Bifunctional catalytic electrode with metal defects as well as preparation method and application thereof
By introducing phosphorus modification and cobalt defects on cobalt nanosheets and growing nanosheet arrays on foam nickel, a highly active catalytic electrode was prepared, which solved the problem of insufficient catalytic electrode activity in the prior art and achieved an efficient co-electrolytic reaction.
Patent Information
- Application Number
- CN202510230705.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-28
- Publication Date
- 2025-05-30
AI Technical Summary
The prior art is difficult to develop economical and highly active catalytic electrodes for high-efficiency electrocatalytic reactions in co-electrolytic systems of nitrite and glycerol.
Catalytic electrodes with different metal defect concentrations were prepared by introducing phosphorus modification and cobalt defects into metal cobalt nanosheets and growing uniformly in situ on the foam nickel support with nanosheet array morphology.
The catalytic electrode exhibits excellent catalytic performance in the co-electrolysis reaction of ammonia from nitrite reduction and glycerol oxidation to formate, which can provide high efficiency and high yield products at lower voltages.
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Figure CN120060909A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of electrocatalysis, and particularly to a bifunctional catalytic electrode with metal defects, a preparation method thereof, and an application thereof. Background Art
[0002] With the growing demand for sustainable and renewable energy, electrosynthesis of high-value chemicals, as a strategy to alleviate energy crises and environmental problems, has been gradually attracting attention. In recent years, due to the high economy of formic acid ($0.022 / mol) and the high hydrogen capacity of NH 3 (53.4 g / L), electro-synthesis of formic acid and NH 3 chemicals has received extensive attention. Among various reactions, electrocatalytic glycerol oxidation reaction (GOR) and nitrate / nitrite reduction (NRR) are becoming effective methods for producing formic acid and NH 3 which can ideally obtain raw materials from by-products of the biodiesel industry and industrial wastewater containing nitrogen salts. Although the feasibility of these electrolysis technologies has been demonstrated by previous studies, the core of improving product selectivity and energy efficiency lies in the development of high-performance electrocatalysts. Given the disadvantages of noble metal materials such as high price and low reserves, there is an urgent need to develop an economical and highly active catalytic electrode for the co-electrolysis system of GOR and NRR. Therefore, it is particularly important to develop a simple and efficient preparation method for the development of high-performance catalytic electrodes and their practical applications in the co-electrolysis system of nitrite and glycerol. Summary of the Invention
[0003] (1) Technical Problems to be Solved
[0004] Aiming at the deficiencies of the prior art, the present invention provides a bifunctional catalytic electrode with metal defects, a preparation method thereof, and an application thereof. Phosphorus modification and cobalt defects are simultaneously introduced into metal cobalt nanosheets, and they are uniformly and in-situ grown on a nickel foam carrier in the form of a nanosheet array morphology, realizing a catalytic electrode with adjustable different metal defect concentrations, which can show potential applications in the co-electrolysis system of nitrite reduction to ammonia and glycerol oxidation to formate, and solves the problems raised in the above background art.
[0005] (2) Technical Solutions
[0006] To achieve the above objectives, the present invention is realized through the following technical solutions:
[0007] According to a first aspect of the present invention, there is provided a bifunctional catalytic electrode with metal defects, including nickel foam and nanosheets loaded on the surface of the nickel foam, and the nanosheets are phosphorus-modified low-coordination metal cobalt nanosheets.
[0008] Preferably, the nanosheets are in the form of a sheet-like nanosheet array structure, and the size of the nanosheets is 20 - 500 nm.
[0009] Preferably, the exposed crystal plane of the nanosheet is the Co(200) plane, and there are metal Co defects with different concentrations.
[0010] According to the second aspect of the present invention, a method for preparing a bifunctional catalytic electrode with metal defects is provided, including the following steps:
[0011] (1) Add cobalt salt, ammonium salt and sodium hypophosphite into water and stir evenly to obtain a salt solution;
[0012] (2) Construct an electrolytic cell with a three-electrode system, use nickel foam as the working electrode, a saturated silver / silver chloride electrode as the reference electrode, a platinum sheet electrode as the counter electrode, use the salt solution as the electrolyte, apply a constant voltage for electrochemical deposition to obtain a catalytic electrode;
[0013] (3) Alternately wash the catalytic electrode with ethanol and distilled water, and dry it in vacuum to obtain the bifunctional catalytic electrode with metal defects.
[0014] Preferably, in step (1), the mass ratio of the cobalt salt to the ammonium salt is 1:1 to 3;
[0015] The mass ratio of the cobalt salt to the sodium hypophosphite is 1:1 to 5;
[0016] The mass ratio of the cobalt salt to the volume of water is 1 g: 30 to 80 mL.
[0017] Preferably, in step (1), the cobalt salt is selected from at least one of cobalt nitrate, cobalt chloride, and cobalt sulfate;
[0018] The ammonium salt is selected from at least one of ammonium chloride and ammonium fluoride.
[0019] Preferably, in step (2), during the electrochemical deposition, the applied constant voltage is -1 to -3 V, and the time for applying the constant voltage is 200 to 1000 s.
[0020] Preferably, in step (3), the number of times of alternately washing the catalytic electrode with ethanol and distilled water is ≥ 3 times.
[0021] Preferably, in step (3), the temperature of the vacuum drying is 40 to 80 °C, and the time for the vacuum drying is 30 to 90 min.
[0022] According to the third aspect of the present invention, an application of a bifunctional catalytic electrode with metal defects or a bifunctional catalytic electrode with metal defects obtained by the above preparation method in the co-electrolysis reaction of nitrite reduction to ammonia and glycerol oxidation to formate is provided.
[0023] (3) Beneficial Effects
[0024] The present invention provides a bifunctional catalytic electrode with metal defects, a preparation method thereof, and an application thereof. The beneficial effects are as follows:
[0025] (1) A preparation method of a bifunctional catalytic electrode with metal defects provided by this solution simultaneously introduces phosphorus modification and cobalt defects into metal cobalt nanosheets through a simple one-step electrodeposition strategy. This catalytic electrode has abundant catalytic sites, optimized electronic structures, and fast reaction kinetic processes, and is proved to be an excellent catalyst for the GOR and NO 2 RR system.
[0026] (2) In the application of a bifunctional catalytic electrode with metal defects provided by this solution in the co-electrolysis reaction of nitrite reduction to ammonia and glycerol oxidation to formate, using this catalytic electrode as the cathode and anode to construct an anion exchange membrane co-electrolysis device, the co-electrolysis synthesis of ammonia and formate products can be realized synchronously. In the cathode nitrite reduction to ammonia reaction, this co-electrolysis device can provide an ammonia Faraday efficiency of 98.2% and an ammonia production rate of 29.3 mg h -1 cm -2 at a cell voltage of 1.5 V. In the anode glycerol oxidation to formate reaction, this co-electrolysis device can provide a formate Faraday efficiency of 93.4% and a formate production rate of 85.7 mg h -1 cm -2 at a cell voltage of 1.5 V.
[0027] (3) The application of a bifunctional catalytic electrode with metal defects provided by this solution in the co-electrolysis reaction of nitrite reduction to ammonia and glycerol oxidation to formate demonstrates great application potential and economic value in the field of electrocatalytic co-electrolysis synthesis of high-value chemicals. Description of the Drawings
[0028] Figure 1 is the X-ray diffraction pattern of the catalytic electrodes prepared in Examples 1 to 3 and Comparative Example 1 of the present invention;
[0029] Figure 2 is the scanning electron microscope image of the P 3 -Co catalytic electrode prepared in Example 1 of the present invention. Among them, Figure a is the SEM image at 20 μm, and Figure b is the SEM image at 500 nm;
[0030] Figure 3 is the transmission electron microscope image of the P 3 -Co catalytic electrode prepared in Example 1 of the present invention. Figure a is the TEM image at 100 nm, and Figure b is the HRTEM image at 1 nm;
[0031] Figure 4P prepared in Example 1 of the present invention 3 EDS elemental mapping of the -Co catalytic electrode;
[0032] Figure 5 EPR spectra of the catalytic electrodes prepared in Examples 1 to 3 and Comparative Example 1 of the present invention;
[0033] Figure 6 P prepared in Example 1 of the present invention 3 XPS spectra of the -Co catalytic electrode, where Figure a is the XPS spectrum of P 2p and Figure b is the XPS spectrum of Co 2p;
[0034] Figure 7 Performance graphs of the catalytic electrodes prepared in Examples 1 to 3 and Comparative Example 1 of the present invention in an electrolytic solution containing 0.1M NaNO 2 and 1M KOH for testing the performance of nitrite reduction reaction (NO 2 RR), where Figure a is the LSV curve graph, and Figure b is the ammonia Faraday efficiency and ammonia production rate of the P 3 -Co catalytic electrode prepared in Example 1 at different reaction potentials;
[0035] Figure 8 Performance graphs of the catalytic electrodes prepared in Examples 1 to 3 and Comparative Example 1 of the present invention in an electrolytic solution containing 0.1M glycerol and 1M KOH for testing the performance of glycerol oxidation reaction (GRR), where Figure a is the LSV curve graph, and the P 3 -Co catalytic electrode prepared in Example 1 has formate Faraday efficiency and formate production rate at different reaction potentials;
[0036] Figure 9 Using the catalytic electrodes prepared in Example 1 and Comparative Example 1 of the present invention as the cathode and anode, constructing a two-electrode with an anion exchange membrane, using 0.1M NaNO 2 and 1M KOH as the cathode electrolyte, and 0.1M glycerol and 1M KOH as the anode electrolyte, the LSV curve graph of the nitrite reduction coupled glycerol oxidation reaction (NO 2 RR / / GOR) is tested;
[0037] Figure 10 Using the catalytic electrodes prepared in Example 1 and Comparative Example 1 of the present invention as the cathode and anode, constructing a two-electrode reaction (NO 2 RR / / GOR), with a current density of 100mA cm -2 for 300h of electrolysis, the stability performance graph and the product Faraday efficiency and production rate detected every 30h. Detailed implementation method
[0038] To better illustrate the content of the present invention, the following will be described in detail with specific embodiments.
[0039] Example 1
[0040] In this example, a bifunctional catalytic electrode with metal defects is prepared, and the preparation process is as follows:
[0041] Step 1: Add 1 g of Co(NO 3 ) 2 ·6H 2 O, 1.5 g of NH 4 Cl, and 3 g of sodium hypophosphite into 50 ml of deionized water, stir evenly to obtain a light red electrolyte solution;
[0042] Step 2: Select a 1×2 cm 2 foam nickel as the working electrode, a saturated Ag / AgCl electrode as the reference electrode, and a platinum plate electrode as the counter electrode. Immerse the three electrodes in the electrolyte solution and apply a constant voltage of -2V to the working electrode for 400 s to obtain a light gray P 3 -Co nanosheet array loaded on the foam nickel skeleton;
[0043] Step 3: Wash the prepared catalyst repeatedly with ethanol and distilled water to remove the surface residues, and then place it in a vacuum oven at 80°C for 60 min to dry, obtaining a bifunctional catalytic electrode with metal defects, named P 3 -Co.
[0044] Example 2
[0045] In this example, a bifunctional catalytic electrode with metal defects is prepared, and the preparation process is as follows:
[0046] Step 1: Add 1 g of Co(NO 3 ) 2 ·6H 2 O, 1.5 g of NH 4 Cl, and 1 g of sodium hypophosphite into 50 ml of deionized water, stir evenly to obtain a light red electrolyte solution;
[0047] Step 2: Select a 1×2 cm 2 foam nickel as the working electrode, a saturated Ag / AgCl electrode as the reference electrode, and a platinum plate electrode as the counter electrode. Immerse the three electrodes in the electrolyte solution and apply a constant voltage of -2V to the working electrode for 400 s to obtain a light gray P 1 -Co nanosheet array loaded on the foam nickel skeleton;
[0048] Step 3: Wash the prepared catalyst repeatedly with ethanol and distilled water to remove surface residues, and then place it in a vacuum oven at 80 °C for drying for 60 min to obtain a bifunctional catalytic electrode with metal defects, named P 1 -Co.
[0049] Example 3
[0050] In this example, a bifunctional catalytic electrode with metal defects is prepared, and the preparation process is as follows:
[0051] Step 1: Add 1 g of Co(NO 3 ) 2 ·6H 2 O, 1.5 g of NH 4 Cl and 5 g of sodium hypophosphite into 50 ml of deionized water, stir evenly to obtain a light red electrolyte solution;
[0052] Step 2: Select a 1×2 cm 2 foam nickel as the working electrode, use a saturated Ag / AgCl electrode as the reference electrode, and a platinum plate electrode as the counter electrode. Immerse the three electrodes in the electrolyte solution, apply a constant voltage of -2 V to the working electrode for 400 s to obtain light gray P 1 -Co nanosheet arrays loaded on the foam nickel skeleton;
[0053] Step 3: Wash the prepared catalyst repeatedly with ethanol and distilled water to remove surface residues, and then place it in a vacuum oven at 80 °C for drying for 60 min to obtain a bifunctional catalytic electrode with metal defects, named P 5 -Co.
[0054] Example 4
[0055] This example has the same preparation method as Example 1, except that in Step 2, the constant voltage applied during electrodeposition is -1 V, named P 3 -Co-1V.
[0056] Example 5
[0057] This example has the same preparation method as Example 1, except that in Step 2, the constant voltage applied during electrodeposition is -3 V, named P 3 -Co-3V.
[0058] Example 6
[0059] This example has the same preparation method as Example 1, except that in Step 2, the time for applying a constant voltage of -2 V during electrodeposition is 200 s, named P 3 -Co-200s.
[0060] Example 7
[0061] The preparation method of this example is the same as that of Example 1, except that in Step 2, the time for applying a constant voltage of -2V during electrodeposition is 600s, named P 3 -Co-600s.
[0062] Example 8
[0063] The preparation method of this example is the same as that of Example 1, except that in Step 2, the time for applying a constant voltage of -2V during electrodeposition is 800s, named P 3 -Co-800s.
[0064] Example 9
[0065] The preparation method of this example is the same as that of Example 1, except that in Step 2, the time for applying a constant voltage of -2V during electrodeposition is 1000s, named P 3 -Co-1000s.
[0066] Comparative Example 1
[0067] The preparation method of the Co catalytic electrode includes the following steps:
[0068] Step 1: Add 1g of Co(NO 3 ) 2 ·6H 2 O and 1.5g of NH 4 Cl to 50 ml of deionized water, stir evenly to obtain a light red electrolyte solution;
[0069] Step 2: Select a 1×2 cm 2 foam nickel as the working electrode, use a saturated Ag / AgCl electrode as the reference electrode, and a platinum sheet electrode as the counter electrode. Immerse the three electrodes in the electrolyte solution and apply a constant voltage of -2V to the working electrode for 400s to obtain a light gray Co catalyst loaded on the foam nickel skeleton;
[0070] Step 3: Wash the prepared catalyst repeatedly with ethanol and distilled water to remove the residues on the surface, and then place it in a vacuum oven at 80°C for 60 min to dry, obtaining a bifunctional catalytic electrode with metal defects, named Co.
[0071] Performance detection
[0072] Perform XRD analysis on the catalytic electrodes of Examples 1 to 3 and Comparative Example 1, as Figure 1As shown, the diffraction peaks of the four prepared catalytic electrodes can all match well with the standard Co having a hexagonal structure (PDF#05-0727). The crystallinity of the P-modified Co sample is weaker than that of the simple Co, indicating that the P source has an impact on the structural growth of the catalyst.
[0073] The catalytic electrodes of Examples 1 to 3 and Comparative Example 1 were analyzed by scanning electron microscopy (SEM). As Figure 2 shown in Figures 4 - 5 a and Figure 3 shown, the surface has a morphology of hierarchical nanosheets. The abundant hierarchical nanosheets grow uniformly on the nickel foam skeleton, which is beneficial to the full contact with the substrate during the reaction process, thereby exposing more catalytic active sites and promoting the occurrence of the catalytic reaction.
[0074] The catalytic electrode prepared in Example 1 was analyzed by scanning electron microscopy (SEM). As Figure 2 shown, the surface has a morphology of hierarchical nanosheets. The abundant hierarchical nanosheets grow uniformly on the nickel foam skeleton, which is beneficial to the full contact with the substrate during the reaction process, thereby exposing more catalytic active sites and promoting the occurrence of the catalytic reaction.
[0075] Example 1 was analyzed by TEM. As Figure 3 shown in Figures a and b of 3 , the image of P
[0076] -Co further shows its hierarchical nanosheet structure. The high-resolution TEM (HRTEM) image shows that the lattice fringe distance is 0.200 nm, which can be attributed to the (002) plane of Co. Figure 4 EDS analysis of Example 1 3 showed that P and Co elements are uniformly distributed throughout the P
[0077] The catalytic electrodes of Examples 1 to 3 and Comparative Example 1 were analyzed by electron paramagnetic resonance (EPR). Combining Figure 5 it can be seen that the signal appearing at g = 2.004 belongs to the defect of metallic Co. With the increase of P modification, the signal of Co defects gradually increases, indicating that the metal defect concentration of the P 5 -Co catalyst gradually increases.
[0078] The catalytic electrodes of Examples 1 to 3 and Comparative Example 1 were tested by X-ray photoelectron spectroscopy (XPS). As Figure 6 shown, in the XPS spectrum of Co 2p, the two peaks at 796.9 eV and 781.2 eV respectively belong to Co 2+ 's 2p 1 / 2 and 2p 2 / 3, In addition, there are also two satellite peaks located at 803.1 eV and 786.2 eV. With the addition of P, the peak of Co 2+ 2p 2 / 3 orbital shifts to lower binding energy, indicating a slight decrease in the Co valence state. In addition, the modification of P can be further confirmed by a typical peak located at 132.7 eV in the P 2p spectrum..
[0079] Application Example 1
[0080] Using the catalytic electrodes prepared in Example 1 and Comparative Example 1 as the cathode and anode, a two-electrode system was constructed with an anion exchange membrane. Using 0.1 M NaNO 2 and 1 M KOH as the cathode electrolyte, and 0.1 M glycerol and 1 M KOH as the anode electrolyte, the nitrite reduction coupled with glycerol oxidation reaction (NO 2 RR / / GOR) was tested. After applying a voltage of 1.2 V for continuous electrolysis for 1 hour, the cathode and anode electrolytes were collected for product (ammonia and formate) detection.
[0081] Application Example 2
[0082] This application example is the same as that of Application Example 1, except that the applied potential in the step is 1.3 V.
[0083] Application Example 3
[0084] This application example is the same as that of Application Example 1, except that the applied potential in the step is 1.4 V.
[0085] Application Example 4
[0086] This application example is the same as that of Application Example 1, except that the applied potential in the step is 1.5 V.
[0087] Application Example 5
[0088] This application example is the same as that of Application Example 1, except that the applied potential in the step is 1.6 V.
[0089] Application Example 6
[0090] This application example is the same as that of Application Example 1, except that the applied potential in the step is 1.7 V.
[0091] Performance Test
[0092] The NO 2 RR linear voltammetry curves of the catalytic electrodes prepared in Examples 1 to 3 and Comparative Example 1 were tested. The electrolyte was 1 M KOH solution with / without 0.1 M NaNO 2 , as Figure 7 shown in a. After adding 0.1 M NaNO 2After that, all the catalysts showed a significantly increased current density at the same potential, indicating that Co has intrinsic high activity for NO 2 RR. Among them, the P 3 -Co sample of Example 1 provided the highest current density and the lowest onset potential, revealing the catalytic performance synergistically promoted by the two factors of moderate P modification and metal defects.
[0093] For the P 3 -Co catalytic electrode prepared in Example 1, the product detection was carried out after electrolyzing for 1 h at different applied voltages by the three-electrode method in an electrolyte containing 0.1 M NaNO 2 and 1 M KOH in the cathode, as shown in Figure 7 b. The P 3 -Co catalyst had the highest ammonia Faraday efficiency of 98.0% at -0.2 V vs. RHE, and the yield reached 33.35 mg h -1 cm -2 .
[0094] The linear voltammetry curves of NO 2 RR were tested for the catalytic electrodes prepared in Examples 1 to 3 and Comparative Example 1 by the three-electrode method, and the electrolyte was 1 M KOH solution with / without 0.1 M glycerol, as shown in Figure 8 a. The P 3 -Co catalyst only needed a small potential of 1.68 V vs. RHE to reach a current density of 200 mA cm -2 , which was much lower than 1.81 V vs. RHE of the traditional oxygen evolution reaction. At the same potential, the P 3 -Co catalyst had the best current density, indicating that P modification and metal Co defects could simultaneously promote the GOR activity.
[0095] For the P 3 -Co catalytic electrode prepared in Example 1, the product detection was carried out after electrolyzing for 1 h at different applied voltages by the three-electrode method in an electrolyte containing 0.1 M glycerol and 1 M KOH in the cathode, as shown in Figure 8 b. The P 3 -Co catalyst had the highest formate Faraday efficiency of 98.3% at 1.5 V vs. RHE, and the yield reached 35.20 mg h -1 cm -2 .
[0096] Using the catalytic electrodes prepared in Example 1 and Comparative Example 1 as the anode and cathode to construct an anion exchange membrane (AEM) electrolyzer (NO 2 RR / / GOR), where 1 M KOH and 0.1 M NaNO 2Using the electrolyte as the cathode and 1M KOH and 0.1M glycerol as the electrolyte as the anode. NO 2 The LSV curves of the RR / / GOR electrolyzer are as follows Figure 9 shown. Based on P 3 -Co catalyst for NO 2 The RR / / GOR electrolyzer only requires 1.191 V to achieve a current density of 100 mA cm -2 , which is approximately 342 mV lower than the current density (1.533 V) required by the Co catalyst. For both catalysts, compared with the HER / / OER electrolyzer, the assembled NO 2 RR / / GOR electrolyzer can provide a lower voltage and a higher current density, indicating that constructing a coupled catalytic system can significantly reduce energy consumption and improve energy efficiency.
[0097] The NO 2 RR / / GOR electrolyzer was further studied in Example 1 for its stability at a constant current density of 100 mA cm -2 . As Figure 10 shown, the NO 2 RR / / GOR electrolyzer maintained high stability during electrolysis for more than 300 hours. The Faraday efficiency and yield of formate and NH 3 could remain stable without decay within 300 h, indicating that P 3 -Co catalyst has excellent activity and stability in the practical application of efficient co-electrolysis of nitrite and glycerol and can be applied to actual industrial production.
[0098] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A bifunctional catalytic electrode with metal defects, characterized in that: The invention comprises foamed nickel and nanosheets loaded on the surface of the foamed nickel, wherein the nanosheets are phosphorus-modified low-coordination metal cobalt nanosheets.
2. The bifunctional catalytic electrode with metal defects according to claim 1, characterized in that: The nanosheet is a sheet-like nanosheet array structure, and the size of the nanosheet is 20-500nm.
3. The bifunctional catalytic electrode with metal defects according to claim 1, characterized in that: The exposed crystal plane of the nanosheet is a Co (200) plane, and there are metal Co defects of different concentrations.
4. A method for preparing a bifunctional catalytic electrode with metal defects according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) adding cobalt salt, ammonium salt and sodium hypophosphite into water and stirring evenly to obtain a salt solution; (2) constructing an electrolytic cell with a three-electrode system, using nickel foam as a working electrode, a saturated silver / silver chloride electrode as a reference electrode, a platinum sheet electrode as a counter electrode, and the salt solution as an electrolyte, applying a constant voltage for electrochemical deposition to obtain a catalytic electrode; (3) The catalytic electrode is alternately cleaned with ethanol and distilled water, and vacuum dried to obtain the bifunctional catalytic electrode with metal defects.
5. The method for preparing a bifunctional catalytic electrode with metal defects according to claim 4, characterized in that: In step (1), the mass ratio of the cobalt salt to the ammonium salt is 1:1 to 3; The mass ratio of the cobalt salt to the sodium hypophosphite is 1:1-5; The mass ratio of the cobalt salt to the volume of the water is 1 g: 30-80 mL.
6. The method for preparing a bifunctional catalytic electrode with metal defects according to claim 4, characterized in that: In step (1), the cobalt salt is selected from at least one of cobalt nitrate, cobalt chloride and cobalt sulfate; The ammonium salt is selected from at least one of ammonium chloride and ammonium fluoride.
7. The method for preparing a bifunctional catalytic electrode with metal defects according to claim 4, characterized in that: In step (2), during the electrochemical deposition process, the constant voltage applied is -1 to -3 V, and the time for applying the constant voltage is 200 to 1000 s.
8. The method for preparing a bifunctional catalytic electrode with metal defects according to claim 4, characterized in that: In step (3), the catalytic electrode is washed alternately with ethanol and distilled water for ≥ 3 times.
9. The method for preparing a bifunctional catalytic electrode with metal defects according to claim 4, characterized in that: In step (3), the vacuum drying temperature is 40 to 80° C., and the vacuum drying time is 30 to 90 minutes.
10. Use of a bifunctional catalytic electrode with metal defects as claimed in any one of claims 1 to 3 or a bifunctional catalytic electrode with metal defects obtained by the preparation method according to any one of claims 4 to 9 in the co-electrolysis reaction of nitrite to ammonia and glycerol oxidation to formate.