A foam nickel loaded copper-cobalt bimetallic composite catalyst, a preparation method and application thereof

Abstract

The application discloses a kind of foam nickel supported copper-cobalt bimetallic composite catalyst and preparation method and application, belong to electrocatalytic material technical field.CuSO4·5H2O, CoSO4·7H2O and C6H5Na3O7 are mixed and using constant voltage deposition method is loaded on foam nickel substrate, and CuCo / NF precursor is obtained, and copper-cobalt bimetallic composite catalyst Cu x O-Co3O4 / NF with excellent catalytic activity and stability is successfully prepared by temperature programmed calcination.The application significantly enhances the adsorption capacity of nitrate molecules on the catalyst surface by utilizing the synergistic effect of Cu and Co, reducing the incidence of side reactions, thereby improving the catalytic efficiency of nitrate reduction reaction.Compared with traditional single catalyst, it shows higher ammonia yield, Faraday efficiency (FE) and better stability, and has broad application prospect.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalytic materials technology, specifically relating to a copper-cobalt bimetallic composite catalyst supported on nickel foam, its preparation method, and its application. Background Technology

[0002] Electrocatalytic nitrate reduction to ammonia (NO3RR) is a green technology that replaces the energy-intensive Haber-Bosch process and treats nitrate pollution in water bodies. It is crucial for achieving the dual goals of carbon neutrality and environmental pollution control. This reaction utilizes nitrate ions (NO3) in an aqueous system. - Using nitrogen as a nitrogen source, it can be efficiently converted into ammonia (NH3) through a multi-electron coupled proton transfer process. This not only avoids the high cracking energy barrier required for nitrogen (N2) activation, but also provides a sustainable technical route for distributed ammonia synthesis and wastewater denitrification. However, existing catalytic systems still face bottlenecks such as complex reaction pathways, diverse intermediate products, difficulty in selective control, and significant competitive hydrogen evolution reaction (HER), resulting in generally low Faraday efficiency and ammonia yield, which limits their practical application prospects.

[0003] In the field of electrocatalytic nitrate reduction, copper (Cu)-based materials are widely recognized as one of the most promising active components due to their unique electronic structure and adsorption properties of reaction intermediates. Cu has a high d-orbital electron cloud density, which is conducive to the adsorption of nitrate ions (NO3-). - ) and its key reduction intermediates (such as NO2) - NO has a moderate adsorption free energy, which can effectively reduce NO3. - Converted to NO2 - The energy barrier of this rate-determining step endows it with excellent intrinsic catalytic activity. However, Cu-based materials have a low energy barrier for the dissociation and adsorption of water under negative potential conditions, readily catalyzing the hydrogen evolution reaction; and nitrate reduction involves a complex multi-step process of 8 electron transfers, resulting in a wide variety of intermediate products. Cu-based catalysts exhibit poor catalytic activity for nitrite (NO2). - ), hydroxylamine (NH2OH), and even gaseous products (N2O, NO, N2) all exhibit certain generating activity.

[0004] Furthermore, traditional synthesis methods (such as high-temperature solid-state methods, hydrothermal methods, and coprecipitation methods) suffer from significant structural defects when constructing such heterojunctions: high-temperature processes easily lead to grain coarsening and loss of active sites; wet chemical methods generally face problems such as loose heterojunction interface contact and uneven element distribution, resulting in material particle agglomeration, limited specific surface area, and low carrier separation and transport efficiency. In addition, existing heterojunction materials often experience phase separation or component dissolution during electrochemical cycling due to weak interfacial bonding and insufficient structural stability, severely limiting their catalytic activity and long-term stability. To address these challenges, this invention overcomes the limitations of two-component composites and innovatively employs an electrodeposition-supported-partial oxidation method to construct CuO with a composite valence state. x -Co3O4 / NF, retaining Cu's NO3- - While exhibiting significant adsorption capacity, the synergistic effect between Cu and Co optimizes the reaction selectivity, ultimately achieving breakthrough catalytic efficiency and stability at low overpotentials. This technology not only provides a revolutionary solution for nitrate reduction systems, but its universal interface engineering strategy can also be extended to the field of clean energy conversion, demonstrating broad application prospects. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a copper-cobalt bimetallic composite catalyst supported on nickel foam, its preparation method, and its application.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for preparing a copper-cobalt bimetallic composite catalyst supported on nickel foam, comprising the following steps:

[0008] (1) Dissolve CuSO4·5H2O, CoSO4·7H2O and C6H5Na3O7 in ultrapure water and stir vigorously at room temperature for 15 min to ensure complete dissolution, to obtain a mixed solution;

[0009] (2) The mixed solution from step (1) is transferred to a single-chamber electrolytic cell, with nickel foam as the working electrode, platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode, and constant voltage deposition is performed under stirring.

[0010] (3) Take out the foamed nickel after step (2), rinse with deionized water, then vacuum dry, and then calcine in a muffle furnace under air atmosphere to obtain the copper-cobalt bimetallic composite catalyst supported on foamed nickel.

[0011] In step (2), the constant voltage deposition conditions are: voltage -2.25V vs RHE, time 15min;

[0012] In step (3), the temperature of vacuum drying is 50°C; the calcination conditions are: heating from room temperature to 300~400°C at a heating rate of 2°C / min and calcining at a constant temperature for 2 hours; preferably, the calcination conditions are: heating from room temperature to 350°C at a heating rate of 2°C / min and calcining at a constant temperature for 2 hours.

[0013] A copper-cobalt bimetallic composite catalyst supported on nickel foam is prepared by the above-described preparation method;

[0014] The molar ratio of Cu to Co in the copper-cobalt bimetallic composite catalyst is 1~2:1~2; preferably, the molar ratio of Cu to Co in the copper-cobalt bimetallic composite catalyst is 2:1.

[0015] The above-mentioned application of a copper-cobalt bimetallic composite catalyst supported on nickel foam in the electrocatalytic reduction of nitrate to ammonia.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] (1) Overcoming the limitations of binary composites, a three-component composite catalyst was constructed through a "partial oxidation" strategy. First, efficient loading was achieved using electrodeposition, and then CuO with mixed valence states was obtained through partial oxidation. x Compared to traditional materials, this strategy effectively overcomes the shortcomings of single-component materials, achieving efficient nitrate reduction and suppression of side reactions.

[0018] (2) Unlike traditional two-component composite catalysts, CuO with multiple valence states coexisting is achieved through temperature and time control. x This method retains the adsorption capacity of Cu-based materials for nitrate while effectively suppressing side reactions. It provides a novel material development approach to address the problems of severe side reactions and easy loss of active components in Cu-based catalysts.

[0019] (3) This method can be adapted to multi-component oxide composite systems by adjusting the precursor ratio and reaction conditions. The resulting catalyst has both high nitrate reduction activity and universality, and can be extended to clean energy fields such as carbon dioxide conversion and hydrogen evolution reaction. Attached Figure Description

[0020] Figure 1 CuO of Example 1 x (a) SEM image and (b) HRTEM image of the -Co3O4 / NF catalyst.

[0021] Figure 2 The images show the XRD patterns of the catalysts in Examples 1-3 and Comparative Examples 1-2.

[0022] Figure 3X-ray photoelectron spectroscopy (XPS) of the catalysts in Example 1 and Comparative Examples 1-2: (a) CuO x -Co3O4 / NF catalyst and CuO x Cu 2p spectrum of / NF catalyst, (b) CuO x -Co 2p spectra of Co3O4 / NF catalyst and Co3O4 / NF catalyst.

[0023] Figure 4 CuO for Comparative Example 1 x Electrocatalytic nitrate reduction performance of the catalyst.

[0024] Figure 5 The graph shows the electrocatalytic nitrate reduction performance of the Co3O4 catalyst in Comparative Example 2.

[0025] Figure 6 CuO of Example 1 x - Performance diagram of electrocatalytic nitrate reduction of Co3O4 / NF catalyst.

[0026] Figure 7 The images show the electrocatalytic nitrate reduction performance of the catalysts in Examples 1-3 and Comparative Examples 1-3.

[0027] Figure 8 CuO x Co3O4 and CuO from Example 1 x Comparison of electrochemical double-layer capacitance (a) and electrochemical surface area (b) of -Co3O4 / NF.

[0028] Figure 9 CuO of Example 1 x -Co3O4 / NF and CuO x EIS impedance spectra of / NF and Co3O4 / NF. Detailed Implementation

[0029] To facilitate understanding of the present invention, the invention will be further described below through embodiments and accompanying drawings. Although the following description is illustrated by specific examples, it does not imply that the scope of the invention is limited to these embodiments. Any equivalent changes and modifications that conform to the basic principles and technical solutions of the present invention should be considered as part of the present invention.

[0030] Example 1:

[0031] 1.25 g CuSO4·5H2O, 0.7 g CoSO4·7H2O, and 1.76 g C6H5Na3O7 were dissolved in 50 mL of ultrapure water, and then stirred vigorously at room temperature for 15 min to ensure complete dissolution, resulting in a mixed solution. The resulting mixed solution was then transferred to a 50 mL single-chamber electrolytic cell. Using nickel foam as the working electrode, a platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode, a constant voltage deposition was performed for 15 min at -2.25 V vs. RHE under stirring. The deposited nickel foam was removed, rinsed with deionized water, and then vacuum dried at 50 °C to constant weight. It was then placed in a muffle furnace and calcined in air at a heating rate of 2 °C / min from room temperature to 350 °C for 2 h, finally yielding a nickel foam-supported copper-cobalt bimetallic composite catalyst CuO. x -Co3O4 / NF, where the molar ratio of Cu to Co is 2:1.

[0032] Example 2:

[0033] 0.625 g CuSO4·5H2O, 0.7 g CoSO4·7H2O, and 1.76 g C6H5Na3O7 were dissolved in 50 mL of ultrapure water, and then stirred vigorously at room temperature for 15 min to ensure complete dissolution, resulting in a mixed solution. The resulting mixed solution was then transferred to a 50 mL single-chamber electrolytic cell. Using nickel foam as the working electrode, a platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode, a constant voltage deposition was performed for 15 min at -2.25 V vs. RHE under stirring. The deposited nickel foam was removed, rinsed with deionized water, and then vacuum dried at 50 °C to constant weight. It was then placed in a muffle furnace and calcined in air at a heating rate of 2 °C / min from room temperature to 350 °C for 2 h, finally yielding a nickel foam-supported copper-cobalt bimetallic composite catalyst CuO. x -Co3O4 / NF, where the molar ratio of Cu to Co is 1:1.

[0034] Example 3:

[0035] 0.625 g CuSO4·5H2O, 1.4 g CoSO4·7H2O, and 1.76 g C6H5Na3O7 were dissolved in 50 mL of ultrapure water, and then stirred vigorously at room temperature for 15 min to ensure complete dissolution, resulting in a mixed solution. The resulting mixed solution was then transferred to a 50 mL single-chamber electrolytic cell. Using nickel foam as the working electrode, a platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode, a constant voltage deposition was performed for 15 min at -2.25 V vs. RHE under stirring. The deposited nickel foam was removed, rinsed with deionized water, and then vacuum dried at 50 °C to constant weight. It was then placed in a muffle furnace and calcined in air at a heating rate of 2 °C / min from room temperature to 350 °C for 2 h, finally yielding a nickel foam-supported copper-cobalt bimetallic composite catalyst CuO. x -Co3O4 / NF, where the molar ratio of Cu to Co is 1:2.

[0036] Example 4:

[0037] 1.25 g CuSO4·5H2O, 0.7 g CoSO4·7H2O, and 1.76 g C6H5Na3O7 were dissolved in 50 mL of ultrapure water, and then stirred vigorously at room temperature for 15 min to ensure complete dissolution, resulting in a mixed solution. The resulting mixed solution was then transferred to a 50 mL single-chamber electrolytic cell. Using nickel foam as the working electrode, a platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode, a constant voltage deposition was performed for 15 min at -2.25 V vs. RHE under stirring. The deposited nickel foam was removed, rinsed with deionized water, and then vacuum dried at 50 °C to constant weight. It was then placed in a muffle furnace and calcined in air at a heating rate of 2 °C / min from room temperature to 300 °C for 2 h, finally yielding a nickel foam-supported copper-cobalt bimetallic composite catalyst CuO. x -Co3O4 / NF.

[0038] Example 5:

[0039] 1.25 g CuSO4·5H2O, 0.7 g CoSO4·7H2O, and 1.76 g C6H5Na3O7 were dissolved in 50 mL of ultrapure water, and then stirred vigorously at room temperature for 15 min to ensure complete dissolution, resulting in a mixed solution. The resulting mixed solution was then transferred to a 50 mL single-chamber electrolytic cell. Using nickel foam as the working electrode, a platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode, a constant voltage deposition was performed for 15 min at -2.25 V vs. RHE under stirring. The deposited nickel foam was removed, rinsed with deionized water, and then vacuum dried at 50 °C to constant weight. It was then placed in a muffle furnace and calcined in air at a heating rate of 2 °C / min from room temperature to 400 °C for 2 h, finally yielding a nickel foam-supported copper-cobalt bimetallic composite catalyst CuO. x -Co3O4 / NF.

[0040] Comparative Example 1:

[0041] 1.25 g CuSO4·5H2O and 1.76 g C6H5Na3O7 were dissolved in 50 mL of ultrapure water, and then stirred vigorously at room temperature for 15 min to ensure complete dissolution, resulting in a mixed solution. The resulting mixed solution was then transferred to a 50 mL single-chamber electrolytic cell. Using nickel foam as the working electrode, a platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode, a constant voltage deposition was performed for 15 min at -2.25 V vs. RHE under stirring. The deposited nickel foam was removed, rinsed with deionized water, and then vacuum dried at 50 °C to constant weight. It was then placed in a muffle furnace and calcined in air at a heating rate of 2 °C / min from room temperature to 350 °C for 2 h to finally obtain CuO. x / NF catalyst.

[0042] Comparative Example 2:

[0043] 1.4 g CoSO4·7H2O and 1.76 g C6H5Na3O7 were dissolved in 50 mL of ultrapure water, and then stirred vigorously at room temperature for 15 min to ensure complete dissolution, resulting in a mixed solution. The resulting mixed solution was then transferred to a 50 mL single-chamber electrolytic cell. Using nickel foam as the working electrode, a platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode, a constant voltage deposition was performed for 15 min at -2.25 V vs. RHE under stirring. The deposited nickel foam was removed, rinsed with deionized water, and then vacuum dried at 50 °C to constant weight. It was then placed in a muffle furnace and calcined in air at a heating rate of 2 °C / min from room temperature to 350 °C for 2 h, finally yielding the Co3O4 / NF catalyst.

[0044] Application instance performance testing:

[0045] Figure 1 CuO of Example 1 x SEM images (a) and HRTEM images (b) of the -Co3O4 / NF catalyst. The SEM images show CuO x The microstructure of the Co3O4 / NF catalyst exhibits a "nanoflower" structure formed by the stacking of sheets. High-resolution transmission electron microscopy (HRTEM) images clearly show its Cu(111) crystal plane, Cu2O(110) crystal plane, and Co3O4(111) crystal plane, with lattice spacings of 0.208 nm, 0.297 nm, and 0.246 nm, respectively, proving that the catalyst forms a three-component composite structure.

[0046] Figure 2 The XRD patterns of the catalysts in Examples 1-3 and Comparative Examples 1-2 are shown. X-ray diffraction (XRD) analysis was performed to study the material composition and crystal structure of the samples. By comparing the obtained diffraction curves with the standard PDF card for Ni [PDF#00-004-0850], the diffraction peaks at 44.5°, 51.8°, and 76.3° correspond to the crystal planes (111), (200), and (220), respectively, indicating that the nickel foam substrate did not participate in the material reaction. The diffraction peaks at 43.3°, 50.4°, and 74.1° correspond to the (111), (200), and (220) crystal planes of Cu [PDF#00-004-0836]. The diffraction peaks at 29.9° and 37.1° correspond to the (110) and (111) crystal planes of Cu2O, respectively, and the diffraction peak at 36.8° corresponds to the (311) crystal plane of Co3O4. CuO with different Cu / Co molar ratios was observed x The diffraction peaks of the -Co3O4 / NF catalyst showed no significant shift, indicating that the crystal structure was not significantly affected by the formation of the composite structure. The absence of many impurity peaks and the strong, sharp diffraction peaks indicate that the sample has good crystallinity.

[0047] Figure 3 X-ray photoelectron spectroscopy (XPS) was used to characterize Cu and Co, verify their existence forms, obtain detailed information on their chemical environments, and systematically analyze all spectra. Figure 3 (a) shows the CuO of Example 1 x -Co3O4 / NF catalyst and CuO (Comparative Example 1) x High-resolution Cu 2p spectra of the / NF catalyst. The main peaks at binding energies of 930.8 eV and 933.1 eV correspond to Cu. 0 The characteristic peaks at 931.4 eV and 933.8 eV are attributed to Cu. + Characteristic peaks of Cu. In addition, obvious peaks related to Cu can be observed.2+ The characteristic peaks and satellite peaks are due to the partial oxidation of the catalyst surface, forming CuO. x Compared to / NF catalysts, CuO x The Cu 2p peak of the -Co3O4 / NF catalyst shows a shift to a lower binding energy of approximately 2.3 eV, indicating that Cu and Cu + The electron density on the atoms has increased. This change indicates that CuO x In the Co3O4 / NF catalyst, CuO x Part of Cu and Cu + The electron density changed due to interface effects, possibly related to CuO. x It is related to the electronic structure interactions of / NF. Figure 3 (b) The CuO of Example 1 is shown. x The Co 2p spectra of the Co3O4 / NF catalyst and the Co3O4 / NF catalyst of Comparative Example 2 were obtained. By fitting, CuO... x The Co 2p spectrum of -Co3O4 / NF can be decomposed into two characteristic peaks, located at 781.1 eV and 796.6 eV, corresponding to the Co 2p of Co3O4, respectively. 3 / 2 and 2p 1 / 2 The binding energy of the orbitals. Compared to the corresponding peaks (778.2 eV and 793.6 eV) in the Co3O4 / NF catalyst, CuO... x The Co 2p peak of the -Co3O4 / NF catalyst shows a shift to a higher binding energy of approximately 2.9 eV. This shift in binding energy indicates that CuO... x The electron density of the Co3O4 moiety in the -Co3O4 / NF catalyst is reduced, while that of CuO is reduced. x The electron density of some parts increased. This change in electron density further supports the hypothesis that CuO... x Electrons on the Co3O4 / NF catalyst transfer from Co3O4 to Cu. 0 and Cu + The phenomenon of directional transfer. XPS system analysis shows that CuO x The Co3O4 / NF catalyst exhibits a significant electronic structure reconstruction effect. The positive shift of the Co 2p binding energy (+2.9 eV) and the negative shift of the Cu 2p binding energy (-2.3 eV) form a mirror-symmetric relationship, confirming the Co3O4→CuO transformation process within the catalyst. x The directed electron transfer. This modulation of the electronic structure confirms the presence of CuO. x There is a strong electronic cooperation effect between CuO and Co3O4: xUpon gaining electrons, the electron cloud density increases, while Co3O4 loses electrons, forming an electron-deficient state. This redistribution of interfacial charge not only enhances the interaction force between the two phases and optimizes the electronic configuration of the material, but also helps to improve the catalytic performance of the material, especially in applications such as the electrocatalytic nitrate reduction reaction (NO3RR), where it exhibits higher catalytic efficiency.

[0048] Electrochemical tests were conducted in an H-type electrolytic cell. Both the cathode and anode chambers were made of transparent glass, and the covers were made of polytetrafluoroethylene (PTFE). A Nafion 211 membrane separated the two chambers, allowing only protons (cations) to pass through, preventing problems such as ammonia oxidation. Before the reaction, the membrane required pretreatment: boiling in a 3% hydrogen peroxide solution for 1 hour, washing with deionized water, then boiling in deionized water for 2 hours, followed by boiling in a 0.5M sulfuric acid solution for 1 hour, and rinsing with deionized water before assembly into the electrolytic cell. The remaining treated membrane was sealed and stored in deionized water. The reaction employed a three-electrode system, with the prepared catalyst serving as the working electrode (working area 1 cm²). 2 The counter electrode is a platinum sheet electrode, and the reference electrode is Hg / HgO. This can be determined according to the Nernst equation (E... RHE =E Hg / HgO The measured potential was converted from a scale relative to Hg / HgO to a scale relative to a reversible hydrogen electrode (RHE) using a voltage of +0.059pH +0.197V. The electrolyte was 0.1M KOH + 200ppm KNO3. A constant voltage of -0.1V to -0.5V (vs. RHE) was applied to induce an electrocatalytic reduction of nitrate in the cathode chamber. After 1 hour of reaction, the product was collected, and its ammonia concentration was determined.

[0049] Ammonia detection uses indophenol blue indicator, and the ammonia concentration in the electrolyte is determined colorimetrically. Specifically, 2 mL of the test solution is added to a beaker, followed by 2 mL of 1M NaOH solution (containing 5 wt% salicylic acid and 5 wt% sodium citrate), 1 mL of 0.05M NaClO solution, and 0.2 mL of 1 wt% sodium nitroferricyanide solution. After staining for 1 hour, the absorption spectrum is recorded using a UV-Vis spectrophotometer. A calibration curve is plotted based on the absorbance of the standard solution at 665 nm, and the ammonia concentration in the electrolyte is calculated from the calibration curve. The ammonia standard curve in this chapter is calculated by measuring the absorbance at a series of ammonia concentrations (0, 0.2, 0.4, 0.6, 1.2, 1.5, 1.8 ppm) in 0.1M KOH solution. The fitted standard curve is: y = 0.0413 + 0.4514x (R 2 =0.9992), where y represents absorbance and x represents ammonia concentration (ppm).

[0050] Figure 4 CuO for Comparative Example 1 xElectrocatalytic nitrate reduction performance of / NF catalyst. Ammonia yield is 2392 μg / h at -0.5V vs. RHE. -1 cm -1 The Faraday efficiency is 80.47%.

[0051] Figure 5 The graph shows the electrocatalytic nitrate reduction performance of the Co3O4 / NF catalyst in Comparative Example 2. The ammonia yield at -0.5 V vs. RHE was 2123.39 μg h⁻¹. -1 cm -1 The Faraday efficiency is 92.93%.

[0052] Figure 6 CuO of Example 1 x - Performance graph of electrocatalytic nitrate reduction using Co3O4 / NF catalyst. Ammonia yield is 2671.68 μg / h at -0.4 V vs. RHE. -1 cm -1 The Faraday efficiency is 91.79%. Compared to CuO... x / NF catalyst and Co3O4 / NF catalyst, CuO x The Co3O4 / NF catalyst significantly improved ammonia yield, demonstrating excellent catalytic activity. Furthermore, its optimal reaction potential was lower than that of CuO. x / NF and Co3O4 / NF individual catalysts optimized energy utilization efficiency. CuO x The introduction of the Co3O4 composite structure significantly improved the charge separation and transport efficiency of the catalyst, thereby enhancing the reaction rate.

[0053] Figure 7 CuO from Examples 1-3 x A comparison of the electrocatalytic nitrate reduction performance of Co3O4 / NF catalysts. This was achieved by synthesizing CuO with different Cu / Co molar ratios. x The -Co3O4 / NF complex was further validated by comparing the ammonia yield and Faraday efficiency under different Cu:Co feed ratios, and the optimal Cu:Co feed ratio of 2:1 was determined.

[0054] Figure 8 The graph shows a comparison of the electrochemical double-layer capacitance (a) and electrochemical surface area (b) of the catalysts in Examples 1-3 and Comparative Examples 1-2. To further compare the differences in catalyst activity, cyclic voltammetry tests were performed in the non-Radida region at different scan rates. As can be seen from the graph, CuO... x The -Co3O4 / NF catalyst exhibits a higher electrochemical active area than any of the comparative examples. This increased active area leads to a greater number of active sites, resulting in a higher yield of ammonia generated through nitrate adsorption and activation.

[0055] Figure 9 CuO of Example 1 x -Co3O4 / NF catalyst and CuO (Comparative Example 1) x EIS impedance spectra of CuO / NF catalyst and Comparative Example 2's Co3O4 / NF catalyst. As can be seen from the figure, CuO... x The impedance of the Co3O4 / NF catalyst is lower than that of CuO. x / NF catalyst and Co3O4 / NF catalyst, indicating CuO x The electronic conductivity and charge transfer efficiency of the Co3O4 composite structure are higher than those of a single component, thus the rate of nitrate reaction to produce ammonia is faster.

[0056] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for preparing a copper-cobalt bimetallic composite catalyst supported on nickel foam, characterized in that: Includes the following steps: (1) Dissolve CuSO4·5H2O, CoSO4·7H2O and C6H5Na3O7 in ultrapure water and stir vigorously at room temperature for 15 min to ensure complete dissolution, to obtain a mixed solution; (2) The mixed solution from step (1) is transferred to a single-chamber electrolytic cell, with nickel foam as the working electrode, platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode, and constant voltage deposition is performed under stirring. (3) Take out the foamed nickel deposited in step (2), rinse it with deionized water, then dry it under vacuum, and then calcine it in a muffle furnace under an air atmosphere to obtain a copper-cobalt bimetallic composite catalyst supported on foamed nickel.

2. The preparation method according to claim 1, characterized in that: In step (2), the constant voltage deposition conditions are: voltage -2.25V vs RHE, time 15min.

3. The preparation method according to claim 1, characterized in that: In step (3), the vacuum drying temperature is 50°C; the calcination conditions are: heating from room temperature to 300~400°C at a heating rate of 2°C / min and calcining at a constant temperature for 2 hours.

4. The preparation method according to claim 4, characterized in that: The calcination conditions are as follows: heating from room temperature to 350℃ at a heating rate of 2℃ / min and calcining at a constant temperature for 2 hours.

5. A copper-cobalt bimetallic composite catalyst supported on nickel foam, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 4.

6. The copper-cobalt bimetallic composite catalyst according to claim 5, characterized in that: The molar ratio of Cu to Co in the copper-cobalt bimetallic composite catalyst is 1~2:1~2.

7. The copper-cobalt bimetallic composite catalyst according to claim 6, characterized in that: The molar ratio of Cu to Co in the copper-cobalt bimetallic composite catalyst is 2:

1.

8. The application of the copper-cobalt bimetallic composite catalyst as described in any one of claims 5 to 7 in the electrocatalytic reduction of nitrate to ammonia.

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