High-efficiency oxygen evolution anode and preparation method and application thereof

Abstract

The application belongs to the technical field of preparation of water electrolysis oxygen evolution electrodes, and particularly relates to a high-efficiency oxygen evolution anode and a preparation method and application thereof. The high-efficiency oxygen evolution anode provided by the application comprises a substrate and a bottom layer (including a composite oxide formed by Ni and a metal (Zr, Ce, Ta, Nb) with a valence of greater than or equal to +4) sequentially loaded on the surface of the substrate, an active layer (including a composite oxide formed by Ni, Fe and a doping metal (Mn, Ce, Zr, Co, W, Mo, Cu)) and a stable layer (including a composite oxide formed by Ni, P and a high-valence metal (Ce, Zr, W)), and the active layer is n layers, and n = 2-10. Through the synergistic design of element hierarchical doping and a layered coating structure, the adhesion between the coating and the substrate is improved, and the unification of high activity, high stability and low-cost industrial production of the oxygen evolution anode is realized.

Description

Technical Field

[0001] This invention belongs to the field of preparation technology of oxygen evolution electrodes for water electrolysis, specifically relating to a high-efficiency oxygen evolution anode, its preparation method, and its application. Background Technology

[0002] The development of intermittent renewable energy sources such as wind and solar power has spurred significant interest in developing novel electrochemical technologies for energy storage and conversion. Hydrogen production via water electrolysis is one of the most attractive technologies for addressing the challenges of these renewable energy fluctuations and is suitable for long-term energy storage. The oxygen evolution reaction (OER) is the core anolyte reaction in energy conversion technologies such as hydrogen production via water electrolysis and electrochemical synthesis. Its slow reaction kinetics necessitate highly efficient catalysts to reduce overpotential and improve energy conversion efficiency. Currently, nickel-iron (Ni-Fe) based catalysts have become a research hotspot among non-precious metal OER catalysts due to their combination of high activity and low cost. In particular, the key to their large-scale application in the field of hydrogen production via water electrolysis lies in how to achieve low-cost, large-scale production.

[0003] In industrial water electrolysis for hydrogen production, the stability of self-supporting electrodes is a core indicator determining their service life and practical application value. Catalytic layer failure manifests in two main forms: first, insufficient mechanical stability, where poor bonding between the catalyst layer and the substrate leads to physical peeling and detachment under prolonged bubble scouring and liquid flow disturbance; second, insufficient chemical stability, where active components gradually dissolve and are lost in the corrosive environment of the electrolyte, or substrate metal elements diffuse into the active layer, poisoning active sites and causing continuous degradation of catalytic performance. Existing technologies mostly focus only on improving catalytic activity, failing to simultaneously consider mechanical and chemical stability from a structural design perspective. For example, existing technologies disclose a supported nickel-iron-based oxygen evolution electrode, its preparation method, and its application. The catalyst layer prepared by this method is a homogeneous, non-layered, integral structure directly grown on the substrate surface. This type of non-layered electrode structure has two obvious defects: First, the bonding force between the catalytic coating and the substrate is poor, and the coating is prone to peeling and delamination under high current conditions in industrial applications, leading to a rapid decline in electrode activity. Second, due to the lack of a transition buffer layer to provide a soft interface connection between the substrate and the active layer, metal elements from the substrate are prone to diffuse into the active layer and interfere with the electronic structure of the active sites during long-term operation. At the same time, the iron active components in the active layer are prone to dissolution and loss, further aggravating the decline in electrode performance and making it difficult to meet the stable operation requirements of thousands of hours under industrial electrolysis conditions.

[0004] To address the shortcomings of lacking a layered structure, some existing technologies have attempted to introduce multilayer structures. For example, existing technologies disclose a composite catalytic electrode for water electrolysis and oxygen evolution, along with its preparation method and apparatus, which involves a composite preparation process for the catalytic layer. However, the multilayer structures of such schemes are mainly characterized by a gradual distribution of component ratios or simple composites, with no clear functional division between the layers. Their design purpose is to optimize electrochemical reaction efficiency, rather than to address the physical peeling or chemical corrosion problems of the catalytic layer. Due to the lack of a functional layer design specifically designed to enhance mechanical bonding, such structures still face the risk of catalytic layer detachment under prolonged bubble erosion and electrolyte corrosion conditions.

[0005] Building upon this, existing technologies have further disclosed an iridium-based dual-catalyst layer for oxygen evolution electrodes and its preparation method. This method employs a two-layer structure, first spraying iridium supported on carbon and then spraying iridium oxide. The carbon-supported iridium layer enhances conductivity and porosity, while the iridium oxide layer improves stability, demonstrating a preliminary concept of functional layering. However, this scheme only has two layers and lacks an independent protective layer to resist external mechanical erosion and chemical attack. The active layer is directly exposed to the electrolyte environment, and the active components will gradually be lost over long-term operation. Furthermore, the layers in this scheme primarily rely on physical stacking for bonding, lacking a mechanism for mechanical interlocking through interlayer coupling, resulting in limited interfacial adhesion. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a high-efficiency oxygen evolution anode, its preparation method and application. This invention improves the adhesion between the coating and the substrate through the synergistic design of element-level doping and layered coating structure, thereby achieving a balance between high activity, high stability and low-cost industrial production of oxygen evolution anodes.

[0007] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a high-efficiency oxygen evolution anode, comprising a substrate and a bottom layer, an active layer, and a stabilizing layer sequentially loaded on the surface of the substrate, wherein the active layer comprises n layers, n=2~10; The bottom layer comprises a composite oxide formed of Ni and a metal with a valence of +4 or higher; the metal with a valence of +4 or higher includes one or more of Zr, Ce, Ta, and Nb; The active layer comprises a composite oxide formed from Ni, Fe, and doped metals; the doped metals include one or more of Mn, Ce, Zr, Co, W, Mo, and Cu. The stabilizing layer comprises a composite oxide formed of Ni, P, and high-valence metals; the high-valence metals include one or more of Ce, Zr, and W.

[0008] Preferably, the total coating thickness after the bottom layer, active layer and stabilizing layer are stacked is 20~150μm.

[0009] This invention also provides a method for preparing the high-efficiency oxygen evolution anode described in the above technical solution, comprising the following steps: The substrate surface after pretreatment is coated with a bottom coating solution, an active layer coating solution and a stabilizing layer coating solution in sequence. The active layer coating solution is coated n times, where n = 2~10. After each coating, the substrate is dried and calcined in sequence to finally obtain a high-efficiency oxygen evolution anode. The underlying coating solution comprises Ni salt, a metal salt with a ≥+4 valence, a first organic additive, and water; the metal salt with a ≥+4 valence comprises one or more of Zr, Ce, Ta, and Nb; The active layer coating solution comprises Ni salt, Fe salt, doped metal salt, a second organic additive, and water; the doped metal salt comprises one or more of Mn salt, Ce salt, Zr salt, Co salt, W salt, Mo salt, and Cu salt; The stabilizing coating solution comprises Ni salt, phosphate, high-valence metal salt, a third organic additive, and water; the high-valence metal salt comprises one or more of Ce salt, Zr salt, and W salt.

[0010] Preferably, the first organic additive, the second organic additive, and the third organic additive are each one or more of urea, ethylene glycol, propylene glycol, n-butanol, and citric acid.

[0011] Preferably, the thickness of the liquid film formed by the bottom coating liquid is 5~20μm.

[0012] Preferably, the thickness of the liquid film formed by each active layer coating liquid coating is 10~30μm.

[0013] Preferably, the thickness of the liquid film formed by the stabilizing layer coating liquid is 5~20μm.

[0014] Preferably, the roasting temperature is 200~550℃ and the holding time is 3~60min.

[0015] Preferably, after the final firing, the process further includes a curing treatment; the curing treatment temperature is 350~700℃, and the holding time is 30~120min.

[0016] The present invention also provides the application of the high-efficiency oxygen evolution anode described in the above technical solution or the high-efficiency oxygen evolution anode prepared by the preparation method described in the above technical solution in oxygen evolution during water electrolysis.

[0017] This invention provides a high-efficiency oxygen evolution anode, comprising a substrate and a bottom layer, an active layer, and a stabilizing layer sequentially loaded on the surface of the substrate, wherein the active layer comprises n layers, n=2~10; The bottom layer comprises a composite oxide formed of Ni and a metal with a valence of +4 or higher; the metal with a valence of +4 or higher includes one or more of Zr, Ce, Ta, and Nb; The active layer comprises a composite oxide formed from Ni, Fe, and doped metals; the doped metals include one or more of Mn, Ce, Zr, Co, W, Mo, and Cu. The stabilizing layer comprises a composite oxide formed of Ni, P, and high-valence metals; the high-valence metals include one or more of Ce, Zr, and W.

[0018] Beneficial effects: To address the technical bottleneck of existing technologies that cannot simultaneously achieve both mechanical and chemical stability, this invention provides a high-efficiency oxygen evolution anode with a layered structure. Its core innovation lies in constructing a three-layered structure with distinct functions: a bottom layer, an active layer, and a stabilizing layer. These layers address two different stability requirements: In terms of mechanical stability, the bottom layer forms a strong chemical bond and physical interlock with the substrate, achieving mechanical bonding through interlayer coupling; the stabilizing layer prevents direct impact from air bubbles on the active layer. In terms of chemical stability, the bottom layer, composed of metal oxides with a valence of +4 or higher, and the metal-doped active layer possess corrosion resistance. Their dense structure and low ion diffusion coefficient act as a physical barrier, preventing the diffusion of substrate metal elements into the active layer. The stabilizing layer encapsulates the active layer internally, inhibiting the dissolution and loss of active components. Thanks to the functional compatibility and gradient dispersion effect between the constructed bottom layer, active layer and stable layer: interlayer gradient dispersion anchors and releases stress, improving the mechanical stability of the electrode; gradient continuous interface reduces charge transfer resistance, giving the electrode excellent oxygen evolution catalytic activity; gradient barrier extends the diffusion path of corrosive media, and combined with the three-layer hierarchical corrosion protection synergy, it enhances the chemical stability of the electrode, so that the high-efficiency oxygen evolution anode provided by the present invention has good mechanical stability, activity and chemical stability. Attached Figure Description

[0019] Figure 1 The images shown are SEM images of the high-efficiency oxygen evolution anode prepared in Example 1 of this invention, where a is a low-magnification scanning electron microscope image, b is a medium-magnification scanning electron microscope image, and c is a high-magnification scanning electron microscope image. Figure 2 EDS elemental distribution diagram of the high-efficiency oxygen evolution anode prepared in Example 1 of this invention; Figure 3 This is a performance comparison diagram of the high-efficiency oxygen evolution anodes prepared in Example 1, Example 2 and Comparative Example 1; Figure 4 The cell voltage-time curves for different anodes in the electrolysis system are shown. Figure 5 SEM image of the high-efficiency oxygen evolution anodic electrolysis reaction prepared in Example 1; Figure 6The images show a comparison of the electrode materials after sonication in pure water for 1 hour. In the images, a is the high-efficiency oxygen-evolving anode prepared in Example 1, b is the high-efficiency oxygen-evolving anode prepared in Comparative Example 1, and c is the high-efficiency oxygen-evolving anode prepared in Comparative Example 2. Detailed Implementation

[0020] This invention provides a high-efficiency oxygen evolution anode, comprising a substrate and a bottom layer, an active layer, and a stabilizing layer sequentially loaded on the surface of the substrate, wherein the active layer comprises n layers, n=2~10; The bottom layer comprises a composite oxide formed of Ni and a metal with a valence of +4 or higher; the metal with a valence of +4 or higher includes one or more of Zr, Ce, Ta, and Nb; The active layer comprises a composite oxide formed from Ni, Fe, and doped metals; the doped metals include one or more of Mn, Ce, Zr, Co, W, Mo, and Cu. The stabilizing layer comprises a composite oxide formed of Ni, P, and high-valence metals; the high-valence metals include one or more of Ce, Zr, and W.

[0021] Unless otherwise specified, the present invention does not have special requirements on the source of raw materials used, and commercially available products well known to those skilled in the art can be used.

[0022] As one implementation method, n = 2~7, and in a specific embodiment it is 2~5.

[0023] In one implementation, the total coating thickness after the bottom layer, active layer and stabilizing layer are stacked is 20~150μm, and in a specific embodiment it is 70~130μm; this thickness can ensure the high activity and high stability of the anode, and avoid the decrease in mechanical strength, cracking and peeling caused by excessive coating thickness.

[0024] The high-efficiency oxygen evolution anode prepared by this invention benefits from the functional interplay and gradient dispersion between the constructed bottom layer, active layer, and stabilizing layer, endowing the water electrolysis anode with excellent mechanical stability, activity, and chemical stability. The bottom layer contains high-valence oxides (W, Zr, Ce, Ti with valence ≥ +4), possessing an etching effect and forming a trench structure. This increases the electrode's mechanical stability, resistance to chemical corrosion, and stress relief, while also enhancing the physical interlocking effect with the substrate. The active layer, primarily composed of NiFe, uses high-valence metal oxides to regulate intrinsic activity, providing electrochemical redox buffering capacity and tolerance to power fluctuations. Its main function is to provide the active phase and accelerate the electrochemical oxygen evolution reaction. The stabilizing layer contains sparingly soluble high-valence elements, primarily protecting the electrode, providing redox buffering, and improving electrode stability.

[0025] This invention also provides a method for preparing the high-efficiency oxygen evolution anode described in the above technical solution, comprising the following steps: The substrate surface after pretreatment is coated with a bottom coating solution, an active layer coating solution and a stabilizing layer coating solution in sequence. The active layer coating solution is coated n times, where n = 2~10. After each coating, the substrate is dried and calcined in sequence to obtain a high-efficiency oxygen evolution anode. The underlying coating solution comprises Ni salt, a metal salt with a ≥+4 valence, a first organic additive, and water; the metal salt with a ≥+4 valence comprises one or more of Zr, Ce, Ta, and Nb; The active layer coating solution comprises Ni salt, Fe salt, doped metal salt, a second organic additive, and water; the doped metal salt comprises one or more of Mn salt, Ce salt, Zr salt, Co salt, W salt, Mo salt, and Cu salt; The stabilizing coating solution comprises Ni salt, phosphate, high-valence metal salt, a third organic additive, and water; the high-valence metal salt comprises one or more of Ce salt, Zr salt, and W salt.

[0026] In one embodiment, the substrate is a nickel-based metal mesh; the nickel-based metal mesh is either foamed nickel or twill-woven nickel mesh, specifically a twill-woven nickel mesh; the areal density of the foamed nickel is 400~440 g / m³. 2 In the specific embodiment, it is 420g / m 2 The porosity is 85-95%, with 90% in a specific embodiment; the twill woven nickel mesh has a mesh count of 40-80, with 46 mesh in a specific embodiment, and a wire diameter of 0.18-0.30 mm, with 0.25 mm in a specific embodiment. The substrate used in this invention has good electrical conductivity, corrosion resistance, and mechanical strength, making it suitable for the working environment of oxygen evolution anodes.

[0027] As one implementation method, the surface roughness Ra of the pretreated substrate is 1.0~10 μm, and in a specific embodiment Ra is 1.0~4 μm; the pretreatment is as follows: the substrate is sequentially subjected to degreasing, first water washing, acid washing, second water washing, and drying to obtain a pretreated substrate with a rough and clean surface; the degreasing is performed by ultrasonic degreasing of the substrate using a mixed solution of sodium carbonate and sodium hydroxide; the concentration of sodium carbonate in the mixed solution of sodium carbonate and sodium hydroxide is 15~50 g / L, and in a specific embodiment it is 25 g / L, and the concentration of sodium hydroxide is 9~3 g / L. The concentration of the ultrasonic degreasing treatment is 0 g / L, specifically 15 g / L in this embodiment; the power of the ultrasonic degreasing treatment is 60~3000W, specifically 300~500W in this embodiment, the frequency is 28~40kHz, specifically 28kHz in this embodiment, and the time is 15~30min, specifically 20min in this embodiment; the acid washing is ultrasonic acid washing treatment in hydrochloric acid solution; the concentration of the hydrochloric acid is 0.05~3mol / L, specifically 1mol / L in this embodiment; the power of the ultrasonic acid washing treatment is 60~3000W, specifically 300~500W in this embodiment, the frequency is 28~40kHz, specifically 28kHz in this embodiment, and the time is 5~15min, specifically 10min in this embodiment; the first and second water washes are both deionized water rinses; the drying temperature is 50~100℃, specifically 70℃ in this embodiment, and the time is 10~60min, specifically 10~20min in this embodiment. This invention removes oil, oxide film and impurities from the surface of the substrate through pretreatment, while controlling the surface roughness of the substrate. The residual alkali and acid on the surface of the substrate after degreasing and pickling are cleaned by water washing.

[0028] In one embodiment, the underlying coating solution comprises Ni salt, a metal salt with a ≥+4 valence, a first organic additive, and water; the concentration of Ni salt in the underlying coating solution is 0.01~0.5 mol / L, specifically 0.02~0.1 mol / L in this embodiment; the concentration of the metal salt with a ≥+4 valence is 0.01~0.5 mol / L, specifically 0.02~0.1 mol / L in this embodiment; and the concentration of the first organic additive is 0.02~0.5 mol / L, specifically 0.02~0.5 mol / L in this embodiment. The concentration of the solvent is 2~0.2 mol / L; the metal in the ≥+4 valence metal salt includes one or more of Zr, Ce, Ta, and Nb, with Ce or Zr in a specific embodiment; the first organic additive includes one or more of urea, ethylene glycol, propylene glycol, n-butanol, and citric acid, with ethylene glycol in a specific embodiment; the pH value of the bottom coating solution is 1~3, with 1.4 in a specific embodiment; the thickness of the liquid film formed by the bottom coating solution is 5~20 μm, with 8~20 μm in a specific embodiment. The bottom coating solution is uniformly coated on the surface of the pretreated substrate, and the coating thickness is controlled within the above range, with uniform thickness, no missed coating, and no accumulation.

[0029] In one embodiment, the active layer coating solution comprises Ni salt, Fe salt, doped metal salt, a second organic additive, and water; the concentration of Ni salt in the active layer coating solution is 0.01~0.5 mol / L, specifically 0.04~0.3 mol / L in this embodiment; the concentration of Fe salt is 0.005~0.5 mol / L, specifically 0.01~0.1 mol / L in this embodiment; the concentration of doped metal salt is 0.001~0.02 mol / L, specifically 0.005~0.1 mol / L in this embodiment; and the concentration of the second organic additive is 0.02~0.5 mol / L. In a specific embodiment, the concentration is 0.1~0.5 mol / L; the doped metal salt includes one or more of Mn salt, Ce salt, Zr salt, Co salt, W salt, Mo salt, and Cu salt, specifically W salt and Mo salt, or Zr salt; the second organic additive includes one or more of urea, ethylene glycol, propylene glycol, n-butanol, and citric acid, specifically urea, ethylene glycol, and citric acid; the pH value of the active layer coating solution is 1~6, specifically 1.7 or 3.5 in a specific embodiment; the thickness of the liquid film formed by each active layer coating solution is 10~30 μm, specifically 15~30 μm in a specific embodiment. This invention coats the active layer coating solution in n layers onto the bottom surface, with the thickness of each layer controlled at 10~30 μm to ensure uniform thickness of each layer.

[0030] Stacking multiple active layers can increase catalyst loading and further enhance oxygen evolution activity, while avoiding coating cracking caused by excessive thickness of a single active layer; each coating layer is dried and calcined immediately after completion to ensure a dense coating structure and prevent coating peeling caused by multiple layers stacking.

[0031] In one embodiment, the stabilizing layer coating solution comprises Ni salt, phosphate, high-valent metal salt, a third organic additive, and water; the concentration of Ni salt in the stabilizing layer coating solution is 0.01~0.5 mol / L, specifically 0.02~0.2 mol / L in this embodiment; the concentration of phosphate is 0.01~0.5 mol / L, specifically 0.02~0.2 mol / L in this embodiment; the concentration of high-valent metal salt is 0.001~0.2 mol / L, specifically 0.001~0.1 mol / L in this embodiment; and the concentration of the third organic additive is 0. The concentration of the stabilizing layer coating solution is 0.02~0.5 mol / L, specifically 0.02~0.2 mol / L in this embodiment; the high-valence metal salt includes one or more of Ce salt, Zr salt, and W salt, specifically Ce salt or Zr salt in this embodiment; the third organic additive includes one or more of urea, ethylene glycol, propylene glycol, n-butanol, and citric acid, specifically ethylene glycol in this embodiment; the pH value of the stabilizing layer coating solution is 3~6, ​​specifically 4~4.5 in this embodiment; the thickness of the liquid film formed by the stabilizing layer coating solution is 5~20 μm, specifically 10~20 μm in this embodiment. This invention uniformly coats the outermost active layer surface with the stabilizing layer coating solution, controlling the coating thickness to 5~20 μm to ensure a dense, non-porous coating.

[0032] In this invention, the coating liquid adopts a three-layer structure design of bottom layer, active layer and stabilizing layer to achieve functional layering and synergistic effect; the bottom layer is responsible for improving the adhesion between the coating and the substrate, the active layer provides high oxygen evolution activity, and the stabilizing layer inhibits Fe dissolution and improves anode stability. The three are organically combined to solve the problem that it is difficult to balance the existing anode activity and stability.

[0033] In one embodiment, the Mo salt is sodium molybdate or ammonium molybdate, specifically ammonium molybdate; the W salt is one or two of sodium tungstate, ammonium tungstate, and ammonium metatungstate, specifically ammonium metatungstate; in addition to the Mo salt and W salt, the other metal salts used in this invention are nitrates; the phosphate salt is one or more of sodium phosphate, ammonium dihydrogen phosphate, sodium dihydrogen phosphate, sodium hypophosphite, disodium hydrogen phosphate, and diammonium hydrogen phosphate, specifically sodium dihydrogen phosphate.

[0034] In one embodiment, the loading method is coating; the drying temperature is 50~100℃, specifically 70℃ in this embodiment, and the time is 5~20min, specifically 10~20min in this embodiment; the calcination temperature is 200~550℃, specifically 350~400℃ in this embodiment, and the holding time is 3~60min, specifically 6~60min in this embodiment; the calcination is carried out in an air atmosphere.

[0035] As one implementation method, after the final firing, the process further includes: a curing treatment; the curing treatment temperature is 350~700℃, specifically 350~450℃ in this embodiment, and the holding time is 30~120min, specifically 30~90min in this embodiment; the curing treatment is carried out in an air atmosphere.

[0036] To address the problem of physical and chemical delamination of the catalytic layer in self-supporting electrodes in existing technologies, this invention provides a simple and controllable technical solution. The preparation method includes four steps: substrate pretreatment, coating solution preparation, layered coating, and drying and calcination. By controlling the number of layered coatings and key component parameters, this invention utilizes the coupling effects between the bottom layer and the substrate, the active layer and the bottom layer, and the protective layer and the active layer to enhance the mechanical bonding ability and electronic conductivity of the electrode, achieving the preparation of a highly stable catalytic layer that can be widely applied in the field of water electrolysis for hydrogen production. This invention has advantages such as good coating controllability, strong component tunability, excellent catalytic activity of the resulting anode material, and good stability, making it suitable for industrial-scale mass production.

[0037] The present invention also provides the application of the high-efficiency oxygen evolution anode described in the above technical solution or the high-efficiency oxygen evolution anode prepared by the preparation method described in the above technical solution in oxygen evolution during water electrolysis.

[0038] The present invention does not impose any particular limitation on the application of the high-efficiency oxygen-evolving anode in oxygen evolution in water electrolysis; any application method known in the art can be used.

[0039] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0040] Example 1 Step 1: Substrate pretreatment. A 46-mesh, 0.25mm diameter twill woven nickel mesh was selected as the substrate. The substrate underwent a series of processes including degreasing, washing, pickling, washing, and drying. Degreasing was performed using a mixed solution of 25g / L sodium carbonate and 15g / L sodium hydroxide, with an ultrasonic degreasing power of 300W, a frequency of 28kHz, and a time of 20min. Pickling was performed using a 1mol / L hydrochloric acid solution with an ultrasonic pickling power of 300W, a frequency of 28kHz, and a time of 10min. Washing was done with deionized water. Drying was performed at 70℃ for 10min. After pretreatment, the surface roughness of the substrate was Ra = 1.0~2.5μm. Step 2: Preparation of the three coating solutions: base layer, active layer, and stabilizing layer. Prepare the bottom coating solution (n=1 layer) using deionized water: nickel nitrate, cerium nitrate, and ethylene glycol in a molar ratio of 5:4:10, pH=1.4. The concentration of nickel nitrate in the bottom coating solution is 0.05 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of ethylene glycol is 0.10 mol / L. The active layer coating solution (n=4 layers) was prepared using deionized water: nickel nitrate, ferric nitrate, ammonium molybdate, ammonium metatungstate, and organic additives (urea, ethylene glycol, and citric acid) in a molar ratio of 20:2:1:1:30, with a pH of 3.5. The concentrations of nickel nitrate, ferric nitrate, ammonium molybdate, and ammonium metatungstate in the active layer coating solution were 0.24 mol / L, 0.024 mol / L, 0.012 mol / L, and 0.012 mol / L, respectively. The total concentration of urea, ethylene glycol, and citric acid was 0.36 mol / L. The stabilizing layer coating solution (n=1 layer) was prepared using deionized water: nickel nitrate, sodium dihydrogen phosphate, cerium nitrate, and ethylene glycol in a molar ratio of 7:7:2:5, with a pH of 4.5. The concentrations of nickel nitrate, sodium dihydrogen phosphate, cerium nitrate, and ethylene glycol in the stabilizing layer coating solution were 0.07 mol / L, 0.07 mol / L, 0.02 mol / L, and 0.05 mol / L. Bottom Coating: The bottom coating solution is evenly applied to the pretreated substrate surface, controlling the coating thickness to approximately 8 μm. After coating, it is dried at 70°C for 10 min, and then calcined at 350°C in air for 6 min. Active Layer Coating: The active layer coating solution is applied to the bottom surface in four layers, each 15 μm thick. After each layer is coated, it is dried at 70°C for 10 min, and then calcined at 350°C in air for 6 min.

[0041] Stabilizing layer coating: A stabilizing layer coating liquid is uniformly coated on the surface of the active layer, with a coating thickness of 10μm. After coating, the coating is dried at 70℃ for 10min, then calcined at 400℃ for 60min in air atmosphere, and finally cured at 380℃ for 30min in air atmosphere. After cooling to 25℃, the total thickness of the complete coating is 78μm, and the coating is dense and non-porous. Performance: The high-efficiency oxygen evolution anode prepared in this embodiment, according to the relevant requirements of GB / T 45092-2024 standard, exhibits a detachment rate of 0.5 mg / cm³ after 1 hour of ultrasonication in pure water. 2 Oxygen evolution overpotential 275mV@10mA / cm 2 At 300mA·cm -2 It operated stably for 600 hours at current density with a cell voltage decay rate of 8.3µV / h, demonstrating good mechanical stability, oxygen evolution activity, and electrochemical stability.

[0042] Example 2 Step 1: Substrate pretreatment, selecting an areal density of 420 g / m³ 2 Nickel foam with a porosity of 90% was used as the substrate and underwent continuous treatment including degreasing, washing, pickling, washing, and drying. Degreasing was performed by ultrasonic degreasing of the substrate with a mixed solution of 25 g / L sodium carbonate and 15 g / L sodium hydroxide at a power of 500 W, a frequency of 28 kHz, and a time of 20 min. Pickling was performed by ultrasonic pickling in a 1 mol / L hydrochloric acid solution at a power of 500 W, a frequency of 28 Hz, and a time of 10 min. Washing was performed by rinsing with deionized water. Drying was performed at a temperature of 70℃ for 20 min. The surface roughness of the substrate after pretreatment was 2.0~4.0 μm.

[0043] Step 2: Preparation of coating solutions for the active layer and stabilizing layer: Prepare the bottom coating solution (n=1 layer) using deionized water: nickel nitrate, zirconium nitrate, and ethylene glycol in a molar ratio of 1:1:3, pH=1.4. The concentration of nickel nitrate in the bottom coating solution is 0.05 mol / L, the concentration of zirconium nitrate is 0.05 mol / L, and the concentration of ethylene glycol is 0.15 mol / L. The active layer coating solution (n=3 layers) was prepared using deionized water: nickel nitrate, ferric nitrate, zirconium nitrate, and ethylene glycol in a molar ratio of 8:2:1:13, with a pH of 1.7. The concentrations of nickel nitrate, ferric nitrate, zirconium nitrate, and ethylene glycol in the bottom coating solution were 0.08 mol / L, 0.02 mol / L, 0.01 mol / L, and 0.13 mol / L, respectively.

[0044] The stabilizing coating solution was prepared using deionized water: nickel nitrate, sodium dihydrogen phosphate, zirconium nitrate, and ethylene glycol in a molar ratio of 5:5:1:7, with pH=4. The concentrations of nickel nitrate, sodium dihydrogen phosphate, zirconium nitrate, and ethylene glycol in the stabilizing coating solution were 0.05 mol / L, 0.05 mol / L, 0.01 mol / L, and 0.07 mol / L.

[0045] Step 3: Layered lamination Underlayer coating: The underlayer coating liquid is evenly coated on the surface of the pretreated substrate, and the coating thickness is controlled to be about 16μm. After coating, it is dried at 70℃ for 20min and then calcined at 400℃ for 15min in air atmosphere.

[0046] Active layer coating: The active layer coating solution is coated in 3 layers on the bottom surface, each layer is 30μm thick. After each layer is coated, it is dried at 70℃ for 20min and then calcined at 400℃ for 15min in air atmosphere.

[0047] Stabilizing layer coating: A stabilizing layer coating solution is uniformly coated on the surface of the active layer, with a coating thickness of 20 μm. After coating, the coating is dried at 70℃ for 20 min, then calcined at 400℃ for 15 min in air atmosphere, and cooled to 25℃. The total thickness of the complete coating is 126 μm, and the coating is dense and non-porous. Performance: The high-efficiency oxygen evolution anode prepared in this embodiment exhibits a shedding rate of 0.3 mg / cm³ in pure water after 1 hour of ultrasonication. 2 Oxygen evolution overpotential 270mV@10mA / cm 2 At 300mA·cm -2 It operates stably for 600 hours at current density with a cell voltage decay rate of 10µV / h.

[0048] Comparative Example 1 The preparation method is the same as in Example 1, except that there is no layered structure of bottom layer and stable layer, only active layer.

[0049] The active layer coating solution (n=6 layers) consists of nickel nitrate, ferric nitrate, cerium nitrate, urea, ethylene glycol, and citric acid in a molar ratio of 10:2:1:10:10:2, with a pH of 3.5.

[0050] Six layers of film were applied to the surface of the pretreated substrate, each layer being 3 μm thick. After each layer was applied, the substrate was calcined at 300°C for 6 min in an air atmosphere. Finally, the substrate was cured at 400°C for 1 h after the film was applied.

[0051] Performance: The high-efficiency oxygen evolution anode prepared in this comparative example, according to the relevant requirements of GB / T 45092-2024 standard, exhibited a detachment rate of less than 1 mg / cm³ after 1 hour of ultrasonication in pure water. 2 Oxygen evolution overpotential 280mV@10mA / cm 2 .

[0052] Comparative Example 2 The preparation method is the same as in Example 1, except that the coating solution of the bottom layer, active layer and stabilizing layer is mainly composed of nickel or nickel-iron components.

[0053] The bottom coating solution is nickel nitrate and ethylene glycol in a molar ratio of 1:1.

[0054] Active layer coating solution (n=4 layers): nickel nitrate, ferric nitrate, urea, ethylene glycol and citric acid, with a molar ratio of 10:2:10:10:2, pH=3.5.

[0055] The stabilizing coating solution is composed of nickel nitrate and ethylene glycol in a molar ratio of 1:1.

[0056] The obtained anodic oxygen evolution overpotential is 290 mV (10 mA / cm). 2 The concentration was significantly higher than that in Example 1.

[0057] Performance testing (1) Figure 1 This is a SEM image of the high-efficiency oxygen evolution anode prepared in Example 1 of the present invention, wherein... from Figure 1 As can be seen from the above, the electrode active components in the high-efficiency oxygen evolution anode prepared by the present invention are uniformly loaded and free from agglomeration and shedding defects, providing sufficient and uniformly distributed oxygen evolution active sites for the electrode.

[0058] (2) Figure 2 The image shows the EDS elemental distribution of the high-efficiency oxygen evolution anode prepared in Example 1 of this invention.

[0059] Figure 2 The results demonstrate that Ni, Fe, Ce, Mo, W, and P elements were successfully doped into the electrode material, achieving multi-element synergistic modification.

[0060] (3) Figure 3 This is a performance comparison chart of the high-efficiency oxygen evolution anodes prepared in Examples 1, 2, and Comparative Example 1. The anodes were measured using the three-electrode constant current step method at 10, 100, 300, 500, 800, and 1000 mA / cm². 2 Under these conditions, each electrical density was continuously tested for 150 seconds without IR compensation.

[0061] from Figure 3 As can be seen from the results, the oxygen evolution catalytic performance of the electrode in the embodiment is significantly better than that in the comparative example, and multi-element doping modification can effectively improve the electrode catalytic activity.

[0062] (4) Figure 4 The graph shows the cell voltage-time curves for different anodes in the electrolytic system at 3000 A / m. 2 The test was conducted under industrial electrolysis conditions at 85℃. Figure 4 As can be seen, compared with commercial Raney nickel anodes, the anodes prepared in this embodiment of the invention have lower electrolysis energy consumption and better operational stability.

[0063] (5) Figure 5 The image shows the SEM morphology of the high-efficiency oxygen evolution anodic electrolysis reaction prepared in Example 1.

[0064] from Figure 5 It can be seen that the high-efficiency oxygen evolution anode prepared by the present invention can be reconstructed in situ to form a dense nanosheet structure through electrolysis, further optimizing the catalytic interface.

[0065] (6) Figure 6 The images show a comparison of the electrode materials after sonication in pure water for 1 hour. In the images, a is the high-efficiency oxygen-evolving anode prepared in Example 1, b is the high-efficiency oxygen-evolving anode prepared in the comparative example, and c is the high-efficiency oxygen-evolving anode prepared in the comparative example.

[0066] from Figure 6 It can be seen that after bottom-contact ultrasonication for 1 hour in aqueous solution, the solution of material in Example 1 is clear, while the other two solutions are yellow. This shows that the mechanical stability of the high-efficiency oxygen-evolving anode prepared in Example 1 is better than the others, indicating that the layered structure can effectively improve the bonding force.

[0067] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A high-efficiency oxygen evolution anode, characterized in that, It includes a substrate and a bottom layer, an active layer and a stabilizing layer sequentially loaded on the surface of the substrate, wherein the active layer has n layers, n=2~10; The bottom layer comprises a composite oxide formed of Ni and a metal with a valence of +4 or higher; the metal with a valence of +4 or higher includes one or more of Zr, Ce, Ta, and Nb; The active layer comprises a composite oxide formed from Ni, Fe, and doped metals; the doped metals include one or more of Mn, Ce, Zr, Co, W, Mo, and Cu. The stabilizing layer comprises a composite oxide formed of Ni, P, and high-valence metals; the high-valence metals include one or more of Ce, Zr, and W.

2. The high-efficiency oxygen evolution anode according to claim 1, characterized in that, The total coating thickness after the bottom layer, active layer and stabilizing layer are stacked is 20~150μm.

3. The method for preparing the high-efficiency oxygen evolution anode according to claim 1 or 2, characterized in that, Includes the following steps: The substrate surface after pretreatment is coated with a bottom coating solution, an active layer coating solution and a stabilizing layer coating solution in sequence. The active layer coating solution is coated n times, where n = 2~10. After each coating, the substrate is dried and calcined in sequence to finally obtain a high-efficiency oxygen evolution anode. The underlying coating solution comprises Ni salt, a metal salt with a ≥+4 valence, a first organic additive, and water; the metal salt with a ≥+4 valence comprises one or more of Zr, Ce, Ta, and Nb; The active layer coating solution comprises Ni salt, Fe salt, doped metal salt, a second organic additive, and water; the doped metal salt comprises one or more of Mn salt, Ce salt, Zr salt, Co salt, W salt, Mo salt, and Cu salt; The stabilizing coating solution comprises Ni salt, phosphate, high-valence metal salt, a third organic additive, and water; the high-valence metal salt comprises one or more of Ce salt, Zr salt, and W salt.

4. The preparation method according to claim 3, characterized in that, The first organic additive, the second organic additive, and the third organic additive are each one or more of urea, ethylene glycol, propylene glycol, n-butanol, and citric acid.

5. The preparation method according to claim 3, characterized in that, The thickness of the liquid film formed by the bottom coating liquid is 5~20μm.

6. The preparation method according to claim 3, characterized in that, The thickness of the liquid film formed by each active layer coating solution is 10~30μm.

7. The preparation method according to claim 3, characterized in that, The thickness of the liquid film formed by the stabilizing layer coating liquid is 5~20μm.

8. The preparation method according to claim 3, characterized in that, The roasting temperature is 200~550℃, and the holding time is 3~60min.

9. The preparation method according to claim 3, characterized in that, After the final firing, the process also includes a curing treatment; the curing treatment temperature is 350~700℃, and the holding time is 30~120min.

10. The application of the high-efficiency oxygen evolution anode according to claim 1 or 2 or the high-efficiency oxygen evolution anode prepared by the preparation method according to any one of claims 3 to 9 in oxygen evolution during water electrolysis.

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