Porous nickel electrode with high activity and preparation method thereof
The formation of porous nickel electrodes through electrodeposition and high-temperature sintering solves the problems of high cost and poor stability of traditional electrolytic water electrode materials, and achieves low-cost and efficient hydrogen generation and long-term stability, which is suitable for large-scale production.
Patent Information
- Application Number
- CN202411174079.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-26
- Publication Date
- 2024-12-06
AI Technical Summary
The precious metal catalysts of traditional electrolytic water electrode materials are costly, complex preparation processes and poor stability, which limits the widespread application of electrolytic water hydrogen production technology.
The nickel-zinc alloy is generated on the nickel network by electrodeposition method, and a porous nickel structure is formed through dezincification treatment and high-temperature sintering, which simplifies process steps, reduces costs and improves the mechanical strength and chemical stability of the electrode.
It achieves low-cost and efficient hydrogen generation, significantly improves the catalytic activity and service life of the electrode, and meets the demand for high-performance electrode materials by electrolytic water hydrogen production technology.
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Figure CN119082762A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of water electrolysis electrode materials, and in particular to a porous nickel electrode with high activity and a preparation method thereof. Background Art
[0002] As a clean and efficient secondary energy source, hydrogen energy is widely regarded as an important component of future energy because its combustion product is water and has high energy density. Among various hydrogen production technologies, hydrogen production by water electrolysis has become one of the main technical approaches to obtain hydrogen energy because of its high purity of hydrogen production and environmentally friendly and pollution-free process. The efficiency and cost of the water electrolysis process depend to a large extent on the performance of the electrode material. Traditional water electrolysis electrode materials mainly rely on precious metals such as platinum and iridium. Although these materials have excellent catalytic properties, their high cost and scarcity limit their large-scale application. In order to achieve the widespread promotion of hydrogen production by water electrolysis, it is urgent to develop non-precious metal electrode materials with low cost and excellent performance.
[0003] As a nickel-based catalyst with a porous structure, Raney nickel has been widely used in fields such as organic synthesis and water electrolysis due to its high specific surface area and excellent catalytic activity. Especially in the process of water electrolysis, the Raney nickel electrode can significantly reduce the overpotential of water electrolysis and increase the rate of hydrogen generation. However, the Raney nickel electrode also has significant defects, which limits its wide application in hydrogen production by water electrolysis. First, the preparation process of Raney nickel is complicated and requires multiple steps such as smelting, quenching, and dealuminization, which is time-consuming, labor-intensive and costly. Secondly, the stability of the Raney nickel electrode in the water electrolysis environment is poor, and it is prone to problems such as decreased mechanical strength and decay of catalytic performance, which limits its service life.
[0004] At present, the demand for water electrolysis electrode materials focuses on simplifying the preparation process and improving stability and performance. The ideal electrode material should have simple preparation steps to facilitate large-scale production, while maintaining long-term stability and high catalytic performance in the water electrolysis environment. Improving its catalytic activity and durability by optimizing the microstructure and chemical composition of the material is an important direction for the current research and development of water electrolysis electrode materials. Summary of the invention
[0005] The purpose of the present invention is to provide a porous nickel electrode with high activity and a preparation method thereof in order to overcome the defects of the above-mentioned prior art. A nickel-zinc alloy is generated on a nickel mesh by electrodeposition, and then a porous nickel structure is formed by dezincification and high-temperature sintering. The process steps are simple and easy to operate.
[0006] The purpose of the present invention can be achieved by the following technical solutions:
[0007] The present invention provides a method for preparing a porous nickel electrode with high activity, comprising the following steps:
[0008] S1: immersing the nickel mesh in an electroplating solution containing nickel chloride and zinc chloride, and using the nickel mesh as a cathode and the inert electrode as an anode to perform an electrodeposition process to obtain a nickel-zinc alloy electrode after electrodeposition;
[0009] S2: The nickel-zinc alloy electrode obtained in S1 is completely immersed in a concentrated potassium hydroxide solution for dezincification treatment until no bubbles are generated, then taken out and washed with deionized water to obtain a dezincified porous nickel electrode;
[0010] S3: The dezincified porous nickel electrode obtained in S2 is rapidly sintered, and after sintering, the temperature is rapidly cooled to room temperature to obtain a porous nickel electrode with high activity.
[0011] Further, in S1, the electroplating solution also includes boric acid, and the concentration of the boric acid is 0.1-0.2M;
[0012] The concentration of the nickel chloride is 0.1-0.5M, the concentration of the zinc chloride is 0.05-0.2M; preferably, the concentration of the boric acid is 0.15M;
[0013] The concentration of the nickel chloride is 0.2M, and the concentration of the zinc chloride is 0.1M.
[0014] Furthermore, in S1, the electrodeposition time is 30-60 min, and the current density is 10-30 mA / cm 2 The electroplating temperature is 20-30°C and the stirring speed is 200-500rpm; preferably, the electroplating time is 45min and the current density is 20mA / cm 2 , the electroplating temperature is 25℃.
[0015] Further, in S1, the pH value of the electroplating solution is maintained at 4.0-5.5 during the electroplating process, and preferably, the pH value of the electroplating solution is maintained at 4.5.
[0016] Furthermore, the pH value is adjusted using dilute hydrochloric acid or dilute ammonia water, the concentration of the dilute hydrochloric acid is 0.5-1 mol / L, and the concentration of the dilute ammonia water is 0.5-1 mol / L; preferably, the concentration of the dilute hydrochloric acid is 1 mol / L, and the concentration of the dilute ammonia water is 1 mol / L.
[0017] Further, in S2, the mass concentration of the concentrated potassium hydroxide is 20-40%; preferably, the mass concentration of the concentrated potassium hydroxide is 30%.
[0018] Further, in S3, the sintering temperature is 600-800°C, the heating rate is 300°C / s, and the sintering time is 10-60s; preferably, the sintering temperature is 700°C, and the sintering time is 15s.
[0019] Furthermore, in S3, nitrogen protection is used in the rapid sintering process, and the nitrogen flow rate is 80-120 mL / min; preferably, the nitrogen flow rate is 100 mL / min.
[0020] The invention also provides a porous nickel electrode with high activity, wherein porous structures are evenly distributed on the surface of the porous nickel electrode.
[0021] Furthermore, the pore size of the porous structure is nanometer scale.
[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:
[0023] 1. The present invention uses an electrodeposition method to generate a nickel-zinc alloy on a nickel mesh, and then forms a porous nickel structure through dezincification and high-temperature sintering. The process steps are simple, easy to operate, and suitable for large-scale production. Compared with traditional precious metal electrode materials, the cost is greatly reduced and the resources are abundant, making the preparation process more economical and affordable.
[0024] 2. The porous nickel structure formed by dezincification treatment in the present invention can significantly increase the specific surface area of the electrode, provide more active sites, and help improve the catalytic efficiency in the electrolysis of water. The porous structure not only accelerates the emission of gas, but also reduces the covering effect of bubbles, thereby improving the overall performance of the electrode. In addition, the high-temperature sintering treatment further enhances the mechanical strength and chemical stability of the electrode, so that it maintains excellent performance in long-term use and has a long service life, solving the problem of poor stability of Raney nickel electrodes in the electrolysis of water environment.
[0025] 3. The electrode material prepared by the present invention exhibits low overpotential and high hydrogen evolution rate in the process of water electrolysis, significantly improves the hydrogen generation efficiency, reduces energy consumption, has excellent electrochemical properties and long-term stability, and meets the high performance requirements of modern water electrolysis hydrogen production technology for electrode materials. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 is a SEM image of the porous nickel electrode after sintering in Example 1;
[0027] Figure 2 is the LSV diagram of the porous nickel electrode in Example 1;
[0028] Figure 3 is a tensile performance diagram of the porous nickel electrode in Example 1;
[0029] Figure 4 This is the performance diagram of water electrolysis of the porous nickel electrode in Example 1. DETAILED DESCRIPTION
[0030] The specific implementation methods of the present invention are described in detail below through examples. These examples are implemented on the premise of the scheme described in the present invention, and provide detailed implementation methods and specific operating processes, but the protection scope of the present invention is not limited to the following examples.
[0031] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. Any features such as component models, material names, connection structures, preparation methods, materials, structures or composition ratios not clearly described in this technical solution are deemed to be common technical features disclosed in the prior art.
[0032] Example 1
[0033] This embodiment provides a method for preparing a highly active electrode material, comprising the following steps:
[0034] S1: Prepare electroplating solution: Dissolve 25.96 g nickel chloride, 13.61 g zinc chloride, and 9.27 g boric acid in 1 liter of deionized water to prepare an electroplating solution, wherein the concentration of nickel chloride is 0.2 M, the concentration of zinc chloride is 0.1 M, and the concentration of boric acid is 0.15 M. Boric acid is used as a buffer to ensure the stability of the solution and the uniformity of the electroplating process.
[0035] Electroplating: Immerse a nickel mesh with a thickness of 0.2 mm and a mesh size of 40 mesh into the prepared electroplating solution as the cathode, and a platinum sheet as the anode. Use a constant current power supply with a current density of 20 mA / cm 2 , the electroplating temperature is controlled at 25°C and the electroplating time is 45 minutes. The size of the nickel mesh is 10cm×10cm, and the area of the platinum sheet is 10cm 2 During the electroplating process, 1 mol / L of dilute hydrochloric acid or dilute ammonia is added to maintain the pH of the solution at 4.5. After the electroplating is completed, the nickel mesh is removed and rinsed with deionized water to remove the residual electroplating solution on the surface.
[0036] S2: Prepare a dezincification solution: dissolve 300 g of potassium hydroxide in 700 ml of deionized water to prepare a potassium hydroxide solution with a mass concentration of 30%.
[0037] Dezincification treatment: immerse the nickel-zinc alloy electrode after electroplating in S1 in a 30% concentration potassium hydroxide solution, control the temperature to 80°C, and perform dezincification treatment. Slightly stir the dezincification solution to ensure that the solution is in full contact with the electrode surface to promote the dissolution of zinc until no bubbles emerge.
[0038] During the reaction, zinc reacts with potassium hydroxide to generate soluble potassium zincate and hydrogen. The reaction equation is:
[0039] Zn+2KOH+2H2O→K2[Zn(OH)4]+H2↑
[0040] After the reaction is completed, the electrode is taken out and thoroughly washed with deionized water for several times until the pH value of the washing solution is close to neutral, so as to remove the residual potassium hydroxide and dissolved zinc compounds and obtain the dezincified electrode material.
[0041] S3: Sintering treatment: Place the dezincified electrode material in S2 in a ceramic crucible in a high-temperature furnace and sinter at 700°C for 15 seconds under nitrogen protection to ensure the stability of the porous structure and enhance its mechanical strength. Set the heating rate to 300°C / s and the nitrogen flow rate to 100mL / min. After sintering, gradually cool down to room temperature at a cooling rate of 300°C / s to prevent the grain growth in the electrode material during the cooling process, resulting in a decrease in specific surface area.
[0042] After the temperature drops to room temperature, the flow of nitrogen or argon is stopped, and the sintered porous nickel electrode is taken out to obtain an electrode material with high activity.
[0043] The microstructure of the prepared electrode material was characterized by SEM. Figure 1 It can be seen that the porous nickel electrode has a uniformly distributed porous structure, and its pore size is at the nanoscale, which can help provide a high specific surface area.
[0044] Test Example 1
[0045] The porous nickel electrode prepared in Example 1 and the commercial Raney nickel electrode were subjected to linear sweep voltammetry (LSV) test, using 0.1M KOH solution as the electrolyte, the test range was -0.2V to 0.6V (relative to standard hydrogen electrode), and the scan rate was 10mV / s. The results are shown in FIG. Figure 2 As shown by Figure 2 It can be seen that compared with the commercial Raney nickel electrode, the prepared porous nickel electrode material has a lower hydrogen evolution overpotential in the process of water electrolysis and excellent catalytic activity.
[0046] Test Example 2
[0047] The porous nickel electrode prepared in Example 1 and the commercial Raney nickel electrode were subjected to mechanical peel strength test to test the adhesion and mechanical strength of the electrode material. The specific preparation process is as follows: the porous nickel electrode and the commercial Raney nickel electrode were cut into 5cm*5cm sizes, attached to the surface of the electrode material with strong adhesive tape of the same effective area, and the edge of the tape was stretched using a universal testing machine. When the catalyst adhered to the surface of the electrode material fell off the electrode surface, the tensile force value was recorded as the adhesion of the electrode material. The results are shown in Figure 1. Figure 3 As shown in the figure, it can be seen that the porous nickel electrode prepared in Example 1 has higher mechanical strength and good adhesion than the Raney nickel electrode, and can withstand the mechanical stress in the water electrolysis process.
[0048] Test Example 3
[0049] The porous nickel electrode prepared in Example 1 was tested for durability. The prepared porous nickel electrode was installed in a water electrolysis device. The electrolytic cell device consisted of a cathode plate and an anode plate, and each plate had an electrode. The prepared porous nickel electrode was used as the electrode on the cathode plate to generate hydrogen in the electrolysis of water; the anode electrode used an ordinary nickel mesh to generate oxygen in the electrolysis of water. A long-term water electrolysis experiment was carried out to test the stability of the electrode under constant current density conditions. The test current density was 500mA / cm 2 , the duration is 1000 hours. The results are as follows Figure 4 As shown, the porous nickel electrode maintained high catalytic performance and stability during long-term operation, and there was no obvious increase in voltage, proving its excellent durability.
[0050] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.
Claims
1. A method for preparing a porous nickel electrode with high activity, characterized in that: The following steps are involved: S1: immersing the nickel mesh in an electroplating solution containing nickel chloride and zinc chloride, and using the nickel mesh as a cathode and the inert electrode as an anode to perform an electrodeposition process to obtain a nickel-zinc alloy electrode after electrodeposition; S2: The nickel-zinc alloy electrode obtained in S1 is completely immersed in a concentrated potassium hydroxide solution for dezincification treatment until no bubbles are generated, then taken out and washed with deionized water to obtain a dezincified porous nickel electrode; S3: The dezincified porous nickel electrode obtained in S2 is rapidly sintered, and after sintering, the temperature is rapidly cooled to room temperature to obtain a porous nickel electrode with high activity.
2. The method for preparing a porous nickel electrode with high activity according to claim 1, characterized in that: In S1, the electroplating solution further comprises boric acid, and the concentration of the boric acid is 0.1-0.2M; The concentration of the nickel chloride is 0.1-0.5M, and the concentration of the zinc chloride is 0.05-0.2M.
3. The method for preparing a porous nickel electrode with high activity according to claim 1, characterized in that: In S1, the electrodeposition time is 30-60 min, and the current density is 10-30 mA / cm 2 , the electroplating temperature is 20-30℃, and the stirring speed is 200-500rpm.
4. The method for preparing a porous nickel electrode with high activity according to claim 1, characterized in that: In S1, the pH value of the electroplating solution is maintained at 4.0-5.5 during the electroplating process.
5. The method for preparing a porous nickel electrode with high activity according to claim 4, characterized in that: The pH value is adjusted using dilute hydrochloric acid or dilute ammonia water, wherein the concentration of the dilute hydrochloric acid is 0.5-1 mol / L, and the concentration of the dilute ammonia water is 0.5-1 mol / L.
6. The method for preparing a porous nickel electrode with high activity according to claim 1, characterized in that: In S2, the mass concentration of the concentrated potassium hydroxide is 20-40%.
7. The method for preparing a porous nickel electrode with high activity according to claim 1, characterized in that: In S3, the sintering temperature is 600-800°C, the heating rate is 300°C / s, and the sintering time is 10-60s.
8. The method for preparing a porous nickel electrode with high activity according to claim 1, characterized in that: In S3, nitrogen protection is used in the rapid sintering process, and the nitrogen inlet flow rate is 80-120 mL / min.
9. A porous nickel electrode with high activity prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The porous structure is evenly distributed on the surface of the porous nickel electrode.
10. A porous nickel electrode with high activity according to claim 9, characterized in that: The pore size of the porous structure is nanometer scale.