Heat treatment and activation method of electrode net for hydrogen production
Through layered vertical placement and gradient activation, the unevenness and catalyst peeling problems of the electrode network for hydrogen production in electrolytic cell during the heat treatment and activation process are solved, and the high performance and stability of the electrode network are achieved and the hydrogen production efficiency is improved.
Patent Information
- Application Number
- CN202510700958.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-28
- Publication Date
- 2025-08-15
AI Technical Summary
During the activation process, the existing electrode network for hydrogen production in electrolytic cells has problems such as the reduction of central KOH concentration, the reduction of activation rate, the peeling of the catalyst coating and uneven heat treatment, which affects the performance and stability of the electrode network.
The method of heat treatment and gradient activation is adopted for layered vertical placement of the electrode network to ensure uniformity of heat treatment and activation efficiency. The diffusion reaction of the nickel-aluminum catalytic layer is used to form fine holes, improve the binding force between the catalytic layer and the substrate, and gradient activation is used to reduce precipitate blockage.
It improves the performance and stability of the electrode network, enhances the binding force between the catalyst coating and the substrate, increases the specific surface area of the electrode network, and improves the hydrogen production efficiency and the service life of the electrode network.
Smart Images
Figure CN120485832A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of electrode nets for hydrogen production in electrolyzers, and in particular to a heat treatment and activation method for the electrode nets for hydrogen production. Background Art
[0002] The activation process for electrode mesh used in electrolyzer hydrogen production primarily involves placing catalyst-sprayed mesh in multiple layers horizontally in an activation tank for activation. The overall activation reaction is: 2Al + 2KOH + 2H2O → 2KAlO2 + 3H2↑. However, as the reaction progresses, the KOH concentration in the center of the multi-layered mesh decreases, slowing the activation rate and thus reducing activation efficiency. Furthermore, as the solution in the activation tank ages, or as K2Al2O4·3H2O precipitates form, the surface of the multi-layered mesh will adhere to the precipitate, affecting pore formation during activation and clogging the pores in the coating, reducing the mesh's performance.
[0003] In addition, the electrode mesh for hydrogen production in the electrolyzer can be heat-treated after being sprayed with the catalyst and before being activated. The heat treatment process can reduce the over-point of the electrode mesh in the electrolyzer, making the bonding force between the catalytic layer of the electrode mesh and the base mesh stronger, more corrosion-resistant, and longer-lasting.
[0004] During the actual production heat treatment process, the horizontally stacked nickel meshes rub against each other, or the weight of the upper electrode mesh presses against the lower sprayed nickel mesh, causing the sprayed layer to fall off, affecting the pore formation during the activation process, and reducing the performance of the electrode mesh and the bonding strength between the coating and the nickel mesh. In addition, the horizontally stacked nickel meshes are prone to uneven heating during the heat treatment process. The upper layer and surrounding areas of the nickel mesh heat up quickly and are kept warm, while the core heats up slowly due to thermal radiation limitations. This results in different bonding strengths between the coating and the base nickel mesh at different locations on a single electrode mesh sheet. Part of the catalyst coating may fall off during the activation process or during hydrogen production in the electrolyzer, affecting hydrogen production efficiency. Summary of the Invention
[0005] Purpose of the invention: In response to the problems existing in the prior art, the present invention provides a method for heat treatment and activation of an electrode mesh for hydrogen production. The electrode mesh prepared by the present invention has better performance and better stability.
[0006] Technical solution: The present invention provides a method for heat treatment and activation of an electrode mesh for hydrogen production, comprising the following steps: S1. The hydrogen production electrode mesh after spraying the nickel-aluminum catalyst layer is layered and placed vertically in a heat treatment furnace, leaving a certain gap between each of the electrode meshes; The electrode meshes are placed vertically in layers in a heat treatment furnace with gaps between them. This prevents friction and shedding of the coating between the two electrode meshes. Furthermore, when multiple layers of electrode meshes are stacked, the periphery of the electrode meshes preferentially absorbs heat radiation during heat treatment, while the core receives less heat radiation energy due to the multiple layers stacked internally. The present invention adopts vertical layered placement to ensure that the electrode meshes are evenly heated during the heat treatment process, resulting in higher heat treatment efficiency and reduced electrical energy. S2. The heat treatment furnace is evacuated, heated to 620-650°C and held for 15-30 minutes. Then, protective gas is introduced and the temperature is lowered to 400-500°C and held for 2-3 hours. Finally, protective gas is introduced and the material is rapidly cooled to below 200°C, removed from the furnace, and air-cooled. The electrode mesh for hydrogen production after spraying the nickel-aluminum catalytic layer is subjected to a step heat treatment: during the 620-650℃ process, the aluminum is in a molten state, absorbing more nickel and nickel-based alloy powder nearby, and the contact area with the base nickel mesh becomes larger, and the nickel and aluminum diffuse and penetrate each other. The single layer of the electrode mesh is heated evenly, and the diffusion reaction is rapid; after a period of high temperature insulation, it is quickly cooled. The rapid cooling prevents the aluminum grains from growing to form lamellar crystals and maintains the fine grain structure inside the aluminum. Rapid cooling to 400-500℃ and insulation promotes the continuous diffusion of nickel and aluminum. Then, rapid cooling to 200℃ is carried out to refine the grain structure of nickel and aluminum and improve the activation efficiency. During the activation process, the base nickel mesh, nickel and nickel-based alloy powder diffuse and penetrate into many fine aluminum and react with the alkali solution to form many fine holes. The specific surface area of the electrode mesh is high, and the coating on the surface of the electrode mesh is evenly combined with the base nickel mesh without falling off or cracking, thereby improving the performance of the electrode mesh. S3. Place the electrode meshes heat-treated in S2 vertically and layered in an activation tank for activation treatment.
[0007] Preferably, if Figure 1-2 As shown, the present invention is provided with a material rack fixing frame in the heat treatment furnace, and a plurality of material racks are provided on the material rack fixing frame. The two ends of the material racks are mounted on the supporting rods provided at the two ends of the material rack fixing frame, and a certain gap is provided between each material rack. The electrode mesh is vertically clamped on the material rack by a clamp, and one electrode mesh corresponds to one material rack. Furthermore, in S3, the specific conditions of the activation treatment are: first activation treatment at room temperature for 1-2 hours, and then heat preservation activation at 70-90°C for 8-10 hours; The electrode mesh is clamped vertically on the rack. After the heat treatment is completed, the rack can be taken out and placed directly on the activated fixed rack, thereby activating the electrode mesh on the rack to improve production efficiency. At the same time, each electrode mesh is fully in contact with the KOH solution, the solution concentration is uniform, the reaction rate is fast, the activation efficiency is improved, the sediment attached to the surface of the electrode mesh is reduced, the aluminum residue in the coating is reduced, and the stability of the electrode mesh performance is improved.
[0008] Gradient activation: Conventional activation directly uses high-temperature activation, which reacts very quickly, releases a large amount of hydrogen, causes the KOH melt to boil and overflow, and produces a large amount of KOH vapor, which causes steam corrosion to equipment and people; at the same time, the force generated by the large amount of hydrogen released will cause the coating to peel off and fall off from the substrate; the reaction products will collide with the escape of hydrogen, and will also clog the cavities formed inside the electrode mesh, reducing the specific surface area of the electrode mesh. Therefore, the present invention adopts gradient activation, first activating at room temperature, at room temperature, only the Al on the coating surface reacts with KOH at a relatively fast rate, and the reaction products slowly dissolve and fall off into the activation solution, and then heating to 70-90 ° C for activation, thereby improving the activation efficiency, accelerating the reaction rate and degree of aluminum and alkali solution, and consuming more aluminum in the coating during the activation process. More small holes are formed on the coating and the substrate nickel mesh, increasing the specific surface area of the electrode mesh, and the holes on the coating surface of the electrode mesh are uniform, thereby improving the performance of the electrode mesh, and at the same time, reducing the aluminum residue after activation and improving the performance stability of the electrode mesh.
[0009] Furthermore, in S1, the catalytic layer is specifically a nickel-aluminum binary alloy, a nickel-aluminum ternary alloy or a nickel-aluminum quaternary alloy.
[0010] Furthermore, in S1, the gap is 10-20 mm.
[0011] Preferably, in S2, the protective gas is argon, nitrogen or helium.
[0012] Furthermore, in S3, the activation solution is 30% concentration KOH.
[0013] Beneficial effects: Compared with the prior art, the present invention has the following specific beneficial effects: The heat treatment and activation method for the hydrogen production electrode mesh provided by the present invention can reduce the problem of catalytic layer shedding during the heat treatment of the electrode mesh, ensure that the electrode mesh is heated evenly during the heat treatment, avoid the problem of different coating adhesion at different positions of the electrode mesh due to uneven heating, improve the adhesion of the catalyst coating on the electrode mesh, and thus improve the performance and stability of the electrode mesh; The heat treatment and activation method for the hydrogen production electrode mesh provided by the present invention can reduce the pore formation of the coating caused by the precipitates attached to the surface of the electrode mesh after the reaction during the activation process, thereby further improving the performance of the electrode mesh. The present invention provides a heat treatment and activation method for an electrode mesh for hydrogen production. The step heat treatment refines the grain structure of nickel and aluminum in the catalytic layer, and the step activation improves the activation efficiency and accelerates the reaction rate and degree of aluminum and alkaline solution. The two work together to form more small and uniform pores on the base nickel mesh and its catalytic coating, further increasing the specific surface area of the electrode mesh and enhancing the performance of the electrode mesh. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1This is a schematic diagram of the electrode mesh for hydrogen production in the present invention being vertically clamped on a material rack; Figure 2 This is a three-dimensional diagram of the electrode mesh for hydrogen production in the present invention being vertically clamped on a material rack; Figure 3 、 4 This is an electron microscope image of the electrode mesh obtained by the heat treatment and activation method of the present invention; Figure 5 This is an electron microscope image of the electrode mesh prepared by conventional methods; Figure 6 Graph showing the performance of an electrode mesh prepared by the heat treatment and activation method of the present invention and an electrode mesh prepared by a conventional method. DETAILED DESCRIPTION
[0014] The present invention is described in detail below with reference to the embodiments.
[0015] Implementation method 1: (1) Clamp one side of the hydrogen production electrode mesh after spraying the nickel-aluminum catalyst layer with a clamp and place it vertically on the material rack. One hydrogen production electrode mesh corresponds to one material rack. Then, place the material rack on the material rack fixing frame. The two ends of the material rack are mounted on the supporting rods set at both ends of the material rack fixing frame. A certain gap is set between each material rack. Optionally, the nickel-aluminum catalyst layer is a nickel-aluminum binary alloy, a nickel-aluminum ternary alloy, or a nickel-aluminum quaternary alloy; The material rack fixed frame hung with the electrode mesh for hydrogen production is placed in the heat treatment furnace; Heat treatment: vacuum the chamber to ≤1Pa, quickly heat up to 640℃, keep warm for 15min, then use inert gas to quickly reduce the temperature inside the furnace to 450℃, keep warm for 3h, then use inert gas to quickly reduce the temperature inside the furnace to below 200℃, then take out the rack and air cool it; After the heat treatment is completed, the rack with the electrode mesh is taken out and placed directly on the fixed rack in the activation tank for room temperature activation. After activation for 1 hour, the activation tank is heated to 85°C and kept warm for 10 hours. After activation, the electrode mesh is taken out, cleaned, dried, and cut.
[0016] Implementation 2: (1) Clamp one side of the hydrogen production electrode mesh after spraying the nickel-aluminum catalyst layer with a clamp and place it vertically on the material rack. One hydrogen production electrode mesh corresponds to one material rack. Then, place the material rack on the material rack fixing frame. The two ends of the material rack are mounted on the supporting rods set at both ends of the material rack fixing frame. A certain gap is set between each material rack. Optionally, the nickel-aluminum catalyst layer is a nickel-aluminum binary alloy, a nickel-aluminum ternary alloy, or a nickel-aluminum quaternary alloy; The material rack fixed frame hung with the electrode mesh for hydrogen production is placed in the heat treatment furnace; Heat treatment: vacuum the chamber to ≤1Pa, quickly heat up to 620℃, keep warm for 30min, then use inert gas to quickly reduce the temperature inside the furnace to 500℃, keep warm for 2.5h, then use inert gas to quickly reduce the temperature inside the furnace to below 200℃, then take out the rack for air cooling; After the heat treatment is completed, the rack with the electrode mesh is taken out and placed directly on the fixed rack in the activation tank for room temperature activation. After activation for 1.5 hours, the activation tank is heated to 90°C and kept warm for 10 hours. After activation, the electrode mesh is taken out, cleaned, dried, and cut.
[0017] Implementation 3: (1) Clamp one side of the hydrogen production electrode mesh after spraying the nickel-aluminum catalyst layer with a clamp and place it vertically on the material rack. One hydrogen production electrode mesh corresponds to one material rack. Then, place the material rack on the material rack fixing frame. The two ends of the material rack are mounted on the supporting rods set at both ends of the material rack fixing frame. A certain gap is set between each material rack. Optionally, the nickel-aluminum catalyst layer is a nickel-aluminum binary alloy, a nickel-aluminum ternary alloy, or a nickel-aluminum quaternary alloy; The material rack fixed frame hung with the electrode mesh for hydrogen production is placed in the heat treatment furnace; Heat treatment: vacuum the chamber to ≤1Pa, quickly heat up to 650℃, keep warm for 15min, then use inert gas to quickly reduce the temperature inside the furnace to 400℃, keep warm for 3h, then use inert gas to quickly reduce the temperature inside the furnace to below 200℃, then take out the rack for air cooling; After the heat treatment, the rack with the electrode mesh was taken out and placed directly on the fixed rack in the activation tank for activation treatment at room temperature. After activation for 2 hours, the activation tank was heated to 70°C and kept warm for 8 hours. After activation, the electrode mesh is taken out, cleaned, dried, and cut.
[0018] The electrode mesh heat treated and activated by the method of the present invention is compared with the electrode mesh heat treated and activated by the conventional normal process. Figure 3-5 As shown in the figure: in terms of microstructure, the electrode mesh prepared by the method of the present invention is evenly heat treated and activated, the surface microstructure has even pores and unevenness, the coating has good bonding with the base nickel mesh, and there is no peeling or cracking; in terms of performance, the electrode mesh prepared by the method of the present invention has better performance and stability.
[0019] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.
Claims
1. A method for heat treatment and activation of an electrode mesh for hydrogen production, characterized in that: The following steps are involved: S1. The hydrogen production electrode mesh after spraying the nickel-aluminum catalyst layer is layered and placed vertically in a heat treatment furnace, leaving a certain gap between each of the electrode meshes; S2. The heat treatment furnace is evacuated, heated to 620-650°C and held for 15-30 minutes. Then, protective gas is introduced and the temperature is lowered to 400-500°C and held for 2-3 hours. Finally, protective gas is introduced and the material is rapidly cooled to below 200°C, removed from the furnace, and air-cooled. S3. Place the electrode meshes heat-treated in S2 vertically and layered in an activation tank for activation treatment.
2. The heat treatment and activation method of the electrode mesh for hydrogen production according to claim 1, characterized in that: In S3, the specific conditions of the activation treatment are: first activation treatment at room temperature for 1-2 hours, and then heat preservation activation at 70-90°C for 8-10 hours.
3. The heat treatment and activation method of the hydrogen production electrode mesh according to claim 1, characterized in that: In S1, the catalytic layer is specifically a nickel-aluminum binary alloy, a nickel-aluminum ternary alloy or a nickel-aluminum quaternary alloy.
4. The heat treatment and activation method of the electrode mesh for hydrogen production according to claim 1, characterized in that: In S1, the gap is 10-20 mm.
5. The heat treatment and activation method of the electrode mesh for hydrogen production according to claim 1, characterized in that: In S2, the protective gas is argon, nitrogen or helium.
6. The heat treatment and activation method of the hydrogen production electrode mesh according to claim 1, characterized in that: In S3, the activation solution is 30% concentration of KOH.