Preparation method of nickel-based catalyst capable of synchronously improving hydrogen evolution and oxygen evolution performance
By pretreating and potential activation of the nickel mesh substrate, doping phosphorus and molybdenum, adjusting the electronic structure and nanostructure of the nickel mesh surface, the catalytic performance and stability of nickel-based catalysts in electrolyzed hydrogen production is solved, and efficient and stable hydrogen evolution and oxygen evolution performance are achieved.
Patent Information
- Application Number
- CN202510528114.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-25
- Publication Date
- 2025-06-03
AI Technical Summary
There is room for improvement in catalytic performance in the process of electrolyzing water hydrogen production, and it is unstable in high-concentration alkali liquid, resulting in the catalyst layer being easily shedding, affecting performance stability.
By pretreating and potentially activating the nickel mesh substrate, doping phosphorus and molybdenum, the electronic structure and nanostructure of the nickel mesh surface are adjusted to form a high-performance nickel-based catalyst.
The hydrogen and oxygen evolution performance of nickel-based catalysts is synchronously improved, the cost of electrode catalysts is reduced, the structural stability of the catalyst is improved, the catalyst is prevented from falling off in a strong alkali environment, and the performance stability is enhanced.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of preparation processes of electrolyzed water catalysts, and particularly to a preparation method of a nickel-based catalyst for simultaneously improving hydrogen evolution and oxygen evolution performances. Background Art
[0002] As the most promising green energy, the demand for hydrogen energy is increasing continuously. Among numerous hydrogen production technologies, hydrogen production by electrolyzing water is considered to be one of the most promising hydrogen production technologies because of its characteristics such as safety, cost-effectiveness and environmental friendliness. However, the slow kinetics and high energy barriers of hydrogen evolution at the cathode and oxygen evolution at the anode seriously hinder the industrialization of electrochemical hydrogen production. To solve this problem, the overall reaction can be effectively promoted by using highly efficient catalysts. However, most highly efficient catalysts are noble metals and are difficult to be widely applied in the industrial application of hydrogen production by electrolyzing water. Therefore, improving the catalytic performance and structural stability of non-noble metal catalytic materials by different methods is the research focus in this field.
[0003] Currently, transition metal-based catalysts have attracted much attention because of their low cost, rich reserves and potential electrocatalytic performance. Among them, nickel-based catalysts have been widely used because of their advantages such as corrosion resistance, excellent stability and high raw material reserves. However, there is still much room for improvement in their catalytic performance, and there are problems such as low utilization rate of catalyst raw materials and instability of the catalyst layer in high-concentration alkaline solutions. To further improve the electrocatalytic performance and stability of nickel-based catalysts, methods such as electronic structure regulation, morphology modification and catalyst surface functionalization are mostly adopted. For example, the nickel mesh substrate used in the actual hydrogen production system by electrolyzing water needs to be additionally loaded with a high-performance catalyst by methods such as thermal spraying and plasma spraying. Loading a high-performance catalyst additionally on the nickel mesh substrate has problems such as weak binding force between the catalyst and the nickel mesh, which is easy to fall off in a strong alkaline environment, resulting in unstable performance, and low utilization rate and high cost of the additionally sprayed catalyst. Summary of the Invention
[0004] To solve the above technical problems, one technical solution adopted by the present invention is: Provide a preparation method of a nickel-based catalyst for simultaneously improving hydrogen evolution and oxygen evolution performances, and the steps include: (1) Pretreat the nickel mesh substrate: Immerse the nickel mesh substrate in a sodium hydroxide solution and heat it, the heating temperature is 20-120 °C, the concentration of the sodium hydroxide solution is 1-10 M, and the immersion time is 0.5-24 h; (2) Immerse the pretreated nickel mesh in an electrolyte containing phosphorus and molybdenum, and use a two-electrode system to perform potentiostatic activation on the pretreated nickel mesh. Add sodium hypophosphite and ammonium molybdate to the potassium hydroxide solution in sequence, and make the concentration of potassium hydroxide be 1 - 6 M, the concentration of sodium hypophosphite be 0.01 - 2 M, and the concentration of ammonium molybdate be 0.01 - 1 M. The applied activation potential is 1 - 15 V, and the activation time is 1 - 200 min; (3) After cleaning and drying the electrochemically activated nickel mesh, immediately place it in a muffle furnace for calcination. The calcination temperature is 120 - 300 °C, and the calcination time is 10 - 300 min; (4) Rinse the calcined nickel mesh thoroughly with deionized water and dry it to obtain a high-performance nickel-based catalyst, which can be used as the positive / negative electrode in water electrolysis for hydrogen production.
[0005] In a preferred embodiment of the present invention, the nickel mesh is a single-sided or double-sided sandblasted nickel mesh.
[0006] In a preferred embodiment of the present invention, in step (2), the pretreated nickel mesh substrate serves as the working electrode in the two-electrode system, and the nickel optical mesh serves as the counter electrode in the two-electrode system.
[0007] In a preferred embodiment of the present invention, the activated nickel mesh is washed with deionized water.
[0008] The beneficial effects of the present invention are as follows: By performing potentiostatic activation on the nickel mesh substrate and doping other metals in the activation electrolyte, the electronic structure of the active sites on the surface of the nickel mesh is adjusted, and the nanostructure on the surface of the nickel mesh is changed, thereby simultaneously improving the hydrogen evolution and oxygen evolution performance of the nickel-based catalyst, effectively reducing the cost of the electrode catalyst, and at the same time improving the stability of the structure of the nickel-based catalyst itself, avoiding the shedding of the catalyst coating in a strong alkaline environment, so as to improve the stability of the hydrogen evolution and oxygen evolution performance, and further promote the sustainable development of the water electrolysis for hydrogen production technology. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings, where: Figure 1 It is a schematic diagram of the applied electrochemical activation potential in Embodiment 1 of the present invention; Figure 2 It is a surface morphology diagram of the nickel-based catalyst prepared in Embodiment 1 of the present invention magnified 100 times; Figure 3The surface morphology diagram of the nickel-based catalyst prepared in Example 1 of the present invention magnified 2000 times; Figure 4 The surface morphology diagram of the nickel-based catalyst prepared in Example 1 of the present invention magnified 20000 times; Figure 5 The surface morphology diagram of the nickel-based catalyst prepared in Example 1 of the present invention magnified 50000 times; Figure 6 The XPS spectrum of Ni in the nickel-based catalyst prepared in Example 2 of the present invention; Figure 7 The XPS spectrum of Mo in the nickel-based catalyst prepared in Example 2 of the present invention; Figure 8 The XPS spectrum of P in the nickel-based catalyst prepared in Example 2 of the present invention; Figure 9 The hydrogen evolution performance curve of the nickel-based catalyst prepared in the examples of the present invention; Figure 10 The oxygen evolution performance curve of the nickel-based catalyst prepared in the examples of the present invention; Figure 11 The stability test diagram of the nickel-based catalyst prepared in Example 4 of the present invention. Detailed implementation manners
[0010] 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, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0011] Please refer to Figures 1-11 , the embodiments of the present invention include: A preparation method of a nickel-based catalyst for simultaneously improving hydrogen evolution and oxygen evolution performance, the steps of which include: (1) Pretreat the sandblasted nickel mesh substrate: Immerse the nickel mesh in a sodium hydroxide solution and heat it, the heating temperature is 20~120°C, the concentration of the sodium hydroxide solution is 1~10M, and the immersion time is 0.5~24h.
[0012] Further preferably, the sandblasted nickel mesh is a single-sided or double-sided sandblasted nickel mesh (2) Immerse the pretreated nickel mesh in an electrolyte containing phosphorus and molybdenum, and use a two-electrode system to perform potentiostatic activation on the pretreated nickel mesh. Add sodium hypophosphite and ammonium molybdate to the potassium hydroxide solution in sequence, and make the concentration of potassium hydroxide be 1 - 6 M, the concentration of sodium hypophosphite be 0.01 - 2 M, and the concentration of ammonium molybdate be 0.01 - 1 M. The applied activation potential is 1 - 15 V, and the activation time is 1 - 200 min.
[0013] (3) After cleaning and drying the electrochemically activated nickel mesh, immediately place it in a muffle furnace for calcination to stabilize the activation performance. The calcination temperature is 120 - 300 °C, and the calcination time is 10 - 300 min.
[0014] (4) Rinse the calcined nickel mesh thoroughly with deionized water and dry it to obtain a high-performance nickel-based catalyst, which can be used as the positive / negative electrode in water electrolysis for hydrogen production. Example 1
[0015] Immerse the double-sided sandblasted nickel mesh substrate in an 8 M sodium hydroxide solution at a constant temperature of 30 °C for 1 h to remove the oxide layer and oil on the surface of the nickel mesh substrate, so as to fully perform electrochemical activation subsequently; Immerse the pretreated nickel mesh in the electrolyte. The concentrations of each component in the electrolyte are: 1 M potassium hydroxide, 0.1 M sodium hypophosphite, and 0.02 M ammonium molybdate. The pretreated nickel mesh substrate serves as the working electrode, and the nickel light mesh serves as the counter electrode to form a two-electrode system. Apply a constant potential of 1.5 V for activation for 150 min. The schematic diagram of potential application is as Figure 1 shown; After rinsing the electrochemically activated nickel mesh thoroughly with deionized water and drying it, immediately place it in a muffle furnace for calcination for 30 min. The calcination temperature is set at 300 °C to stabilize the activation performance. After that, rinse it thoroughly with deionized water and dry it.
[0016] Figures 2-5 is the surface morphology diagram of the nickel-based catalyst prepared in Example 1. New nanostructures appear on the surface of this nickel-based catalyst. When magnified to 50,000 times, it is observed that it presents a three-dimensional scaly nanostructure, which can effectively increase the surface area of the catalyst and thus improve the catalytic performance.
[0017] The hydrogen evolution and oxygen evolution performance curves of the nickel-based catalyst prepared in Example 1 are respectively Figure 9 、 10 The curves corresponding to the activation voltage of 1.5 V in. The hydrogen evolution overpotential of this nickel-based catalyst is 739 mV and the oxygen evolution overpotential is 850 mV under the condition of 1 mol / L KOH and a current density of 300 mA / cm 2 Compared with before activation, the hydrogen evolution performance has been improved by 62 mV, and the oxygen evolution performance has been improved by 114 mV. Example 2
[0018] The nickel mesh substrate with double-sided sandblasting was soaked in 6M sodium hydroxide solution at a constant temperature of 50 °C for 4 h to remove the oxide layer and oil on the surface of the nickel mesh substrate, so as to fully carry out electrochemical activation subsequently; the pretreated nickel mesh was soaked in the electrolyte solution, and the concentrations of each component in the electrolyte solution were 2M potassium hydroxide, 0.2M sodium hypophosphite and 0.05M ammonium molybdate respectively. The pretreated nickel mesh substrate was used as the working electrode, and the counter electrode was a nickel light mesh, forming a two-electrode system. A constant potential of 2V was applied for activation for 90 min; the nickel mesh after electrochemical activation was rinsed with deionized water, dried, and immediately placed in a muffle furnace for calcination for 60 min. The calcination temperature was set at 260 °C to stabilize the activation performance. After that, it was rinsed with deionized water, cleaned and dried.
[0019] As Figures 6-8 shown, the nickel-based catalyst prepared in Example 2 was characterized by XPS to analyze the composition and valence states of nickel, molybdenum and phosphorus elements on its surface. The nickel element on the surface of this catalyst presented divalent and trivalent states, the molybdenum element mainly existed in the hexavalent form, and the existence forms of phosphorus element included elemental phosphorus and phosphate with low and high valence. The existence of molybdenum and phosphorus elements with different valence states could effectively promote the further improvement of the hydrogen evolution and oxygen evolution performance of the nickel-based catalyst.
[0020] The hydrogen evolution and oxygen evolution performance curves of the prepared nickel-based catalyst are respectively Figure 9 、 10 The corresponding curves for the activation voltage of 2V. Under the condition of 1mol / L KOH, the hydrogen evolution overpotential of this nickel-based catalyst with a current density of 300mA / cm 2 was 684mV, and the oxygen evolution overpotential was 780mV. Compared with before activation, the hydrogen evolution performance was improved by 117mV, and the oxygen evolution performance was improved by 184mV. Example 3
[0021] The nickel mesh substrate with double-sided sandblasting was soaked in 4M sodium hydroxide solution at a constant temperature of 80 °C for 8 h to remove the oxide layer and oil on the surface of the nickel mesh substrate, so as to fully carry out electrochemical activation subsequently; the pretreated nickel mesh was soaked in the electrolyte solution, and the concentrations of each component in the electrolyte solution were 4M potassium hydroxide, 0.5M sodium hypophosphite and 0.2M ammonium molybdate respectively. The pretreated nickel mesh substrate was used as the working electrode, and the counter electrode was a nickel light mesh, forming a two-electrode system. A constant potential of 4V was applied for activation for 60 min; the nickel mesh after electrochemical activation was rinsed with deionized water, dried, and immediately placed in a muffle furnace for calcination for 90 min. The calcination temperature was set at 210 °C to stabilize the activation performance. After that, it was rinsed with deionized water, cleaned and dried.
[0022] The hydrogen evolution and oxygen evolution performance curves of the nickel-based catalyst prepared in Example 3 are respectively Figure 9 、 10The activation voltage of 4 V in the corresponding curve. Under the condition of 1 mol / L KOH, the current density of this nickel-based catalyst is 300 mA / cm 2 The hydrogen evolution overpotential is 626 mV, and the oxygen evolution overpotential is 688 mV. Compared with before activation, the hydrogen evolution performance has been improved by 175 mV, and the oxygen evolution performance has been improved by 276 mV. Example 4
[0023] The nickel mesh substrate with double-sided sandblasting was soaked in 2 M sodium hydroxide solution at a constant temperature of 100 °C for 12 h to remove the oxide layer and oil stain on the surface of the nickel mesh substrate for subsequent full electrochemical activation; the pretreated nickel mesh was soaked in the electrolyte. The concentrations of each component in the electrolyte were 6 M potassium hydroxide, 1 M sodium hypophosphite, and 0.5 M ammonium molybdate. The pretreated nickel mesh substrate was used as the working electrode, and the counter electrode was a nickel light mesh to form a two-electrode system. A constant potential of 6 V was applied for 30 min for activation; the electrochemically activated nickel mesh was rinsed with deionized water and dried, and then immediately placed in a muffle furnace for calcination for 120 min. The calcination temperature was set at 160 °C to stabilize the activation performance. After that, it was rinsed with deionized water and dried.
[0024] The hydrogen evolution and oxygen evolution performance curves of the nickel-based catalyst prepared in Example 4 are respectively Figure 9 and 10 The activation voltage of 6 V in the corresponding curve. Under the condition of 1 mol / L KOH, the current density of this nickel-based catalyst is 300 mA / cm 2 The hydrogen evolution overpotential is 569 mV, and the oxygen evolution overpotential is 632 mV. Compared with before activation, the hydrogen evolution performance has been improved by 232 mV, and the oxygen evolution performance has been improved by 332 mV.
[0025] Figure 11 is the stability test curve of the nickel-based catalyst prepared in Example 4. In the two-electrode system, the double-sided sandblasted nickel mesh is used as the cathode, and the prepared nickel-based catalyst is used as the anode. The electrolyte is 6 M KOH, and the constant current density is 300 mA / cm 2 Under the condition of, it runs for 168 h, and the voltage data is recorded every 3 h. The voltage is stable at about 2.53 V, indicating that the prepared nickel-based catalyst can still maintain good performance during long-term operation.
[0026] The beneficial effects of the preparation method of the nickel-based catalyst for simultaneously improving hydrogen evolution and oxygen evolution performance of the present invention are: (1) Using a nickel mesh substrate as the nickel source, doping phosphorus and molybdenum in the electrolyte, and activating by applying a constant potential can effectively regulate the electronic structure of the active sites on the nickel mesh surface, thereby accelerating the internal reaction kinetics of the catalyst. At the same time, the doping of molybdenum elements can adjust the surface morphology of the nickel mesh and change the nanostructure on the nickel mesh surface. The obtained nanostructure greatly increases the surface area of the catalyst, further increasing the active sites on the surface of the nickel-based catalyst, effectively improving the hydrogen evolution and oxygen evolution performance of the catalyst, and effectively reducing the cost of the electrode catalyst.
[0027] (2) The practical operation of preparing the nickel-based catalyst by the double-doping electrochemical activation method is relatively strong, with high economy, easy to expand the process production, and the modified nickel-based catalyst has excellent stability, which can further improve the stability of the hydrogen evolution and oxygen evolution performance, promote the sustainable development of the electrolytic water hydrogen production technology, and has broad application prospects in the alkaline electrolytic water hydrogen production industry.
[0028] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification of the present invention, or directly or indirectly applied to other related technical fields, shall be equally included in the patent protection scope of the present invention.
Claims
1. A method for preparing a nickel-based catalyst for simultaneously improving the performance of hydrogen and oxygen evolution, characterized in that the steps include: (1) Pretreatment of the nickel mesh substrate: soaking the nickel mesh substrate in a sodium hydroxide solution and heating it, the heating temperature is 20-120°C, the concentration of the sodium hydroxide solution is 1-10M, and the soaking time is 0.5-24h; (2) Soaking the pretreated nickel mesh in an electrolyte containing phosphorus and molybdenum, and using a double electrode system to perform constant potential activation on the pretreated nickel mesh, sodium hypophosphite and ammonium molybdate are added to the potassium hydroxide solution in sequence, and the concentration of potassium hydroxide is 1~6M, the concentration of sodium hypophosphite is 0.01~2M, and the concentration of ammonium molybdate is 0.01~1M, the applied activation potential is 1~15V, and the activation time is 1~200min; (3) After cleaning and drying the electrochemically activated nickel mesh, the mesh is placed in a muffle furnace for calcination at a temperature of 120 to 300° C. for a calcination time of 10 to 300 min; (4) The calcined nickel mesh is rinsed with deionized water and dried to obtain a high-performance nickel-based catalyst that can be used as the positive / negative electrode in hydrogen production by water electrolysis.
2. The method for preparing a nickel-based catalyst for simultaneously improving hydrogen and oxygen evolution performance according to claim 1, characterized in that: The nickel mesh is a single-sided or double-sided sandblasted nickel mesh.
3. The method for preparing a nickel-based catalyst for simultaneously improving hydrogen and oxygen evolution performance according to claim 1, characterized in that: In step (2), the pretreated nickel mesh substrate is used as the working electrode in the dual-electrode system, and the nickel optical mesh is used as the counter electrode in the dual-electrode system.
4. The method for preparing a nickel-based catalyst for simultaneously improving hydrogen and oxygen evolution performance according to claim 1, characterized in that: In step (3), the activated nickel mesh is washed with deionized water.