenum alloy self-supporting electrode by electrochemical deposition.
[0005] In addition, the method for preparing a nickel-molybdenum alloy self-supporting electrode according to the above embodiments of the present invention may also have the following additional technical features:
[0006] In some embodiments of the present invention, the method for preparing silica nanosphere electrodeposition templates is as follows: a silica gel solution is prepared using a modified Stober method based on the sol-gel method, and silica nanospheres of different diameters with controllable particle size are constructed on a nickel foam substrate by gravity sedimentation as electrodeposition templates.
[0007] In some embodiments of the present invention, the preparation of the silica gel solution specifically includes the following steps: adding deionized water, anhydrous ethanol and 25% ammonia solution in different proportions to containers, stirring evenly at room temperature, adding tetraethyl orthosilicate, sealing the container after the addition is complete, and waiting for the solution to react completely. After centrifugation, washing and drying, spherical silica with different particle sizes are obtained. Deionized water is added to the spherical silica to obtain the silica gel solution.
[0008] In some embodiments of the present invention, the volume ratio of deionized water, anhydrous ethanol, 25% ammonia solution, and tetraethyl orthosilicate is 0-25.75:64.75-90:2.1-9:1.5-6; after sealing the container, the solution is stirred with a magnetic stirrer for 6-8 hours to ensure complete reaction; the drying temperature is 60-70℃ and the time is 2-4 hours; after adding deionized water to the spherical silica, it is dissolved by sonication at 40-50℃ for 2 hours; the size range of the spherical silica is 50-500 nm; and the concentration of the silica gel solution is 50-100 mg / mL.
[0009] In some embodiments of the present invention, the preparation method of the electrodeposition template includes the following steps: by natural sedimentation, nickel foam is placed in a silica gel solution at room temperature for 12-48 hours and then dried in an oven to ensure that spherical silica of different diameters self-assembles from disordered to three-dimensional ordered arrangement on the nickel foam, thereby obtaining a silica nanosphere electrodeposition template with uniform size and regular three-dimensional arrangement.
[0010] In some embodiments of the present invention, the drying temperature is 60-70°C and the drying time is 2-4 hours.
[0011] In some embodiments of the present invention, the concentration of sodium citrate hydrate is 0.3-0.6 mol / L, the concentration of nickel sulfate hexahydrate is 0.15-0.3 mol / L, the concentration of sodium molybdate dihydrate is 0.05-0.1 mol / L, the concentration ratio of sodium citrate hydrate, nickel sulfate hexahydrate, and sodium molybdate dihydrate in the electrolyte is 6:3:1, the molar ratio of Ni to Mo is 3:1, and the pH of the electrolyte is adjusted to 10.0-11.0 using 25% ammonia solution.
[0012] In some embodiments of the present invention, the current density of electrochemical deposition is 25-50 mA cm⁻¹. -2 The electrodeposition time is 300-3000s. The synthesized material after electrodeposition is immersed in 0.1-1mol / L potassium hydroxide for 12-48h for chemical etching to remove the silica nanosphere electrodeposition template and leave the filler skeleton, thus obtaining the nickel-molybdenum alloy self-supporting electrode.
[0013] In another aspect of the present invention, the present invention provides a nickel-molybdenum alloy self-supporting electrode prepared according to the preparation method of the nickel-molybdenum alloy self-supporting electrode described above.
[0014] In another aspect, the present invention proposes a method for catalytic hydrogen production via water electrolysis. According to an embodiment of the present invention, the aforementioned nickel-molybdenum alloy self-supporting electrode is used as the water electrolysis catalyst.
[0015] Compared with the prior art, the beneficial effects of the present invention are:
[0016] 1) This invention utilizes the self-assembly of silica nanospheres to construct an opal structure as an electrodeposition template, which is then naturally deposited onto nickel foam. A nickel-molybdenum alloy active layer is then prepared in the gaps between the template agents using electrochemical deposition. Finally, the silica nanosphere template is dissolved in an alkaline solvent to obtain a nickel-molybdenum alloy electrode with a porous structure. The macroporous array nickel-molybdenum alloy self-supporting electrode of this invention possesses a three-dimensionally ordered porous structure with a large specific surface area and numerous electrochemical active sites. Compared to electrodes with traditional structures, it exhibits superhydrophobicity, effectively overcoming the shortcomings of traditional nickel-molybdenum alloy electrodes with dense structures and gas-blocked active sites. It also solves the defect of unsatisfactory electrochemical performance at high current densities, and has significant application value in the field of electrochemical catalysis.
[0017] 2) This invention introduces a three-dimensional ordered porous structure to provide a fast diffusion channel for ions and electrons, thereby improving the transport efficiency of ions within the electrode.
[0018] 3) The electrode prepared by this invention has multi-scale porosity and independent support characteristics, which helps to enrich active sites and provides a highly exposed solid-liquid-gas interface, allowing the electrode loading to be as high as 5.8 mg / cm³. 2 catalyst.
[0019] 4) The electrode prepared by this invention is a nanoarray electrode with a rough surface structure, which has ideal superhydrophilic and superhydrophobic surface wettability, which is conducive to the penetration of liquid electrolyte. Its superhydrophobic structure ensures the removal of gas products and effectively improves mass transfer efficiency.
[0020] 5) The electrode of this invention can efficiently evolve hydrogen at ultra-high current densities of 500-1000 mA cm-2. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of the structure of the large-pore array nickel-molybdenum alloy in Embodiment 1 of the present invention;
[0022] Figure 2 This is a schematic diagram of the structure of the macroporous array nickel-molybdenum alloy self-supporting electrode in Embodiment 1 of the present invention. In the figure, 1 is foamed nickel and 2 is macroporous array nickel-molybdenum alloy.
[0023] Figure 3 The images shown are SEM and TEM images of the macroporous array nickel-molybdenum alloy self-supporting electrode in Embodiment 1 of the present invention. (a) is a low-magnification SEM image of the macroporous array nickel-molybdenum alloy self-supporting electrode, showing a clear nickel foam skeleton. (b) is a high-magnification SEM image of the macroporous array nickel-molybdenum alloy self-supporting electrode. (c) is an even higher-magnification SEM image of the macroporous array nickel-molybdenum alloy self-supporting electrode, showing the approximate diameter of the macroporous array. (d) is a STEM image of the macroporous array nickel-molybdenum alloy self-supporting electrode. (e) is a low-magnification TEM image of the macroporous array nickel-molybdenum alloy self-supporting electrode. (f) is a high-magnification TEM image of the macroporous array nickel-molybdenum alloy self-supporting electrode, showing the nanosheet structure.
[0024] Figure 4 The image shows the polarization curves of the macroporous array nickel-molybdenum alloy self-supporting electrode in 1.0 mol / L potassium hydroxide solution in Example 1 of the present invention. Among them, (a) is the HER activity diagram of different electrodes (foamed nickel, macroporous array nickel-molybdenum alloy self-supporting electrode and Pt / C) in 1 MkOH at a scan rate of 5 mV / s; (b) is the magnified part of (a) in the low overpotential region.
[0025] Figure 5 In the middle, (a) from left to right, the values at 50 mA / cm 2 (a) H2 bubble diagrams separated from commercial platinum-carbon, nickel-molybdenum alloy self-supporting electrode prepared in Example 5, and macroporous array nickel-molybdenum alloy self-supporting electrode prepared in Example 1 at current density; (b) bubble size distribution diagrams on different electrodes. Detailed Implementation
[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0027] Experimental Example 1
[0028] A method for preparing a nickel-molybdenum alloy self-supporting electrode includes the following steps:
[0029] (1) Preparation of SiO2 colloidal solution:
[0030] Spherical silica nanospheres of varying diameters with controllable particle size and good monodispersity were prepared using a modified Stober method based on the solution-gel process. Deionized water, anhydrous ethanol, 25% ammonia solution, and tetraethyl orthosilicate (TEOS) were added sequentially to a beaker in a volume ratio of 25:65:9:4.5. The mixture was stirred with a magnetic stirrer for 8 hours to ensure complete reaction. The mixture was then centrifuged for 5 minutes, washed with deionized water and anhydrous ethanol, and dried in an oven at 60°C for 4 hours to obtain 200 nm SiO2 nanospheres. A certain amount of deionized water was added to the SiO2 nanospheres, and the mixture was sonicated at 40°C for 2 hours to ensure complete dissolution, resulting in a 50 mg / mL SiO2 colloidal solution.
[0031] (2) Preparation of silica nanosphere electrodeposition template
[0032] By allowing natural sedimentation, 1cm*1cm nickel foam was placed in a SiO2 colloidal solution at room temperature and allowed to settle for 24 hours before being placed in an oven and dried at 60℃ for 2 hours. This ensured that the SiO2 nanospheres self-assembled from disordered to three-dimensional ordered arrangement on the nickel foam, resulting in a uniform-sized and regularly arranged SiO2 nanosphere electrodeposition template.
[0033] (3) Preparation of nickel-molybdenum alloy electrolyte
[0034] Nickel-molybdenum alloy electrolyte: Sodium citrate (0.3 mol / L), nickel sulfate hexahydrate (0.15 mol / L), and sodium molybdate dihydrate (0.05 mol / L) were added to a beaker and stirred with a magnetic stirrer for 2 hours to prepare the nickel-molybdenum alloy electrolyte. The pH value was adjusted to 10.0 by adding 25% ammonia solution.
[0035] (4) Fabrication of macroporous array nickel-molybdenum alloy self-supporting electrodes
[0036] Using an electrochemical workstation, set the current density to 25 mA / cm². 2 An electrodeposition time of 900 s was set to fill the template gaps with nickel-molybdenum alloy to prepare a nickel-molybdenum alloy active layer. The synthesized material after electrodeposition was immersed in 1 mol / L potassium hydroxide for 24 h for chemical etching to remove the original SiO2 nanosphere template, leaving the filler skeleton, to obtain a macroporous array nickel-molybdenum alloy self-supporting electrode, which can be used as a catalyst for water electrolysis.
[0037] SiO2 nanospheres with a diameter of approximately 200 nm were uniformly deposited on the surface of nickel foam as a template for NiMo electrodeposition. Electrodeposition was performed at 900 s using 1 mol L... -1 After KOH removes the SiO2 spheres, the NiMo alloy particles aggregate and form an inverted bowl-shaped array. Figure 3(a, b, and c). It consists of a network of interconnected holes with an average diameter of approximately 210 nm, slightly larger than the diameter of the silica spheres. Figure 3 d,e), whose pore walls are made of many small and thin intersecting nanosheets (magnified TEM image). Figure 3 f).
[0038] Electrochemical testing of hydrogen production via electrolysis using a macroporous array nickel-molybdenum alloy self-supporting electrode includes the following steps:
[0039] A blank control group was set up, with nickel-molybdenum alloy electrodes and Pt / C as control groups, and performance comparison tests were conducted.
[0040] The HER performance of a large-pore array nickel-molybdenum alloy self-supporting electrode was tested using the Shanghai Chenhua electrochemical workstation CHI760e. Figure 4 As shown in Figures a and b, at high current densities of 500-1000 mA cm⁻¹ -2 The macroporous array nickel-molybdenum alloy self-supporting electrode of this invention exhibits excellent electrocatalytic activity and better performance than commercial Pt / C catalysts. For example, as a HER electrode, the macroporous array nickel-molybdenum alloy self-supporting electrode can provide up to 500 and 1000 mA cm⁻¹ at overpotentials of 306 mV and 491 mV, respectively. -2 High current density, but commercial Pt / C requires a higher overpotential, providing 500 mA cm⁻¹ at an overpotential of 307 mV. -2 The current density could not be achieved at 1000 mA cm⁻¹ under the test conditions. -2 The current density.
[0041] Example 2
[0042] A method for preparing a nickel-molybdenum alloy self-supporting electrode includes the following steps:
[0043] (1) Preparation of SiO2 colloidal solution:
[0044] Spherical silica nanospheres of varying diameters with controllable particle size and good monodispersity were prepared using a modified Stober method based on the solution-gel process. Deionized water, anhydrous ethanol, 25% ammonia solution, and tetraethyl orthosilicate (TEOS) were added sequentially to a beaker in a volume ratio of 15:75:2.1:2.25. The mixture was stirred with a magnetic stirrer for 8 hours to ensure complete reaction. The mixture was then centrifuged for 5 minutes, washed with deionized water and anhydrous ethanol, and dried in an oven at 60°C for 4 hours to obtain 100 nm SiO2 nanospheres. A certain amount of deionized water was added to the SiO2 nanospheres, and the mixture was sonicated at 40°C for 2 hours to ensure complete dissolution, resulting in a 50 mg / mL SiO2 colloidal solution.
[0045] (2) Preparation of silica nanosphere electrodeposition template
[0046] By allowing natural sedimentation, 1cm*1cm nickel foam was placed in a SiO2 colloidal solution at room temperature and allowed to settle for 24 hours before being placed in an oven and dried at 60℃ for 2 hours. This ensured that the SiO2 nanospheres self-assembled from disordered to three-dimensional ordered arrangement on the nickel foam, resulting in a uniform-sized and regularly arranged SiO2 nanosphere electrodeposition template.
[0047] (3) Preparation of nickel-molybdenum alloy electrolyte
[0048] Nickel-molybdenum alloy electrolyte: Sodium citrate (0.3 mol / L), nickel sulfate hexahydrate (0.15 mol / L), and sodium molybdate dihydrate (0.05 mol / L) were added to a beaker and stirred with a magnetic stirrer for 2 hours to prepare the nickel-molybdenum alloy electrolyte. The pH value was adjusted to 10.0 by adding 25% ammonia solution.
[0049] (4) Fabrication of macroporous array nickel-molybdenum alloy self-supporting electrodes
[0050] Using an electrochemical workstation, set the current density to 25 mA / cm². 2 An electrodeposition time of 300 s was set to fill the template gaps with nickel-molybdenum alloy to prepare a nickel-molybdenum alloy active layer. The synthesized material after electrodeposition was immersed in 1 mol / L potassium hydroxide for 24 h for chemical etching to remove the original SiO2 nanosphere template, leaving the filler skeleton, to obtain a macroporous array nickel-molybdenum alloy self-supporting electrode, which can be used as a catalyst for water electrolysis.
[0051] The HER performance of a large-pore array nickel-molybdenum alloy self-supporting electrode was tested using the Shanghai Chenhua electrochemical workstation CHI760e.
[0052] Example 3
[0053] A method for preparing a nickel-molybdenum alloy self-supporting electrode includes the following steps:
[0054] (1) Preparation of SiO2 colloidal solution:
[0055] A modified Stobel method based on the solution-gel process was used to prepare spherical silica nanospheres of different diameters with controllable particle size and good monodispersity. Anhydrous ethanol, 25% ammonia solution, and tetraethyl orthosilicate were added sequentially to a beaker at a volume ratio of 90:6:1.5. The mixture was stirred with a magnetic stirrer for 8 hours to ensure complete reaction. The mixture was then centrifuged for 5 minutes, washed with deionized water and anhydrous ethanol, and dried in an oven at 60°C for 2 hours to obtain 50 nm spherical silica nanospheres, i.e., SiO2 nanospheres. A certain amount of deionized water was added to the SiO2 nanospheres, and the mixture was sonicated at 40°C for 2 hours to ensure complete dissolution, resulting in a 50 mg / mL SiO2 colloidal solution.
[0056] (2) Preparation of silica nanosphere electrodeposition template
[0057] By allowing natural sedimentation, 1cm*1cm nickel foam was placed in a SiO2 colloidal solution at room temperature and allowed to settle for 24 hours before being placed in an oven and dried at 60℃ for 2 hours. This ensured that the SiO2 nanospheres self-assembled from disordered to three-dimensional ordered arrangement on the nickel foam, resulting in a uniform-sized and regularly arranged SiO2 nanosphere electrodeposition template.
[0058] (3) Preparation of nickel-molybdenum alloy electrolyte
[0059] Nickel-molybdenum alloy electrolyte: Sodium citrate (0.3 mol / L), nickel sulfate hexahydrate (0.15 mol / L), and sodium molybdate dihydrate (0.05 mol / L) were added to a beaker and stirred with a magnetic stirrer for 2 hours to prepare the nickel-molybdenum alloy electrolyte. The pH value was adjusted to 10.0 by adding 25% ammonia solution.
[0060] (4) Fabrication of macroporous array nickel-molybdenum alloy self-supporting electrodes
[0061] Using an electrochemical workstation, set the current density to 25 mA / cm². 2 An electrodeposition time of 3000 s was set to fill the template gaps with nickel-molybdenum alloy to prepare a nickel-molybdenum alloy active layer. The synthesized material after electrodeposition was immersed in 1 mol / L potassium hydroxide for 24 h for chemical etching to remove the original SiO2 nanosphere template, leaving the filler skeleton, to obtain a macroporous array nickel-molybdenum alloy self-supporting electrode, which can be used as a catalyst for water electrolysis.
[0062] The HER performance of a large-pore array nickel-molybdenum alloy self-supporting electrode was tested using the Shanghai Chenhua electrochemical workstation CHI760e.
[0063] Example 4
[0064] A method for preparing a nickel-molybdenum alloy self-supporting electrode includes the following steps:
[0065] (1) Preparation of SiO2 colloidal solution:
[0066] A modified Stobel method based on the solution-gel process was used to prepare spherical silica nanospheres of different diameters with controllable particle size and good monodispersity. Deionized water, anhydrous ethanol, 25% ammonia solution, and tetraethyl orthosilicate (TEOS) were added sequentially to a beaker in a volume ratio of 25.75:64.25:9:6. The mixture was stirred with a magnetic stirrer for 8 hours to ensure complete reaction. The mixture was then centrifuged for 5 minutes, washed with deionized water and anhydrous ethanol, and dried in an oven at 60°C for 4 hours to obtain 50 nm spherical silica nanospheres, i.e., SiO2 nanospheres. A certain amount of deionized water was added to the SiO2 nanospheres, and the mixture was sonicated at 40°C for 2 hours to ensure complete dissolution, resulting in a 50 mg / mL SiO2 colloidal solution.
[0067] (2) Preparation of silica nanosphere electrodeposition template
[0068] By allowing natural sedimentation, 1cm*1cm nickel foam was placed in a SiO2 colloidal solution at room temperature and allowed to settle for 24 hours before being placed in an oven and dried at 60℃ for 2 hours. This ensured that the SiO2 nanospheres self-assembled from disordered to three-dimensional ordered arrangement on the nickel foam, resulting in a uniform-sized and regularly arranged SiO2 nanosphere electrodeposition template.
[0069] (3) Preparation of nickel-molybdenum alloy electrolyte
[0070] Nickel-molybdenum alloy electrolyte: Sodium citrate (0.3 mol / L), nickel sulfate hexahydrate (0.15 mol / L), and sodium molybdate dihydrate (0.05 mol / L) were added to a beaker and stirred with a magnetic stirrer for 2 hours to prepare the nickel-molybdenum alloy electrolyte. The pH value was adjusted to 10.0 by adding 25% ammonia solution.
[0071] (4) Fabrication of macroporous array nickel-molybdenum alloy self-supporting electrodes
[0072] Using an electrochemical workstation, set the current density to 25 mA / cm². 2 An electrodeposition time of 3000 s was set to fill the template gaps with nickel-molybdenum alloy to prepare a nickel-molybdenum alloy active layer. The synthesized material after electrodeposition was immersed in 1 mol / L potassium hydroxide for 24 h for chemical etching to remove the original SiO2 nanosphere template, leaving the filler skeleton, to obtain a macroporous array nickel-molybdenum alloy self-supporting electrode, which can be used as a catalyst for water electrolysis.
[0073] The HER performance of a large-pore array nickel-molybdenum alloy self-supporting electrode was tested using the Shanghai Chenhua electrochemical workstation CHI760e.
[0074] Electrochemical cathode hydrogen evolution performance test of macroporous array nickel-molybdenum alloy self-supporting electrode: A three-electrode system was adopted, with the fabricated nickel-molybdenum alloy self-supporting electrode as the working electrode, a graphite rod as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The three electrodes were connected to a Shanghai Chenhua CHI760E electrochemical workstation. The hydrogen evolution performance was studied in 1.0 mol / L potassium hydroxide solution using linear sweep voltammetry. The test potential relative to the reversible hydrogen electrode potential was -0.6 to 0.1 V, and the scan rate was 2 mV / s.
[0075] Example 5
[0076] A method for preparing a nickel-molybdenum alloy self-supporting electrode includes the following steps:
[0077] (1) Preparation of nickel-molybdenum alloy electrolyte
[0078] Nickel-molybdenum alloy electrolyte: Sodium citrate (0.3 mol / L), nickel sulfate hexahydrate (0.15 mol / L), and sodium molybdate dihydrate (0.05 mol / L) were added to a beaker and stirred with a magnetic stirrer for 2 hours to prepare the nickel-molybdenum alloy electrolyte. The pH value was adjusted to 10.0 by adding 25% ammonia solution.
[0079] (2) Preparation of nickel-molybdenum alloy self-supporting electrode
[0080] Using an electrochemical workstation, set the current density to 25 mA / cm². 2 The electrodeposition time was set to 3000 s, and a nickel-molybdenum alloy was electrodeposited onto the surface of nickel foam. After electroplating, the surface was cleaned with water and alcohol to obtain a self-supporting nickel-molybdenum alloy electrode, which can be used as a catalyst for water electrolysis.
[0081] The HER performance of a nickel-molybdenum alloy self-supporting electrode was tested using the Shanghai Chenhua electrochemical workstation CHI760e.
[0082] Electrochemical cathode hydrogen evolution performance test of nickel-molybdenum alloy self-supporting electrode: A three-electrode system was adopted, with the fabricated nickel-molybdenum alloy self-supporting electrode as the working electrode, a graphite rod as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The three electrodes were connected to a Shanghai Chenhua CHI760E electrochemical workstation. The hydrogen evolution performance was studied using linear sweep voltammetry in 1.0 mol / L potassium hydroxide solution. The test potential relative to the reversible hydrogen electrode potential was -0.6 to 0.1 V, and the scan rate was 2 mV / s.
[0083] Observation of a large-aperture array nickel-molybdenum alloy self-supporting electrode at a constant current density of 50 mA / cm² using a high-speed camera. 2 The behavior of bubble release. For example... Figure 5As shown in a and b, for the macroporous array nickel-molybdenum alloy self-supporting electrode, a large number of H2 bubbles smaller than 0.2 mm in size rapidly escape from the electrode. In contrast, bubbles on other electrodes gradually grow to a larger size and can no longer detach from the electrode surface.
[0084] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the present invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.
Claims
1. A method for preparing a nickel-molybdenum alloy self-supporting electrode, characterized in that, Includes the following steps: A self-supporting nickel-molybdenum alloy electrode was prepared by self-assembling silica nanospheres on a nickel foam substrate to form a silica nanosphere electrodeposition template. A mixed aqueous solution of sodium citrate hydrate, nickel sulfate hexahydrate, and sodium molybdate dihydrate was used as the electrolyte for electrodeposition of nickel-molybdenum alloy. The electrodeposition template of the synthesized material was removed by chemical etching to leave the filler skeleton, thus preparing a self-supporting nickel-molybdenum alloy electrode with controllable size. The method for preparing silica nanosphere electrodeposition templates is as follows: a silica gel solution is prepared using the improved Stober method based on the sol-gel method, and silica nanospheres with controllable particle size are constructed on a nickel foam substrate by gravity sedimentation as electrodeposition templates. The preparation method of the electrodeposition template includes the following steps: by natural sedimentation, nickel foam is placed in a silica gel solution at room temperature for 20-24 hours and then dried in an oven to ensure that spherical silica of different diameters self-assembles from disordered to three-dimensional ordered arrangement on the nickel foam, thus obtaining a silica nanosphere electrodeposition template with uniform size and regular three-dimensional arrangement.
2. The method for preparing a nickel-molybdenum alloy self-supporting electrode according to claim 1, characterized in that: The preparation of silica gel solution specifically includes the following steps: adding deionized water, anhydrous ethanol and 25% ammonia solution in different proportions into containers, stirring evenly at room temperature, adding tetraethyl orthosilicate, sealing the container after the addition is complete, and waiting for the solution to react completely. After centrifugation, washing and drying, spherical silica with different particle sizes are obtained. Deionized water is added to the spherical silica to obtain silica gel solution.
3. The method for preparing a nickel-molybdenum alloy self-supporting electrode according to claim 2, characterized in that, In the preparation steps of silica gel solution: The volume ratio of deionized water, anhydrous ethanol, 25% ammonia solution, and tetraethyl orthosilicate is 0-25.75:64.75-90:2.1-9:1.5-6. After the container opening is sealed, the solution is stirred for 6-8 hours using a magnetic stirrer to ensure complete reaction. The drying temperature is 60-70℃, and the drying time is 2-4 hours; The spherical silica was dissolved by adding deionized water and then sonicating at 40-50℃ for 2-4 hours. The size range of spherical silica is 50-500 nm; The concentration of the silica gel solution is 50-100 mg / mL.
4. The method for preparing a nickel-molybdenum alloy self-supporting electrode according to claim 1, characterized in that, In the preparation method of the electrodeposition template: the drying temperature is 60-70℃ and the drying time is 2-4h.
5. The method for preparing a nickel-molybdenum alloy self-supporting electrode according to claim 1, characterized in that: The concentration of sodium citrate hydrate is 0.3-0.6 mol / L, the concentration of nickel sulfate hexahydrate is 0.15-0.3 mol / L, and the concentration of sodium molybdate dihydrate is 0.05-0.1 mol / L. In the electrolyte, the concentration ratio of sodium citrate hydrate, nickel sulfate hexahydrate, and sodium molybdate dihydrate is 6:3:1, the molar ratio of Ni to Mo is 3:1, and the pH of the electrolyte is adjusted to 10.0-11.0 using 25% ammonia solution.
6. The method for preparing a nickel-molybdenum alloy self-supporting electrode according to claim 1, characterized in that: The electrodeposition current density is 25 mA cm⁻¹ -2 The electrodeposition time is 300-3000 s, and the synthesized material after electrodeposition is immersed in 1 mol L⁻¹ water. -1 The silicon dioxide nanosphere electrodeposition template is removed by chemical etching in potassium hydroxide for 24 hours, leaving a filler skeleton, thus obtaining the nickel-molybdenum alloy self-supporting electrode.
7. A nickel-molybdenum alloy self-supporting electrode prepared by the method according to any one of claims 1-6.
8. A method for catalytic hydrogen production via water electrolysis, characterized in that: The nickel-molybdenum alloy self-supporting electrode as described in claim 7 is used as the catalyst for water electrolysis.