High-performance Raney nickel net oxygen evolution electrode based on time sequence step-by-step chemical conversion and preparation method of high-performance Raney nickel net oxygen evolution electrode

Abstract

The invention discloses a high-performance Raney nickel net oxygen evolution electrode based on time sequence step-by-step chemical conversion. The high-performance Raney nickel net oxygen evolution electrode is obtained by sequentially constructing an interface stable layer on a substrate Raney nickel net through a step-by-step chemical impregnation method and then growing a catalytic functional layer, the interface stable layer precursor solution comprises at least one of cerium ions, lanthanum ions and yttrium ions; the catalytic functional layer precursor solution comprises main active metal ions and coordinated regulation element ions, the main active metal ions comprise nickel ions and iron ions or nickel ions and ferrous ions, and the coordinated regulation element ions comprise at least one of cobalt ions, manganese ions and vanadium ions. The Raney nickel net oxygen evolution electrode has a gradient composite structure in which the interface stable layer and the catalytic functional layer are tightly combined, the microstructure, the macroscopic performance and the long-term stability are remarkably optimized, and the preparation process is suitable for industrial large-scale production; and a feasible solution is provided for the technical bottleneck restricting the development of the industrial oxygen evolution electrode.

Description

Technical Field

[0001] This invention relates to the field of Raney nickel mesh oxygen evolution electrode preparation technology, specifically to a high-performance Raney nickel mesh oxygen evolution electrode based on time-series stepwise chemical transformation, and its preparation method. Background Technology

[0002] The oxygen evolution reaction (OER) is the core anodic half-reaction in alkaline water electrolysis for hydrogen production, coupled with the hydrogen evolution reaction (HER) at the cathode to complete the electrolytic decomposition of water. Raney nickel mesh is one of the most widely used OER electrodes in industrial alkaline water electrolysis for hydrogen production. Using Raney nickel as the catalytically active matrix, it leverages its porous structure and nickel-based catalytic properties to achieve the oxygen evolution process. However, its intrinsic catalytic activity and long-term stability are insufficient, directly limiting the overall energy efficiency and service life of the electrolyzer. Currently, two main modification methods exist to improve the catalytic performance of Raney nickel mesh, but both have significant drawbacks.

[0003] Electrodeposition (electroplating): This is a commonly used modification process, but its fundamental drawback is that it relies on an external electric field, making it difficult to achieve full and uniform deposition coverage on Raney nickel mesh with a complex three-dimensional porous structure during industrial-scale production. Moreover, the electrodeposition process is a "physical / electrochemical adhesion" process, and the resulting coating has a weak bond with the Raney nickel substrate. Under industrial conditions of high current density and long-term operation, this uneven and poorly bonded coating is prone to problems such as local peeling and dissolution of active components, leading to rapid degradation of electrode performance.

[0004] Hydrothermal / solvothermal method: This method can synthesize high-performance materials in laboratory research, but its stringent requirements for high-pressure closed reaction conditions and the safety requirements and risks of high-pressure reactor equipment for industrial scale-up production severely limit its practicality in the industrial-scale modification of Raney nickel mesh electrodes.

[0005] Therefore, developing a modification process that can overcome the limitations of electric field and high voltage, is safe to operate, and is easy to scale up industrially, to achieve full-domain, uniform, and robust modification and optimization of Raney nickel mesh, is a technological innovation that fundamentally improves the catalytic activity and long-term operational stability of Raney nickel mesh. Summary of the Invention

[0006] This invention addresses the limitations in practicality, intrinsic catalytic activity, and long-term stability of industrially modified Raney nickel mesh oxygen evolution electrodes. It provides a high-performance Raney nickel mesh oxygen evolution electrode by employing a chemical potential-driven, atmospheric pressure liquid-phase impregnation process that sequentially constructs an "interface stabilization layer" and a "catalytic functional layer" on a Raney nickel mesh substrate in a time-series manner. This achieves a gradient composite structure with a tight integration of the two layers, resulting in a Raney nickel mesh oxygen evolution electrode with significantly optimized microstructure, macroscopic performance, and long-term stability. Furthermore, this preparation process is suitable for large-scale industrial production, providing a feasible solution to the technical bottlenecks restricting the development of industrial oxygen evolution electrodes.

[0007] To achieve the above objectives, the present invention provides a high-performance Raney nickel mesh oxygen evolution electrode based on time-series stepwise chemical transformation. This electrode is obtained by sequentially constructing an interface stabilizing layer on a Raney nickel mesh substrate using a stepwise chemical impregnation method, followed by the growth of a catalytic functional layer. The interface stabilizing layer precursor solution used for constructing the interface stabilizing layer contains at least one of cerium ions, lanthanum ions, and yttrium ions. The catalytic functional layer precursor solution used for growing the catalytic functional layer contains a main active metal ion and synergistic regulating element ions. The main active metal ions include nickel ions and iron ions, or nickel ions and ferrous ions, and the synergistic regulating element ions include at least one of cobalt ions, manganese ions, and vanadium ions.

[0008] This invention employs a chemical potential-driven, atmospheric pressure chemical impregnation method that requires no external electric field to sequentially construct an "interface stabilization layer" and a "catalytic functional layer" on a Raney nickel mesh substrate in a time sequence. This forms a gradient composite structure in which the interface stabilization layer and the catalytic functional layer are tightly bonded. The surface and internal pores of the Raney nickel mesh are completely covered by continuous, dense, and uniform deposits, while maintaining the integrity of the pore structure. This effectively solves the problems of low utilization rate of deep pores, poor long-term stability of the catalyst-substrate interface, and insufficient intrinsic activity of active sites in existing industrial Raney nickel mesh electrodes, resulting in a highly active and stable oxygen evolution electrode that can be industrially scaled up.

[0009] The interface stabilizing layer precursor solution utilizes the interaction between Ce / La / Y ions and Ni atoms on the substrate surface to form strong Ni-O-Ce / La / Y interfacial chemical bonds, constructing an "interfacial stabilizing layer" with both strong adhesion and stress dispersion capabilities, achieving a transformation from physical adhesion to atomic-level chemical bonding. Driven by the chemical potential of the catalytic functional layer precursor solution, Ni... 2 + Fe 3+ Fe 2+ Plasma is deposited and grown in situ on the constructed stable layer, and is strongly coupled with the underlying layer through Ce / La / YOM (M = active metal, including the main active metal and cooperating elements) chemical bonds, ultimately forming a "catalytic functional layer" with gradient changes in composition and function.

[0010] As a limitation of the above technical solution, the cerium salt providing cerium ions is selected from at least one of cerium nitrate, cerium chloride, and cerium sulfate; the lanthanum salt providing lanthanum ions is selected from at least one of lanthanum nitrate, lanthanum chloride, and lanthanum sulfate; the yttrium salt providing yttrium ions is selected from at least one of yttrium nitrate, yttrium chloride, and yttrium sulfate; and / or, the nickel salt providing nickel ions is selected from at least one of nickel chloride, nickel nitrate, and nickel sulfate; the iron salt providing ferric ions is selected from at least one of ferric chloride, ferric nitrate, and ferric sulfate; the ferrous salt providing ferrous ions is selected from at least one of ferrous chloride, ferrous nitrate, and ferrous sulfate; and / or, the cobalt salt providing cobalt ions is selected from at least one of cobalt chloride, cobalt nitrate, and cobalt sulfate; the manganese salt providing manganese ions is selected from at least one of manganese chloride, manganese nitrate, and manganese sulfate; and the vanadium salt providing vanadium ions is selected from at least one of ammonium metavanadate, vanadium oxysulfate, and sodium vanadate.

[0011] As a limitation of the above technical solution, the total concentration of cerium ions, lanthanum ions, and yttrium ions in the interface stabilization layer precursor solution is 0.05~0.5 mol / L.

[0012] As a limitation of the above technical solution, the total concentration of the main active metal ions in the catalyst functional layer precursor solution is 0.1~1.0 mol / L; and / or, the molar ratio of nickel ions to iron ions or nickel ions to ferrous ions in the main active metal ions is 2~15:1; and / or, the total concentration of the synergistic regulatory element ions is 1~50% of the total molar amount of the main active metal ions.

[0013] The raw materials providing various ions in the precursor solution are optimized to ensure the smooth impregnation reaction of the Raney nickel mesh in the precursor solution. The concentrations of different functional ions in the precursor solution are limited. When using a single ion, the concentration of the single ion is controlled to meet the total concentration requirement; when using multiple elemental ions, the sum of the concentrations of the multiple elements is controlled to meet the total concentration requirement. Furthermore, the ratio of nickel ions to iron / ferrous ions used for the main active metal ion is limited, while the ratio of other multi-element composites does not need to be limited, thereby improving the activity and stability of the Raney nickel mesh oxygen evolution electrode.

[0014] As a limitation of the above technical solution, the catalyst functional layer precursor solution also contains doped anions. Preferably, the amount of doped anions is 10 to 100% of the total molar amount of the main active metal ions and the synergistic regulatory element ions in the catalyst functional layer precursor solution.

[0015] As a limitation of the above technical solution, the doped anion includes at least one of phosphorus ion, sulfur ion, and selenium ion. Preferably, the compound providing phosphorus ion, sulfur ion, and selenium ion is selected from at least one of hypophosphite, phosphate, thiosulfate, sulfide, thiourea, selenite, and selenourea.

[0016] When phosphorus, sulfur, and selenium-containing doped anions are introduced into the precursor solution of the catalytic functional layer, the reaction system will open up a rapid interfacial chemical transformation pathway that is different from the traditional metal hydroxyl deposition. The doped anions can significantly reduce the interfacial nucleation energy barrier in the early stage of the reaction, accelerate the deposition of metal species on the surface of the interfacial stabilization layer, and promote the chemical transformation process.

[0017] As a limitation of the above technical solution, a complexing agent is added to the precursor solution of the catalytic functional layer. Preferably, the complexing agent is selected from at least one of citric acid, citrate, tartaric acid, tartrate, ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid salt, and aminotriacetic acid; and / or, the amount of complexing agent added is 10 to 150% of the total molar amount of the main active metal ions and the synergistic regulatory element ions, preferably 30 to 100%.

[0018] As a limitation of the above technical solution, the pH value of the catalytic functional layer precursor solution is 4.0~7.0, preferably 5.0~6.5.

[0019] The use of complexing agents in the precursor solution of the catalytic functional layer not only stabilizes metal ions, but also regulates the effective release rate of metal species such as nickel and iron by forming reversible complex structures during the stepwise chemical transformation process in a time series. This inhibits rapid hydrolysis and homogeneous precipitation in the early stage of the reaction, making the deposition process more inclined to heterogeneous nucleation on the surface of the interface stabilization layer and accompanied by continuous deposition. At the same time, the stepwise decomposition of the complexing agent also helps to reduce the proportion of weakly coordinated or unstable bound metal species, and synergistically improves the binding state between the catalytic functional layer and the substrate with the interface stabilization layer, thereby improving structural stability while ensuring the effective construction of active sites.

[0020] Meanwhile, this invention also provides a method for preparing a high-performance Raney nickel mesh oxygen evolution electrode based on time-series stepwise chemical transformation, comprising the following preparation steps: a. Preparation of precursor solutions: Prepare interface stabilizing layer precursor solution and catalytic functional layer precursor solution that meet the concentration requirements respectively; preferably, the preparation of catalytic functional layer precursor solution requires first dissolving the main active metal ions and synergistic regulatory element ions, then adding the complexing agent, and adjusting the pH value with ammonia. b. Modification of Raney nickel mesh by stepwise chemical transformation according to time series: The first step is to construct the interface stabilization layer: Immerse the Raney nickel mesh in the interface stabilization layer precursor solution and react at 80~95℃ for 6~48h to complete the construction of the interface stabilization layer. Then remove it and wash it with water. The second step is to grow the catalytic functional layer: The Raney nickel mesh with an interface stabilization layer is immersed in the catalytic functional layer precursor solution and reacted at 80~95℃ for 2~10h to complete the growth of the catalytic functional layer. Then it is taken out, washed with water and dried to obtain the Raney nickel mesh oxygen evolution electrode. Preferably, when the functional layer precursor solution contains doped anions, the catalytic functional layer is grown at 80~95℃ for 1~10min.

[0021] The high-performance Raney nickel mesh oxygen evolution electrode of this invention is prepared by a stepwise chemical conversion method based on a time sequence. Adding doped anions to the precursor solution of the catalytic functional layer allows for uniform growth of the catalytic functional layer within minutes, significantly shortening the preparation cycle. However, both the interface stabilization layer precursor solution and the catalytic functional layer precursor solution are chemically active, especially in the reaction system with added doped anions, where their chemical activity is greatly enhanced. Further extending the reaction time may lead to corrosion or structural reconstruction of the substrate. Therefore, this invention further precisely controls the chemical conversion reaction time, keeping the reaction process within a kinetic time window more conducive to the construction of the interface stabilization layer and the catalytic functional layer, avoiding substrate degradation, and ensuring significant optimization of the electrode's microstructure, macroscopic performance, and long-term stability.

[0022] As a limitation of the above technical solution, the Raney nickel mesh is pretreated by acid washing and activation before modification. Preferably, the Raney nickel mesh is ultrasonically cleaned with acetone and ethanol respectively, then immersed in HCl solution for acid washing, and then taken out, cleaned and dried.

[0023] Improve the acid washing and activation pretreatment operation before chemical impregnation modification of Raney nickel mesh. This is used to remove oil and oxide layer from the surface of Raney nickel mesh, expose the highly reactive fresh nickel skeleton, provide a clean interface for the subsequent formation of strong chemical bonds, facilitate the subsequent stepwise chemical conversion reaction, optimize the electrode structure, and improve application performance.

[0024] In summary, the Raney nickel mesh oxygen evolution electrode of the present invention possesses a gradient composite structure in which the interface stabilizing layer and the catalytic functional layer are tightly integrated, and uniform loading is achieved on both the outer surface and deep channels of the three-dimensional porous framework of the Raney nickel mesh. These structural advantages enable the electrode to exhibit excellent oxygen evolution catalytic activity and long-term stability under strongly alkaline environments and high current densities. Furthermore, the preparation process of the present invention is mild, simple to operate, and low in cost, possessing promising industrial application prospects and providing a feasible solution to the technical bottleneck restricting the development of industrial oxygen evolution electrodes. Attached Figure Description

[0025] Figure 1 This is a cross-sectional SEM-EDS line scan analysis image of the Ni-Fe-Ce-Co multi-component Raney nickel mesh oxygen evolution electrode in Example 1.

[0026] Figure 2SEM images of the surface morphology of each electrode in Comparative Example 1 (A), Example 1 (B), and Example 4 (C).

[0027] Figure 3 The cyclic voltammetry curves of each electrode in the non-Radidatic region for Example 1 (A), Comparative Example 2 (B), and Comparative Example 3 (C) are shown; as well as the double-layer capacitance C of each electrode in Example 1, Comparative Example 2, and Comparative Example 3. dl Comparison with electrochemically active area ECSA (D).

[0028] Figure 4 Linear sweep voltammetric curves of the oxygen evolution reaction for each electrode in Examples 1-5 and Comparative Examples 1-5 are shown.

[0029] Figure 5 The electrodes of Examples 1-5 and Comparative Examples 1-5 were used at 500 mA / cm 2 The results of a long-term stability test at current density for 1000 hours are shown in the figure.

[0030] Figure 6 This is a comparison chart of the ICP-MS dissolution concentrations of iron ions and stabilizing layer ions in the working solution after the stability tests of the electrodes in Examples 1, 3, and Comparative Example 2.

[0031] Figure 7 The in-situ Raman spectra of the electrode in Example 1 are shown in the initial state, after electrochemical activation, and after 1000 hours of stability testing.

[0032] Figure 8 Macroscopic photographs (A-B) and elemental mapping comparison diagrams (C-D) of the electrodes of Example 5 and Comparative Example 4. Detailed Implementation

[0033] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] Unless otherwise specified, the experimental methods described below are conventional methods; the raw materials or test materials used are typical products purchased from the market, unless otherwise specified. In the quantitative experiments of the following examples and comparative examples, three replicate experiments were conducted, and the results were averaged.

[0035] Example High-performance Raney nickel mesh oxygen evolution electrodes are prepared using an atmospheric pressure liquid-phase impregnation process driven by chemical potential and requiring no external electric field.

[0036] Example 1

[0037] A Ni-Fe-Ce-Co multi-component Raney nickel mesh oxygen evolution electrode is prepared as follows.

[0038] s. Substrate pretreatment: The Raney nickel mesh (60 mesh, area 1cm×1.5cm, effective reaction area 1cm×1cm) was ultrasonically cleaned with acetone and ethanol respectively, then immersed in 1.0 M HCl solution for acid washing for 5 minutes, removed, cleaned with deionized water, and vacuum dried at 60℃ (in actual applications, the drying conditions of the preparation process can be the conventional industrial conditions).

[0039] a. Preparation of the precursor solution: Precursor solution for interfacial stabilization layer: Weigh CeCl3·6H2O and dissolve it in deionized water to prepare a CeCl3·6H2O solution with a concentration of 0.1 mol / L; Catalytic functional layer precursor solution: Weigh out Ni(NO3)2·6H2O, FeCl3·6H2O and CoCl2·6H2O respectively, mix them, dissolve them in deionized water, and prepare a mixed solution with concentrations of 0.2 mol / L for Ni(NO3)2·6H2O, 0.02 mol / L for FeCl3·6H2O and 0.05 mol / L for CoCl2·6H2O; then add citric acid (C6H8O7) to the mixed solution to make the concentration of citric acid in the mixed solution reach 0.135 mol / L (that is, the molar amount of citric acid added is 50% of the total molar amount of Ni, Fe and Co ions in the mixed solution); finally, under continuous stirring, slowly add ammonia water to adjust the pH of the mixed solution to 5.5.

[0040] b. Modification of Raney nickel mesh electrodes through stepwise chemical transformation according to time series: The first step is to construct the interface stabilization layer: the pretreated Raney nickel mesh is immersed in the interface stabilization layer precursor solution and reacted at 85°C for 12 hours to complete the construction of the interface stabilization layer. Then it is taken out and washed with deionized water. The second step is to grow the catalytic functional layer: The Raney nickel mesh with an interface stabilization layer is immersed in the catalytic functional layer precursor solution and reacted at 90°C for 10 hours to complete the growth of the catalytic functional layer. Then it is taken out, washed with deionized water, and vacuum dried at 60°C to obtain the Ni-Fe-Ce-Co multi-element composite Raney nickel mesh oxygen evolution electrode.

[0041] Example 2

[0042] A Ni-Fe-La-Mn-Se multi-element composite Raney nickel mesh oxygen evolution electrode is prepared using the following process.

[0043] s. Substrate pretreatment: Same as in Example 1.

[0044] a. Preparation of the precursor solution: Precursor solution for interfacial stabilization layer: Weigh La(NO3)3·6H2O and dissolve it in deionized water to prepare a La(NO3)3·6H2O solution with a concentration of 0.15mol / L; Catalytic functional layer precursor solution: Weigh out NiSO4·6H2O, FeCl2·4H2O, MnCl2·4H2O and CH4N2Se respectively, mix them, dissolve them in deionized water, and prepare mixed solutions with concentrations of 0.15 mol / L NiSO4·6H2O, 0.01 mol / L FeCl2·4H2O, 0.04 mol / L MnCl2·4H2O and 0.15 mol / L CH4N2Se respectively; then add ammonium citrate ((NH4)3C6H5O7) and aminotriacetic acid (NTA) to the mixed solution to make the concentration of ammonium citrate reach 0.04 mol / L (that is, the molar amount of ammonium citrate added is 20% of the total molar amount of Ni, Fe and Mn ions in the mixed solution) and the concentration of aminotriacetic acid reach 0.04 mol / L; finally, under continuous stirring, slowly add ammonia water to adjust the pH of the mixed solution to 5.8.

[0045] b. Modification of Raney nickel mesh electrodes through stepwise chemical transformation according to time series: The first step is to construct the interface stabilization layer: the pretreated Raney nickel mesh is immersed in the interface stabilization layer precursor solution and reacted at 90°C for 10 hours to complete the construction of the interface stabilization layer. Then it is taken out and washed with deionized water. The second step is the growth of the catalytic functional layer: the Raney nickel mesh with an interface stabilization layer is immersed in the catalytic functional layer precursor solution and reacted at 85°C for 8 min to complete the growth of the catalytic functional layer. Then it is taken out, washed with deionized water, and vacuum dried at 60°C to obtain the Ni-Fe-La-Mn-Se multi-element composite Raney nickel mesh oxygen evolution electrode.

[0046] Compared to Example 1, the introduction of a selenium-containing doped anion source into the catalytic functional layer precursor solution opens up a rapid interfacial chemical transformation pathway distinct from traditional metal hydroxyl deposition. Specifically, the doped anions significantly reduce the interfacial nucleation energy barrier in the early stages of the reaction and accelerate the interfacial-induced chemical transformation of metal species on the surface of the interfacial stabilization layer, enabling the catalytic functional layer to grow rapidly within minutes. However, these anions exhibit high chemical activity in the reaction system, and further extension of the reaction time may lead to corrosion or structural reconstruction of the substrate. Therefore, this invention precisely controls the reaction time, keeping the reaction process within a kinetic time window conducive to the growth of the catalytic functional layer, effectively avoiding substrate degradation and achieving the preparation of a highly active and stable electrode.

[0047] Example 3

[0048] A Ni-Fe-La-Y-Ce-Co-Mn-S multi-element composite Raney nickel mesh oxygen evolution electrode is prepared as follows.

[0049] s. Substrate pretreatment: Same as in Example 1.

[0050] a. Preparation of the precursor solution: Precursor solution for interfacial stabilization layer: Weigh out LaCl3·7H2O, Y(NO3)3·6H2O and Ce(NO3)3·6H2O respectively, mix them, dissolve them in deionized water, and prepare mixed solutions with concentrations of LaCl3·7H2O 0.04 mol / L, Y(NO3)3·6H2O 0.03 mol / L and Ce(NO3)3·6H2O 0.03 mol / L respectively; Catalytic functional layer precursor solution: Weigh out NiCl2·6H2O, FeSO4·7H2O, Co(NO3)2·6H2O, MnCl2·4H2O and Na2S2O3 respectively, mix them, dissolve them in deionized water, and prepare solutions with concentrations of 0.18 mol / L for NiCl2·6H2O, 0.015 mol / L for FeSO4·7H2O, 0.03 mol / L for Co(NO3)2·6H2O, 0.02 mol / L for MnCl2·4H2O, and 0.06 mol / L for Na2S2O3. The mixture was prepared by adding potassium sodium tartrate (KNaC4H4O6·4H2O), disodium ethylenediaminetetraacetate (Na2EDTA·2H2O), and tartaric acid to the mixed solution. The concentration of potassium sodium tartrate in the mixed solution reached 0.098 mol / L (i.e., the molar amount of potassium sodium tartrate added was 40% of the total molar amount of Ni, Fe, Co, and Mn ions in the mixed solution), the concentration of disodium ethylenediaminetetraacetate reached 0.049 mol / L, and the concentration of tartaric acid reached 0.0245 mol / L. Finally, under continuous stirring, ammonia water was slowly added dropwise to adjust the pH of the mixed solution to 6.2.

[0051] b. Modification of Raney nickel mesh electrodes through stepwise chemical transformation according to time series: The first step is to construct the interface stabilization layer: the pretreated Raney nickel mesh is immersed in the interface stabilization layer precursor solution and reacted at 88°C for 18 hours to complete the construction of the interface stabilization layer. Then it is taken out and washed with deionized water. The second step is the growth of the catalytic functional layer: the Raney nickel mesh with an interface stabilization layer is immersed in the catalytic functional layer precursor solution and reacted at 85°C for 6 hours to complete the growth of the catalytic functional layer. Then it is taken out, washed with deionized water, and vacuum dried at 60°C to obtain the Ni-Fe-La-Y-Ce-Co-Mn-S multi-element composite Raney nickel mesh oxygen evolution electrode.

[0052] This embodiment verifies the successful preparation of a multifunctional element system. Regarding functional elements, a relatively small number of functional elements are usually sufficient to effectively control the performance of Raney nickel mesh electrodes. However, under certain application conditions, a multifunctional element system is required. Specifically, in the following particular applications, introducing a multifunctional element system offers significant engineering adaptability advantages.

[0053] (1) Applications with large fluctuations in operating conditions When the electrolytic cell operates under different current density ranges, start-up and shutdown conditions, or load changes, the multifunctional element system can reduce the sensitivity of a single component to specific operating conditions by sharing different regulatory roles, thus making the electrode performance more adaptable to changes in operating conditions.

[0054] (2) Applications of electrodes with complex structures and comprehensive performance orientation In three-dimensional porous substrates, the reaction interface environment varies spatially. At the same time, when the application requirements are not solely focused on a single performance indicator, but rather require a balance in terms of structural stability, reaction kinetics control, and interface adaptation, the multifunctional element system can play its respective role in different micro-regions, enabling the overall electrode to exhibit a more consistent structure and reaction behavior in space, and achieving comprehensive performance optimization.

[0055] (3) Applications requiring a wide preparation process window In large-scale or repetitive preparation processes, it is difficult to maintain highly consistent process conditions. Multifunctional elemental systems can improve the tolerance of the preparation process to a certain extent, enabling the resulting electrodes to maintain stable structural characteristics across different preparation batches.

[0056] Example 4

[0057] A Ni-Fe-Y-Mn-VP multi-component Raney nickel mesh oxygen evolution electrode is prepared using the following process.

[0058] s. Substrate pretreatment: Same as in Example 1.

[0059] a. Preparation of the precursor solution: Precursor solution for interfacial stabilization layer: Weigh YCl3·6H2O and dissolve it in deionized water to prepare a YCl3·6H2O solution with a concentration of 0.08 mol / L; Catalytic functional layer precursor solution: Weigh out Ni(NO3)2·6H2O, FeCl3·6H2O, MnSO4·H2O, NH4VO3 and NaH2PO2·H2O respectively, mix them, dissolve them in deionized water, and prepare mixed solutions with concentrations of 0.20 mol / L Ni(NO3)2·6H2O, 0.018 mol / L FeCl3·6H2O, 0.025 mol / L MnSO4·H2O, 0.015 mol / L NH4VO3, and 0.08 mol / L NaH2PO2·H2O; then add ethylenediaminetetraacetic acid (H4EDTA) to the mixed solution to achieve a concentration of 0.1548 mol / L. (That is, the molar amount of ethylenediaminetetraacetic acid added is 60% of the total molar amount of Ni, Fe, Mn, and V ions in the mixed solution); finally, under continuous stirring, ammonia water is slowly added dropwise to adjust the pH of the mixed solution to 6.0.

[0060] b. Modification of Raney nickel mesh electrodes through stepwise chemical transformation according to time series: The first step is to construct the interface stabilization layer: the pretreated Raney nickel mesh is immersed in the interface stabilization layer precursor solution and reacted at 82℃ for 20h to complete the construction of the interface stabilization layer. Then it is taken out and washed with deionized water. The second step is the growth of the catalytic functional layer: the Raney nickel mesh with an interface stabilization layer is immersed in the catalytic functional layer precursor solution and reacted at 90℃ for 8 min to complete the growth of the catalytic functional layer. Then it is taken out, washed with deionized water, and vacuum dried at 60℃ to obtain the Ni-Fe-Ce-Co multi-element composite Raney nickel mesh oxygen evolution electrode.

[0061] Example 5

[0062] To verify the feasibility of the preparation method of the present invention in achieving uniform modification of large-size Raney nickel mesh oxygen evolution electrodes, a Ni-Fe-Ce-Co multi-element composite Raney nickel mesh oxygen evolution electrode with the same preparation process as in Example 1 was prepared, and the preparation process is as follows.

[0063] s. Substrate pretreatment: Take a large area Raney nickel mesh of 5cm × 5.5cm (reaction area is 5cm × 5cm), and clean it with acetone and ethanol in sequence by ultrasonic cleaning. Then, immerse it in 1.0 M HCl solution for acid washing for 5 minutes. Take it out, clean it with deionized water, and vacuum dry it at 60℃.

[0064] a. Preparation of precursor solution: Same as in Example 1.

[0065] b. Modification of Raney nickel mesh electrode by stepwise chemical transformation according to time sequence: Same as Example 1.

[0066] The macroscopic effect of the fabricated large-area Raney nickel mesh oxygen evolution electrode is as follows: Figure 8As shown in Figure A, the electrode surface has a uniform color with no visible color difference, streaks, or mottles, indicating that the modified layer has achieved uniform coverage on a large-area substrate.

[0067] Comparative Example Compared to the examples, the comparative examples used different processes to prepare Raney nickel mesh oxygen evolution electrodes.

[0068] Comparative Example 1 The conventional Raney nickel mesh oxygen evolution electrode uses the acid-washed and activated Raney nickel mesh directly as the oxygen evolution electrode. The specific acid washing and activation operation is the same as the substrate pretreatment step in Example 1.

[0069] Comparative Example 2 Ni-Fe-Ce-Co / Raney nickel mesh oxygen evolution electrode was prepared by a one-step mixed impregnation method. The preparation process is as follows.

[0070] (1) Substrate pretreatment: Same as in Example 1.

[0071] (2) Impregnation solution: Prepare a mixed solution of Ni(NO3)2·6H2O, FeCl3·6H2O, CeCl3·6H2O and CoCl2·6H2O with concentrations of 0.2 mol / L for Ni(NO3)2·6H2O, 0.02 mol / L for FeCl3·6H2O, 0.1 mol / L for CeCl3·6H2O and 0.05 mol / L for CoCl2·6H2O. Add the same amount of citric acid as in Example 1 to the mixed solution to make the citric acid concentration 0.135 mol / L. Under continuous stirring, slowly add ammonia water to adjust the pH of the solution to 5.5.

[0072] (3) Impregnation reaction: The pretreated Raney nickel mesh is immersed in the impregnation solution and reacted at 90°C for 22 hours. Then it is taken out, washed with deionized water, and dried under vacuum at 60°C to obtain Ni-Fe-Ce-Co / Raney nickel mesh oxygen evolution electrode.

[0073] Comparative Example 3 A Ni-Fe-Ce-Co / Raney nickel mesh oxygen evolution electrode was prepared using a two-step electrodeposition method, and the preparation process is as follows.

[0074] (1) Substrate pretreatment: Same as in Example 1.

[0075] (2) Preparation of two-step electroplating solution: First step electroplating solution: 0.1 mol / L CeCl3·6H2O solution; The second step of the electroplating solution: Prepare a mixed solution with concentrations of Ni(NO3)2·6H2O 0.2 mol / L, FeCl3·6H2O 0.02 mol / L, and CoCl2·6H2O 0.05 mol / L, and add the same amount of citric acid as in Example 1 to the mixed solution to make the concentration of citric acid in the mixed solution reach 0.135 mol / L. Under continuous stirring, slowly add ammonia water to adjust the pH of the solution to 5.5.

[0076] (3) Two-step electrodeposition process: Step 1: Electrodeposition of Ce layer: A pretreated Raney nickel mesh is used as the working electrode, a carbon rod as the counter electrode, and an Hg / HgO electrode as the reference electrode. The working electrode is clamped with a platinum electrode holder and immersed in the first-step electroplating solution to form a three-electrode system, at -50 mA / cm². 2 Perform constant current electrodeposition at the current density for 15 minutes, then remove and rinse with water. The second step involves electrodepositing a Ni-Fe-Co layer: A Raney nickel mesh with a Ce layer is used as the working electrode, a carbon rod as the counter electrode, and an Hg / HgO electrode as the reference electrode. The working electrode is clamped with a platinum electrode holder and immersed in the second-step electroplating solution to form a three-electrode system, at -50 mA / cm². 2 Constant current electrodeposition was performed at the current density for 15 min. After completion, the electrode was removed, washed with water, and dried under vacuum at 60℃ to obtain a Ni-Fe-Ce-Co / Raney nickel mesh oxygen evolution electrode.

[0077] Comparative Example 4 By changing the interface stabilization layer and using the stabilizing element Zr, a Ni-Fe-Zr-Co multi-component Raney nickel mesh oxygen evolution electrode was prepared, as follows.

[0078] (1) Substrate pretreatment: Same as in Example 1.

[0079] (2) Preparation of precursor solution: Interfacial stabilizing layer precursor solution: 0.1 mol / L ZrCl4 solution.

[0080] Catalytic functional layer precursor solution: Prepare a mixed solution with concentrations of 0.2 mol / L Ni(NO3)2·6H2O, 0.02 mol / L FeCl3·6H2O, and 0.05 mol / L CoCl2·6H2O, and add the same amount of citric acid as in Example 1 to the mixed solution to make the concentration of citric acid in the mixed solution reach 0.135 mol / L. Under continuous stirring, slowly add ammonia water to adjust the pH of the solution to 5.5.

[0081] (3) Modification of Raney nickel mesh electrodes by stepwise chemical transformation according to time series: The first step is to construct the interface stabilization layer: the pretreated Raney nickel mesh is immersed in the interface stabilization layer precursor solution and reacted at 85°C for 12 hours to complete the construction of the interface stabilization layer. Then it is taken out and washed with deionized water. Step 2: Growth of the catalytic functional layer: The Raney nickel mesh with an interface stabilization layer is immersed in the catalytic functional layer precursor solution and reacted at 90℃ for 10h to complete the growth of the catalytic functional layer. Then it is taken out, washed with deionized water, and vacuum dried at 60℃ to obtain the Ni-Fe-Zr-Co multi-element composite Raney nickel mesh oxygen evolution electrode.

[0082] Comparative Example 5 The electrodeposition method was used to process a large-area Raney nickel mesh electrode, highlighting the inherent defects of the electrodeposition method in large-area modification. The preparation process is as follows.

[0083] (1) Substrate pretreatment: Same as in Example 5.

[0084] (2) Prepare two-step electroplating solution: Same as comparative example 3.

[0085] (3) Two-step electrodeposition process: Same as comparative example 3.

[0086] The macroscopic effect of the fabricated large-area Raney nickel mesh oxygen evolution electrode is as follows: Figure 8 As shown in B, the electrode surface exhibits obvious inhomogeneity, with a significant increase in color intensity at the edges (edge ​​effect), and areas of varying color intensity and deposition patterns on the surface.

[0087] Electrode characterization and performance testing The Raney nickel mesh oxygen evolution electrodes of the examples and comparative examples were characterized and their performance was tested and analyzed.

[0088] 1. Gradient composite structure of electrode cross section The cross-section of the Ni-Fe-Ce-Co multi-component Raney nickel mesh oxygen evolution electrode of Example 1 was analyzed by SEM-EDS line scan, and the results are as follows: Figure 1 As shown, Ce forms a sharp enrichment peak near the substrate, thus constructing an interfacial stabilizing layer; while Ni, Fe, and Co elements show a continuous increasing trend from the substrate outwards, forming a catalytic functional layer. The clear spatial gradient distribution of the elements proves that the time-series stepwise chemical transformation strategy of this invention successfully constructs a gradient structure, thereby forming a gradient-bonded interface.

[0089] 2. Electrode surface morphology The surface morphology of the electrodes of Comparative Example 1 and Examples 1 and 4 was observed using a scanning electron microscope, as follows: Figure 2 As shown, Figure 2 A presents the original three-dimensional skeleton structure of the Raney nickel mesh substrate. Figure 2B and 2C are the three-dimensional porous frameworks of the electrodes in Examples 1 and 4, respectively. As can be seen from the comparison, the surfaces of the electrodes in Examples 1 and 4 are completely covered by continuous, dense and uniform deposits, forming a full-area coverage state, while the pore structure remains intact.

[0090] The cyclic voltammetry curves, linear sweep voltammetry curves, and stability tests below all use general test conditions, as detailed below: Test system: Standard three-electrode system; The working electrode is a self-supporting electrode (test area is 1 cm²). 2 The counter electrode is a carbon rod, and the reference electrode is an Hg / HgO electrode; Electrolyte: 6.0 M KOH solution; Temperature: 25℃; Potential conversion: All potentials are calibrated relative to the reversible hydrogen electrode (RHE).

[0091] 3. Electrochemical active area and interfacial properties The double-layer capacitance (C0) was measured in the non-Radal region using cyclic voltammetry (CV). dl ), and calculate the electrochemical active area (ECSA) based on this.

[0092] Figure 3 A through C represent the CV curves of the three electrodes in Example 1, Comparative Example 2, and Comparative Example 3, respectively. Figure 3 D represents the calculated double-layer capacitance and ECSA values ​​of the three electrodes in Example 1, Comparative Example 2, and Comparative Example 3. The results show that the ECSA of the electrode in Example 1 is significantly higher than that in Comparative Example 2 (one-step mixing method with the same chemical composition) and Comparative Example 3 (two-step electrodeposition method). This indicates that the gradient structure constructed stepwise in this invention provides more accessible and stable active interfaces, while optimizing electron transport between the conductive substrate and the catalyst layer.

[0093] 4. Catalytic activity Oxygen evolution reaction (OER) tests were performed on the electrodes of Examples 1-5 and Comparative Examples 1-5, and the obtained linear sweep voltammetry (LSV) curves are shown below. Figure 4 As shown, at 100 mA / cm 2 At the given current density, the overpotential of the electrodes in all embodiments was 200–300 mV, significantly lower than the 320–360 mV of the electrodes in all comparative embodiments. This result indicates that the time-series stepwise chemical conversion strategy of the present invention significantly enhances the catalytic activity of the oxygen evolution reaction.

[0094] 5. Long-term stability At 500 mA / cm 2The electrodes of Examples 1-5 and Comparative Examples 1-5 were subjected to a 1000-hour stability test at industrial-grade current density. The results are as follows: Figure 5 As shown, the overpotential decay of the electrodes in each embodiment is less than 50 mV, while the decay of the comparative electrode exceeds 100 mV.

[0095] ICP-MS results are as follows Figure 6 As shown, in Example 1, the Fe ion concentration in the electrode working solution was 46 ppb, and the Ce ion concentration was less than 5 ppb; in Example 3, the Fe ion concentration was 39 ppb, and the La / Y / Ce ion concentration was less than 5 ppb; while in Comparative Example 2, the Fe ion concentration exceeded 300 ppb, and the Ce ion dissolution reached 78 ppb. This result confirms that the integrated active layer constructed in this invention can effectively inhibit the dissolution of the key active component (Fe), and simultaneously achieves a "dual low dissolution" characteristic for both Fe and the stable component through the first stabilizing layer.

[0096] Figure 7 The images show the in-situ Raman spectra of the electrode in Example 1 at its initial state, after cyclic voltammetry (CV) activation, and after a 1000-hour stability test. After CV activation, a highly active NiFeOOH phase is formed. After 1000 hours of operation, its characteristic peaks remain clear and stable, indicating that the gradient composite structure effectively maintains the structural integrity and chemical stability of NiFeOOH.

[0097] 6. Verification of uniformity at industrial scale As can be seen from the macroscopic photographs of the electrodes of Example 5 (large-area chemical impregnation) and Comparative Example 5 (large-area electrodeposition), the surface of the electrode of Example 5 has a uniform color and no visible defects. Figure 8 As shown in Figure A; the electrode surface of Comparative Example 4 exhibits obvious edge effects and uneven color deposition patterns, such as... Figure 8 As shown in B.

[0098] Elemental mapping analysis showed that Ni, Fe, Ce, and Co in the electrode of Example 5 were uniformly and continuously distributed on the skeleton surface, such as... Figure 8 As shown in C; in contrast, the elemental distribution of the electrode in Comparative Example 4 is "island-like" or patchy, with low overlap between elements, such as Figure 8 As shown in D.

[0099] The “continuous, overlapping, and consistent with the morphology” of Example 5 stands in stark contrast to the “isolated, discrete, and disconnected from the morphology” of Comparative Example 5, revealing the essential advantages of the preparation method of the present invention in terms of microstructure. In addition, the atmospheric pressure chemical impregnation method of the present invention can also overcome the uniformity problem of traditional electrodeposition method in large-area modification, and has good potential for industrial scale-up.

[0100] The above analysis of the electrode microstructure, elemental distribution, ICP-MS dissolution data, macroscopic performance, and long-term stability fully demonstrates that the time-series stepwise chemical transformation strategy of this invention achieves a balance of high activity, high stability, and industrial scalability by constructing a gradient bonding structure, providing an innovative and feasible solution to the core technical bottleneck of industrial oxygen evolution electrodes.

[0101] In summary, the Raney nickel mesh oxygen evolution electrode of this invention possesses a gradient composite structure with a tightly integrated interface stabilizing layer and catalytic functional layer. It achieves uniform loading on both the outer surface and deep channels of the three-dimensional porous framework of the Raney nickel mesh, overcoming the problems of low utilization of deep channels, insufficient adhesion of the modified layer, and limited activity inherent in traditional Raney nickel mesh oxygen evolution electrodes. Significant optimizations have been achieved in terms of microstructure, macroscopic performance, and long-term stability. The preparation process of this invention meets the requirements for industrial-scale production, possesses promising industrial application prospects, and provides technical support for the development of industrial oxygen evolution electrodes.

[0102] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A high-performance Raney nickel mesh oxygen evolution electrode based on time-series stepwise chemical transformation, characterized in that: The Raney nickel mesh oxygen evolution electrode is obtained by sequentially constructing an interface stabilizing layer on a Raney nickel mesh substrate and then growing a catalytic functional layer using a stepwise chemical impregnation method. The interface stabilizing layer precursor solution used to construct the interface stabilizing layer contains at least one of cerium ions, lanthanum ions, and yttrium ions. The catalytic functional layer precursor solution used to grow the catalytic functional layer contains a main active metal ion and a co-regulating element ion. The main active metal ion contains nickel ions and iron ions, or nickel ions and ferrous ions. The co-regulating element ion contains at least one of cobalt ions, manganese ions, and vanadium ions.

2. The high-performance Raney nickel mesh oxygen evolution electrode based on time-series stepwise chemical transformation according to claim 1, characterized in that: The cerium salt providing cerium ions is selected from at least one of cerium nitrate, cerium chloride, and cerium sulfate; the lanthanum salt providing lanthanum ions is selected from at least one of lanthanum nitrate, lanthanum chloride, and lanthanum sulfate; the yttrium salt providing yttrium ions is selected from at least one of yttrium nitrate, yttrium chloride, and yttrium sulfate; and / or, the nickel salt providing nickel ions is selected from at least one of nickel chloride, nickel nitrate, and nickel sulfate; the ferric salt providing ferric ions is selected from at least one of ferric chloride, ferric nitrate, and ferric sulfate; the ferrous salt providing ferrous ions is selected from at least one of ferrous chloride, ferrous nitrate, and ferrous sulfate; and / or, the cobalt salt providing cobalt ions is selected from at least one of cobalt chloride, cobalt nitrate, and cobalt sulfate; the manganese salt providing manganese ions is selected from at least one of manganese chloride, manganese nitrate, and manganese sulfate; and the vanadium salt providing vanadium ions is selected from at least one of ammonium metavanadate, vanadium oxysulfate, and sodium vanadate.

3. The high-performance Raney nickel mesh oxygen evolution electrode based on time-series stepwise chemical transformation according to claim 1, characterized in that: The total concentration of cerium ions, lanthanum ions, and yttrium ions in the precursor solution of the interface stabilizing layer is 0.05~0.5 mol / L.

4. The high-performance Raney nickel mesh oxygen evolution electrode based on time-series stepwise chemical transformation according to claim 1, characterized in that: The total concentration of the main active metal ions in the precursor solution of the catalytic functional layer is 0.1~1.0 mol / L; and / or, the molar ratio of nickel ions to iron ions or nickel ions to ferrous ions in the main active metal ions is 2~15:1; and / or, the total concentration of the synergistic regulatory element ions is 1~50% of the total molar amount of the main active metal ions.

5. The high-performance Raney nickel mesh oxygen evolution electrode based on time-series stepwise chemical transformation according to claim 1, characterized in that: The precursor solution of the catalytic functional layer also contains doped anions. Preferably, the amount of doped anions is 10 to 100% of the total molar amount of the main active metal ions and the synergistic regulatory element ions in the precursor solution of the catalytic functional layer.

6. The high-performance Raney nickel mesh oxygen evolution electrode based on time-series stepwise chemical transformation according to claim 5, characterized in that: The doped anion includes at least one of phosphorus ions, sulfur ions, and selenium ions. Preferably, the compound providing phosphorus ions, sulfur ions, and selenium ions is selected from at least one of hypophosphite, phosphate, thiosulfate, sulfide, thiourea, selenite, and selenourea.

7. The high-performance Raney nickel mesh oxygen evolution electrode based on time-series stepwise chemical transformation according to claim 1, characterized in that: A complexing agent is added to the precursor solution of the catalytic functional layer. Preferably, the complexing agent is selected from at least one of citric acid, citrate, tartaric acid, tartrate, ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid salt, and aminotriacetic acid; and / or, the amount of complexing agent added is 10 to 150% of the total molar amount of the main active metal ion and the synergistic regulatory element ion, preferably 30 to 100%.

8. The high-performance Raney nickel mesh oxygen evolution electrode based on time-series stepwise chemical transformation according to claim 7, characterized in that: The pH value of the precursor solution for the catalytic functional layer is 4.0~7.0, preferably 5.0~6.

5.

9. The method for preparing a high-performance Raney nickel mesh oxygen evolution electrode based on time-series stepwise chemical transformation as described in any one of claims 1 to 8, characterized in that, The preparation steps include the following: a. Preparation of precursor solutions: Prepare interface stabilizing layer precursor solution and catalytic functional layer precursor solution that meet the concentration requirements respectively; preferably, the preparation of catalytic functional layer precursor solution requires first dissolving the main active metal ions and synergistic regulatory element ions, then adding the complexing agent, and adjusting the pH value with ammonia. b. Modification of Raney nickel mesh by stepwise chemical transformation according to time series: The first step is to construct the interface stabilization layer: Immerse the Raney nickel mesh in the interface stabilization layer precursor solution and react at 80~95℃ for 6~48h to complete the construction of the interface stabilization layer. Then remove it and wash it with water. The second step is to grow the catalytic functional layer: The Raney nickel mesh with an interface stabilization layer is immersed in the catalytic functional layer precursor solution and reacted at 80~95℃ for 2~10h to complete the growth of the catalytic functional layer. Then it is taken out, washed with water and dried to obtain the Raney nickel mesh oxygen evolution electrode. Preferably, when the functional layer precursor solution contains doped anions, the catalytic functional layer is grown at 80~95℃ for 1~10min.

10. The method for preparing a high-performance Raney nickel mesh oxygen evolution electrode based on time-series stepwise chemical transformation according to claim 9, characterized in that: Pre-treatment of Raney nickel mesh with acid washing and activation is preferred before modification. The Raney nickel mesh is ultrasonically cleaned with acetone and ethanol respectively, then immersed in HCl solution for acid washing, and then taken out, cleaned and dried.

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