Anion-cation-doped oxygen vacancy-rich nickel-molybdenum-based nano composite material and preparation and application thereof

Abstract

The invention discloses an anion-cation-doped oxygen vacancy-rich nickel-molybdenum-based nano composite material as well as preparation and application thereof, and belongs to the technical field of electro-catalytic materials. The preparation method comprises the following steps: growing a Cu-doped NiMoO4 nanorod array on foamed nickel in situ through a hydrothermal method; carrying out surface vulcanization through secondary hydrothermal reaction; and finally, performing electrochemical reconstruction under high current density to form the nickel-molybdenum-based nano composite material rich in 1T-MoS2 / Ni (OH) 2 heterojunction, hydroxyl vacancy and mesoporous structure. The catalyst shows excellent hydrogen evolution activity and stability in a 1.0 M KOH electrolyte, the overpotential is only 247mV under the industrial-grade current density of 1000mA cm <-2 >, and the catalyst can stably run for more than 1000 hours, and is suitable for an efficient and long-life system for producing hydrogen by electrolyzing water.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalytic materials technology, specifically relating to nickel-molybdenum-based nanocomposites doped with cations and anions and rich in oxygen vacancies, and their preparation and application. Background Technology

[0002] Hydrogen energy, as a clean and efficient energy source, is an important component of the future energy system. Electrolysis of water to produce hydrogen is one of the most promising green hydrogen production technologies. However, the hydrogen evolution reaction kinetics are slow, requiring highly efficient catalysts to reduce overpotential and improve energy conversion efficiency. Currently, platinum (Pt)-based catalysts are the best-performing hydrogen evolution catalysts, but their high cost and scarcity severely limit large-scale industrial applications. Therefore, developing efficient, stable, and inexpensive non-precious metal hydrogen evolution catalysts has become a research hotspot.

[0003] Among numerous non-noble metal materials, 3d transition metal compounds, especially those of molybdenum (Mo) and nickel (Ni), have attracted considerable attention due to their abundant reserves, tunable electronic structures, and excellent catalytic potential. NiMoO4, as a typical bimetallic oxide, possesses advantages such as a large specific surface area, excellent electrical conductivity, and ease of preparation. Its one-dimensional nanorod structure can provide abundant surface defects and active sites. However, the hydrogen evolution activity of pure-phase NiMoO4 is still insufficient to meet industrial requirements, and its performance is typically further enhanced through strategies such as elemental doping, heterostructure construction, and surface engineering.

[0004] Copper (Cu), as a common doping element, can modulate the electronic structure and surface properties of materials. Sulfur (S) doping or sulfidation can convert oxides into sulfides, which typically exhibit superior hydrogen evolution activity. Furthermore, electrochemical reconstruction is an effective post-processing method that can induce structural evolution on the catalyst surface under operating conditions, forming a truly highly active phase. However, currently, how to precisely control the composition and structure of the active phase on the catalyst surface while maintaining the advantages of the nanostructure through synergistic doping strategies and extreme activation conditions, thereby obtaining hydrogen evolution catalysts with both high activity and ultralong-term stability at industrial-scale high current densities, remains a challenge. Summary of the Invention

[0005] In view of the above-mentioned prior art, the present invention provides a nickel-molybdenum-based nanocomposite material doped with cations and anions and rich in oxygen vacancies, and its preparation and application, which solves the problems of insufficient stability and catalytic performance of existing catalysts.

[0006] To achieve the above objectives, the technical solution adopted by this invention is: a method for preparing anion-cation doped nickel-molybdenum-based nanocomposite materials rich in oxygen vacancies, comprising the following steps: S1: The nickel foam was washed sequentially with 1.0M hydrochloric acid, acetone, anhydrous ethanol and deionized water to obtain pretreated nickel foam; S2: Dissolve the nickel source, molybdenum source, and copper source in deionized water and stir until homogeneous to obtain a precursor solution; S3: Immerse the pretreated nickel foam in the precursor solution and carry out a hydrothermal reaction to obtain Cu-NiMoO4 / NF; S4: Cu-NiMoO4 / NF is reacted with a sulfur source in deionized water in a secondary hydrothermal reaction to obtain S-Cu-NiMoO4 / NF; S5: Using S-Cu-NiMoO4 / NF as the working electrode, electrochemical reconstruction treatment is carried out in the electrolyte to obtain anion and cation doped nickel-molybdenum-based nanocomposite material rich in oxygen vacancies.

[0007] Furthermore, the nickel source is nickel nitrate hexahydrate, the molybdenum source is ammonium molybdate tetrahydrate, and the copper source is copper nitrate trihydrate.

[0008] Furthermore, the molar ratio of nickel source, molybdenum source, and copper source is 80~85:20~25:1.

[0009] Furthermore, the hydrothermal reaction temperature is 140~160℃, and the time is 4~8h.

[0010] Furthermore, the sulfur source is thioacetamide, and the reaction temperature of the secondary hydrothermal reaction is 110~130℃, and the time is 1~3h.

[0011] Furthermore, the electrolyte was a 1.0 M KOH solution, and the electrochemical reconstruction treatment was performed using a chronopotential method with a current density of 1.5–2.5 A / cm². -2 The processing time is 0.5 to 2 hours.

[0012] The present invention also provides anion-cation doped nickel-molybdenum-based nanocomposites rich in oxygen vacancies prepared by the above preparation method.

[0013] This invention also provides the application of anion-cation doped nickel-molybdenum-based nanocomposites rich in oxygen vacancies in water electrolysis for hydrogen production.

[0014] The beneficial effects of this invention are: the preparation method provided by this invention innovatively uses "Cu 2+ Cation doping → S 2-A multi-step strategy of "anionic sulfidation → high current density electrochemical reconstruction" was adopted. Cu doping not only modulated the electronic structure, but more importantly, it effectively suppressed the excessive growth of sulfides during the subsequent sulfidation process, maintained the macroscopic structure of the nanorod array, and provided an ideal channel for the transport of reactants and products. Subsequently, electrochemical reconstruction promoted the in-situ transformation of the surface into a heterojunction rich in highly active 1T phases MoS2 and Ni(OH)2, and simultaneously generated a large number of hydroxyl vacancies. This synergistic effect of Cu doping regulating the structure and electrochemical reconstruction creating active sites ultimately yielded a nickel-molybdenum-based nanocomposite material doped with anions and cations and rich in oxygen vacancies.

[0015] Experimental results show that a 1T-MoS2 / Ni(OH)2 heterojunction interface was successfully constructed on the surface of this material. Because 1T-MoS2 possesses metallic conductivity and higher intrinsic catalytic activity, and Ni(OH)2 optimizes hydrogen adsorption energy, the resulting tight heterojunction facilitates electron redistribution and synergistic catalysis. Furthermore, this material exhibits significantly superior hydrogen evolution performance in 1.0 M KOH electrolyte compared to single-doped or unreconstructed samples, reaching 10, 100, 500, and 1000 mA cm⁻¹. -2 The overpotentials required for the current densities are only 36, 122, 197, and 247 mV, respectively, with Tafel slopes as low as 80 mV dec. -1 This indicates that it possesses excellent activity and rapid reaction kinetics. Moreover, one of the most prominent advantages of this material is its outstanding stability, reaching up to 1000 mA cm⁻¹. -2 Accelerated durability testing was conducted at industrial-grade current densities, and the overpotential remained essentially unchanged during continuous operation for up to 1000 hours. This makes the material provided by this invention not only suitable for laboratory research but also has the potential to withstand the harsh operating conditions of actual water electrolysis for hydrogen production.

[0016] In summary, this invention successfully prepared a nickel-molybdenum-based nanocomposite material with a highly active 1T-MoS2 / Ni(OH)2 heterojunction and abundant hydroxyl vacancies on its surface through a sophisticated anion-cation synergistic doping design and an extreme electrochemical reconstruction process. This material simultaneously achieved low overpotential, fast reaction kinetics, and ultra-long lifetime in the alkaline hydrogen evolution reaction. In particular, its performance and stability at high current densities reached advanced levels, providing a new approach and material system for developing efficient, durable, and low-cost non-precious metal electrolytic water electrolysis catalysts for hydrogen production. Attached Figure Description

[0017] Figure 1 a is S SEM images of NiMoO4 / NF-CP; Figure 1 b is S Cu SEM images of NiMoO4 / NF-CP; Figure 1 c is S Cu EDS plot of NiMoO4 / NF-CP; Figure 1 d is S TEM image of NiMoO4 / NF-CP; Figure 1 e is S HRTEM image of NiMoO4 / NF-CP; Figure 1 f is S Cu TEM image of NiMoO4 / NF-CP; Figure 1 g is S Cu HRTEM image of NiMoO4 / NF-CP; Figure 1 h is S Cu NiMoO4 / NF-CP and S XRD pattern of NiMoO4 / NF-CP; Figure 1 i is S Cu NiMoO4 / NF-CP and S Raman spectrum of NiMoO4 / NF-CP; Figure 2 a is S Cu NiMoO4 / NF-CP and S XPS spectrum of NiMoO4 / NF-CP (Mo 3d); Figure 2 b is S Cu NiMoO4 / NF-CP and S XPS spectra of NiMoO4 / NF-CP (Ni 2p); Figure 2 c is S Cu NiMoO4 / NF-CP and S XPS spectrum of NiMoO4 / NF-CP (O1s). Figure 2 d is S Cu NiMoO4 / NF-CP and S XPS spectrum of NiMoO4 / NF-CP (S2p); Figure 3 a represents the LSV curves of different samples; Figure 3 b is a comparison diagram of overpotentials of different samples; Figure 3 c represents the Tafel curves for different samples; Figure 3 d represents the equivalent circuit diagrams for different samples; Figure 3e represents the Nyquist curves for different samples; Figure 3 f represents the LSV polarization curves of ECSA-normalized samples for different samples; Figure 3 g represents the durability test of S-Cu-NiMoO4 / NF-CP; Figure 3 h is the η of S-Cu-NiMoO4 / NF 10 A comparison chart with values ​​reported in the literature. Detailed Implementation

[0018] The specific embodiments of the present invention will be described in detail below with reference to examples.

[0019] Example 1 A nickel-molybdenum-based nanocomposite material doped with cations and anions and rich in oxygen vacancies, the preparation method of which includes the following steps: S1: First, cut the nickel foam into small pieces (1 cm × 4 cm), and then wash them in sequence with hydrochloric acid (1.0 M), acetone, anhydrous ethanol and deionized water to remove the surface oxide layer, thus obtaining pretreated nickel foam. S2: Dissolve 0.297g nickel nitrate hexahydrate, 0.353g ammonium molybdate tetrahydrate and 0.003g copper nitrate trihydrate in 25mL of deionized water and stir until homogeneous to obtain the precursor solution; S3: Transfer the precursor solution to an autoclave, then immerse the pretreated nickel foam in the precursor solution and react at 150°C for 6 hours. After the reaction is completed and cooled to room temperature, take out the sample and wash it with deionized water and ethanol to obtain Cu-NiMoO4 / NF. S4: After drying Cu-NiMoO4 / NF at 60℃, it was placed back into an autoclave, and 25mL of deionized water and 0.075g of thioacetamide were added. After reacting at 120℃ for 2h, S-Cu-NiMoO4 / NF was obtained. S5: Using S-Cu-NiMoO4 / NF as the working electrode, and Hg / HgO electrode and platinum sheet as the reference and counter electrodes respectively, in 1.0M KOH solution, 1.8A cm -2 The nickel-molybdenum based nanocomposite material S-Cu-NiMoO4 / NF-CP was obtained by performing chronopotential method treatment at a current density for 1 hour.

[0020] Example 2 A nickel-molybdenum-based nanocomposite material doped with cations and anions and rich in oxygen vacancies, the preparation method of which includes the following steps: S1: First, cut the nickel foam into small pieces (1 cm × 4 cm), and then wash them in sequence with hydrochloric acid (1.0 M), acetone, anhydrous ethanol and deionized water to remove the surface oxide layer, thus obtaining pretreated nickel foam. S2: Dissolve 0.300g nickel nitrate hexahydrate, 0.353g ammonium molybdate tetrahydrate and 0.003g copper nitrate trihydrate in 25mL of deionized water and stir until homogeneous to obtain the precursor solution; S3: Transfer the precursor solution to an autoclave, then immerse the pretreated nickel foam in the precursor solution and react at 140°C for 8 hours. After the reaction is completed and cooled to room temperature, take out the sample and wash it with deionized water and ethanol to obtain Cu-NiMoO4 / NF. S4: After drying Cu-NiMoO4 / NF at 60℃, it was placed back into an autoclave, and 25mL of deionized water and 0.075g of thioacetamide were added. After reacting at 110℃ for 3h, S-Cu-NiMoO4 / NF was obtained. S5: Using S-Cu-NiMoO4 / NF as the working electrode, and Hg / HgO electrode and platinum sheet as the reference and counter electrodes respectively, in 1.0M KOH solution, 1.5A cm -2 The nickel-molybdenum based nanocomposite material S-Cu-NiMoO4 / NF-CP was obtained by chronopotential method treatment at a current density of 2 h.

[0021] Example 3 A nickel-molybdenum-based nanocomposite material doped with cations and anions and rich in oxygen vacancies, the preparation method of which includes the following steps: S1: First, cut the nickel foam into small pieces (1 cm × 4 cm), and then wash them in sequence with hydrochloric acid (1.0 M), acetone, anhydrous ethanol and deionized water to remove the surface oxide layer, thus obtaining pretreated nickel foam. S2: Dissolve 0.290g nickel nitrate hexahydrate, 0.353g ammonium molybdate tetrahydrate and 0.003g copper nitrate trihydrate in 25mL of deionized water and stir until homogeneous to obtain the precursor solution; S3: Transfer the precursor solution to an autoclave, then immerse the pretreated nickel foam in the precursor solution and react at 160°C for 4 hours. After the reaction is completed and cooled to room temperature, take out the sample and wash it with deionized water and ethanol to obtain Cu-NiMoO4 / NF. S4: After drying Cu-NiMoO4 / NF at 60℃, it was placed back into an autoclave, and 25mL of deionized water and 0.075g of thioacetamide were added. After reacting at 120℃ for 2h, S-Cu-NiMoO4 / NF was obtained. S5: Using S-Cu-NiMoO4 / NF as the working electrode, and Hg / HgO electrode and platinum sheet as the reference and counter electrodes respectively, in 1.0M KOH solution, 2.5A cm -2By performing chronopotential bonding at a current density for 0.5 h, the anion-cation doped nickel-molybdenum based nanocomposite material S-Cu-NiMoO4 / NF-CP rich in oxygen vacancies was obtained.

[0022] Comparative Example 1 A nickel-molybdenum-based nanocomposite material, the preparation method of which includes the following steps: S1: First, cut the nickel foam into small pieces (1 cm × 4 cm), and then wash them in sequence with hydrochloric acid (1.0 M), acetone, anhydrous ethanol and deionized water to remove the surface oxide layer, thus obtaining pretreated nickel foam. S2: Dissolve 0.297g of nickel nitrate hexahydrate and 0.353g of ammonium molybdate tetrahydrate in 25mL of deionized water and stir until homogeneous to obtain the precursor solution; S3: Transfer the precursor solution to an autoclave, then immerse the pretreated nickel foam in the precursor solution and react at 150°C for 6 hours. After the reaction is completed and cooled to room temperature, take out the sample and wash it with deionized water and ethanol to obtain NiMoO4 / NF. S4: After drying NiMoO4 / NF at 60℃, it was placed back into the autoclave, and 25mL of deionized water and 0.075g of thioacetamide were added. After reacting at 120℃ for 2h, S-NiMoO4 / NF was obtained. S5: Using S-NiMoO4 / NF as the working electrode, and Hg / HgO electrode and platinum sheet as the reference and counter electrodes respectively, in 1.0M KOH solution, 1.8A cm -2 The nickel-molybdenum based nanocomposite material S-NiMoO4 / NF-CP was obtained by 1 hour of chronopotential treatment at a current density.

[0023] The anion-cation doped nickel-molybdenum-based nanocomposites rich in oxygen vacancies prepared in Examples 1-3 have similar performance. Subsequent experiments used the anion-cation doped nickel-molybdenum-based nanocomposites rich in oxygen vacancies prepared in Example 1.

[0024] Experimental Example 1 Microscopic Analysis 1: The S-Cu-NiMoO4 / NF-CP of Example 1 and the S-NiMoO4 / NF-CP of the comparative example were analyzed using a scanning electron microscope. The results are as follows: Figure 1 a and Figure 1 As shown in b, both S-Cu-NiMoO4 / NF and the reconstructed S-Cu-NiMoO4 / NF-CP exhibit a nanorod morphology with uniform distribution on the NF substrate; further analysis of S-Cu-NiMoO4 / NF-CP using energy dispersive spectroscopy shows that Ni, Mo, O, S, and Cu elements are uniformly distributed on the nanorod surface. Figure 1c) Further analysis of S-Cu-NiMoO4 / NF-CP and S-Cu-NiMoO4 / NF-CP was performed using transmission electron microscopy. Figure 2 The d~2g data show that both S-Cu-NiMoO4 / NF and S-Cu-NiMoO4 / NF-CP nanorods have formed loose and porous catalytic layers on their surfaces.

[0025] The crystal structures of S-Cu-NiMoO4 / NF-CP, S-NiMoO4 / NF-CP, S-Cu-NiMoO4 / NF in Example 1, Cu-NiMoO4 / NF in Comparative Example 1, and NiMoO4 / NF in Comparative Example 1 were analyzed using X-ray diffraction. The results are as follows: Figure 1 To eliminate signal interference from the NF substrate, all test samples underwent ultrasonic exfoliation. High-crystallinity NiMoO4 diffraction peaks (JCPDS no. 04-017-0338) were detected in all samples, originating from the precursor nanorods. Cu doping and sulfidation treatment did not cause significant changes in the XRD patterns, possibly because the Cu doping concentration was low and the sulfide only covered the NiMoO4 surface, its signal being masked by strong substrate diffraction. However, after high-current-density electrochemical reconstruction, obvious characteristic peaks of MoS2 (JCPDS no. 37-1492) and Ni(OH)2 (JCPDS no. 14-0117) appeared in the S-Cu-NiMoO4 / NF-CP spectrum, indicating that the electrochemical process significantly changed the catalyst structure. Furthermore, diffraction rings belonging to Ni3S2 and MoS2, as well as lattice fringes (0.286 and 0.236 nm) corresponding to the Ni3S2 (110) and (003) crystal planes, were identifiable in the pre-reconstruction sample, along with layered structures of the MoS2 (002) crystal plane. In the post-reconstruction sample, diffraction rings of MoS2 and Ni(OH)2, as well as lattice fringes with inter-laminar spacings of 0.214 and 0.156 nm, were detected, matching the (101) and (110) crystal planes of Ni(OH)2, respectively. Furthermore, a typical octahedral atomic arrangement was observed, characteristic of the 1T-MoS2 structure, and a distinct heterojunction interface between 1T-MoS2 and Ni(OH)2 was also observed. Raman spectroscopy further confirmed the formation of Ni(OH)2 and the retention of 1T-MoS2 after electrochemical reconstruction. Figure 1 i) The S-Cu-NiMoO4 / NF sample reveals the Mo=O bond vibration mode, as well as the characteristic vibration modes of Ni–S bonds and 2H / 1T-MoS2. The Mo=O vibration is still present in the reconstructed sample, indicating that the NiMoO4 matrix still exists; at the same time, obvious Ni-O and OO vibration modes are observed, confirming the formation of Ni(OH)2, while the enhancement of the J1 vibration mode indicates that the reconstructed MoS2 is dominated by the 1T phase.

[0026] Experiment Example 2 Microscopic Analysis 2: X-ray photoelectron spectroscopy was used to analyze S-Cu-NiMoO4 / NF-CP and S-Cu-NiMoO4 / NF from Example 1. The results are as follows: Figure 2 As shown, the Mo 3d spectrum can be fitted into three sets of bimodal peaks ( Figure 2 a): In S-Cu-NiMoO4 / NF, the peaks at 232.37 eV and 235.53 eV are attributed to Mo. 6+ 3D 5 / 2 and 3D 3 / 2 (From NiMoO4), the peaks at 229.85 eV and 232.97 eV are attributed to Mo. 5+ 3D 5 / 2 and 3D 3 / 2 (Partially sulfurized Mo species), the peaks at 225.04 eV and 228.29 eV are attributed to Mo. 4+ 3D 5 / 2 and 3D 3 / 2 (From MoS2). Figure 2 b shows the XPS plot of Ni 2p, which is unwound into four doublet states. The signals at 225.04 eV and 228.29 eV originate from Ni 3+ 2p 3 / 2 and 2p 1 / 2 The signals located at 225.04 eV and 228.29 eV originate from Ni, respectively. 2+ 2p 3 / 2 and 2p 1 / 2 The signals located at 225.04 eV and 228.29 eV are associated with high-spin Ni. 2+ The vibration excitation was related to the reaction, and Ni belonging to nickel foam was also found at 225.04 eV and 228.29 eV. 0 The signal. Figure 3 c shows the XPS spectra of O1s. The sample S-Cu-NiMoO4 / NF can be decomposed into three surface components at 530.65, 531.9, and 533.15 eV, which are attributed to lattice oxygen (MO), oxygen vacancies (O), and lattice oxygen (MO). O-V ) and adsorbed water molecules (H2O). Figure 3 Figure d shows the XPS spectrum of S2p, with signals at 225.04 eV and 228.29 eV originating from S2p. 2- 2p 3 / 2 and 2p 1 / 2 The signal at 168.1 eV is mainly related to the inevitable oxidation of S. A significant signal was also observed in S-Cu-NiMoO4 / NF-CP after electrochemical reconstruction, confirming the presence of sulfides, and all peaks shifted towards lower binding energies.

[0027] Experimental Example 3 Electrocatalytic experiments: S-Cu-NiMoO4 / NF-CP, S-NiMoO4 / NF-CP, S-Cu-NiMoO4 / NF, Cu-NiMoO4 / NF, NiMoO4 / NF, and S-NiMoO4 / NF from Example 1 and Comparative Example 1 were tested using a standard three-electrode system in 1M KOH electrolyte solution. The results are as follows: Figure 3 As shown, the linear sweep voltammetry curve ( Figure 3 a) and overpotential comparison diagram ( Figure 3 b) indicates that S-Cu-NiMoO4 / NF-CP exhibits the best HER activity, reaching 10, 100, 500, and 1000 mA / cm². 2 The required current densities are only 36, 122, 197 and 247 mV, respectively. Figure 3 c shows the corresponding Tafel slope of the sample; the Tafel slope of S-Cu-NiMoO4 / NF-CP is 80 mV dec. -1 Lower than NiMoO4 / NF (160mV dec) -1 ), Cu-NiMoO4 / NF (133mV dec -1 ), S-NiMoO4 / NF (95mV dec -1 ), S-NiMoO4 / NF-CP (91mV dec -1 ), S-Cu-NiMoO4 / NF (85mV dec -1 The lower Tafel slope indicates better HER kinetics. Electrochemical impedance spectroscopy (EIS) was used to study charge transfer characteristics, based on... Figure 3 The equivalent circuit diagram in d shows that the Rct values ​​of S-NiMoO4 / NF (10.66Ω) and S-Cu-NiMoO4 / NF (10.74Ω) after sulfidation are much lower than those of NiMoO4 / NF (117.67Ω) and Cu-NiMoO4 / NF (99.59Ω). However, after electrochemical reconstruction, the Rct values ​​of S-NiMoO4 / NF-CP (21.87Ω) and S-Cu-NiMoO4 / NF-CP (15.70Ω) are improved to some extent. Furthermore, the electrochemical surface area (ECSA) of the electrocatalyst is briefly characterized by measuring the double-layer capacitance (Cdl), which is proportional to the Cdl value. Therefore, cyclic voltammetry (CV) is used to estimate Cdl and ECSA. Figure 3 As shown in e, after sulfidation, S-NiMoO4 / NF (240mFcm) -2 ) and S-Cu-NiMoO4 / NF (310 mFcm -2The Cdl value of ) is much higher than that of NiMoO4 / NF (0.61 mFcm). -2 ) and Cu-NiMoO4 / NF (0.17 mFcm -2 After electrochemical reconstruction, S-NiMoO4 / NF-CP (119 mFcm) -2 ) and S-Cu-NiMoO4 / NF-CP (203 mFcm -2 The Cdl value of ) decreased to some extent. After ECSA normalization ( Figure 3 f), the electrochemically reconstructed samples S-NiMoO4 / NF-CP and S-Cu-NiMoO4 / NF-CP exhibited better HER performance, indicating that electrochemical reconstruction significantly enhanced the intrinsic HER activity of the catalyst. Furthermore, after 300 hours of time-potential (CP) testing, the overpotential of S-Cu-NiMoO4 / NF-CP did not increase, indicating its superior long-term stability in alkaline media. Figure 3 g). Finally, the S-Cu-NiMoO4 / NF-CP of the present invention is combined with the η of a catalyst in the prior art. 10 The comparison yielded the following results: Figure 3 h, S-Cu-NiMoO4 / NF-CP at 1Acm -2 The overpotential at industrial-grade current density is lower than that of catalysts reported in existing technologies.

[0028] While specific embodiments of the present invention have been described in detail, they should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by those skilled in the art without inventive effort within the scope described in the claims still fall within the scope of protection of this patent.

Claims

1. Preparation of anion- and cation-doped nickel-molybdenum-based nanocomposites rich in oxygen vacancies, characterized in that, Includes the following steps: S1: Wash the nickel foam sequentially with hydrochloric acid, acetone, anhydrous ethanol and deionized water to obtain pretreated nickel foam. S2: Dissolve the nickel source, molybdenum source, and copper source in deionized water and stir until homogeneous to obtain a precursor solution; S3: Immerse the pretreated nickel foam in the precursor solution and carry out a hydrothermal reaction to obtain Cu-NiMoO4 / NF; S4: Cu-NiMoO4 / NF is reacted with a sulfur source in deionized water in a secondary hydrothermal reaction to obtain S-Cu-NiMoO4 / NF; S5: Using S-Cu-NiMoO4 / NF as the working electrode, electrochemical reconstruction treatment is carried out in the electrolyte to obtain anion and cation doped nickel-molybdenum-based nanocomposite material rich in oxygen vacancies.

2. The preparation of the anion-cation doped nickel-molybdenum-based nanocomposite material rich in oxygen vacancies according to claim 1, characterized in that: The nickel source is nickel nitrate hexahydrate, the molybdenum source is ammonium molybdate tetrahydrate, and the copper source is copper nitrate trihydrate.

3. The preparation of the anion-cation doped nickel-molybdenum-based nanocomposite material rich in oxygen vacancies according to claim 1 or 2, characterized in that: The molar ratio of the nickel source, molybdenum source, and copper source is 80~85:20~25:

1.

4. The preparation of the anion-cation doped nickel-molybdenum-based nanocomposite material rich in oxygen vacancies according to claim 1, characterized in that: The hydrothermal reaction is carried out at a temperature of 140-160°C for 4-8 hours.

5. The preparation of the anion-cation doped nickel-molybdenum-based nanocomposite material rich in oxygen vacancies according to claim 1, characterized in that: The sulfur source is thioacetamide, and the reaction temperature of the secondary hydrothermal reaction is 110~130℃, and the time is 1~3h.

6. The preparation of the anion-cation doped nickel-molybdenum-based nanocomposite material rich in oxygen vacancies according to claim 1, characterized in that: The electrolyte is a 1.0 M KOH solution, and the electrochemical reconstruction treatment is performed using a chronopotential method with a current density of 1.5~2.5 A cm⁻¹. -2 The processing time is 0.5 to 2 hours.

7. The preparation of the anion-cation doped nickel-molybdenum-based nanocomposite material rich in oxygen vacancies according to any one of claims 1 to 6.

8. The application of the anion and cation doped nickel-molybdenum-based nanocomposite material rich in oxygen vacancies as described in claim 7 in hydrogen production by water electrolysis.

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