Cu-loaded oxygen-vacancy-rich molybdenum-based hetero-material, method for preparing same and use thereof

Abstract

The application belongs to the technical field of catalysts, and particularly relates to a Cu-loaded oxygen-vacancy-rich molybdenum-based heteromaterial and a preparation method and application thereof. Specifically, L-glutamic acid and 1,3,5-benzene tricarboxylic acid are used as organic ligands, and the organic ligands, a copper source and a molybdenum source are mixed in a mixed solvent to obtain a NENU-5 precursor through a coordination reaction; the NENU-5 precursor is calcined at high temperature under an inert atmosphere, and the organic ligand pyrolysis initiates the lattice oxygen atoms in the molybdenum-based oxide to separate to form oxygen vacancies, and the Cu 2+ is reduced to a metal element Cu to obtain the Cu-loaded oxygen-vacancy-rich molybdenum-based heteromaterial. The application uses copper and molybdenum which are rich in reserves as raw materials, and has a simple synthesis method and low cost, thereby avoiding the high cost problem of a noble metal catalyst. Meanwhile, the catalyst material can realize efficient synthesis of ammonia under mild conditions, is low in energy consumption and environment-friendly, and has dual benefits of pollution treatment and resource utilization.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to Cu-supported oxygen-vacancy-rich molybdenum-based heteromaterials, their preparation methods, and applications. Background Technology

[0002] Nitrate is a typical pollutant in groundwater systems. Its excessive accumulation not only leads to eutrophication and damages aquatic ecosystems, but also poses potential health risks through drinking water pathways, such as methemoglobinemia. Electrocatalytic nitrate reduction technology, due to its dual attributes of pollution control and ammonia resource synthesis, has become a research hotspot in environmental remediation and green synthesis. Compared to the traditional Haber-Bosch process, this technology can achieve nitrogen cycling under mild conditions, offering advantages such as low energy consumption and environmental friendliness. However, electrocatalytic nitrate reduction technology faces key challenges such as sluggish eight-electron transfer kinetics, competition from hydrogen evolution side reactions, and the control of product selectivity. These problems severely restrict its practical application.

[0003] In recent years, metal-based electrocatalysts, including Ru, Ir, Pd, Pt, Ni, Co, Cu, Fe, and their derivatives, have shown significant potential in the electroreduction of nitrates to produce ammonia. Among them, copper-based materials have attracted much attention due to their excellent catalytic performance. From an economic perspective, although noble metal catalysts excel in activity and selectivity, their high cost and stability severely restrict their industrial application; in contrast, abundant and inexpensive copper-based materials show a better prospect for industrialization. At the reaction kinetics level, theoretical calculations show that the d-orbital energy levels of copper and the LUMO π* orbitals of nitrate have good energy level matching characteristics. This electronic structure advantage can effectively promote charge transfer to NO3. - The transfer of molecules endows copper-based catalysts with higher intrinsic activity and faster reaction kinetics. However, elemental copper and its traditional composite materials still face multiple technical challenges due to the physicochemical properties of the materials themselves: (1) insufficient affinity for adsorbed hydrogen atoms, which leads to the obstruction of subsequent hydrogenation steps; (2) competition for side reactions at higher overpotentials; and (3) the cumulative effect of intermediate product nitrite. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides Cu-supported oxygen-vacancy-rich molybdenum-based heteromaterials, their preparation methods, and applications.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a Cu-supported, oxygen-vacancy-rich molybdenum-based heteromaterial includes the following steps:

[0007] Using L-glutamic acid and 1,3,5-benzenetricarboxylic acid as organic ligands, the organic ligands, copper source and molybdenum source were combined in a mixed solvent to obtain the NENU-5 precursor through a coordination reaction.

[0008] Under an inert atmosphere, the NENU-5 precursor was calcined at high temperature. The pyrolysis of the organic ligands triggered the detachment of lattice oxygen atoms in the molybdenum-based oxide, forming oxygen vacancies. Simultaneously, Cu... 2+ The material is reduced to elemental Cu to obtain Cu-supported molybdenum-based heteromaterials rich in oxygen vacancies.

[0009] Furthermore, the molar ratio of copper acetate, phosphomolybdic acid, L-glutamic acid, and 1,3,5-benzenetricarboxylic acid is 1:0.16~0.58:0.5~0.75:0.6~0.8.

[0010] Furthermore, the coordination reaction was carried out at room temperature, and the stirring time was 12-14 hours.

[0011] Furthermore, the mixed solvent consists of equal volumes of deionized water and ethanol.

[0012] Furthermore, the copper source is copper acetate, and the molybdenum source is phosphomolybdic acid.

[0013] Furthermore, the high-temperature calcination temperature is 800℃~1000℃, and the time is 5h~7h.

[0014] Furthermore, the heating rate of the high-temperature calcination is 2℃ / min to 4℃ / min.

[0015] Cu-supported molybdenum-based heteromaterials rich in oxygen vacancies were prepared using the above method.

[0016] This invention employs a synergistic control strategy of heteroatomic doping and defect engineering: using molybdenum to construct a heterostructure optimizes the electronic structure, modulates the intermediate adsorption energy, suppresses side reactions, and simultaneously acts as a proton source to promote water dissociation and generate adsorbed hydrogen atoms, thus facilitating subsequent hydrogenation. Cu is used as the first-stage NO loading agent. 3- Convert to NO 2- The reactive sites of NO are located in molybdenum-based materials, which possess excellent proton sources, making them suitable for subsequent NO reactions. 2- →NH3 provides adsorbed hydrogen atoms; the introduction of oxygen vacancies during calcination provides electron-deficient sites to capture free ions in the electrolyte, such as NO. 3- NO 2- The reaction proceeds by constructing oxygen vacancies to enhance the reactant capture capability, thereby simultaneously improving the density and stability of active sites.

[0017] The above-mentioned Cu-supported molybdenum-based heteromaterials rich in oxygen vacancies are used in the electrocatalytic reduction of nitrate to ammonia.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] This invention uses copper acetate as the copper source, phosphomolybdic acid as the molybdenum source, and L-glutamic acid and 1,3,5-benzenetricarboxylic acid as organic ligands. In a mixed solvent, a coordination reaction yields the NENU-5 precursor. Subsequently, the NENU-5 precursor is calcined at high temperature under an inert atmosphere. The pyrolysis of the organic ligands induces the detachment of lattice oxygen atoms in the molybdenum-based oxide, forming oxygen vacancies, while simultaneously releasing Cu... 2+ The material is reduced to elemental Cu, yielding a Cu-supported molybdenum-based heteromaterial rich in oxygen vacancies. The Cu-supported molybdenum-based heteromaterial constructed in this invention exhibits significantly improved catalytic performance during the electrocatalytic reduction of nitrate. The introduction of the molybdenum-based material mimics the active site characteristics of natural nitrate reductase, effectively promoting water dissociation to generate active hydrogen species, thus overcoming the insufficient affinity of traditional copper-based materials for hydrogen and significantly improving reaction kinetic efficiency. The synergistic effect of the heterostructure and oxygen vacancies optimizes the interfacial electronic structure, reduces the reaction overpotential, and minimizes side reactions such as hydrogen evolution, achieving a Faraday efficiency of up to 98.1%. Copper sites dominate NO3. - To NO2 - The efficient conversion of NO2 is achieved through a rapid hydrogenation step at molybdenum sites. - Further reduction to NH3 effectively avoids the accumulation of intermediate products, ultimately increasing the ammonia yield to 5.657 mg·h⁻¹. -1 ·cm -2 The synergistic effect of oxygen vacancies and heterogeneous interfaces not only enhances the structural stability of the material and inhibits the aggregation and deactivation of active sites, but also ensures the long-term performance of the catalyst material through a high-temperature calcination process under nitrogen protection.

[0020] This invention addresses the low ammonia production efficiency caused by insufficient adsorbed hydrogen atoms, the accumulation of intermediate byproduct nitrite, and intense competition from side reactions in elemental copper and its traditional composite materials by constructing a Cu-supported molybdenum-based heterostructure rich in oxygen vacancies. The invention utilizes abundant copper and molybdenum as raw materials, employing a simple and low-cost synthesis method that avoids the high cost of precious metal catalysts. Furthermore, the catalyst material provided by this invention enables efficient ammonia synthesis under mild conditions, with low energy consumption and environmental friendliness, offering the dual benefits of pollution control and resource utilization. This provides an innovative pathway for efficient, stable, and low-cost green ammonia synthesis. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced 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.

[0022] Figure 1 Cu / O prepared in Example 1 v XRD pattern of MoO2.

[0023] Figure 2 Cu / O prepared in Example 1 v - SEM, TEM and EDS elemental distribution images of MoO2, where (a) is the SEM image, (b) is the TEM image, (c) is the high-resolution transmission electron microscope image, (d) is the EDS elemental analysis image of Mo, and (e) is the EDS elemental analysis image of Cu.

[0024] Figure 3 Cu / O prepared in Example 1 v XPS plot of MoO2.

[0025] Figure 4 Cu / O prepared in Example 1 v EPR plot of -MoO2.

[0026] Figure 5 To utilize the Cu / O prepared in Example 1 v -Faraday efficiency and ammonia yield of ammonia production by electrocatalytic reduction of nitrate with MoO2.

[0027] Figure 6 To utilize the Cu / O prepared in Examples 1 to 3 v -Faraday efficiency and ammonia yield of ammonia production by electrocatalytic reduction of nitrate with MoO2.

[0028] Figure 7 To utilize the Cu / O prepared in Example 1 v Ammonia yield from electrocatalytic reduction of nitrate with MoO2, Cu Nps (Comparative Example 1), and MoO2 (Comparative Example 2).

[0029] Figure 8 To utilize the Cu / O prepared in Example 4 v -Faraday efficiency and ammonia yield of ammonia production by electrocatalytic reduction of nitrate with MoO2.

[0030] Figure 9 To utilize the Cu / O prepared in Example 5 v-Faraday efficiency and ammonia yield of ammonia production by electrocatalytic reduction of nitrate with MoO2.

[0031] Figure 10 To utilize the Cu / O prepared in Example 6 v -Faraday efficiency and ammonia yield of ammonia production by electrocatalytic reduction of nitrate with MoO2.

[0032] Figure 11 To utilize the Cu / O prepared in Example 7 v -Faraday efficiency and ammonia yield of ammonia production by electrocatalytic reduction of nitrate with MoO2.

[0033] Figure 12 To utilize the Cu / O prepared in Example 8 v -Faraday efficiency and ammonia yield of ammonia production by electrocatalytic reduction of nitrate with MoO2. Detailed Implementation

[0034] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific 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. Unless otherwise specified, the experimental methods described in the embodiments of the present invention are conventional methods, and the materials and reagents used in the following embodiments are commercially available unless otherwise specified.

[0035] Example 1

[0036] A method for preparing a Cu-supported, oxygen-vacancy-rich molybdenum-based heteromaterial includes the following steps:

[0037] 1) Mixing of raw materials and preliminary reaction: Accurately weigh 1 mmol copper acetate, 0.5 mmol L-glutamic acid and 0.16 mmol phosphomolybdic acid, dissolve the three together in 40 mL deionized water, and stir continuously for 20 min at room temperature to obtain mixed solution A.

[0038] 2) Solution mixing and reaction: Weigh 0.6 mmol of 1,3,5-benzenetricarboxylic acid and dissolve it completely in 40 mL of ethanol to obtain solution B; while continuously stirring solution A, slowly pour solution B into solution A, and then continue stirring at room temperature for 14 h.

[0039] 3) Precipitation treatment: After the above reaction is completed, the green precipitate generated by the reaction is collected by centrifugation at 10,000 rpm for 5 min, and the precipitate is washed twice with ethanol.

[0040] 4) Drying treatment: The washed product was dried at 70℃ for 12h to obtain the NENU-5 precursor.

[0041] 5) Calcination treatment: The NENU-5 precursor was placed in a tube furnace and heated to 900℃ at a rate of 2℃ / min under nitrogen protection. After reaching this temperature, it was held for 6 hours and then naturally cooled to room temperature to obtain a Cu-supported molybdenum-based heteromaterial rich in oxygen vacancies, named Cu / O. v -MoO2.

[0042] Example 2

[0043] A method for preparing a Cu-supported, oxygen-vacancy-rich molybdenum-based heteromaterial, prepared according to the method described in Example 1, except that the calcination temperature in step 5 is 800℃.

[0044] Example 3

[0045] A method for preparing a Cu-supported, oxygen-vacancy-rich molybdenum-based heteromaterial, prepared according to the method described in Example 1, except that the calcination temperature in step 5 is 1000℃.

[0046] Example 4

[0047] A method for preparing a Cu-supported oxygen-vacancy-rich molybdenum-based heteromaterial, prepared according to the method described in Example 1, except that in step 5, the temperature is increased to 900°C at a heating rate of 4°C / min.

[0048] Example 5

[0049] A method for preparing Cu-supported oxygen-vacancy molybdenum-based heteromaterials, prepared according to the method described in Example 1, except that the holding time in step 5 is adjusted to 5 hours.

[0050] Example 6

[0051] A method for preparing Cu-supported oxygen-vacancy molybdenum-based heteromaterials, prepared according to the method described in Example 1, except that the holding time in step 5 is adjusted to 7 hours.

[0052] Example 7

[0053] A method for preparing a Cu-supported, oxygen-vacancy-rich molybdenum-based heteromaterial, prepared according to the method described in Example 1, except that the molar amounts of copper acetate, phosphomolybdic acid, L-glutamic acid, and 1,3,5-benzenetricarboxylic acid are 2 mmol, 1.16 mmol, 1.5 mmol, and 1.6 mmol, respectively.

[0054] Example 8

[0055] A method for preparing a Cu-supported molybdenum-rich heteromaterial with oxygen vacancies, prepared according to the method described in Example 1, except that the stirring time at room temperature in step 2 is 12 h.

[0056] Comparative Example 1

[0057] Commercially available metallic copper nanoparticles are denoted as Cu Nps.

[0058] Comparative Example 2

[0059] Commercially available molybdenum dioxide is denoted as MoO2.

[0060] Application Example 1

[0061] The application of Cu-supported molybdenum-based heteromaterials rich in oxygen vacancies in the electrocatalytic reduction of nitrate to ammonia includes the following steps:

[0062] 5 mg of the catalyst powder prepared in Example 1 was dispersed in a mixed solution containing 980 μL of ethanol and 20 μL of naphthol, and stirred to form a homogeneous suspension. The suspension was sonicated for 30 min. 200 μL of the sonicated mixture was then dropped onto a 1*1.5 cm plate. 2 The catalyst-supported working electrode is formed on the carbon cloth after natural drying.

[0063] All measurements were performed in H-type cells separated by Nafion 117 ion-exchange membranes. Electrochemical tests were conducted at room temperature in an Ar-saturated electrolyte containing 1 M KOH and 0.1 M KNO3 using a three-electrode system on a CHI 660E electrochemical workstation, with an Hg / HgO electrode and a carbon rod as the reference and counter electrodes.

[0064] Performance testing

[0065] Figure 1 Cu / O prepared in Example 1 v XRD patterns of MoO2 and Cu Nps from Comparative Example 1. XRD analysis shows that Cu / O... v - The 2θ angle corresponding to the characteristic diffraction peak of MoO2 is completely matched with the PDF standard card PDF#85-1326 of Cu and the PDF standard card PDF#32-0671 of MoO2, which correspond to the (111), (200), and (220) crystal planes of Cu and the (011), (200), and (220) crystal planes of MoO2, respectively.

[0066] Figure 2 Cu / O prepared in Example 1 v - SEM, TEM, and EDS elemental distribution images of MoO2, where (a) is the SEM image, (b) is the TEM image, (c) is the high-resolution transmission electron microscope image, (d) is the EDS elemental analysis image of Mo, and (e) is the EDS elemental analysis image of Cu. Figure 2 Showing Cu / Ov -MoO2 was successfully synthesized and copper and molybdenum elements were uniformly distributed in the material.

[0067] Figure 3 Cu / O prepared in Example 1 v XPS plot of MoO2; Figure 4 Cu / O prepared in Example 1 v EPR plot of MoO2. Cu / O ratio was studied using XPS. v - Surface chemical state of MoO2. Catalyst Cu / O v In the XPS spectrum of -MoO2 at 1s, the peaks at 528.9 eV, 530.4 eV, and 531.9 eV correspond to lattice oxygen, oxygen vacancies, and surface hydroxyl groups, respectively, which initially proves that oxygen vacancies have been successfully introduced. Subsequent EPR experimental results further confirm the existence of oxygen vacancies.

[0068] Figure 5 To utilize the Cu / O prepared in Example 1 v - Yield diagram of ammonia production from nitrate via electrocatalytic reduction using MoO2. Quantitative analysis of Cu / O ratio was performed using a colorimetric method. v The electrocatalytic reduction of nitrate to ammonia using MoO2 achieved a yield of 5.4 ± 0.2 mg·h⁻¹ at -0.3 V vs. RHE potential. -1 ·cm -2 The ammonia yield and Faraday efficiency were 93.7 ± 3.9%.

[0069] Figure 6 To utilize the Cu / O prepared in Examples 1 to 3 v The Faradaic efficiency and ammonia yield of the electrocatalytic reduction of nitrate to ammonia using MoO2 were tested at -0.3 V vs. RHE potential. The ammonia yield was quantified by the indophenol blue colorimetric method, and then the obtained yield was substituted into the Faradaic equation for the electrocatalytic reduction of nitrate to ammonia: FE NH3 =(8F×C NH3 ×V) / (17Q); where F is the Faraday constant, which is 96485 C·mol⁻¹. -1 C NH3 V represents the concentration of ammonium ions; V is the volume of the electrolyte in the cathode chamber; Q is the charge generated during electrolysis over several hours. The calcination temperature is controlled within the range of 800℃ to 1000℃, preferably 800℃, 900℃, or 1000℃. Figure 6 It can be seen that when the calcination temperature is 800℃, the Faradaic efficiency of the obtained Cu / Ov-MoO2 material is 80%, and the ammonia yield is 2.688 mg·h⁻¹. -1 ·cm -2When the calcination temperature is 1000℃, the obtained Cu / Ov-MoO2 material has a Faradaic efficiency of 72% and an ammonia yield of 2.616 mg·h⁻¹. -1 ·cm -2 When the calcination temperature is 900℃, the obtained Cu / Ov-MoO2 material exhibits the best electrocatalytic reduction performance of nitrate, with a Faradaic efficiency of 98.1% and an ammonia yield of 5.657 mg·h⁻¹. -1 ·cm -2 It is significantly superior to samples prepared under other calcination temperature conditions.

[0070] Figure 7 To utilize the Cu / O prepared in Example 1 v The ammonia yields of the electrocatalytic reduction of nitrate to ammonia using MoO2, Cu Nps (Comparative Example 1), and MoO2 (Comparative Example 2) are shown in the figure. The graph illustrates the differences in ammonia yields between MoO2, Cu Nps, and Cu / O at -0.3 V vs. RHE potential. v The ammonia yield of nitrate oxidized by MoO2 was 0.21 mg·h⁻¹. -1 ·cm -2 2.86 mg·h -1 ·cm -2 5.4 mg·h -1 ·cm -2 .

[0071] Figures 8-12 To utilize the Cu / O prepared in Examples 4 to 8 respectively v - The Faradaic efficiency and ammonia yield of the electrocatalytic reduction of nitrate to ammonia using MoO2. As can be seen from the figure, the Cu / O2 prepared in Example 4... v -MoO2 exhibits optimal performance under reaction conditions of -0.3 V vs. RHE, with a maximum yield of 2.57 mg·h⁻¹. -1 ·cm -2 The Faraday efficiency is 86.02%; the Cu / O prepared in Example 5 v -MoO2 exhibits optimal performance under reaction conditions of -0.5V vs. RHE, with a maximum yield of 7.39 mg·h⁻¹. -1 ·cm -2 The Faraday efficiency is 71.72%; the Cu / O prepared in Example 6 v -MoO2 exhibits optimal performance under reaction conditions of -0.3V vs. RHE, with a maximum yield of 5.31 mg·h⁻¹. -1 ·cm -2 The Faraday efficiency is 92.26%. The Cu / O prepared in Examples 7 and 8... v-MoO2 exhibits optimal performance under reaction conditions of -0.3V vs. RHE, with the best yield being 5.22 mg·h⁻¹. -1 ·cm -2 5.31 mg·h -1 ·cm -2 The Faraday efficiencies were 90.7% and 92.26%, respectively.

[0072] Combined with experimental results from XPS, EPR, SEM, TEM, and EDS, it was found that metallic copper nanoparticles were supported on molybdenum dioxide rich in oxygen vacancies. Further performance tests showed that the catalyst achieved a yield of 5.4 ± 0.2 mg·h⁻¹ at -0.3 V vs. RHE potential. -1 ·cm -2 The ammonia yield and Faraday efficiency of 93.7 ± 3.9% exceed those of most current copper-based catalysts. Theoretical calculations combined with experimental characterization confirm that oxygen vacancies enhance NO3 production. - Adsorption energy optimizes the interfacial electronic structure, with copper sites dominating NO3. - To NO2 - In the conversion process, molybdenum sites provide active hydrogen species through a hydrogen spillover effect, and the synergistic effect of these three factors lowers the rate-determining step energy barrier. The multi-site design and defect engineering strategy proposed in this invention provides a new pathway for efficient electrocatalytic ammonia synthesis, demonstrating significant application potential in the field of sustainable nitrogen chemistry.

[0073] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the inventive concept of the present invention, can make other changes and modifications to these embodiments, all of which fall within the scope of the present invention.

[0074] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. If such modifications and variations fall within the scope of equivalents of this invention, then this invention also intends to include these modifications and variations.

Claims

1. The application of Cu-supported oxygen-vacancy-rich molybdenum-based heteromaterials in the electrocatalytic reduction of nitrate to ammonia, characterized in that, A method for preparing Cu-supported oxygen-vacancy-rich molybdenum-based heteromaterials includes the following steps: Using L-glutamic acid and 1,3,5-benzenetricarboxylic acid as organic ligands, the organic ligands, copper source and molybdenum source were combined in a mixed solvent to obtain the NENU-5 precursor through a coordination reaction. Under an inert atmosphere, the NENU-5 precursor was calcined at high temperature. The pyrolysis of the organic ligands triggered the detachment of lattice oxygen atoms in the molybdenum-based oxide, forming oxygen vacancies. Simultaneously, Cu... 2+ The material is reduced to elemental Cu to obtain Cu-supported molybdenum-based heteromaterials rich in oxygen vacancies.

2. The application of the Cu-supported oxygen-vacancy-rich molybdenum-based heteromaterial according to claim 1 in the electrocatalytic reduction of nitrate to ammonia, characterized in that, The high-temperature calcination temperature is 800℃~1000℃, and the time is 5h~7h.

3. The application of the Cu-supported oxygen-vacancy-rich molybdenum-based heteromaterial according to claim 1 in the electrocatalytic reduction of nitrate to ammonia, characterized in that, The heating rate for high-temperature calcination is 2℃ / min to 4℃ / min.

4. The application of the Cu-supported oxygen-vacancy-rich molybdenum-based heteromaterial according to claim 1 in the electrocatalytic reduction of nitrate to ammonia, characterized in that, The molar ratio of the copper source, molybdenum source, L-glutamic acid, and 1,3,5-benzenetricarboxylic acid is 1:0.16~0.58:0.5~0.75:0.6~0.

8.

5. The application of the Cu-supported oxygen-vacancy-rich molybdenum-based heteromaterial according to claim 1 in the electrocatalytic reduction of nitrate to ammonia, characterized in that, The coordination reaction was carried out at room temperature for 12-14 hours.

6. The application of the Cu-supported oxygen-vacancy-rich molybdenum-based heteromaterial according to claim 1 in the electrocatalytic reduction of nitrate to ammonia, characterized in that, The mixed solvent consists of equal volumes of deionized water and ethanol.

7. The application of the Cu-supported oxygen-vacancy-rich molybdenum-based heteromaterial according to claim 1 in the electrocatalytic reduction of nitrate to ammonia, characterized in that, The copper source is copper acetate, and the molybdenum source is phosphomolybdic acid.

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