Catalyst for in-situ reconstruction of gamma-phase nickel oxyhydroxide on foamed nickel and preparation and application thereof

Abstract

The invention belongs to the technical field of electrode materials, and particularly relates to an in-situ reconstruction gamma-phase nickel oxyhydroxide catalyst on foamed nickel as well as preparation and application of the in-situ reconstruction gamma-phase nickel oxyhydroxide catalyst. The preparation method comprises the following steps: immersing foamed nickel in a 0.5-5.0 g / L ammonium molybdate solution for ultrasonic treatment, and then placing the foamed nickel and the ammonium molybdate solution in a stable temperature field of 30-60 DEG C for reaction to obtain a foamed nickel loaded nickel molybdate precursor; carrying out ultrasonic cleaning on the precursor by using ultrapure water, and then drying in an inert gas atmosphere; and fixing the dried precursor as a working electrode, KOH as an electrolyte, a Pt sheet as a counter electrode and an Ag / AgCl electrode as a reference electrode to form a three-electrode system, communicating an electrochemical workstation, performing cyclic voltammetry scanning in a 1.0-3.0 VvsRHE interval, and completing in-situ reconstruction to obtain the target catalyst. The catalyst prepared in the invention has excellent activity in alkaline water electrolysis oxygen evolution reaction, can effectively reduce system energy consumption, and has high electron transfer efficiency and abundant active sites.

Description

Technical Field

[0001] This invention belongs to the field of electrode material technology, and particularly relates to an in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam and its preparation and application. Background Technology

[0002] my country's new energy industry is developing rapidly—in the first quarter of 2025, wind and solar power generation added a combined 74.33 million kilowatts of installed capacity, bringing the cumulative installed capacity to 1.482 billion kilowatts, surpassing thermal power capacity for the first time. However, the rapid expansion of new energy capacity makes the traditional grid-dependent consumption model difficult to adapt to the high proportion of wind and solar power integrated into the power system. Meanwhile, hydrogen energy, as a core carrier for end-use green carbon transformation, is experiencing continuous market demand growth and has become a key component of the future national energy system. Against this backdrop, water electrolysis technology, as a cornerstone for reshaping the global energy landscape, can not only solve the problem of high-proportion renewable energy consumption but also produce green hydrogen on a large scale, playing an irreplaceable role in accelerating energy structure transformation.

[0003] Currently, although alkaline water electrolysis (AWE) technology has achieved industrial application, with electrolyzer hydrogen production exceeding 4000 Nm³ / h, high DC power consumption (4.4 kWh / Nm³) remains the core bottleneck restricting its economic viability. The root cause of this excessive power consumption lies in the insufficient performance of electrode materials. As the core component of water electrolysis technology, the electrode directly determines reaction efficiency and energy consumption. Limited by raw material costs and the difficulty of scaling up the synthesis process, current mainstream AWE anodes still rely on nickel mesh or nickel foam substrates, resulting in a significantly high overpotential (η) for the oxygen evolution reaction (OER), further increasing the energy consumption of the device. Therefore, developing an anode catalyst that is easy to scale up industrially, can withstand harsh electrolysis environments, and possesses high activity has become a key requirement for overcoming the current bottlenecks in AWE technology.

[0004] Existing strategies for optimizing the performance of nickel foam substrates include non-metallic element doping, alloying, and in-situ reconstruction. Among these, nickel-iron layered double hydroxide (NiFe LDH) is a widely studied alkaline water electrolysis catalyst. However, this type of material has a significant drawback: it cannot withstand industrial-grade high current densities (≥500 mA / cm²). -2During operation, Fe is prone to leaching due to its thermodynamic properties, leading to damage to the catalyst's crystal structure and a sharp decline in activity and stability. Furthermore, the synthesis of NiFe LDH requires high temperature and high pressure conditions, which not only increases preparation costs but also limits the large-scale application of the process. Therefore, developing single nickel-based catalysts with comparable activity to NiFe LDH and capable of long-term stability has become an important research direction in this field.

[0005] For pure nickel-based catalysts, the core active site for OER (Oxygen Response) has been confirmed to be nickel oxyhydroxide (NiOOH). Efficiently inducing the reconstruction of nickel-based precursors to form NiOOH is a key pathway to reduce OER overpotential. Furthermore, in-situ reconstruction of NiOOH on a nickel foam substrate offers significant advantages: it avoids the use of polymer binders and conductive additives, promotes the exposure of active sites, reduces charge transfer resistance, and simplifies electrode production and electrolytic cell assembly processes. Currently, nickel molybdate is one of the commonly used precursors for in-situ reconstruction to generate NiOOH—under both alkaline and high bias conditions, Mo is converted into NiO4. 2- The nickel molybdate precursor exists in a stable form, and its desorption process can drive the reconstruction of nickel molybdate into NiOOH. However, existing nickel molybdate precursor preparation technologies have significant shortcomings: they rely on energy-intensive operations (such as high-temperature treatment) and require the addition of nickel salts, which weakens the interaction between the synthesized nickel molybdate layer and the nickel foam substrate. Simultaneously, the Ni framework is susceptible to high-temperature oxidation and embrittlement. Ultimately, the reconstructed catalyst has a loose structure and cannot meet the ampere-level current densities (≥1.0 Acm⁻¹) required in industrial applications. -2 To achieve long-term stable operation.

[0006] To address the core technical problems of "high overpotential, high energy consumption in synthesis, and poor stability at high current density" in the above-mentioned alkaline water electrolysis anode catalysts, this invention provides an in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam and its preparation and application: using optimized nickel foam supported on nickel molybdate as a precursor, by innovatively adopting a stable and mild temperature field (avoiding high energy consumption) and eliminating the addition of additional nickel salts, the controllable formation of the precursor layer on the surface of nickel foam and the moderate reconstruction of the catalyst are achieved. Ultimately, the catalyst can overcome the bottleneck of long-term stability at ampere-level current densities while possessing excellent OER activity. Summary of the Invention

[0007] The purpose of this invention is to provide an in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam, its preparation and application, to solve the problems in existing alkaline water electrolysis technology, such as high DC power consumption due to the high overpotential of the oxygen evolution reaction in the mainstream anode, and the difficulty in optimization due to the limitations of raw material costs and the difficulty of scale-up synthesis processes. It also addresses the problems in existing nickel foam modification strategies, such as the easy leaching of Fe elements and lattice structure damage of nickel-iron layered double hydroxide catalysts under high current densities, leading to a significant decrease in activity and stability, and the high cost of high-temperature and high-pressure operation required for their synthesis. Furthermore, it solves the problems in pure nickel-based catalysts, such as the need for high-energy-consuming conditions and the addition of nickel salts in the preparation of nickel molybdate precursors, which weakens the bonding force between the nickel molybdate layer and the nickel foam substrate, makes the Ni framework susceptible to high-temperature oxidation and embrittlement, and ultimately prevents the reconstructed catalyst from operating stably for a long time at ampere-level current densities.

[0008] To achieve the above objectives, the present invention provides the following solution: A method for preparing an in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam, comprising: S1. Immerse nickel foam in a 0.5~5.0 g / L ammonium molybdate solution and sonicate. Then place both in a stable temperature field of 30~60℃ to react and obtain nickel foam-supported nickel molybdate precursor. S2. The precursor is ultrasonically cleaned with ultrapure water and then dried in an inert gas atmosphere. S3. The dried precursor was fixed as the working electrode. A three-electrode system was formed using O2-saturated 0.1~1.0M KOH as the electrolyte, Pt sheet as the counter electrode and Ag / AgCl electrode as the reference electrode. After connecting to the electrochemical workstation, cyclic voltammetry was performed in the range of 1.0~3.0V vs RHE to complete in-situ reconstruction and obtain the target catalyst.

[0009] Preferably, the ultrasonic treatment time in step S1 is 2-5 minutes.

[0010] Preferably, the reaction time in step S1, which involves placing the sample in a stable temperature field of 30-60°C, is 4-8 hours.

[0011] Preferably, the ultrasonic cleaning time in step S2 is 2-5 minutes.

[0012] Preferably, the temperature of the inert gas atmosphere in step S2 is 30~60℃.

[0013] Preferably, the drying time under an inert gas atmosphere in step S2 is 12-18 hours.

[0014] Preferably, the number of cyclic voltammetric scans in the 1.0~3.0V vs RHE range in step S3 is 20~100 times.

[0015] An in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam is prepared by the aforementioned preparation method.

[0016] Application of the aforementioned in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam in the oxygen evolution reaction of water electrolysis under alkaline conditions.

[0017] Compared with the prior art, the present invention has the following advantages and technical effects: In this invention, the in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam exhibits excellent activity in the alkaline water electrolysis oxygen evolution reaction, effectively reducing system energy consumption, and possesses high electron transfer efficiency and abundant active sites. This catalyst can achieve long-term stable operation at ampere-level current densities, preventing damage to the nickel foam substrate due to localized environmental erosion.

[0018] The synthesis process employs mild conditions, requires no high-energy-consuming operations or additional complex reagents, is simple and cost-effective, and can achieve controllable formation of the precursor layer and moderate catalyst reconstruction. It is easy to scale up production and can serve as an ideal replacement for traditional alkaline water electrolysis anode materials, with broad application prospects. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1 This is a schematic diagram of the preparation process of the in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam of the present invention; Figure 2 This is a high-resolution transmission electron microscope (TEM) characterization image of the catalyst prepared in Example 1 of the present invention; Figure 3 a is a low-magnification (scale bar 10 μm) scanning electron microscope (SEM) image of the catalyst in Example 1; Figure 3 b is a low-rate (scale bar 1 μm) magnified SEM image of the catalyst in Example 1; Figure 3 c is a high-rate (scale bar 200 nm) magnified SEM image of the catalyst in Example 1; Figure 3 d is a pseudo-color image of the elemental distribution of the catalyst in Example 1; Figure 3 e is the molybdenum (Mo) element mapping distribution diagram of the catalyst in Example 1; Figure 3 f is the nickel (Ni) element mapping distribution diagram of the catalyst in Example 1; Figure 3 g is the oxygen (O) element mapping distribution diagram of the catalyst in Example 1; Figure 4 The X-ray diffraction pattern of the catalyst prepared in Example 1 of this invention; Figure 5 Cyclic voltammetry curves were obtained by activating the nickel foam supported nickel molybdate precursor prepared in Example 1 of the present invention in O2-saturated 1.0 M KOH solution to reconstruct the γ-phase nickel hydroxide catalyst on the nickel foam in situ. Figure 6 The linear sweep voltammetric curves of the in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam prepared in Example 1 of this invention are obtained in an O2-saturated 1.0 M KOH solution. Figure 7 The in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam prepared in Example 1 of this invention was subjected to 1.0 M KOH solution at 1.0 A cm⁻¹. -2 Long-term stability curve at current density for 1100 h; Figure 8 The in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam prepared in Example 1 of this invention was subjected to 3.0 A cm⁻¹ in 1.0 M KOH solution. -2 Long-term stability curve at current density for 100 h; Figure 9 a is a low-magnification (scale bar 20 μm) scanning electron microscope (SEM) image of NiMoO4 / NF-1100h; Figure 9 b is a high-magnification (10μm scale bar) SEM image of NiMoO4 / NF-1100h. Figure 9 c is a high-magnification (1 μm scale bar) SEM image of NiMoO4 / NF-1100h; Figure 9 d is a high-magnification (scale bar 200nm) SEM image of NiMoO4 / NF-1100h; Figure 9 e is a pseudo-color image of the elemental distribution of NiMoO4 / NF-1100h; Figure 9 f is the nickel (Ni) element mapping distribution diagram of NiMoO4 / NF-1100h; Figure 9 g is the oxygen (O) element mapping distribution diagram of NiMoO4 / NF-1100h. Detailed Implementation

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

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1: This embodiment provides a method for preparing an in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam, the core process of which is as follows: Figure 1 As shown, the specific steps include: (1) Weigh 2.5g of analytical grade ammonium molybdate heptahydrate ((NH4)6Mo7O 24 7H₂O) slowly dissolves in 1000 mL of ultrapure water (resistivity ≥ 18.2 MΩ). In a solution of ammonium molybdate, the solution was magnetically stirred for 10 minutes until completely dissolved, yielding an ammonium molybdate solution with a concentration of 2.5 g / L. (2) Cut industrial-grade nickel foam with a size of 20cm² (e.g., 5cm×4cm), purity of 99.9%, pore size of 100PPI, and thickness of 1mm. First, rinse the surface impurities with ultrapure water, then completely immerse it in 100mL of the ammonium molybdate solution obtained in step (1), and place it in a 300W, 40kHz ultrasonic cleaner for 2min to promote full contact between the surface of the nickel foam and the ammonium molybdate solution. (3) Place the 500mL open beaker containing nickel foam and ammonium molybdate solution in step (2) into a forced-air drying oven and let it stand for 6 hours in a stable temperature field of 50℃ to generate a nickel molybdate layer on the surface of the nickel foam in situ, and obtain the nickel foam-supported nickel molybdate precursor (NiMoO4 / NF). (4) Take out the nickel foam supported nickel molybdate precursor obtained in step (3) from the solution, soak and wash it three times with ultrapure water (10 min each time), and place it in a 300W, 40kHz ultrasonic cleaner for 2 min to completely remove the unreacted ammonium molybdate residue on the surface. Finally, use filter paper to dry the surface moisture. (5) Place the nickel foam supported nickel molybdate precursor treated in step (4) into a vacuum drying oven, introduce nitrogen gas with a purity of 99.99% (flow rate 20~50mL / min), and dry it for 12h in a dynamic inert gas atmosphere at 30℃ to obtain the dried NiMoO4 / NF precursor. (6) Cut the dried NiMoO4 / NF precursor obtained in step (5) into small pieces of 1cm×1cm and fix them with Pt sheet electrode clamps as working electrodes; select a single cell with a volume of 100mL as the site for in-situ reconstruction of the precursor, add 1.0M KOH solution saturated with O2 (O2 is 99.99% high purity oxygen, the gas flow rate is 50mL / min, and the gas flow is continued for 30min to ensure saturation) to the electrolytic cell as electrolyte; select 1cm×1cm Pt sheet as counter electrode and Ag / AgCl electrode saturated with KCl electrolyte as reference electrode; connect the working electrode, counter electrode and reference electrode to the electrochemical workstation in a three-electrode system to form a test unit; (7) Perform cyclic voltammetry scanning on the test unit obtained in step (6): set the scanning range to 1.0~3.0VvsRHE, the scanning rate to 50mV / s, and perform 30 cyclic scans (observe the peak shape of the cyclic voltammetry curve during the period, and determine that the precursor reconstruction is complete when the peak position and intensity are stable).

[0023] The final in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam, denoted as γ-NiOOH / NF-50-6-2.5, is recorded as follows: Figure 5 As shown.

[0024] To verify whether the microstructure and macromorphology of the catalyst meet the design objectives, the following characterization analysis was performed: High-resolution transmission electron microscopy (TEM) characterization: Results are as follows Figure 2 As shown in the figure, two sets of characteristic lattice spacings are clearly observed in the spectrum: 0.264 nm corresponds to the Ni(OH)2 (100) crystal plane (the intermediate accompanying phase in the in-situ reconstruction process of γ-NiOOH), and 0.668 nm corresponds to the NiOOH (002) crystal plane (the characteristic crystal plane of γ-NiOOH), which proves that the target active phase γ-NiOOH has been successfully generated and the crystal structure is complete. High-resolution scanning electron microscopy (SEM) characterization: Results are as follows Figure 3 a~ Figure 3 As shown in g, low-magnification (10 μm scale) images reveal that the catalyst forms a uniform porous structure along the high curvature region of the nickel foam surface. High-magnification (1 μm, 200 nm scale) images further confirm the good connectivity of the porous structure. Combined with the elemental mapping diagram, it can be observed that the Mo element is absent, indicating that the Mo element is completely dissolved during the reconstruction process. This morphology and elemental distribution characteristics can effectively increase the specific surface area, expose more active sites, and accelerate electrolyte mass transfer, laying a structural foundation for the subsequent excellent catalytic performance.

[0025] Example 2 This embodiment also provides a method for preparing an in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam. The only difference from Example 1 is that the amount of ammonium molybdate heptahydrate in step (1) is changed to 0.5 g, and the γ-NiOOH / NF-50-6-0.5 catalyst is obtained.

[0026] Example 3 This embodiment also provides a method for preparing an in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam. The only difference from Example 1 is that the amount of ammonium molybdate heptahydrate in step (1) is changed to 5.0 g, and the γ-NiOOH / NF-50-6-5.0 catalyst is obtained.

[0027] Example 4 This embodiment also provides a method for preparing an in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam. The only difference from Example 1 is that the synthesis temperature in step (3) is changed to 40℃, and the γ-NiOOH / NF-40-6-2.5 catalyst is obtained.

[0028] Example 5 This embodiment also provides a method for preparing an in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam. The only difference from Example 1 is that the synthesis time in step (3) is changed to 4 h, and the γ-NiOOH / NF-50-4-2.5 catalyst is obtained.

[0029] Experimental Example 1 This experimental example involves testing the electrocatalytic oxygen evolution activity of the in-situ reconstructed γ-phase nickel hydroxide catalyst on the nickel foam prepared in Example 1. The specific process is as follows: (1) Cut the γ-NiOOH / NF-50-6-2.5 catalyst into 1×1cm² size, seal the non-active area with alkali-resistant tape (exposing only 1×1cm² front as the active area), and then fix it with Pt sheet electrode clamp as the working electrode. (2) A single-cell electrolytic cell with a volume of 100 mL was selected as the OER generation site. A 1.0 M KOH solution saturated with 99.99% high-purity O2 (O2 aeration rate of 50 mL / min, continuous aeration for 30 min until saturation, and continuous aeration at a rate of 20 mL / min during the test) was added as the electrolyte. 1×1 cm... 2 The Pt sheet and the Ag / AgCl electrode of saturated KCl electrolyte are used as the counter electrode and reference electrode, respectively. The working electrode described in (1) and the above parts are combined to form a test unit and connected to the electrochemical workstation. (3) The test unit obtained in (2) was subjected to linear scanning voltammetry in the potential range of 1.0~3.0V vs RHE, with a scanning rate of 5mV / s. Before the test, the solution resistance (RΩ) was measured by the current interruption method, and the test curve was 100% IR compensated. The test temperature was controlled at room temperature (25±1℃). (4) Test results are as follows Figure 6 As shown, the γ-NiOOH / NF-50-6-2.5 catalyst requires only 302 mV overpotential to reach 10 mA cm⁻¹. -2 This can significantly reduce the energy consumption of the device.

[0030] Note: Overpotential calculations are based on reference electrode potential calibration. The conversion formula from Ag / AgCl electrode (saturated KCl electrolyte) to reversible hydrogen electrode (RHE) at room temperature is as follows: E(RHE) = E(Ag / AgCl) + 0.059 × pH + E 0 (Ag / AgCl) Where E 0 (Ag / AgCl) (standard electrode potential at room temperature) = 0.1976V, 1.0M KOH solution pH = 14, substituting into the formula, we get: E(RHE) = E(Ag / AgCl) + 1.0536V.

[0031] Experimental Example 2 This experimental example involves testing the electrocatalytic oxygen evolution stability of the in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam prepared in Example 1. The specific process is as follows: (1) Cut the γ-NiOOH / NF-50-6-2.5 catalyst into 1×1cm² size, seal the non-active area with alkali-resistant tape (exposing only 1×1cm² front as the active area), and then fix it with Pt sheet electrode clamp as the working electrode. (2) A single-cell electrolytic cell with a volume of 100 mL was selected as the reaction site. A 1.0 M KOH solution saturated with 99.99% high-purity O2 was added to it (aeration was maintained at a rate of 20 mL / min throughout the test to avoid O2 depletion affecting the reaction) as the electrolyte. 1 × 1 cm 2 The Pt sheet and the Ag / AgCl electrode of saturated KCl electrolyte were used as the counter electrode and reference electrode, respectively. The working electrode described in (1) and the above parts were combined to form a test unit. The electrochemical workstation was connected and a constant potential test of 1.77V vs RHE was set. The current response signal was recorded. During the test, fresh O2 saturated 1.0M KOH electrolyte was replaced every 200h (to avoid electrolyte concentration drift or impurity accumulation). The current density fluctuation range ≤ ±3% was used as the standard for stable operation. (3) Test results are as follows Figure 7 As shown, the γ-NiOOH / NF catalyst can maintain 1.0 Acm at this potential. -2 Stable current density operation for 1100 hours; (4) Change the constant potential test in operation (2) to a constant current test with a step current of 3.0A (corresponding to 1×1cm). 2 The active area has an actual current density of 3.0 A / cm². -2 Record the potential response signal, and use a potential fluctuation range of ≤±50mV as the criterion for stable operation; (5) Test results are as follows Figure 8 As shown, the γ-NiOOH / NF-50-6-2.5 catalyst can maintain a stable operating potential of 2.2V vs RHE for 100h at this current density.

[0032] In addition, after the stability test, the catalyst was characterized by scanning electron microscopy (SEM), and the results are as follows: Figure 9 a~ Figure 9 As shown in g, the results indicate that the γ-NiOOH / NF-50-6-2.5 catalyst operates at 1.0 A cm⁻¹. -2 After running at current density for 1100 hours, the morphology remained basically intact, further confirming its structural stability.

[0033] The activity and stability tests of the catalysts in Experimental Examples 1 and 2 show that γ-NiOOH / NF, which is moderately reconstructed from nickel molybdate precursor synthesized under mild conditions, not only has excellent performance in catalyzing oxygen release from water, but also maintains long-term stable operation at ampere-level current densities.

[0034] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing an in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam, characterized in that, include: S1. Immerse nickel foam in a 0.5~5.0 g / L ammonium molybdate solution and sonicate. Then place both in a stable temperature field of 30~60℃ to react and obtain nickel foam-supported nickel molybdate precursor. S2. The precursor is ultrasonically cleaned with ultrapure water and then dried in an inert gas atmosphere. S3. The dried precursor was fixed as the working electrode. A three-electrode system was formed using O2-saturated 0.1~1.0M KOH as the electrolyte, Pt sheet as the counter electrode and Ag / AgCl electrode as the reference electrode. After connecting to the electrochemical workstation, cyclic voltammetry was performed in the range of 1.0~3.0V vs RHE to complete in-situ reconstruction and obtain the target catalyst.

2. The method for preparing an in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam according to claim 1, characterized in that: The ultrasonic treatment time in step S1 is 2-5 minutes.

3. The method for preparing an in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam according to claim 1, characterized in that: In step S1, the reaction time in a stable temperature field of 30~60℃ is 4~8h.

4. The method for preparing an in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam according to claim 1, characterized in that: The ultrasonic cleaning time in step S2 is 2-5 minutes.

5. The method for preparing an in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam according to claim 1, characterized in that: In step S2, the temperature of the inert gas atmosphere is 30~60℃.

6. The method for preparing an in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam according to claim 1, characterized in that: The drying time under an inert gas atmosphere in step S2 is 12-18 hours.

7. The method for preparing an in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam according to claim 1, characterized in that: The number of cyclic voltammetric scans in the 1.0~3.0V vs RHE range in step S3 is 20~100 times.

8. An in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam, prepared by the preparation method of the in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam as described in any one of claims 1-7.

9. An application of an in-situ reconstructed γ-phase nickel hydroxide catalyst on nickel foam as described in claim 8 in the oxygen evolution reaction of water electrolysis under alkaline conditions.

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