A metal-based active material, its preparation method and application

Abstract

This invention discloses a metal-based active material, its preparation method, and its application, belonging to the field of functional materials technology. The invention utilizes a first plating solution to pre-plat a metal substrate to obtain a pre-plated metal substrate. A second plating solution is then used to electroplate an active layer onto the pre-plated metal substrate to obtain a metal-based alloy material. The metal-based alloy material is then subjected to heat treatment and zinc stripping treatment sequentially to obtain the metal-based active material. The alloy coating of this active material is a Ni / Zn alloy with a specific NiZn3 crystal form or predominantly NiZn3 crystal form. Furthermore, the ratio of the atomic mass of Zn in the alloy coating to the sum of the atomic masses of Zn and Ni is 15% to 25%, which improves the stability and activity of the metal-based active material and solves the problems of poor adhesion and low activity in existing electrode materials.

Description

[0001] Cross-references This disclosure claims that the application date is October 29, 2024, the application number is 202411514029.1, and the invention title is: Priority is claimed in the Chinese invention patent application for "An electrode, its preparation method and application". The entire content is incorporated into this article by reference. Technical Field

[0002] This invention relates to the field of functional materials technology, and in particular to a metal-based active material, its preparation method, and its application. Background Technology

[0003] Hydrogen production by water electrolysis includes the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). In the process of hydrogen production by water electrolysis, the electrode material, as the core component of the electrolyzer, is one of the key factors affecting the performance of the electrolyzer and the efficiency of hydrogen production by water electrolysis.

[0004] Alkaline electrolyzers are commonly used in the process of producing hydrogen through water electrolysis. Currently, the cathode material of large-scale alkaline electrolyzers is generally Raney nickel. This electrode material is usually prepared by plasma spraying, which results in poor adhesion, slagging during long-term operation, and low activity. Therefore, there is an urgent need to develop an active electrode material that can meet the requirements of high activity and high adhesion of electrode materials in large-scale electrolyzers, and whose preparation process can be carried out on a large scale for continuous production, in order to replace Raney nickel electrode materials. Summary of the Invention

[0005] The main objective of this invention is to provide a metal-based active material, its preparation method, and its application, aiming to solve the problems of poor bonding force, slagging during long-term operation, and low activity of Raney nickel electrode materials in the prior art.

[0006] To achieve the above objectives, the present invention provides a method for preparing a metal-based active material, the method comprising the following steps: The metal substrate is pre-plated using the first plating solution to obtain a pre-plated metal substrate; The pre-plated metal substrate is electroplated with an active layer using a second plating solution to obtain a metal-based alloy material. The metal-based alloy material is subjected to heat treatment and zinc stripping treatment in sequence to obtain the metal-based active material; Optionally, the ratio of the atomic mass of Zn to the sum of the atomic masses of Zn and Ni in the alloy coating of the metal-based active material is 15% to 25%.

[0007] Optionally, the second plating solution is alkaline and includes nickel salt, zinc salt, and a complexing system, wherein the complexing system includes a primary complexing agent, a secondary complexing agent, and additives.

[0008] Optionally, the primary complexing agent is at least one of sodium citrate, potassium pyrophosphate, and disodium hydrogen phosphate; the co-complexing agent is glycine and / or glutamic acid; and the additive is at least one of ammonium chloride, ammonia, and sodium chloride.

[0009] Optionally, the current density of the pre-plating treatment is 0.5 A / dm. 2 ~3A / dm 2 The plating solution temperature is 30℃~50℃, and the electroplating time is 2min~10min.

[0010] Optionally, the current density for electroplating the active layer is 1 A / dm². 2 ~5A / dm 2 The plating solution temperature is 30℃~50℃, and the electroplating time is 30min~120min.

[0011] Optionally, the heat treatment and zinc stripping treatment are carried out based on the following steps: The metal-based alloy material is placed in a heating device and heated to a preset temperature at a preset rate. Then, it is kept at the preset temperature. After the heat treatment is completed, the heat treatment is finished. The heat-treated metal-based alloy material is placed in an alkaline solution and immersed at ≤40°C for a preset time to complete the zinc stripping process.

[0012] Optionally, the preset rate is 8℃ / min ~ 12℃ / min, the preset temperature is 200℃ ~ 400℃, the heat preservation time is 1h ~ 4h, and the preset duration is 12h ~ 48h.

[0013] To achieve the above objectives, the present invention also provides a metal-based active material, which is prepared by the above method.

[0014] To achieve the above objectives, the present invention also provides an application of metal-based active materials, which are used in the electrolysis of water to produce hydrogen.

[0015] Compared with the prior art, the beneficial effects that the present invention can achieve are as follows: 1. In the technical solution of the present invention, the metal substrate is first pre-plated using a first plating solution to form a pre-plating layer on the metal substrate, and then an active layer electroplating is performed on the pre-plated metal substrate using a second plating solution to form an alloy coating on the pre-plating layer; wherein, the pre-plating layer can serve as a transition layer between the metal substrate and the alloy coating, thereby balancing the hardness difference between the metal substrate and the alloy coating, improving the bonding force between the metal substrate and the alloy coating, and improving the ductility of the alloy coating; the metal-based active material prepared by the technical solution of the present invention has high activity and strong bonding force, and is not prone to slag shedding during long-term operation. Replacing the Raney nickel electrode material in the prior art with it can solve the problems of poor bonding force, slag shedding during long-term operation, and low activity of the Raney nickel electrode material, and can meet the requirements of large electrolytic cells for high activity and high bonding force of electrode materials. At the same time, its preparation process can be carried out on a large scale for continuous production.

[0016] 2. In the technical solution of this invention, the second plating solution is alkaline and, in conjunction with a specific complexing agent system, can change the deposition potential of different metals, thereby forming a metal alloy. When the complexing agent system is specific, an alloy material with a specific NiZn3 crystal form can be prepared, or a Ni / Zn alloy material with NiZn3 crystal form as the main component can be prepared. This alloy material has high hydrogen evolution activity, that is, it has a high active phase. In addition, in the technical solution of this invention, under specific complexing agent system and specific electroplating parameters, the metal-based active material prepared is a functional material with high catalytic activity, rather than a structural material prepared by traditional electroplating.

[0017] 3. In the technical solution of this invention, the metal-based alloy material obtained by electroplating the active layer is subjected to heat treatment and zinc stripping treatment in sequence. During the treatment, the Ni / Zn grains in the alloy coating will recrystallize and mature, transforming from an amorphous morphology to a crystalline morphology, forming a mixed state of amorphous and crystalline. This not only improves the mechanical strength, thermal stability, and chemical stability of the alloy coating, but also enhances the apparent catalytic activity of the alloy coating. Secondly, heat treatment can effectively eliminate some of the coating stress and form a thin and stable oxide layer on the coating surface, improving the oxidation resistance and corrosion resistance of the coating. Thus, the stability and activity of the metal-based active material can be improved.

[0018] 4. In the technical solution of this invention, the obtained metal-based active material includes a pre-plating layer and an alloy plating layer, wherein the ratio of the atomic mass of Zn to the sum of the atomic masses of Zn and Ni (Zn / Zn+Ni) in the alloy plating layer is 15%~25%. During the zinc stripping process of the Ni / Zn alloy, when zinc is stripped, Ni and Zn undergo a Lewis acid-base reaction, resulting in the gain and loss of electrons. This increases the valence state of Ni electrons in the Ni / Zn alloy, thereby altering the adsorption strength of H*, a key product of the hydrogen evolution reaction, at the active site, thus optimizing its catalytic activity. Simultaneously, a reasonable amount of Zn stripping ensures that the coating's bonding strength does not significantly decrease, and the pore structure distribution is uniform. This solves the problems of poor bonding strength and low activity in existing Raney nickel electrode materials, making it a better choice for low-cost, high-performance applications in large-scale industrial alkaline electrolyzers. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the preparation process of metal-based active materials; Figure 2 The XRD pattern of the metal-based active material in Example 1 is shown below. Figure 3 The XRD pattern of the metal-based material in Comparative Example 1 is shown. Figure 4 The images show X-ray photoelectron spectroscopy (XPS) analysis of the materials obtained in Example 1 and Comparative Example 1, where sub-image a is the Ni 2p spectrum and sub-image b is the Zn 2p spectrum. Figure 5 The images show the scanning electron microscope (SEM) images of the metal-based alloy material obtained in S30 of Example 1 and the metal-based active material obtained in S40. Figure 6 The images show the scanning electron microscope (SEM) images of the metal-based material obtained in S30 and S40 of Comparative Example 1. Figure 7 Linear sweep voltammetry (LSV) curves of the materials obtained in Example 1 and Comparative Example 2; Figure 8 The XRD pattern of the metal-based material in Comparative Example 2 is shown. Figure 9 This is a graph showing the change in cell pressure over time during the water electrolysis hydrogen production process. Figure 10 The graph shows the relationship between Zn / Ni+Zn (%) and overpotential in the alloy coating of the metal-based active material in Example 2. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] To address the problems of poor adhesion, low activity, and slagging during long-term operation of existing Raney nickel electrode materials, this invention provides a method for preparing a metal-based active material, the method being as follows: Figure 1 As shown, it includes the following steps: S10. The metal substrate is sequentially sandblasted, degreased, and pickled.

[0022] Optionally, S10 is an optional step. In the technical solution of the present invention, even if the metal substrate is not treated by S10 before the pre-plating treatment, it will not affect the characteristics of the final metal-based active material.

[0023] Optionally, the metal substrate can be nickel-based, such as nickel mesh, nickel plate, or nickel foam, or it can be a conductive metal substrate such as iron plate, iron mesh, stainless steel plate, stainless steel mesh, titanium plate, or titanium mesh.

[0024] Optionally, in the above sandblasting, the particle size of the sand can be 100 mesh to 200 mesh.

[0025] Alternatively, the above-mentioned degreasing method can be electrochemical degreasing.

[0026] Optionally, the above-mentioned electrochemical degreasing method can be implemented by using a mixed aqueous solution of sodium hydroxide, sodium carbonate, sodium silicate, and trisodium phosphate as the degreasing solution, and a metal substrate as the cathode, at a speed of 1 A / dm³. 2 ~ 5A / dm 2 Under DC current conditions, degreasing takes 5 to 30 minutes.

[0027] Optionally, the concentration of sodium hydroxide can be 50 g / L to 100 g / L, the concentration of sodium carbonate can be 10 g / L to 40 g / L, the concentration of sodium silicate can be 5 g / L to 15 g / L, and the concentration of trisodium phosphate can be 50 g / L to 100 g / L.

[0028] Optionally, the above pickling method can be to soak the degreased metal substrate at room temperature with an acid reagent with a concentration of 10wt%~40wt% for 10min~20min.

[0029] Optionally, the acid reagent mentioned above can be hydrochloric acid or sulfuric acid.

[0030] It should be understood that in the above-mentioned process of sandblasting, degreasing, and pickling the metal substrate, sandblasting can increase the specific surface area of ​​the metal substrate, creating more nucleation sites, thereby improving the adhesion between the substrate and the coating; degreasing and pickling can remove impurities on the metal substrate, avoiding the influence of attached impurities on subsequent processes. At the same time, pickling has an etching effect on the substrate, obtaining a large number of sites through corrosion, which can serve as nucleation sites for subsequent electroplating alloys, thereby improving the adhesion between the substrate and the coating.

[0031] S20. The metal substrate is pre-plated using the first plating solution to obtain a pre-plated metal substrate; Optionally, the first plating solution may include a nickel salt and an activator.

[0032] Optionally, the nickel salt in the first plating solution can be at least one of nickel sulfate and nickel chloride; the activator can be at least one of sulfuric acid, hydrochloric acid and sodium chloride.

[0033] Optionally, the concentration of nickel salt in the first plating solution can be 60 g / L to 300 g / L, the concentration of activator can be 20 g / L to 100 g / L, and the pH value of the first plating solution can be 3 to 6.

[0034] In the above S20, a fine pre-plating layer can be formed on the surface of the metal substrate by pre-plating. Secondly, during electroplating, changes in the metal substrate will affect the particle size and alloy crystal form of the active layer grown on its surface. Therefore, it is necessary to perform pre-plating on the metal substrate to form a fine pre-plating layer. This pre-plating layer can optimize the particle size and orientation of the alloy coating after the active layer electroplating, thereby optimizing the crystal structure and composition distribution of the alloy coating. That is, the pre-plating layer can provide an "anchoring foundation" and "growth guidance" for the uniform deposition of the alloy coating after the active layer electroplating. At the same time, it can also be used to balance the problem of mismatch in hardness and ductility caused by the large difference in particle size between the substrate and the alloy electroplating layer, thereby effectively improving the "static" and "dynamic" bonding force of the coating.

[0035] S30. Using a second plating solution, an active layer is electroplated onto the pre-plated metal substrate to obtain a metal-based alloy material.

[0036] In one possible implementation, the second plating solution is alkaline.

[0037] Optionally, the second plating solution may include nickel salts, zinc salts, and complexing systems.

[0038] Optionally, the concentration of nickel salt in the second plating solution can be 10 g / L to 100 g / L, the concentration of zinc salt can be 10 g / L to 50 g / L, and the concentration of the complexing system can be 5 g / L to 300 g / L.

[0039] In one possible implementation, the complexing system of the second plating solution includes a primary complexing agent, a secondary complexing agent, and additives.

[0040] In one possible implementation, the complexing system of the second plating solution described above comprises at least one of sodium citrate, potassium pyrophosphate, and disodium hydrogen phosphate as the main complexing agent, glycine and / or glutamic acid as the auxiliary complexing agent, and at least one of ammonium chloride, ammonia, and sodium chloride as the additive.

[0041] It should be noted that when performing the above-mentioned active layer electroplating, if the second plating solution is alkaline, the range of complexing agents that can be used in the alkaline electroplating system is richer. Furthermore, the introduction of specific complexing agents can effectively adjust the deposition potential of different metals. When a suitable complexing agent is used, different metal ions can be co-deposited to form an alloy, namely a Ni / Zn alloy. Based on this, when a specific complexing agent system is used, Ni / Zn alloy materials with specific crystal forms can be prepared, or alloy mixtures with one crystal form as the main component. Generally, in the field of catalysis, the catalytic activity and stability of different crystal forms of the same alloy are significantly different.

[0042] Furthermore, when the second plating solution is alkaline and combined with a specific complexing system, co-deposition and alloying of different metals can be achieved, thereby forming an alloy material with NiZn3 as the main crystal form, to obtain a functional metal-based active material. The functional metal-based active material is closely related to its crystal form, particle size, etc., and the catalytic activity of different alloys varies greatly. In the technical solution of this invention, the catalytic activity of the material will only reach its optimal level when the alloy of the active material is NiZn3 or is mainly NiZn3.

[0043] Furthermore, if the second plating solution is acidic and a specific complexing system is removed or replaced, the resulting plating layer is easily oxidized after electroplating, resulting in a surface dominated by oxide impurities such as NiO and ZnO, making it impossible to form an alloy plating layer; and in the subsequent zinc stripping process, ZnO will only react with H2O (OH-). - Electron gain and loss occur, but the electronic valence state of Ni does not change significantly, so the catalytic activity of the material cannot be improved, and the resulting metal-based material has low hydrogen evolution activity.

[0044] As can be seen from the above analysis, in the technical solution of the present invention, there is a synergistic effect between the alkaline conditions of the second plating solution, the specific complexation system and the electroplating process parameters. Through the interaction between the plating solution formulation and the electroplating process, a highly active alloy hydrogen evolution material with NiZn3 as the crystal form or with NiZn3 as the main crystal form is finally obtained.

[0045] Optionally, the nickel salt in the second plating solution can be at least one of nickel chloride, nickel sulfate, nickel nitrate, and nickel acetate.

[0046] Optionally, the zinc salt in the second plating solution can be at least one of zinc sulfate, zinc chloride, zinc nitrate, and zinc acetate.

[0047] Optionally, ammonia water can be used to adjust the second plating solution to make it alkaline, with a pH value of 8-10.

[0048] It should be noted that in the second plating solution mentioned above, when zinc salts such as zinc sulfate, zinc chloride, zinc nitrate, and zinc acetate, which are easily soluble in alkaline solutions, are selected, the zinc content in the coating can be flexibly controlled during co-deposition. This allows zinc to be selectively dissolved during the subsequent zinc stripping process, while nickel is retained and forms a three-dimensional porous structure. The higher the zinc content and the more uniform the distribution in the coating, the more numerous and uniform the pores will be, resulting in a more significant increase in specific surface area. This can effectively improve the escape rate of hydrogen bubbles, thereby optimizing the apparent activity of the hydrogen evolution material.

[0049] Furthermore, in an alkaline plating bath environment, the use of specific nickel salts, such as nickel chloride, nickel sulfate, nickel nitrate, or nickel acetate, can refine the grain size of the nickel-zinc alloy during the co-deposition process. The refined grains result in a shorter and more uniform zinc dissolution path during subsequent zinc stripping, avoiding local zinc residue or uneven porosity caused by coarse grains. At the same time, the refined nickel skeleton structure can also improve the mechanical strength of the material.

[0050] S40. The above-mentioned metal-based alloy material is subjected to heat treatment and zinc stripping treatment in sequence to obtain the above-mentioned metal-based active material.

[0051] It should be noted that, in the alloy coating of the metal-based active material obtained through the above S10~S40 processes, the ratio of the atomic mass of Zn to the sum of the atomic masses of Zn and Ni (Zn / Zn+Ni) is 15%~25%. Within this ratio range, the electronic valence state regulation of Ni at the active site by Zn can reach its optimal level. If the ratio is lower than 15%, the hydrogen evolution catalytic activity will be significantly reduced. At the same time, after zinc stripping treatment, when Zn / Zn+Ni is 15%~25%, the adhesion of the coating is not significantly weakened, and the gap structure distribution is uniform. If Zn / Zn+Ni exceeds 25%, the adhesion of the coating will be significantly weakened. In addition, when Zn / Zn+Ni is 15%~25%, the proportion of NiZn3 in the alloy coating is relatively high, and the high content of NiZn3 can significantly improve the performance of the metal-based active material.

[0052] It should be noted that in S40, the aforementioned metal-based alloy material is first heat-treated and then subjected to zinc stripping. This is because the Ni / Zn alloy in the metal-based alloy material is usually amorphous, with Ni and Zn atoms tightly bonded at the microscale. If zinc stripping is performed directly without heat treatment, Zn will dissolve rapidly, leaving a "sponge-like" framework composed of original fine Ni grains. This microstructure is prone to collapse and recombination, leading to the disappearance of porous structures in some areas, a significant decrease in reaction area, or obvious coating cracks, which is not conducive to long-term application in high current densities of electrolytic cells. At the same time, the particle size formed by direct zinc stripping is too small, making it easy to dissolve during long-term operation, which will reduce the catalytic activity of the material. Furthermore, in the process of alkaline water electrolysis for hydrogen production, the lack of an appropriate amount of metal oxides will inhibit the hydrolysis reaction, resulting in a lower apparent activity of the hydrogen evolution reaction.

[0053] In one possible implementation, the above heat treatment and zinc stripping process are achieved based on the following steps: The above-mentioned metal-based alloy material is placed in a heating device and heated to a preset temperature at a preset rate. Then, it is kept at the preset temperature. After the heat treatment is completed, the heat treatment is finished. The metal-based alloy material that has undergone the above heat treatment is placed in an alkaline solution and immersed at ≤40℃ for a preset time to complete the zinc stripping process.

[0054] In one possible implementation, the preset rate is 8℃ / min ~ 12℃ / min, the preset temperature is 200℃ ~ 400℃, for example, 200℃, 250℃, 300℃, 350℃ or 400℃, the heat preservation time is 1h ~ 4h, for example, 1h, 2h, 3h or 4h; the preset duration is 12h ~ 48h, for example, 12h, 15h, 18h, 20h, 30h, 35h, 40h, 45h or 48h.

[0055] Optionally, the heating device described above can be a muffle furnace.

[0056] Optionally, the above alkaline solution can be in 1M KOH.

[0057] It should be noted that during the heat treatment process, when the temperature is between 200℃ and 400℃, the metal-based alloy material will transform from an amorphous material to a crystalline material, forming a mixed state of amorphous and crystalline materials. This not only improves the mechanical strength, thermal stability, and chemical stability of the material, but also optimizes its catalytic activity. In addition, heat treatment can effectively eliminate some of the coating stress and form a thin and stable oxide layer (such as NiO) on the material, making it more resistant to oxidation and corrosion in electrolytic cell applications.

[0058] Furthermore, after soaking in 1M KOH for 12-48 hours, when zinc is released in the alkaline solution, nickel and zinc undergo a Lewis acid-base reaction, resulting in electron gain and loss. This increases the valence state of Ni in the Ni / Zn alloy coating, altering the adsorption strength of H*, a key product of the hydrogen evolution reaction, at the active sites, thereby optimizing its catalytic activity. Simultaneously, a hydroxylated nickel layer (Ni-OH) forms on the surface of the nickel framework in the Ni / Zn alloy coating. This is due to the interaction between nickel and OH-. - Weak interactions occur, in which the hydroxylated nickel layer can promote the formation rate of intermediates in the hydrogen evolution reaction of water electrolysis, thereby accelerating the reaction rate of hydrogen evolution and further enhancing the activity of hydrogen evolution reaction, thus improving the performance of metal-based active materials as electrodes.

[0059] In one possible implementation, the current density of the pre-plating treatment described above can be 0.5 A / dm³. 2 ~3A / dm 2 The plating solution temperature can be 30℃~50℃, and the electroplating time can be 2min~10min.

[0060] Optionally, in the above pre-plating process, a metal substrate can be used as the cathode and a nickel plate as the anode.

[0061] It should be noted that in the above pre-plating treatment, when the current density is 0.5 A / dm 2 ~3A / dm 2 For example, 0.5A / dm 2 1.0 A / dm 2 1.5 A / dm 2 2.0 A / dm 2 2.5 A / dm 2 Or 3.0 A / dm 2 This process ensures that nickel ions are slowly reduced on the substrate surface to form fine and uniform crystal nuclei, and a dense coating is constructed through a layered growth mode, avoiding dendritic protrusions or porous structures caused by excessively rapid ion reduction under high current. It also balances deposition efficiency and coating quality, because excessive current can cause "concentration polarization," leading to defects such as pinholes and scorching in the coating.

[0062] It should be noted that in the above pre-plating treatment, when the plating bath temperature is 30℃~50℃, such as 30℃, 35℃, 40℃, 45℃ or 50℃, it can accelerate the diffusion rate of nickel ions and activator molecules, ensure timely replenishment of ions on the substrate surface, reduce coating thickness deviation caused by uneven concentration, and avoid side reactions caused by high temperature. Because if the temperature is too high, such as above 50℃, it will accelerate the decomposition of activator or cause the water in the plating bath to evaporate too quickly, resulting in composition fluctuations, and may also increase the internal stress of the coating.

[0063] In one possible implementation, the current density for electroplating the active layer can be 1 A / dm². 2 ~5A / dm 2 The plating solution temperature can be 30℃~50℃, and the electroplating time can be 30min~120min.

[0064] It should be noted that in the above-mentioned active layer electroplating, changing the current density typically affects the deposition ratio of different metals because the numerical ratio of deposition potential to current density varies among different metals. In the technical solution of this invention, there is an optimal Ni / Zn ratio range. Exceeding this specific Ni / Zn ratio range will cause changes in the metal crystal structure in the alloy coating. Since the deposition potential of Zn is lower than that of Ni, as the current density increases, Zn is more likely to deposit on the metal substrate than Ni, thus changing the Ni / Zn alloy ratio and making it difficult to form an alloy coating dominated by the active phase NiZn3, thereby directly affecting the catalytic activity of the functional material. On the other hand, when the current density is 1 A / dm³... 2 ~5A / dm 2 This allows nickel and zinc ions to be stably reduced on the surface of the pre-plated metal substrate, forming a continuous coating. This is because if the current is too low, for example, <1 A / dm², it will prevent this. 2 If the deposition rate is too slow, local compositional fluctuations can easily occur due to plating bath convection, resulting in thickness deviations; if the current is too high, for example, >5A / dm 2 When the ion reduction rate exceeds the diffusion replenishment rate under high current, the nickel-zinc ion concentration on the substrate surface drops sharply, causing defects such as "burning" and pinholes in the coating. Simultaneously, in the electroplating process of this invention, the alkaline environment and specific complexation system also significantly affect the electroplating process of the active layer. Only under defined electroplating parameters, an alkaline environment, and a specific complexation system can the alloy coating described in this invention be formed and the target crystal form obtained. That is, there is a synergistic effect among the electroplating parameters, alkaline environment, and specific complexation system; if any one of these conditions is changed, it will significantly affect the metal crystal form and characteristics of the alloy coating.

[0065] It should be noted that in the above-mentioned active layer electroplating, when the temperature is 30℃~50℃, the diffusion of nickel-zinc complex ions to the substrate surface can be accelerated, ensuring that the depressions of complex-shaped substrates can also obtain sufficient ion supply, avoiding the problem of local lack of coating or excessively thin thickness; secondly, when the temperature is 30℃~50℃, the nickel-zinc atoms are more orderly arranged in the crystal lattice, which can reduce the lattice distortion caused by rapid deposition.

[0066] To achieve the above objectives, the present invention also provides a metal-based active material, which is prepared by the above-described preparation method.

[0067] The metal-based active material prepared by the above method has a high specific surface area and multiple active sites. This is because the nickel-zinc alloy coating formed during the active layer electroplating stage leaves a porous structure formed by zinc dissolution after zinc removal, and the pore size can be controlled by the nickel-zinc concentration ratio in the plating solution. Secondly, the complexation system in the second plating solution ensures that the nickel-zinc alloy coating is dense and uniform, and the pores formed after zinc removal are mostly three-dimensional interconnected. This structure is beneficial for the transport of substances and the escape of hydrogen bubbles in the hydrogen evolution reaction. In addition, the pre-plating treatment forms a pre-plating layer, and the nickel-zinc alloy coating of the active layer electroplating is gradient connected with the bottom layer. During the subsequent zinc removal process, the fine-grained structure controlled by the complexation system can avoid pore collapse or nickel particle agglomeration, so that the specific surface area of ​​the final metal-based active material can be controlled during long-term use, thus extending the service life of the material.

[0068] To achieve the above objectives, the present invention also provides an application of a metal-based active material, which is applied to hydrogen production by water electrolysis.

[0069] It should be noted that when the above-mentioned metal-based active materials are applied to hydrogen production by water electrolysis, the metal-based active materials can be used as cathode electrodes to carry out the hydrogen evolution reaction (HER) and produce hydrogen through water electrolysis.

[0070] In hydrogen production via water electrolysis, the porosity formed during the zinc stripping process of metal-based active materials can significantly increase the number of HER active sites exposed on the material surface. Meanwhile, when the Zn / Ni+Zn ratio in the alloy coating of the metal-based active material is 15%~25%, the zinc dissolved in the nickel lattice increases the electron density on the nickel surface, optimizes the adsorption strength of the HER reaction intermediate (H*), and can reduce the overpotential of the HER reaction.

[0071] Example 1 A method for preparing a metal-based active material includes the following steps: S10. The metal substrate is subjected to sandblasting, degreasing, and pickling in sequence; the details are as follows: The sand used for sandblasting has a particle size of 100 mesh. After sandblasting, the metal substrate is placed in a mixed aqueous solution of sodium hydroxide, sodium carbonate, sodium silicate, and trisodium phosphate, with the metal substrate as the cathode and the nickel plate as the anode, at a speed of 1 A / dm². 2 Under direct current conditions, the substrate was degreased for 30 minutes, with sodium hydroxide concentration of 50 g / L, sodium carbonate concentration of 10 g / L, sodium silicate concentration of 5 g / L, and trisodium phosphate concentration of 50 g / L. After degreasing, the metal substrate was immersed in 10 wt% hydrochloric acid for 10 minutes.

[0072] S20. A first plating solution with a pH of 6, consisting of 60 g / L nickel sulfate and 20 g / L sulfuric acid, is used to pre-plat the metal substrate that has passed S10; wherein, in the pre-plating treatment, the metal substrate is used as the cathode and the nickel plate as the anode, and the current density is 0.5 A / dm³. 2 Electroplating was performed at a bath temperature of 30℃ for 10 minutes to obtain a pre-plated metal substrate.

[0073] S30. Using a second plating solution with a pH of 8, consisting of 10 g / L nickel chloride, 10 g / L zinc sulfate, 5 g / L sodium citrate, 10 g / L glycine, and 10 g / L ammonium chloride, an active layer electroplating is performed on the pre-plated metal substrate obtained in S20. In the active layer electroplating, the pre-plated metal substrate is used as the cathode, and the nickel plate is used as the anode, at a current density of 1 A / dm³. 2 Electroplating was performed at a bath temperature of 30℃ for 120 minutes to obtain a metal-based alloy material.

[0074] S40. The metal-based alloy material obtained from S30 is subjected to heat treatment and zinc stripping treatment in sequence, specifically as follows: The metal-based alloy material obtained by S30 was placed in a muffle furnace and heated at a rate of 10℃ / min. When the temperature reached 200℃, it was held for 4 hours. After the temperature dropped to room temperature, the metal-based alloy material was taken out. Then, the metal-based alloy material was placed in 1M KOH and soaked at 40℃ for 12 hours to complete the zinc removal treatment and obtain the metal-based active material.

[0075] After S10~S40, the Zn / Ni+Zn ratio in the alloy coating of the metal-based active material is in the range of 15%~25%, specifically 18.89%.

[0076] Applying metal-based active materials obtained from S10 to S40 to hydrogen production via water electrolysis can increase the rate of hydrogen evolution reaction.

[0077] Comparative Example 1 is set up under Example 1. In Comparative Example 1, S10, S20 and S40 are the same as in Example 1.

[0078] In S30 of Comparative Example 1, the pH of the second plating solution was adjusted using hydrochloric acid to a value of 4.0-4.2. The nickel and zinc salts in the second plating solution were nickel chloride with a concentration of 251 g / L and zinc chloride with a concentration of 43 g / L, excluding the complexation system.

[0079] Metal-based materials are obtained through S10~S40.

[0080] XRD analysis was performed on the metal-based active material and metal-based material prepared in Example 1 and Comparative Example 1, respectively. The results are as follows: Figure 2 , Figure 3 As shown; where, Figure 2 The image shows the XRD pattern of the metal-based active material in Example 1. Figure 3 The image shows the XRD pattern of the metal-based material in Comparative Example 1.

[0081] Depend on Figure 2 It can be seen that strong diffraction peaks appear at 52.178°, 61.68°, 91.7°, 114.585°, and 123.04°, respectively, corresponding to the (1 1 1), (2 0 0), (2 2 0), (3 1 1), and (2 2 2) crystal planes of Ni (PDF#04-0850), which are single-crystal Ni signals of the metal substrate and alloy coating of the metal-based active material; secondly, the diffraction peaks appearing at 41.725°, 50.91°, 54.825°, and 56.715° correspond to the (11 2 0), (8 1 5), (6 4 2), and (0 2 6) crystal planes of NiZn3 (PDF#47-1019); in addition, the diffraction peaks at 94.795° and 121.21° correspond to Ni3Zn 22 (PDF#10-0209) has (4 2 6) and (6 2 2) crystal planes; and the diffraction peaks at 116.91° and 124.925° correspond to Ni5Zn. 21 (PDF#06-0653) has (8 2 2) and (7 52) crystal planes; the diffraction peak at 101.77° corresponds to the (2 0 0) crystal plane of Zn (PDF#04-0831); the diffraction peaks in the spectrum show slight shifts relative to the diffraction peak positions of the standard material, which is due to the coupling effect between the materials; according to the analysis, the metal-based active material prepared in Example 1 is a mixture of multiple crystal forms, among which the characteristic peak area of ​​NiZn3 is the widest, indicating that the obtained alloy coating is mainly composed of NiZn3 crystal form.

[0082] Depend on Figure 3It can be seen that the diffraction peaks at 31.769°, 34.421°, 36.252°, 47.538°, 56.602°, 62.862°, 67.961°, and 39.098° correspond to the (100), (002), (101), (102), (110), (103), (112), and (201) crystal planes of ZnO (PDF#36-1451); respectively at... The diffraction peaks at 37.245°, 43.275°, 62.861°, 75.392°, and 79.385° correspond to the (111), (200), (220), (311), and (222) crystal planes of NiO (PDF#71-1179). This indicates that the metal-based material prepared by the technique in Comparative Example 1 is a mixture of ZnO and NiO, without the formation of an alloy phase. This is because in the acidic plating solution, H... + High concentrations can easily trigger hydrogen evolution side reactions. In acidic systems, there are no complexing agents, so the deposition potential between metals cannot be brought closer. Therefore, only a single metal can be deposited, and almost no alloy phase is formed. When it comes into contact with oxygen in the air, its surface is oxidized to form ZnO and NiO.

[0083] X-ray photoelectron spectroscopy (XPS) analysis was performed on the metal-based active materials and metal-based materials obtained in Example 1 and Comparative Example 1, respectively. The results are as follows: Figure 4 As stated above.

[0084] Figure 4 In the diagram, sub-figure a is the Ni 2p spectrum, and sub-figure b is the Zn 2p spectrum.

[0085] Figure 4 In sub-figure a, the characteristic peak position of Ni 2p3 / 2 reflects the oxidation state and bonding environment of Ni. As shown in the figure, compared to Comparative Example 1, the binding energy of Ni 2p3 / 2 in Example 1 is higher, indicating that the electron cloud density around Ni atoms in the metal-based active material of Example 1 is lower, suggesting that the Ni in the metal-based active material of Example 1 has a lower binding energy. 3+ The content increases, while Ni 3+ It is the active center for hydrogen evolution, with higher Ni 3+ The ratio means that the material surface has more catalytically active sites, which can enhance the electrochemical reaction activity.

[0086] As shown in sub-figure b, the Zn 2p peak intensity of Example 1 is significantly higher than that of Comparative Example 1, indicating that the surface content of Zn in Example 1 is higher. This suggests that in the alloy coating of the metal-based active material prepared in Example 1, the distribution of Zn is more uniform and the content is more controllable. Furthermore, during the zinc stripping process, the electronic structure of nickel can be optimized through nickel-zinc electron interactions, thereby enhancing the performance of Ni. 3+ The content of these substances can ultimately enhance the electrocatalytic activity of metal-based active materials.

[0087] According to Figure 4 Analysis shows that in Comparative Example 1, when the second plating solution is acidic, the electroplated coating is oxidized by oxygen in the air, and is mainly composed of ZnO and NiO impurities. After zinc stripping treatment, Zn is dissolved, while the valence electrons of Ni remain basically unchanged. Therefore, the catalytic activity of the active sites does not increase.

[0088] Electron microscopy was performed on the metal-based alloy material obtained in S30 of Example 1, and the metal-based active material obtained after zinc stripping treatment in S40. The results are as follows: Figure 5 As shown; the metal matrix material obtained by S30 in Comparative Example 1 and the metal matrix material obtained after zinc stripping treatment by S40 were respectively subjected to electron microscopy scanning, and the results are as follows. Figure 6 As shown.

[0089] like Figure 5 As shown, sub-figure a is an electron microscope (EM) scan of the metal-based alloy material obtained by S30 in Example 1, and sub-figure b is an EEM scan of the metal-based active material obtained after zinc stripping treatment by S40. Sub-figure a shows that the surface of the metal-based alloy material obtained by S30 exhibits large-sized clusters or cellular structures, with individual clusters reaching several micrometers in diameter. There are obvious grooves or boundaries between the clusters, but the overall structure is relatively dense without significant porous structure. This morphology is the result of atomic layering growth during the electroplating deposition process. Sub-figure b shows that after zinc stripping treatment by S40, the large-sized clusters or cellular structures are transformed into a nanoscale porous network structure, composed of interconnected nanowires and nanoskeletons, with pore sizes ranging from tens to hundreds of nanometers. This indicates that zinc stripping treatment by S40 can remove some zinc from the alloy coating while retaining the nickel skeleton. Furthermore, the specific surface area of ​​the alloy coating is significantly increased after zinc stripping treatment, providing sufficient active sites and mass transfer channels for the electrocatalytic process.

[0090] like Figure 6 As shown, sub-figure a is an electron microscope scan of the metal-based material obtained by S30 in Comparative Example 1, and sub-figure b is an electron microscope scan of the metal-based material obtained after zinc stripping treatment by S40. As can be seen from sub-figure a, the surface of the metal-based alloy material obtained by S30 exhibits a micron-sized spherical agglomerate structure, with the size of a single agglomerate being approximately 1μm to 3μm. After zinc stripping treatment by S40, it transforms into a looser "particle agglomeration + porous" structure, which is rougher and more porous than before etching. This is because the coating of the metal-based material obtained by S30 in Comparative Example 1 is mainly composed of ZnO and NiO, and no alloy phase is formed. After zinc stripping treatment, some Zn is removed, and a porous structure and nickel skeleton cannot be formed.

[0091] The elemental composition of the metal-based alloy material obtained in S30 of Example 1 and the metal-based active material obtained in S40 were determined respectively; the elemental composition of the metal-based material obtained in S30 of Comparative Example 1 and the metal-based material obtained in S40 were determined respectively; the results are shown in Table 1.

[0092] Table 1

[0093] Analysis of the data in Table 1 shows that, firstly, compared with Comparative Example 1, the metal-based alloy material obtained in S30 of Example 1 has a higher proportion of Zn and Ni content, indicating a high degree of alloying in the alloy coating; while the proportion of Zn and Ni content in Comparative Example 1 is lower, indicating a poorer degree of alloying with almost no alloy phase formation; secondly, compared with Example 1, the proportion of O content in Comparative Example 1 is higher, indicating a higher proportion of oxide impurities in its alloy coating; furthermore, after zinc stripping treatment, the proportion of Zn content in Example 1 is significantly reduced, indicating a significant zinc stripping effect. At the same time, the proportion of Ni content increases and the proportion of O content decreases, indicating that in S30 of Example 1, during the active layer electroplating process, i.e., during the electroplating of the alloy coating, the degree of oxidation of the coating is low, and the alloy coating is mainly composed of Zn and Ni elements, with a Zn / Zn+Ni ratio of 18.89%; in contrast, after zinc stripping treatment, the Zn content in Comparative Example 1 increases instead of decreasing, and the proportion of O content is higher, indicating a poor zinc stripping effect.

[0094] Comparative Example 2 is set up under Example 1. S10 and S40 in Comparative Example 2 are the same as in Example 1.

[0095] In Comparative Example 2, S20, the electroplating current density was 3.5 A / dm³. 2 The pre-plating time is 15 minutes; In S30, the nickel and zinc salts in the second plating solution are nickel chloride (10 g / L) and zinc sulfate (10 g / L), respectively; the main complexing agent in the complexing system is sodium gluconate (5 g / L), the co-complexing agent is methionine (10 g / L), and the additive is sodium chloride (10 g / L); the plating solution is adjusted to be alkaline, with a pH value > 6; the second plating solution is used to perform active layer electroplating on the pre-plated metal substrate obtained in S20; wherein, in the active layer electroplating, the pre-plated metal substrate is used as the cathode, the nickel plate is used as the anode, and the current density is 0.5 A / dm³. 2 Electroplating was performed at a bath temperature of 25°C for 130 minutes to obtain a metal-based alloy material.

[0096] After passing through S10~S40, a metal-based material is obtained.

[0097] In Comparative Example 2, the main complexing agent of the complexing system can be replaced by at least one of potassium sodium tartrate, potassium gluconate and hydroxyethylidene diphosphonic acid, the co-complexing agent can be replaced by at least one of leucine, cysteine ​​and triethanolamine, and the additive can be replaced by at least one of ammonia and ammonium chloride.

[0098] The metal-based active materials obtained in Example 1 and Comparative Example 2 were applied to hydrogen production via water electrolysis, and their hydrogen evolution response (HER) performance was compared and analyzed using linear sweep voltammetry (LSV) curves. The results are as follows: Figure 7 As shown.

[0099] like Figure 7 The figure shows the relationship between current density and potential in hydrogen production by water electrolysis, i.e., the LSV curve. As can be seen from the figure, firstly, when the current density is -0.3 A / cm²... -2 When using the metal-based material of Comparative Example 2 as the cathode electrode, a potential of approximately -1.41V needs to be applied, while that of Example 1 is only -1.24V. This indicates that, at the same current density, using the metal-based active material of Example 1 as the cathode electrode for water electrolysis to produce hydrogen requires less additional potential and exhibits higher activity. Furthermore, when the current density is -0.5Acm... -2 When comparing the current density, Comparative Example 1 requires an overpotential of approximately -1.55V, while Example 1 only requires -1.39V. This indicates that the higher the current density, the more pronounced the overpotential advantage of the metal-based active material in Example 1, demonstrating its significant activity advantage at high reaction rates. Furthermore, the slope of the curve in the figure reflects the rate of change of current density with potential. The larger the slope, the faster the reaction kinetics. The slope of the curve in Example 1 is significantly greater than that in Comparative Example 2, indicating that the metal-based active material in Example 1 has superior reaction kinetics and a more efficient electron transfer process.

[0100] The metal-based material obtained in Comparative Example 2 was subjected to XRD, and the results are as follows: Figure 8 As shown.

[0101] Depend on Figure 8 It can be seen that the diffraction peaks at 41.725°, 50.91°, 54.825°, and 56.715° correspond to the (11 2 0), (8 1 5), (6 4 2), and (0 2 6) crystal planes of NiZn3 (PDF#47-1019), respectively; and the diffraction peaks at 94.795° and 121.21° correspond to the Ni3Zn 22 The (4 2 6) and (6 6 2) crystal planes of (PDF#10-0209) are compared with the XRD pattern of Example 1. It can be seen that the characteristic peak intensity of NiZn3 in this pattern is weaker, while the corresponding Ni3Zn 22The increase in peak intensity indicates that in the alloy coating of the metal-based material in Comparative Example 2, Ni3Zn... 22 The main crystal form is Ni, therefore, the Ni content in its alloy coating is... 3+ The low content of [something] will significantly reduce the reaction rate of metal-based materials in water electrolysis for hydrogen production.

[0102] Combination Figure 2 , Figure 3 and Figure 8 The analysis results show that, in the technical solution of this invention, if the electroplating parameters of the pre-plating treatment and / or active layer electroplating are changed, the acid-base environment of the second plating solution changes, or the complexing system is deleted or replaced, the composition or alloy crystal form of the electroplated layer will change significantly. Specifically, under the condition that other conditions remain unchanged, if the second plating solution is acidic and no complexing system is added, the electroplated layer will be mainly composed of ZnO and NiO impurities and will not be able to form an alloy phase. Under the condition that other conditions remain unchanged, if the electroplating conditions are changed, including changing the electroplating parameters of the pre-plating treatment and / or active layer electroplating, and at the same time replacing or deleting the components of the complexing system, the alloy coating will be mainly composed of Ni3Zn. 22 The crystalline form is dominant, and the content of NiZn3 will be significantly reduced. Therefore, in the technical solution of this invention, there is a synergistic effect among the electroplating parameters, the alkaline environment of the second plating solution, and the specific complexation system. These factors interact and assist each other during the preparation of the metal-based active material. If any one of these conditions is changed, the properties of the final active material will be reduced.

[0103] Comparative Example 3 was set up under Example 1.

[0104] In Comparative Example 3, S10, S20 and S30 are the same as in Example 1.

[0105] The difference between Comparative Example 3 and Example 1 is that, in S40, the metal-based alloy material obtained in S30 is subjected to direct zinc removal treatment. Specifically, the metal-based alloy material in S30 is placed in 1M KOH and immersed at 40°C for 12 hours to complete the zinc removal treatment and obtain the metal-based material.

[0106] The metal-based active material obtained in Example 1 and the metal-based material obtained in Comparative Example 3 were respectively applied to hydrogen production via water electrolysis. During the hydrogen production process, the cell pressure change over time was measured and plotted as a curve. The results are as follows: Figure 9 As shown.

[0107] like Figure 9The figure shows the cell pressure variation curve over time during the water electrolysis hydrogen production process. As can be seen from the figure, during the water electrolysis hydrogen production process, the cell pressure of Example 1 remained stable between 1.7V and 1.75V, and showed almost no increase during the 80-day test period, exhibiting extremely low and stable cell pressure. In contrast, the initial cell pressure of Comparative Example 2 was 1.8V, which then rose rapidly, exceeding 1.9V after 30 days, and the upward trend did not slow down, exhibiting the characteristics of high cell pressure and continuous increase. Therefore, compared with Comparative Example 3, applying the metal-based active material prepared in Example 1 to water electrolysis hydrogen production has the advantages of low energy consumption and high stability. This is because its porous structure and zinc residue can regulate the electronic structure and improve the coating adhesion, enabling it to maintain a high number and efficiency of active sites during long-term electrolysis, achieving significant advantages of low energy consumption and long lifespan.

[0108] Depend on Figure 9 The analysis results show that, compared with Comparative Example 3, the metal-based active material obtained in Example 1 has superior performance in hydrogen production by water electrolysis. This is because, compared with Example 1, the technical solution of Comparative Example 3 adopts direct zinc stripping treatment, which leads to the rapid dissolution of Zn, leaving a "sponge-like" framework composed of original fine Ni grains. The microstructure of this framework is prone to collapse and recombination, which leads to the disappearance of porous structures in some areas, a significant decrease in reaction area, and easy dissolution during long-term operation, resulting in reduced catalytic activity. Furthermore, due to the lack of metal oxides, the hydrolysis reaction is inhibited, and the apparent activity of the hydrogen evolution reaction is low.

[0109] Analysis of Examples 1, 1, 2, and 3 reveals that in the technical solution of this invention, the complexation system of the second plating solution, the alkaline environment, and the electroplating parameters during the electroplating process all significantly affect the formed alloy coating. Furthermore, only when the second plating solution is alkaline and contains a specific complexing agent can the resulting alloy coating, after heat treatment and zinc stripping, achieve a Zn / Zn+Ni ratio of 15% to 25% in the alloy coating of the obtained metal-based active material. Simultaneously, only under specific electroplating parameter conditions can the obtained metal-based alloy material, after heat treatment and zinc stripping, achieve a Ni ratio of 15% to 25%. 3+ Only when the content of Ni is at a high level can it be achieved; therefore, in the technical solution of this invention, the alkaline environment of the second plating solution, the complexation system, the electroplating conditions, the heat treatment, and the zinc stripping treatment have a synergistic effect, resulting in a uniform distribution of the gap structure of the final metal-based active material and containing a large amount of Ni. 3+ This allows for effective optimization of the HER performance in water electrolysis for hydrogen production.

[0110] Example 2 A method for preparing a metal-based active material includes the following steps: S10. The metal substrate is subjected to sandblasting, degreasing, and pickling in sequence; the details are as follows: The sand used for sandblasting has a particle size of 100 mesh. After sandblasting, the metal substrate is placed in a mixed aqueous solution of sodium hydroxide, sodium carbonate, sodium silicate, and trisodium phosphate, with the metal substrate as the cathode and the nickel plate as the anode, at a speed of 1 A / dm². 2 Under direct current conditions, the substrate was degreased for 30 minutes, with sodium hydroxide concentration of 50 g / L, sodium carbonate concentration of 10 g / L, sodium silicate concentration of 5 g / L, and trisodium phosphate concentration of 50 g / L. After degreasing, the metal substrate was immersed in 10 wt% hydrochloric acid for 10 minutes.

[0111] S20. A pre-plating treatment is performed on the metal substrate treated in S10 using a first plating solution with a pH of 3, consisting of 60 g / L nickel sulfate and 20 g / L sulfuric acid; wherein, in the pre-plating treatment, the metal substrate is used as the cathode and the nickel plate as the anode, and the current density is 0.5 A / dm³. 2 Electroplating was performed at a bath temperature of 30°C for 2 minutes to obtain a pre-plated metal substrate.

[0112] S30. Using a second plating solution with a pH of 8, consisting of 10 g / L nickel chloride, 10 g / L zinc sulfate, 5 g / L sodium citrate, 15 g / L glutamic acid, and 20 g / L sodium chloride, an active layer electroplating is performed on the pre-plated metal substrate obtained in S20. In the active layer electroplating, the pre-plated metal substrate is used as the cathode, and the nickel plate is used as the anode, at a current density of 1 A / dm³. 2 Electroplating was performed at a bath temperature of 30℃ for 30 minutes to obtain a metal-based alloy material.

[0113] S40. The metal-based alloy material obtained from S30 is subjected to heat treatment and zinc stripping treatment in sequence, specifically as follows: The metal-based alloy material obtained by S30 was placed in a muffle furnace and heated at a rate of 10℃ / min. When the temperature reached 200℃, it was held for 4 hours. After the temperature dropped to room temperature, the metal-based alloy material was taken out. Then, the metal-based alloy material was placed in 1M KOH and soaked at 40℃ for 12 hours to complete the zinc removal treatment and obtain the metal-based active material.

[0114] After S10~S40, the Zn / Ni+Zn ratio in the alloy coating of the metal-based active material is 15%~25%.

[0115] Metal-based active materials obtained from S10 to S40 were applied to hydrogen production via water electrolysis, serving as the cathode electrode for the hydrogen evolution reaction. The overpotential during the reaction was measured as a function of the Zn / Ni+Zn (%) atomic mass ratio. The results are as follows: Figure 10 As shown.

[0116] Depend on Figure 10 It can be seen that when the zinc / (nickel + zinc) element ratio deviates from 15% to 25%, for example when the zinc / (nickel + zinc) element ratio is less than 15% or greater than 25%, the overpotential increases significantly, exceeding 350 mV at its highest. When the zinc / (nickel + zinc) element ratio is within the range of 15% to 25%, the overpotential drops to its lowest level, about 180 mV to 200 mV, and the curve is stable, indicating that the catalytic activity is optimal and stable within this range.

[0117] according to Figure 10 Analysis results show that, in the technical solution of this invention, after zinc stripping, the residual Zn can enhance the d-band center of Ni through solid solution strengthening and electronic effects, thereby reducing the adsorption energy barrier of Ni for electrocatalytic reaction intermediates, such as hydrogen evolution H*, and thus reducing overpotential.

[0118] Example 3 A method for preparing a metal-based active material includes the following steps: S10. The metal substrate is subjected to sandblasting, degreasing, and pickling in sequence; the details are as follows: The sand used for sandblasting has a particle size of 150 mesh. After sandblasting, the metal substrate is placed in a mixed aqueous solution of sodium hydroxide, sodium carbonate, sodium silicate, and trisodium phosphate, with the metal substrate as the cathode and the nickel plate as the anode, at a pressure of 1.5 A / dm³. 2 Under direct current conditions, the substrate was degreased for 25 minutes, with sodium hydroxide concentration of 60 g / L, sodium carbonate concentration of 30 g / L, sodium silicate concentration of 10 g / L, and trisodium phosphate concentration of 60 g / L. After degreasing, the metal substrate was immersed in 20 wt% hydrochloric acid for 15 minutes.

[0119] S20. A pre-plating treatment is performed on the metal substrate treated in S10 using a first plating solution with a pH of 5, consisting of 80 g / L nickel chloride and 50 g / L hydrochloric acid; wherein, in the pre-plating treatment, the metal substrate is used as the cathode and the nickel plate as the anode, and the current density is 1.5 A / dm³. 2 Electroplating was performed at a bath temperature of 40℃ for 10 minutes to obtain a pre-plated metal substrate.

[0120] S30. Using a second plating solution with a pH of 8.2, consisting of 10 g / L nickel sulfate, 10 g / L zinc chloride, 5 g / L potassium pyrophosphate, 15 g / L glycine, and 20 g / L ammonium chloride, an active layer electroplating is performed on the pre-plated metal substrate obtained in S20. In this active layer electroplating, the pre-plated metal substrate is used as the cathode, and the nickel plate as the anode, at a current density of 3.0 A / dm³. 2Electroplating was performed at a bath temperature of 40℃ for 50 minutes to obtain a metal-based alloy material.

[0121] S40. The metal-based alloy material obtained from S30 is subjected to heat treatment and zinc stripping treatment in sequence, specifically as follows: The metal-based alloy material obtained by S30 was placed in a muffle furnace and heated at a rate of 10℃ / min. When the temperature reached 300℃, it was held for 3 hours. After the temperature dropped to room temperature, the metal-based alloy material was taken out. Then, the metal-based alloy material was placed in 1M KOH and soaked at 30℃ for 30 hours to complete the zinc removal treatment and obtain the metal-based active material.

[0122] After S10~S40, the Zn / Ni+Zn ratio in the alloy coating of the metal-based active material is 15%~25%.

[0123] Applying metal-based active materials obtained from S10 to S40 to hydrogen production via water electrolysis as cathode electrodes can accelerate the hydrogen evolution reaction rate and exhibit high stability.

[0124] Example 4 A method for preparing a metal-based active material includes the following steps: S10. The metal substrate is subjected to sandblasting, degreasing, and pickling in sequence; the details are as follows: The sand used for sandblasting has a particle size of 200 mesh. After sandblasting, the metal substrate is placed in a mixed aqueous solution of sodium hydroxide, sodium carbonate, sodium silicate, and trisodium phosphate, with the metal substrate as the cathode and the nickel plate as the anode, at a temperature of 5 A / dm². 2 Under direct current conditions, the substrate was degreased for 30 minutes, with sodium hydroxide concentration of 100 g / L, sodium carbonate concentration of 40 g / L, sodium silicate concentration of 15 g / L, and trisodium phosphate concentration of 100 g / L. After degreasing, the metal substrate was immersed in 40 wt% hydrochloric acid for 20 minutes.

[0125] S20. A pre-plating treatment is performed on the metal substrate treated in S10 using a first plating solution with a pH of 6, consisting of 80 g / L nickel chloride, 220 g / L nickel chloride, 50 g / L sulfuric acid, and 50 g / L hydrochloric acid; wherein, in the pre-plating treatment, the metal substrate is used as the cathode, the nickel plate is used as the anode, and the current density is 3 A / dm³. 2 Electroplating was performed at a bath temperature of 50°C for 8 minutes to obtain a pre-plated metal substrate.

[0126] S30. Using a second plating solution with a pH of 10, consisting of 10 g / L nickel sulfate, 20 g / L nickel nitrate, and 70 g / L nickel acetate; 10 g / L zinc chloride, 10 g / L zinc nitrate, and 10 g / L zinc acetate; 5 g / L potassium pyrophosphate and 5 g / L disodium hydrogen phosphate; 15 g / L glycine and 15 g / L glutamic acid; and 20 g / L ammonium chloride and 10 g / L sodium chloride, the pre-plated metal substrate obtained in S20 is subjected to active layer electroplating. In the active layer electroplating, the pre-plated metal substrate is used as the cathode, and the nickel plate is used as the anode, at a current density of 5.0 A / dm³. 2 Electroplating was performed at a bath temperature of 50℃ for 45 minutes to obtain a metal-based alloy material.

[0127] S40. The metal-based alloy material obtained from S30 is subjected to heat treatment and zinc stripping treatment in sequence, specifically as follows: The metal-based alloy material obtained by S30 was placed in a muffle furnace and heated at a rate of 10℃ / min. When the temperature reached 400℃, it was held for 1 hour. After the temperature dropped to room temperature, the metal-based alloy material was taken out. Then, the metal-based alloy material was placed in 1M KOH and soaked at 20℃ for 48 hours to complete the zinc removal treatment and obtain the metal-based active material.

[0128] After S10~S40, the Zn / Ni+Zn ratio in the coating of the metal-based active material is 15%~25%.

[0129] Applying metal-based active materials obtained from S10 to S40 to hydrogen production via water electrolysis as cathode electrodes can accelerate the hydrogen evolution reaction rate and exhibit high stability.

[0130] The metal-based active materials prepared in Examples 1-4 and the metal-based materials prepared in Comparative Examples 1-3 were applied to hydrogen production via water electrolysis. Their hydrogen evolution performance was tested using a three-electrode system and compared with that of commercial nickel mesh, as detailed below: In the three-electrode system, the counter electrode is a platinum mesh, the reference electrode is an Hg / HgO electrode, and the working electrode is the metal-based active material prepared in Examples 1-4, or the metal-based material prepared in Comparative Examples 1-3, or a commercial nickel mesh, with a size of 1cm × 1cm; the electrolyte is a 1mol / L KOH solution; the test temperature is 80℃, and the test current density is 5000A / m. 2 The reference electrode is in contact with the electrolyte through a salt bridge, and the results are shown in Table 2.

[0131] Table 2

[0132] Analysis of the data in Table 2 shows that the hydrogen evolution potential reduction in Examples 1-4 was between 220 and 250 mV, which is much higher than that in Comparative Examples 1-3. This is because the porous nickel structure formed by zinc stripping in Examples 1-4 significantly increases the specific surface area, which is several times that of commercial nickel mesh, providing more active sites for the hydrogen evolution reaction. Secondly, the zinc remaining after zinc stripping optimizes the d-band center of nickel through solid solution effect, reducing the adsorption energy barrier of H* in the hydrogen evolution reaction, thereby reducing the overpotential. In addition, the pre-plating treatment enhances the adhesion between the plating layer and the substrate, and the nickel-zinc alloy layer electroplated in the active layer is densely crystalline, making it less prone to loss of active sites during long-term reactions, thus ensuring the stability of high activity.

[0133] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A method for preparing a metal-based active material, characterized in that, The preparation method includes the following steps: The metal substrate is pre-plated using the first plating solution to obtain a pre-plated metal substrate; The pre-plated metal substrate is electroplated with an active layer using a second plating solution to obtain a metal-based alloy material. The metal-based alloy material is subjected to heat treatment and zinc stripping treatment in sequence to obtain the metal-based active material; The ratio of the atomic mass of Zn to the sum of the atomic masses of Zn and Ni in the alloy coating of the metal-based active material is 15% to 25%. The second plating solution is alkaline and includes nickel salt, zinc salt, and a complexing system. The concentration of nickel salt in the second plating solution is 10 g / L to 100 g / L, the concentration of zinc salt is 10 g / L to 50 g / L, and the concentration of the complexing system is 5 g / L to 300 g / L. The complexing system consists of a main complexing agent, a co-complexing agent, and additives. The primary complexing agent is sodium citrate; the co-complexing agent is glycine and / or glutamic acid; the additive is at least one of ammonium chloride and sodium chloride. The current density for electroplating the active layer is 1 A / dm. 2 ~5A / dm 2 The plating solution temperature is 30℃~50℃, and the electroplating time is 30min~120min; The heat treatment and zinc stripping treatment are carried out based on the following steps: The metal-based alloy material is placed in a heating device and heated to a preset temperature at a preset rate. Then, it is kept at the preset temperature. After the heat treatment is completed, the heat treatment is finished. The heat-treated metal-based alloy material is placed in an alkaline solution and immersed at ≤40°C for a preset time to complete the zinc stripping process. The preset rate is 8℃ / min ~ 12℃ / min, the preset temperature is 200℃ ~ 400℃, the heat preservation time is 1h ~ 4h, and the preset duration is 12h ~ 48h.

2. The preparation method according to claim 1, characterized in that, The current density of the pre-plating treatment is 0.5 A / dm. 2 ~3A / dm 2 The plating solution temperature is 30℃~50℃, and the electroplating time is 2min~10min.

3. A metal-based active material, characterized in that, The metal-based active material is prepared by the preparation method according to any one of claims 1 to 2.

4. An application of a metal-based active material, characterized in that, The metal-based active material described in claim 3 is applied to hydrogen production via water electrolysis.

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