Nano-porous Ag-Cu series catalytic electrode and preparation method thereof

Abstract

The invention belongs to the field of preparation of nano-porous metal materials, and particularly relates to a nano-porous Ag-Cu series catalytic electrode and a preparation method thereof.The preparation method comprises the following steps that metal Ag foil is pretreated to obtain a metal electrode slice, and the metal electrode slice is subjected to oxidation-reduction treatment through a simple electrochemical method to form a porous Ag electrode; immersing the prepared porous Ag electrode in a Cu < 2 + > solution for reduction under negative potential to obtain a porous Ag-Cu electrode with Cu < 2 + > deposited on an Ag substrate; and carrying out positive potential oxidation on the obtained porous Ag-Cu electrode in a C2H2O4 solution, then immersing the porous Ag-Cu electrode in an HCl solution, and finally reducing the electrode by adopting an i-t current time method. The nano-porous Ag-Cu series catalytic electrode manufactured by the method has self-supporting performance and good CO2 electrochemical reduction performance, CO2 series catalysis can be well achieved, and the influence of different catalytic effects caused by different substrates of the same material is avoided.

Description

Technical Field

[0001] The invention belongs to the field of nanoporous metal material preparation, and in particular relates to a nanoporous Ag-Cu series catalytic electrode and a preparation method thereof. Background Art

[0002] In the context of global climate change and energy crisis, excessive carbon dioxide (CO2) emissions have become a pressing global issue. In order to achieve sustainable development and reduce greenhouse gas emissions, electrochemical CO2 reduction reaction (CO2RR) technology provides a way to convert CO2 into valuable chemicals and fuels, which not only helps to mitigate global warming but also promotes sustainable energy utilization. In this field, copper (Cu) has attracted extensive attention due to its high selectivity in reducing CO2 to multi-carbon products (such as ethylene, ethanol, etc.) in CO2RR. However, since electrochemical CO2 reduction is a complex process with multi-step multi-electron transfer, copper-based catalysts still face challenges such as low Faradaic efficiency, large overpotential, and product selectivity dispersion in practical applications.

[0003] In order to overcome these limitations, researchers began to explore copper-based metal tandem catalysts, especially silver-copper (Ag-Cu) catalysts, in order to improve the performance of CO2RR through the tandem catalytic effect. Silver (Ag) was introduced into copper-based catalysts due to its high selectivity for generating CO during CO2 reduction, forming an Ag-Cu tandem surface. This tandem catalytic strategy integrates metals with different active sites, and can generate the key intermediate product *CO at the active site of Ag without separating the intermediates, and then diffuse to the active site of Cu through overflow to achieve CC coupling. Based on this, the inventors hope to provide new insights and strategies for the practical application of electrochemical CO2 reduction technology by in-depth research on the structure-activity relationship of Ag-Cu catalysts. Summary of the invention

[0004] Based on this, it is necessary to provide a nanoporous Ag-Cu tandem catalytic electrode and a preparation method thereof, which can deposit Cu 2+ The content of copper element on the surface of the nanoporous Ag-Cu tandem catalytic electrode can be regulated over a period of time, and the manufactured nanoporous Ag-Cu tandem catalytic electrode has self-support and good CO2 electrochemical reduction performance. Experimental verification shows that it can catalyze CO2 in series well, and can avoid the influence of different catalytic effects of the same material due to different substrates.

[0005] To achieve the above object, the present invention provides a method for preparing a nanoporous Ag-Cu tandem catalytic electrode, comprising the following steps:

[0006] (1) Pre-treating the metal Ag foil to obtain a metal electrode sheet, and then performing oxidation-reduction treatment on the metal electrode sheet using a simple electrochemical method to obtain a porous Ag electrode;

[0007] (2) Immerse the prepared porous Ag electrode in Cu 2+ The solution is reduced at a negative potential to obtain Cu 2+ Porous Ag-Cu electrodes deposited on Ag substrates;

[0008] (3) The obtained porous Ag-Cu electrode is oxidized at a positive potential in a C2H2O4 solution, then immersed in an HCl solution, and finally reduced using the it current time method to obtain the nanoporous Ag-Cu series catalytic electrode.

[0009] Furthermore, in step (1), the metal Ag foil is a high-purity Ag foil, and the purity of the high-purity Ag foil is 99.99%.

[0010] Furthermore, in step (1), the specific steps of the pretreatment are: rolling the metal Ag foil with a rolling mill, then cutting it into 5*8 mm thin sheets, and then placing it in anhydrous ethanol for ultrasonic cleaning for 10 minutes.

[0011] Furthermore, in step (1), the specific steps of the simple electrochemical method redox treatment are: using the metal electrode sheet as the working electrode, the platinum mesh as the counter electrode, the Ag / AgCl electrode as the reference electrode, and a 0.1M saturated KHCO3 solution as the electrolyte, first working at an oxidation potential of 2.7V vs.RHE for 3 minutes, and then working at a reduction potential of -0.7V vs.RHE for 5 minutes.

[0012] Further, in step (2), the Cu 2+ The solution is composed of 0.01M H2SO4+0.05M CuSO4. 2+ The concentration of the solution is 2.5*10 -4 M, the negative potential is 0.2 V vs. RHE.

[0013] Furthermore, in step (2), the specific steps of reduction are: using the porous Ag electrode as the working electrode, the platinum mesh as the counter electrode, the Hg / Hg2SO4 electrode as the reference electrode, and adopting the it current time method, the porous Ag-Cu electrode is obtained by electro-deposition at a reduction potential of 0.2Vvs.RHE, the deposition time is 2h to 3.5h, and the magnetic speed of the solution stirring is 800rpm.

[0014] Furthermore, in step (3), the concentration of the C2H2O4 solution is 0.1 M, and the positive potential is 5.4 V vs. RHE.

[0015] Furthermore, in step (3), the nanoporous Ag-Cu series catalytic electrode is prepared by oxidation-reduction and corrosion of the porous Ag-Cu electrode, which specifically includes the following steps:

[0016] (3.1) using the porous Ag-Cu electrode as the working electrode, the platinum mesh as the counter electrode, the saturated calomel electrode as the reference electrode, and the 0.1M C2H2O4 solution as the electrolyte, the porous Ag-Cu electrode was first oxidized at a constant potential by the it current time method, the oxidation potential was selected to be 5.4V vs.RHE, and the oxidation time was 10s;

[0017] (3.2) The oxidized porous Ag-Cu electrode is immersed in HCl solution for corrosion treatment for 3 seconds;

[0018] (3.3) The porous Ag-Cu electrode after corrosion treatment is used as the working electrode, the platinum mesh is used as the counter electrode, the saturated calomel electrode is used as the reference electrode, and the 0.1M saturated KHCO3 solution is used as the electrolyte. The working electrode is reduced by the it current time method, the reduction potential is -0.4Vvs.RHE, and the reduction time is 300s, thereby obtaining the nanoporous Ag-Cu series catalytic electrode.

[0019] The present invention also provides a nanoporous Ag-Cu series catalytic electrode prepared by the preparation method, characterized in that the nanoporous Ag-Cu series catalytic electrode can be prepared by controlling the deposition of Cu 2+ Time controls the copper content on the surface of the porous Ag-Cu electrode.

[0020] Compared with the prior art, the present invention has the following advantages and technical effects:

[0021] 1. The present invention provides a method for preparing a nanoporous Ag-Cu series catalytic electrode by electrochemical oxidation-reduction. The porous Ag-Cu electrode prepared by the method of corroding the porous Ag-Cu electrode by electrochemical oxidation-reduction has good self-support and porous structure, can avoid the influence of different catalytic effects of the same material due to different substrates, and can avoid the enrichment and uneven distribution of copper elements on the surface of the nanoporous Ag-Cu series catalytic electrode.

[0022] 2. Nanoporous Ag-Cu tandem catalytic electrocatalysis (deposition of Cu 2+ 3h) pole under the same test environment (0.2M KHCO3 electrolyte and -1.2V vs.RHE), CO2 can be reduced to C2 products with a catalytic selectivity of about 73%, and the nanoporous Ag-Cu tandem catalytic electrode (deposited Cu 2+3h) After testing, it was found that the catalytic selectivity of CO decreased by 4 times compared with porous silver. It can be seen that the porous silver-copper tandem catalyst prepared by the present invention has good CO2 tandem catalytic performance.

[0023] 3. Compared with the prior art, the process of preparing the nanoporous Ag-Cu series catalytic electrode of the present invention is simple. And the improvement of the catalytic activity of the present invention is due to the large number of porous structures and the uniform distribution of copper elements around the porous structures, so that CO2 can be efficiently catalyzed in series during the reduction process. The porous structure surface gives the electrode a large electrochemical surface area, and the copper elements are evenly distributed on the porous silver surface to increase the conductivity of the electrode.

[0024] 4. The present invention uses a simple electrochemical method to control the content of copper elements on the surface of the nanoporous Ag-Cu tandem catalytic electrode, effectively increasing the electrochemically active surface area compared to the original silver foil, and has good catalytic performance in CO2 reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 In the preparation of the nanoporous Ag-Cu series catalytic electrode (depositing Cu 2+ 3h) surface morphology changes. (a) Surface morphology of Ag foil. (b) Porous Ag electrode (deposited Cu 2+ 3h) Surface morphology. (c) Porous Ag-Cu electrode (deposited Cu 2+ 3h) Surface morphology. (d) Nanoporous Ag-Cu tandem catalytic electrode (deposited Cu 2+ 3h) surface morphology;

[0027] Figure 2 Schematic diagram of the surface morphology and element distribution of Example 1 of the present invention after preparation. (a) Nanoporous Ag-Cu tandem catalytic electrode (deposited Cu 2+ 3h) Surface morphology. (b) Nanoporous Ag-Cu tandem catalytic electrode (deposited Cu 2+ 3h) Mass ratio and atomic ratio of surface elements (Ag, O, Cu). (cd) Nanoporous Ag-Cu tandem catalytic electrode (deposited Cu 2+ 3h) surface element (Ag, O, Cu) distribution;

[0028] Figure 3 According to different Cu2+ X-ray diffraction patterns (XRD) of the surface of nanoporous Ag-Cu tandem catalytic electrode prepared with different deposition times (2h, 2.5h, 3h, 3.5h). (a) X-ray diffraction patterns (XRD) of nanoporous Ag-Cu tandem catalytic electrode (2~3.5h). (b) Figure 2 Partial enlarged view of a (35.9°-37.1°);

[0029] Figure 4 According to different Cu 2+ X-ray photoelectron spectroscopy (XPS) of the surface of nanoporous Ag-Cu tandem catalytic electrode fabricated with different deposition times (2h, 2.5h, 3h, and 3.5h);

[0030] Figure 5 This is a comparison chart of the Faraday efficiency of the nanoporous Ag-Cu tandem catalytic electrode and the porous Ag electrode with different deposition times in Example 2 of the present invention during the electrochemical reduction of CO2 in 0.2M saturated KHCO3;

[0031] Figure 6 The nanoporous Ag-Cu series catalytic electrode (deposited Cu) of Example 2 of the present invention 2+ 3h) Faradaic efficiency and stability during electrochemical reduction of CO2 in 0.2M saturated KHCO3. (a) Nanoporous Ag-Cu tandem catalytic electrode (deposited Cu 2+ 3h) Average Faradaic efficiency at 0-1.5h and 1.5-2.5h. (b) Nanoporous Ag-Cu tandem catalytic electrode (deposited Cu 2+ 3h) with time trends of current density (left axis) and Faraday efficiency (right axis);

[0032] Figure 7 The nanoporous Ag-Cu series catalytic electrode (deposited Cu) in Example 2 of the present invention 2+ 3h) Schematic diagram of the working principle of the material surface during the electrochemical reduction of CO2;

[0033] Figure 8 This is a Faraday efficiency diagram of the porous Ag electrode in Example 2 of the present invention during the electrochemical reduction of CO2 in 0.2M saturated KHCO3. DETAILED DESCRIPTION

[0034] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0035] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0036] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0037] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0038] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0039] The method for preparing nanoporous Ag-Cu series catalytic electrode by electrochemical oxidation-reduction can deposit Cu 2+ The surface copper content can be regulated over a period of time, and the nanoporous Ag-Cu tandem catalytic electrode has self-supporting properties and good CO2 electrochemical reduction performance. It has been experimentally verified that CO2 can be tandem catalyzed to obtain deep reduction products, C 2+ The Faraday efficiency of the product can reach about 70%, and it has the potential for practical application and industrialization. The specific preparation method is as follows:

[0040] S1, pre-treating the metal foil to obtain a metal electrode sheet, and performing oxidation-reduction treatment on the metal electrode sheet using a simple electrochemical method to obtain a porous Ag electrode;

[0041] S2, immerse the prepared porous Ag electrode in 2.5*10 -4 M concentration of Cu 2+ The solution was reduced at a negative potential (0.2 V vs. RHE) to obtain Cu 2+A porous Ag-Cu electrode is deposited on a Ag substrate, wherein the Cu 2+ Time controls the copper content on the surface of the porous Ag-Cu electrode;

[0042] S3, the obtained porous Ag-Cu electrode was oxidized at a positive potential in a 0.1M C2H2O4 solution, then immersed in a HCl solution, and finally reduced using the it current time method to obtain a nanoporous Ag-Cu tandem catalytic electrode.

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] Example 1

[0045] In this embodiment 1, the method for preparing a nanoporous Ag-Cu series catalytic electrode by electrochemical oxidation-reduction comprises the following steps:

[0046] S1: First, Ag foil was rolled by a rolling mill, and then cut into 5*8mm thin sheets, and then placed in anhydrous ethanol for ultrasonic vibration cleaning for 10 minutes to obtain the pretreated Ag foil as a metal electrode sheet. The metal electrode sheet was placed in an H-type three-electrode electrolytic cell as a working electrode, with 0.1M saturated KHCO3 solution as the electrolyte, saturated silver-silver chloride electrode as the reference electrode, and platinum mesh as the counter electrode. The silver electrode was first worked at an oxidation potential for 3 minutes, and then worked at a reduction potential for 5 minutes to obtain a porous Ag electrode with an oxidation potential of 2.7V vs.RHE and a reduction potential of -0.7V vs.RHE;

[0047] S2: The porous Ag-Cu electrode was placed as the working electrode in an H-type three-electrode electrolytic cell, which was composed of 0.01M H2SO4+0.05MCuSO4 and a 2.5*10 -4 M concentration of Cu 2+ The solution is an electrolyte, in which a saturated mercurous sulfate electrode is used as a reference electrode and a platinum mesh is used as a counter electrode. The it current time method is used to obtain porous Ag-Cu electrodes with different amounts of copper element distribution under negative potential under different time conditions. 2+ The deposition time is 2h-3.5h, the deposition potential is 0.2V vs.RHE, and the deposition of Cu 2+ During the process, the magnetic sub-speed was 800 rpm;

[0048] S3: The porous Ag-Cu electrode was placed in an H-type three-electrode electrolytic cell as a working electrode, the electrolyte was 0.1M C2H2O4 solution, the saturated calomel electrode was the reference electrode, the porous Ag-Cu electrode was oxidized by the it current time method, and then the oxidized electrode was placed in an HCl solution for corrosion treatment, and the electrode after corrosion treatment was placed in a three-electrode electrolytic cell as a working electrode, the 0.1M saturated KHCO3 solution was the electrolyte, the saturated silver-silver chloride electrode was the reference electrode, and the platinum mesh was the counter electrode, and the working electrode was reduced by the it current time method to obtain a nanoporous Ag-Cu series catalytic electrode. The working potential of the oxidized porous Ag-Cu electrode was 5.4V vs.RHE, and the oxidation time was 10s; the oxidized electrode was placed in an HCl solution for corrosion treatment, and the corrosion time was 3s; the electrode after corrosion treatment was reduced by the time potential method, and the reduction potential was -0.4V vs.RHE, and the reduction time was 300s.

[0049] The morphological changes of the Ag foil electrode shown in the present invention after oxidation-reduction (ER-Ag), deposition (porous Ag-Cu electrode), and corrosion (nanoporous Ag-Cu series catalytic electrode) are shown in FIG. Figure 1 As shown;

[0050] Schematic diagram of surface element distribution (EDS) of the prepared nanoporous Ag-Cu tandem catalytic electrode Figure 2 As shown by Figure 2 It can be seen that the copper element is evenly distributed on the silver surface, and the element atomic ratio can reach Cu:Ag=35.33%:55.12%;

[0051] According to different Cu 2+ The X-ray diffraction patterns (XRD) of the nanoporous Ag-Cu tandem catalytic electrode surface prepared with different deposition times (2h, 2.5h, 3h, 3.5h) are as follows: Figure 3 As shown;

[0052] According to different Cu 2+ The X-ray photoelectron spectroscopy (XPS) of the surface of the nanoporous Ag-Cu tandem catalytic electrode prepared with different deposition times (2h, 2.5h, 3h, and 3.5h) is shown in Figure 2. Figure 4 As shown;

[0053] Example 2

[0054] In this embodiment 2, the porous Ag electrode and the nanoporous Ag-Cu series catalytic electrode prepared in embodiment 1 are used to reduce CO2, and the specific steps are as follows:

[0055] In an H-type electrolytic cell in which each chamber contains 30 ml of 0.2M saturated KHCO3 electrolyte, a Nafion-115 membrane is used to separate the two chambers of the H-type electrolytic cell, a platinum mesh is used as a counter electrode, a saturated silver-silver chloride electrode is used as a reference electrode, and the prepared porous Ag electrode and a nanoporous Ag-Cu series catalytic electrode are used as working electrodes, respectively. The it current time method is used to reduce CO2 at a constant potential using the above two electrodes, and the voltage is -1.2 V vs. RHE.

[0056] Finally, the comparison of the Faraday efficiency of the catalysts in the CO2RR process for the reduction products when the porous Ag electrode and four nanoporous Ag-Cu tandem catalytic electrodes were operated at a potential of -1.2 V vs. RHE is shown in the figure below. Figure 5 As shown by Figure 5 It can be seen that the nanoporous Ag-Cu tandem catalytic electrode (deposited Cu 2+ 3h) has the best catalytic performance, C 2+ The product Faraday efficiency can reach about 73% (C 2+ The products include ethanol, ethane, acetic acid and isopropanol, among which the Faraday efficiency of ethanol can reach 44.5%. The CO Faraday efficiency of porous Ag is 4 times that of the nanoporous Ag-Cu tandem catalytic electrode, indicating that the nanoporous Ag-Cu tandem catalytic electrode has good tandem catalytic activity.

[0057] Nanoporous Ag-Cu tandem catalytic electrode (deposited Cu 2+ 3h) The Faraday test results during the electrochemical reduction of CO2 in 0.2M saturated KHCO3 are as follows Figure 6 As shown by Figure 6 It can be seen that it is stable for about 3.5 hours at a voltage of -1.2 V vs. RHE, where the Faraday efficiencies of H2 and CO are both around 15%, and the Faraday efficiency of the C2 product is about 70% at -1.2 V vs. RHE, of which the Faraday efficiency of C2H5OH is 44%. As the material surface gradually loses its activity, the selectivity of the C2 product and H2 gradually decreases, and the selectivity of CO gradually increases.

[0058] The working principle of the nanoporous Ag-Cu tandem catalytic electrode and the test process of Faraday efficiency are as follows Figure 7 As shown by Figure 7 It can be seen that CO2 is reduced to *CO through the porous Ag active sites, and then *CO is reduced to C2 products through the copper particles.

[0059] The Faraday test results of the nanoporous Ag electrode during the electrochemical reduction of CO2 in 0.2M saturated KHCO3 are shown in Figure 8 As shown by Figure 8It can be seen that the nanoporous Ag electrode can be stable at a potential of -1.2 V vs. RHE for about 5 h, and the CO Faraday efficiency can reach up to 90%. As a substrate, it can provide a large amount of *CO for the surface copper element.

[0060] In summary, the method for preparing nanoporous Ag-Cu tandem catalytic electrode by electrochemical oxidation-reduction provided by the present invention is to control the deposition of Cu 2+ The copper content on the surface of the porous Ag-Cu electrode is controlled by time, which has good self-supporting properties, good catalytic performance in the electrochemical reduction of CO2, and the generated C2 product is highly efficient.

[0061] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing a nanoporous Ag-Cu tandem catalytic electrode, characterized in that: The following steps are involved: (1) Pre-treating the metal Ag foil to obtain a metal electrode sheet, and then performing oxidation-reduction treatment on the metal electrode sheet using a simple electrochemical method to obtain a porous Ag electrode; (2) Immerse the prepared porous Ag electrode in Cu 2+ The solution is reduced at a negative potential to obtain Cu 2+ Porous Ag-Cu electrodes deposited on Ag substrates; (3) The obtained porous Ag-Cu electrode is oxidized at a positive potential in a C2H2O4 solution, then immersed in a HCl solution, and finally reduced using the it current time method to obtain a nanoporous Ag-Cu tandem catalytic electrode.

2. The preparation method according to claim 1, characterized in that: In step (1), the metal Ag foil is a high-purity Ag foil, and the purity of the high-purity Ag foil is 99.99%.

3. The preparation method according to claim 1, characterized in that: In step (1), the specific steps of the pretreatment are: rolling the metal Ag foil with a rolling mill, then cutting it into 5*8mm thin sheets, and then placing it in anhydrous ethanol for ultrasonic cleaning for 10 minutes.

4. The preparation method according to claim 1, characterized in that: In step (1), the specific steps of the simple electrochemical method redox treatment are: using the metal electrode sheet as the working electrode, the platinum mesh as the counter electrode, the Ag / AgCl electrode as the reference electrode, and a 0.1M saturated KHCO3 solution as the electrolyte, first working at an oxidation potential of 2.7V vs.RHE for 3 minutes, and then working at a reduction potential of -0.7V vs.RHE for 5 minutes.

5. The preparation method according to claim 1, characterized in that: In step (2), the Cu 2+ The solution is composed of 0.01M H2SO4 + 0.05M CuSO4. 2+ The concentration of the solution is 2.5*10 -4 M, the negative potential is 0.2 V vs. RHE.

6. The preparation method according to claim 1, characterized in that: In step (2), the specific steps of reduction are: using the porous Ag electrode as the working electrode, the platinum mesh as the counter electrode, the Hg / Hg2SO4 electrode as the reference electrode, and adopting the it current time method, electro-depositing the porous Ag-Cu electrode at a reduction potential of 0.2Vvs.RHE, the deposition time is 2h to 3.5h, and the magnetic speed of the solution stirring is 800rpm.

7. The preparation method according to claim 1, characterized in that: In step (3), the concentration of the C2H2O4 solution is 0.1 M, and the positive potential is 5.4 V vs. RHE.

8. The preparation method according to claim 1, characterized in that: In step (3), the nanoporous Ag-Cu series catalytic electrode is prepared by oxidation-reduction and corrosion of the porous Ag-Cu electrode, which specifically includes the following steps: (3.1) using the porous Ag-Cu electrode as the working electrode, the platinum mesh as the counter electrode, the saturated calomel electrode as the reference electrode, and the 0.1M C2H2O4 solution as the electrolyte, the porous Ag-Cu electrode was first oxidized at a constant potential by the it current time method, the oxidation potential was selected to be 5.4V vs.RHE, and the oxidation time was 10s; (3.2) The oxidized porous Ag-Cu electrode is immersed in HCl solution for corrosion treatment for 3 seconds; (3.3) The porous Ag-Cu electrode after corrosion treatment is used as the working electrode, the platinum mesh is used as the counter electrode, the saturated calomel electrode is used as the reference electrode, and the 0.1M saturated KHCO3 solution is used as the electrolyte. The working electrode is reduced by the it current time method, the reduction potential is -0.4Vvs.RHE, and the reduction time is 300s, thereby obtaining the nanoporous Ag-Cu series catalytic electrode.

9. A nanoporous Ag-Cu tandem catalytic electrode prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The nanoporous Ag-Cu tandem catalytic electrode can be deposited by controlled deposition of Cu 2+ Time controls the copper content on the surface of the porous Ag-Cu electrode.

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