A porous nickel electrode for improving the stability of alkaline water electrolysis, its preparation method and application
By controlling the pore size and ligaments of the porous nickel electrode, the problems of bubble desorption in alkaline water electrolysis and electrode structural stability were solved, achieving efficient hydrogen production and long-term electrode stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TIANJIN UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2026-01-23
- Publication Date
- 2026-06-02
AI Technical Summary
In existing alkaline water electrolysis technology, hydrogen bubbles on the cathode electrode surface are difficult to desorb, leading to increased resistance and energy consumption. Furthermore, the electrode structure is easily damaged, making it difficult to balance high catalytic activity with long-term stability.
Porous nickel electrodes were prepared by dealloying and subjected to secondary heat treatment under specific conditions to control the pore size and enhance the porous ligaments, thereby improving mechanical strength and gas-liquid transport capacity.
It achieves rapid hydrogen desorption, reduces bubble blockage, improves mass transfer efficiency, and enhances the mechanical and electrochemical stability of the electrode, making it suitable for industrial alkaline water electrolysis.
Smart Images
Figure CN122125219A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrode materials technology, specifically to a porous electrode for improving the stability of alkaline water electrolysis, its preparation method, and its application. Background Technology
[0002] With the continued depletion of fossil fuels, the energy crisis and environmental problems are becoming increasingly severe, making the development of clean and renewable alternative energy sources a global consensus. Hydrogen, due to its high energy density and zero carbon emissions, is considered a key carrier for achieving energy transition. Currently, industrial hydrogen production mainly relies on fossil fuel reforming, which suffers from high energy consumption and high carbon emissions. In contrast, electrocatalytic water splitting technology, which utilizes renewable energy electricity to directly produce high-purity hydrogen, is one of the ideal ways to achieve large-scale green hydrogen production. Among these technologies, alkaline water electrolysis has a certain industrial foundation due to mature equipment and controllable costs, but its practical application still faces the bottleneck of insufficient stability of electrode materials.
[0003] In alkaline water electrolysis, hydrogen bubbles continuously generated on the cathode electrode surface cannot desorb from the electrode / electrolyte interface in a timely manner. This leads to the covering of active sites, increased local resistance, and hinders the transport of reactants and products, resulting in increased overpotential and energy consumption. Simultaneously, the repeated nucleation, growth, and detachment of bubbles can cause micro-stress impacts on the electrode surface and the scouring effect of electrolyte flow. Long-term operation can lead to pulverization and peeling of the catalyst layer, severely affecting electrode lifespan. Currently, most studies optimize intrinsic electrocatalytic activity through doping and compositing methods, or improve wettability by constructing special morphologies to promote bubble desorption. However, these strategies fail to fundamentally enhance the mechanical robustness of the electrode. Therefore, how to significantly enhance the mechanical strength and structural integrity of its porous framework while endowing the electrode with efficient bubble transport capabilities, achieving both catalytic activity and long-term operational stability, has become a pressing technical challenge in this field. To address this challenge, porous electrode materials with high specific surface area and interconnected pore structures are being constructed. Although nanoporous nickel electrodes prepared by dealloying can alleviate bubble blockage to some extent, their pore structure is often fragile, with small ligament size and insufficient mechanical strength. During long-term electrolysis, pore collapse or active structure stripping is likely to occur, making it difficult to achieve both high catalytic activity and long-term stability.
[0004] Therefore, developing an electrode material that combines good bubble transport capability with strong mechanical stability is of great significance for promoting the practical application of alkaline water electrolysis hydrogen production technology. Summary of the Invention
[0005] This invention addresses the problems in existing technologies by providing a porous electrode for improving the stability of alkaline water electrolysis, its preparation method, and its application. This invention involves subjecting a porous nickel electrode prepared by a dealloying method to secondary heat treatment under specific conditions. Without significantly sacrificing its high specific surface area and interconnected pore structure, the porous electrode achieves selective thickening and structural strengthening of the porous ligaments by controlling the pore size. This method not only controls the pore and ligament sizes but also optimizes the surface state of the material, improving the electrode's mechanical robustness, gas-liquid transport capacity, and bubble desorption kinetics. The resulting porous electrode exhibits high catalytic activity and excellent operational stability during water electrolysis for hydrogen production. This invention is achieved through the following technical solutions: In a first aspect, the present invention provides a method for preparing a highly stable porous electrode, the method comprising the following steps: Step 1: Heat the nickel mesh and zinc powder to 200-400 ℃ in a nitrogen atmosphere, hold for 2-4 hours, and then let it cool naturally to obtain the nickel-zinc alloy material grown on the nickel mesh. Step 2: The nickel-zinc alloy material grown on the nickel mesh is placed in an alkaline solution for chemical etching to obtain a porous nickel electrode; Step 3: The porous nickel electrode is prepared by holding it at 200-700 ℃ in a reducing atmosphere for 2-4 hours.
[0006] Preferably, in step 1, the nickel mesh is ultrasonically cleaned sequentially with ethanol, 1-2 M potassium hydroxide, 1-2 M hydrochloric acid and deionized water to remove metal oxides from the surface of the nickel mesh.
[0007] Preferably, in step 1, the nickel mesh and zinc powder are placed in a porcelain crucible; the muffle furnace is heated to the preset temperature at a heating rate of 5-10 ℃ / min; the temperature is maintained for 2-3 hours and then naturally cooled to obtain the nickel-zinc alloy grown in situ on the nickel mesh.
[0008] Preferably, in step 2, the chemical etching process is as follows: The nickel-zinc alloy grown in situ on the nickel mesh is immersed in a 1-2 M potassium hydroxide solution. The solution is heated to 30-60 ℃ for corrosion. After corrosion, the alkaline solution used to clean the surface is removed and placed in a vacuum pot for vacuuming for 3-4 h. After introducing a small amount of air, it is left to stand for 12-14 h to obtain a porous nickel electrode.
[0009] Preferably, in step 3, the porous nickel electrode is placed in a porcelain crucible; a tube furnace under an argon-hydrogen mixed atmosphere is heated to a preset temperature at a heating rate of 3-5 °C / min; the temperature is maintained for 2-3 hours and then naturally cooled to obtain a highly stable porous nickel electrode material.
[0010] Preferably, step 3 further includes the following steps: immersing the obtained porous nickel electrode material in a 1-2 M potassium hydroxide solution, heating the solution to 30-60 °C for corrosion, removing soluble zinc element, and obtaining a porous nickel electrode.
[0011] Secondly, the present invention provides a porous nickel-based electrode prepared by the preparation method described above.
[0012] Thirdly, the present invention provides the application of the porous nickel electrode described above in alkaline water electrolysis.
[0013] The beneficial effects of this invention are as follows: 1. Constructing a porous structure with interconnected pores through an alloying-dealloying process is beneficial for the rapid desorption of hydrogen during electrolysis, reducing bubble blockage and improving mass transfer efficiency. 2. Through secondary heat treatment within a specific temperature range, the porous ligament is coarsened, enhancing mechanical strength and structural stability, and preventing structural collapse or detachment of the active layer during long-term operation; 3. The prepared electrode maintains high hydrogen evolution activity while exhibiting excellent electrochemical stability and mechanical durability, making it suitable for industrial alkaline water electrolysis. Attached Figure Description
[0014] Figure 1 This is a scanning electron microscope image of the porous nickel electrode prepared in Example 1; Figure 2 This is a scanning electron microscope image of the porous nickel electrode prepared in Example 2; Figure 3 This is a scanning electron microscope image of the porous nickel electrode prepared in Example 3; Figure 4 The image shown is a scanning electron microscope image of Comparative Example 1. Figure 5 This is a scanning electron microscope image of Comparative Example 2; Figure 6 The porous base electrodes prepared in Examples 1-3 and the hydrogen evolution (HER) polarization curves of Comparative Examples 1-2 are shown. Figure 7 The porous nickel electrodes prepared in Examples 1-3 and the Tafel curves of Comparative Examples 1-2 are shown. Figure 8 Electrochemical impedance spectroscopy (EIS) of porous nickel electrodes prepared in Examples 1-3 and Comparative Examples 1-2. Figure 9 The porous nickel electrodes prepared in Examples 1-3 and the double-layer capacitors (C) in Comparative Examples 1-2 are examples of examples of examples 1-3. dl )curve; Figure 10 Stability curves of the porous nickel electrodes prepared in Examples 1 and 3; Figure 11 Images showing the mechanical stability of the porous nickel electrodes prepared in Examples 1-3. Detailed Implementation
[0015] The present invention will be further described below with reference to the embodiments and accompanying drawings, but the scope of protection of the present invention is not limited thereto. Example 1
[0016] This embodiment relates to a porous nickel electrode for alkaline water electrolysis and its preparation method, the steps of which are as follows: (1) The nickel mesh is ultrasonically cleaned in sequence with ethanol, 1-2 M potassium hydroxide, 1-2 M hydrochloric acid and deionized water to remove the metal oxides on the surface of the nickel mesh and obtain a clean nickel mesh.
[0017] (2) The nickel mesh and zinc powder obtained in step (1) are heated to 200-400 ℃ at a heating rate of 5-10 ℃ / min under a nitrogen atmosphere, held for 2-4 hours and then naturally cooled to obtain a nickel-zinc alloy grown on the nickel mesh.
[0018] (3) Immerse the nickel-zinc alloy mesh obtained in step (2) in 1 M potassium hydroxide solution, heat the solution to 30-60 ℃ for corrosion, after corrosion, take out the alkaline solution that cleans the surface and put it into a vacuum pot for vacuuming for 3-4 h, introduce a small amount of air and let it stand for 12-14 h to obtain a porous nickel mesh.
[0019] (4) The porous nickel mesh obtained in step (3) is heated to 250 °C at a heating rate of 3-5 °C / min under an argon-hydrogen mixed atmosphere, and the temperature is maintained for 2-3 hours before natural cooling. Then, the porous nickel electrode material is immersed in a 1-2 M potassium hydroxide solution, and the solution is heated to 30-60 °C for etching to remove soluble zinc. The preparation of the porous nickel electrode is complete. Scanning electron microscopy is shown below. Figure 1 As shown, by Figure 1 It can be seen that the material annealed at 250 ℃ formed a cracked surface. Example 2
[0020] (1) The nickel mesh is ultrasonically cleaned in sequence with ethanol, 1-2 M potassium hydroxide, 1-2 M hydrochloric acid and deionized water to remove the metal oxides on the surface of the nickel mesh and obtain a clean nickel mesh.
[0021] (2) Place the nickel mesh and zinc powder obtained in step (1) in a muffle furnace under a nitrogen atmosphere and heat it to 200-400 ℃ at a heating rate of 8-10 ℃ / min. After maintaining the temperature for 2-3 hours, allow it to cool naturally to obtain a nickel-zinc alloy mesh.
[0022] (3) Immerse the nickel-zinc alloy mesh obtained in step (2) in a 1-2 M potassium hydroxide solution, heat the solution to 30-60 ℃ for corrosion, after corrosion, take out the alkaline solution that cleans the surface and put it into a vacuum pot for 3-4 hours, introduce a small amount of air and let it stand for 12-14 hours to obtain a porous nickel mesh.
[0023] (4) Place the porous nickel mesh obtained in step (3) in a tube furnace under an argon-hydrogen mixed atmosphere and heat it to 450 ℃ at a heating rate of 3-5 ℃ / min. Hold the temperature for 2-3 hours and allow it to cool naturally. Then immerse the porous nickel electrode material in a 1-2 M potassium hydroxide solution and heat the solution to 30-60 ℃ for etching to remove residual zinc oxide from the surface. The preparation of the porous electrode is complete. Scanning electron microscopy results are shown below. Figure 2 As shown, by Figure 2 It can be seen that the porous electrode after annealing at 450 ℃ has thicker ligaments and larger pore size. Example 3
[0024] (1) The nickel mesh is ultrasonically cleaned in sequence with ethanol, 1-2 M potassium hydroxide, 1-2 M hydrochloric acid and deionized water to remove the metal oxides on the surface of the nickel mesh and obtain a clean nickel mesh.
[0025] (2) Place the nickel mesh obtained in step (1) in a muffle furnace under a nitrogen atmosphere and heat it to 200-400 ℃ at a heating rate of 8-10 ℃ / min. After maintaining the temperature for 2-3 hours, allow it to cool naturally to obtain a nickel-zinc alloy mesh.
[0026] (3) Immerse the nickel-zinc alloy mesh obtained in step (2) in a 1-2 M potassium hydroxide solution, heat the solution to 30-60 ℃ for corrosion, after corrosion, take out the alkaline solution that cleans the surface and put it into a vacuum pot for 3-4 hours, introduce a small amount of air and let it stand for 12-14 hours to obtain a porous nickel mesh.
[0027] (4) Place the porous nickel mesh obtained in step (3) in a tube furnace under an argon-hydrogen mixed atmosphere and heat it to 600 ℃ at a heating rate of 3-5 ℃ / min. Hold the temperature for 2-3 hours and allow it to cool naturally. Then immerse the porous nickel electrode material in a 1-2 M potassium hydroxide solution and heat the solution to 30-60 ℃ for etching to complete the preparation of the porous electrode. Scanning electron microscopy (SEM) results are shown below. Figure 3 As shown, by Figure 3 It can be seen that the porous electrode annealed at 650 ℃ has thicker ligaments and larger pore size than the electrode annealed at 450 ℃.
[0028] Comparative Example 1 A commercial electrocatalyst material is purchased directly from an electrode company.
[0029] Figure 4 Scanning electron microscope images of commercial electrodes, by Figure 4 It can be seen that they are irregular particles.
[0030] Comparative Example 1, under 1 M KOH conditions, exhibits lower hydrogen evolution activity than the three examples prepared by the method of the present invention. The Tafel slope and charge transfer impedance are increased, indicating that it has a slow HER kinetic process.
[0031] Comparative Example 2 A nickel mesh electrocatalyst material was purchased directly from a metal mesh manufacturer.
[0032] Figure 5 Here is a scanning electron microscope image of a nickel mesh, from... Figure 5 It can be seen that the surface of the nickel mesh has a smooth and flat structure.
[0033] In Comparative Example 2, under 1 M KOH conditions, the hydrogen evolution activity was lower than that of the three examples of the present invention and Comparative Example 1. At the same time, the Tafel slope and electrochemical impedance were significantly increased, indicating that the hydrogen evolution reaction kinetics under this condition were relatively slow.
[0034] Figure 6 These are the hydrogen evolution (HER) polarization curves tested in 1 M KOH solution for Examples 1-3 and Comparative Examples 1-2, and the Tafel curves are shown below. Figure 7 As shown, the impedance (EIS) curve is as follows: Figure 8 As shown, the double-layer capacitors (C) of Examples 1-3 dl The curve is as follows Figure 9 As shown; by Figure 6 , 7 As shown in Figure 8, during the HER process, the overpotential of the prepared porous electrode material is lower than that of the nickel mesh and commercial electrode, and the overpotential of HER increases with increasing annealing temperature; the catalyst activity of the prepared porous electrode material is higher than that of the nickel mesh and commercial electrode, and the catalyst activity decreases with increasing annealing temperature; the impedance of the prepared porous electrode material is lower than that of the nickel mesh and commercial electrode, and the impedance increases with increasing annealing temperature. Figure 9 It can be seen that the electrochemically active surface area decreases with increasing annealing temperature. The stability curves for Examples 1 and 3 are shown below. Figure 10 As shown, by Figure 10 It can be known that 100 mA cm -2 At the specified current density, during a 50-hour chronopotential test, the voltage decay rate of Example 3 was lower than that of Example 1, indicating improved electrochemical stability. The mechanical stability tests of the electrodes in Examples 1-3 are as follows: Figure 11 As shown, by Figure 11It can be seen that after 10 minutes of ultrasonic treatment, the mechanical stability of the electrode in Example 1 was poor and the catalytic active layer was easy to fall off; the mechanical stability of Example 2 was improved, while the mechanical stability of Example 3 was greatly increased, and even after 30 minutes of ultrasonic treatment, there was no obvious catalytic active layer falling off in the solution.
[0035] The specific embodiments of the present invention have been described above, but are not intended to limit the present invention. The present invention is not limited to the specific embodiments described above. Any changes made by those skilled in the art after reading the specification of the present invention, as long as they are within the scope of the claims of the present invention, will be protected by patent law.
Claims
1. A method for preparing a highly stable porous electrode, characterized in that, The method includes the following steps: Step 1: Heat the nickel mesh and zinc powder to 200-400 ℃ in a nitrogen atmosphere, hold for 2-4 hours, and then let it cool naturally to obtain the nickel-zinc alloy material grown on the nickel mesh. Step 2: The nickel-zinc alloy material grown on the nickel mesh is placed in an alkaline solution for chemical etching to obtain a porous nickel electrode; Step 3: The porous nickel electrode is prepared by holding it at 200-700 ℃ in a reducing atmosphere for 2-4 hours.
2. The method for preparing a highly stable porous electrode according to claim 1, characterized in that, In step 1, the nickel mesh is ultrasonically cleaned sequentially with ethanol, 1-2 M potassium hydroxide, 1-2 M hydrochloric acid and deionized water to remove impurities and metal oxides from the surface of the nickel mesh.
3. The method for preparing a highly stable porous electrode according to claim 1, characterized in that, In step 1, nickel mesh and zinc powder are placed in a porcelain crucible; the muffle furnace is heated to the preset temperature at a heating rate of 5-10 ℃ / min; the temperature is maintained for 2-3 hours and then naturally cooled to obtain a nickel-zinc alloy grown in situ on the nickel mesh.
4. The method for preparing a highly stable porous electrode according to claim 1, characterized in that, In step 2, the chemical etching process is as follows: The nickel-zinc alloy grown in situ on the nickel mesh is immersed in a 1-2 M potassium hydroxide solution. The solution is heated to 30-60 ℃ for corrosion. After corrosion, the alkaline solution used to clean the surface is removed and placed in a vacuum pot for vacuuming for 3-4 h. After introducing a small amount of air, it is left to stand for 12-14 h to obtain a porous nickel electrode.
5. The method for preparing a highly stable porous electrode according to claim 1, characterized in that, In step 3, the porous nickel electrode is placed in a porcelain crucible; the tube furnace is heated to the preset temperature at a heating rate of 3-5 °C / min under an argon-hydrogen mixed atmosphere; the temperature is maintained for 2-3 hours and then naturally cooled to obtain a highly stable porous nickel electrode material.
6. The method for preparing a highly stable porous electrode according to claim 1, characterized in that, Step 3 also includes the following steps: immersing the obtained porous nickel electrode material in a 1-2 M potassium hydroxide solution, heating the solution to 30-60 °C for corrosion to remove soluble zinc elements, and obtaining a porous nickel-based electrode.
7. The porous nickel-based electrode prepared by the preparation method according to any one of claims 1-6.
8. The application of the porous nickel-based electrode according to claim 7 in alkaline water electrolysis.