Silver-doped copper oxide catalytic electrode and preparation method and application thereof

Abstract

The invention discloses a silver-doped copper oxide catalytic electrode as well as a preparation method and application thereof, and belongs to the technical field of electrocatalysts. The preparation method comprises the following steps: firstly, preparing an original copper electrode by a magnetron sputtering method, secondly, putting the copper electrode into a silver nitrate solution, carrying out high-temperature hydrothermal reaction, and finally, washing and drying the reacted electrode to obtain the silver-doped copper oxide catalytic electrode. The silver-doped copper oxide catalytic electrode prepared by the method disclosed by the invention has relatively high catalytic activity and relatively high multi-carbon product selectivity in the aspect of acidic carbon dioxide electrocatalytic reduction. The oxygen vacancy concentration of the catalyst is improved through silver doping, adsorption of carbon dioxide and reaction intermediate carbon monoxide is promoted, and finally the carbon-carbon coupling process is promoted.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrocatalysts, and particularly relates to a silver-doped copper oxide catalytic electrode and a preparation method and application thereof. BACKGROUND

[0002] A large amount of carbon dioxide emissions has caused a global greenhouse effect, which has posed a great threat to the living environment of human beings. Carbon dioxide electrocatalytic reduction reaction (CO2RR) mainly uses the emitted carbon dioxide gas as a raw material, and directly converts it into high-value-added organic fuels, such as single-carbon products (such as carbon monoxide) and multi-carbon products (such as ethylene) through an electrocatalytic reaction process.

[0003] At present, the carbon dioxide electrocatalytic reduction reaction mainly faces problems such as low product selectivity (Faraday efficiency) of the catalyst and large reaction overpotential. Copper catalyst is the only catalyst that can produce multi-carbon products (such as ethylene and ethanol) at present. However, the multi-carbon product selectivity of the traditional copper catalyst is poor, for example, the ethylene selectivity is generally less than 20%, which is difficult to meet the industrial application requirements.

[0004] Chinese patent application with publication number CN115747884A discloses a preparation method of silver-copper alloy nanoparticles. The material is mainly prepared by configuring an ethylene glycol solution of silver nitrate and copper nitrate in different proportions, and obtaining a catalyst precursor through oil bath heating and centrifugal separation. On this basis, the precursor is ultrasonically mixed with Nafion (binder) to prepare an electrode by drop coating on a copper sheet, and a copper-silver alloy nano-catalyst is prepared by electrochemical reduction. By adjusting the silver / copper molar ratio of the raw material, different product selectivities can be obtained. The CO2RR test device is an H-type electrolytic cell, the electrolyte is a CO2-saturated 0.5 mol / L potassium bicarbonate aqueous solution, the working electrode is a silver-copper electrode, the reference electrode is an Ag / AgCl electrode, and the counter electrode is a platinum sheet electrode.

[0005] The test conditions disclosed in the above patent (CN115747884A) are neutral electrolyte. However, neutral or alkaline electrolysis conditions can easily cause additional CO2 loss and carbonate deposition problems. Acidic electrolysis conditions can effectively reduce carbon dioxide loss and alleviate the problem of carbonate deposition. However, under acidic conditions, the stability of the catalyst and the multi-carbon product selectivity will be further deteriorated.

[0006] Therefore, there is an urgent need to provide a new silver-doped copper oxide catalytic electrode and a preparation method and application thereof. SUMMARY

[0007] The present application aims to overcome the defects in the prior art, and provides a silver-doped copper oxide catalytic electrode and a preparation method and application thereof.

[0008] The specific technical solutions adopted by the present application are as follows:

[0009] In a first aspect, the present application provides a preparation method of a silver-doped copper oxide catalytic electrode, which is specifically as follows:

[0010] S1: placing a carbon-based gas diffusion electrode in a magnetron sputtering vacuum chamber, using a copper target as a sputtering source to sputter a layer of copper on one side surface of the carbon-based gas diffusion electrode, and taking the obtained electrode as a raw copper electrode;

[0011] S2: adding silver nitrate solution into a polytetrafluoroethylene lining, placing the raw copper electrode in a reaction kettle, and making the side of the raw copper electrode on which copper is sputtered face downward to be close to the silver nitrate solution, and then placing the polytetrafluoroethylene lining as a whole in a high-pressure reaction kettle to perform a hydrothermal reaction;

[0012] S3: after the hydrothermal reaction is completed, cooling the temperature of the reaction kettle to room temperature, taking out the reacted electrode, and washing and drying the electrode to obtain a silver-doped copper oxide catalytic electrode.

[0013] Preferably, in the sputtering operation of S1, the vacuum degree of the magnetron sputtering vacuum chamber is greater than 5 Torr, and the purity of the copper target is greater than 99%.

[0014] Preferably, in S1, the thickness of the copper layer on the obtained raw copper electrode is 100-500 nm.

[0015] Preferably, in S2, the concentration of the silver nitrate solution is 0.5-5 mmol / L. -1 .

[0016] Preferably, in S2, the temperature of the hydrothermal reaction is 120-200℃, the heating rate is 2-5℃ / min, and the reaction time is 6-12 h.

[0017] Preferably, in S3, the reacted electrode is washed with water and then air-dried.

[0018] In a second aspect, the present application provides a silver-doped copper oxide catalytic electrode obtained by using the preparation method of any one of the first aspect.

[0019] Preferably, the silver-doped copper oxide catalytic electrode has a morphology of nanosheets with a thickness of 2-20 nm.

[0020] In a second aspect, the application provides a use of the silver-doped cupric oxide catalytic electrode in the electrocatalytic reduction of carbon dioxide.

[0021] As preferred, the application is embodied as follows:

[0022] The electrocatalytic reduction of carbon dioxide is performed in a flow electrolytic cell with an in-membrane electrode device, wherein the reaction area of the flow electrolytic cell is 2-50 cm 2 , the cathode electrolyte is a KCl aqueous solution with pH = 1-2, the anode electrolyte is a sulfuric acid aqueous solution with pH = 1-2, the cathode catalyst is the silver-doped cupric oxide catalytic electrode, and the anode catalyst is a titanium felt.

[0023] The electrolysis conditions of the electrocatalytic reduction of carbon dioxide are as follows: a constant current of 50-600 mA cm 2 , and a carbon dioxide gas flow rate of 5-50 ml min -1 .

[0024] Compared with the prior art, the application has the following beneficial effects:

[0025] 1) The silver-doped cupric oxide catalytic electrode is successfully prepared by magnetron sputtering and hydrothermal reaction, and different silver doping concentrations and different nanosheet sizes of the catalyst can be prepared by adjusting the concentration of silver nitrate in the hydrothermal reaction. The doping of silver element effectively increases the concentration of oxygen vacancies of the catalyst, promotes the adsorption of CO2, and improves the reaction rate of the electrocatalytic reduction of carbon dioxide.

[0026] 2) The silver-doped cupric oxide catalytic electrode is successfully prepared, and the introduction of silver element effectively improves the adsorption capacity and concentration of the reaction intermediate CO, thereby promoting carbon-carbon coupling and improving the selectivity of multi-carbon products, and the product selectivity of ethylene is as high as nearly 50%.

[0027] 3) The silver-doped cupric oxide catalytic electrode preparation method provided by the application has fewer reaction steps and a simple preparation method. The silver-doped cupric oxide catalyst prepared by the preparation method is directly deposited on the surface of carbon paper, without the need for additional ultrasonic and spraying processes in the traditional preparation process of nanometer catalyst electrodes, thereby simplifying the electrode preparation steps and helping to improve the preparation efficiency of the catalytic electrode.

[0028] The catalyst preparation method, catalyst structure, and technical effects of the application will be further described below with reference to the accompanying drawings, so as to fully understand the purpose, features, and effects of the application. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 A silver-doped cupric oxide catalytic electrode preparation method provided by the application is shown in the figure.

[0030] Figure 2 a) X-ray diffraction (XRD) patterns of the original copper electrode (Comparative Example 1, Cu) and the silver-doped copper oxide electrode (Example 1, Ag-CuO-1) provided by the present application. Figure 2 b) XRD patterns of the silver-doped copper oxide electrodes (Example 1, Ag-CuO-1; Example 2, Ag-CuO-0.5; Example 3, Ag-CuO-1.5) provided by the present application.

[0031] Figure 3 a) Scanning electron microscope (SEM) images of the original copper electrode (Comparative Example 1, Cu, Figure 3 a) and the silver-doped copper oxide electrode (Example 1, Ag-CuO-1, Figure 3 b).

[0032] Figure 4 a) Scanning electron microscope (SEM) images of the silver-doped copper oxide electrodes with different silver doping concentrations, Example 1 (Ag-CuO-1 Figure 4 a), Example 2 (Ag-CuO-0.5 Figure 4 b) and Example 3 (Ag-CuO-1.5 Figure 4 c).

[0033] Figure 5 a) Low magnification transmission electron microscope (TEM) images of the silver-doped copper oxide electrode catalyst (Example 1, Ag-CuO-1) provided by the present application, Figure 5 a), high resolution TEM images Figure 5 b), elemental mapping images Figure 5 c) of the silver-doped copper oxide electrode catalyst (Example 1, Ag-CuO-1) provided by the present application.

[0034] Figure 6 a) Ag 3d region high resolution X-ray photoelectron spectroscopy (XPS) spectra of the silver-doped copper oxide electrode catalyst (Example 1, Ag-CuO-1) provided by the present application.

[0035] Figure 7 a) Electron paramagnetic resonance (EPR) results of the silver-doped copper oxide electrode catalyst (Example 1, Ag-CuO-1) provided by the present application and the copper electrode (Comparative Example 1, Cu).

[0036] Figure 8 a) Faradaic efficiency of hydrogen (H2) and ethylene (C2H4) of the silver-doped copper oxide electrode catalyst (Example 1, Ag-CuO-1) provided by the present application and the copper electrode (Comparative Example 1, Cu). DETAILED DESCRIPTION

[0037] The application will be further described and illustrated in connection with the drawings and specific embodiments. The technical features of each embodiment of the application can be combined accordingly without conflict.

[0038] The application provides a preparation method of a silver-doped copper oxide catalytic electrode.

[0039] S1: first, place a carbon-based gas diffusion electrode in a magnetron sputtering vacuum chamber, use a high-purity copper target as a sputtering source, sputter a copper layer on one side surface of the carbon-based gas diffusion electrode, and obtain the electrode as a raw copper electrode.

[0040] As a preferred embodiment of the application, the vacuum degree of the magnetron sputtering vacuum chamber is required to be greater than 5 Torr during the sputtering operation, and the purity of the copper target material is required to be greater than 99%.

[0041] As a preferred embodiment of the application, the thickness of the copper layer on the raw copper electrode obtained by magnetron sputtering in this step is 100-500 nm.

[0042] S2: add silver nitrate solution into a polytetrafluoroethylene (PTFE) liner, place the raw copper electrode obtained in S1 in a reaction kettle, and make the side of the raw copper electrode sputtered with copper face downward to be close to the silver nitrate solution, then place the polytetrafluoroethylene liner as a whole in a high-pressure reaction kettle for hydrothermal reaction, and the high-pressure reaction kettle can be placed in a high-temperature oven. The silver element is doped into the raw copper electrode through the hydrothermal reaction.

[0043] As a preferred embodiment of the application, the concentration of the silver nitrate solution is 0.5-5 mmol / L. -1 The size of the nanosheet can be regulated by regulating the concentration of silver nitrate. When the concentration of silver nitrate is 0.5 mmol / L, -1 the surface of the catalyst is a nanorod, and the higher the concentration of silver nitrate, the larger the size of the nanosheet.

[0044] As a preferred embodiment of the application, the temperature of the hydrothermal reaction is 120-200℃ (which can be realized by setting the temperature of the high-temperature oven), the heating rate is 2-5℃ / min, and the reaction time is 6-12 h.

[0045] S3: after the hydrothermal reaction is completed, the temperature of the reaction kettle is cooled to room temperature, the electrode after the reaction is taken out, washed and dried, and a silver-doped copper oxide catalytic electrode is obtained.

[0046] As a preferred embodiment of the application, the electrode after the reaction is washed with deionized water for more than 5 minutes, and then naturally air-dried to obtain a silver-doped copper oxide catalytic electrode.

[0047] The silver-doped cupric oxide catalytic electrode obtained by the method is a silver-doped cupric oxide catalyst, silver is used as a doping element, and the doped silver element can promote the adsorption of CO, a reaction intermediate, and promote the conversion of multi-carbon products. The catalyst has a nanosheet morphology, and the thickness of the nanosheet is 2-20 nm. The silver-doped cuprous oxide nanosheet prepared by the method is directly deposited on the surface of a gas diffusion electrode, without additional ultrasonic and spraying electrode preparation steps. The silver-doped cupric oxide catalyst prepared by the method has a porous structure, which is beneficial to improve the local CO2 concentration and affinity, and promote the catalytic electrolysis of carbon dioxide. The silver-doped cupric oxide catalyst prepared by the method has a high oxygen vacancy concentration, and the high oxygen vacancy concentration is helpful to improve the adsorption of carbon dioxide and promote the electrolytic conversion of carbon dioxide.

[0048] The silver-doped cupric oxide catalytic electrode prepared by the method can be used for carbon dioxide electrocatalytic reduction reaction, and the use method is as follows:

[0049] The carbon dioxide electrocatalytic reduction reaction is carried out in a flow electrolytic cell with an internal membrane electrode device; wherein the reaction area of the flow electrolytic cell is 2-50 cm 2 , the cathode electrolyte is a KCl aqueous solution with pH=1-2 (concentration is 1 mol / L -1 ), the anode electrolyte is a sulfuric acid aqueous solution (i.e. H2SO4 aqueous solution) with pH=1-2, the cathode catalyst is the silver-doped cupric oxide catalytic electrode, and the anode catalyst is titanium felt; the electrolysis conditions of the carbon dioxide electrocatalytic reduction reaction are as follows: constant current condition, current density range is 50-600 mA / cm 2 ; the cathode carbon dioxide gas flow rate is 5-50 ml / min -1 .

[0050] In actual use, the above electrolysis process can record the cathode potential by using an electrochemical workstation, can detect the gas phase products of the CO2 reduction reaction online by using a gas chromatograph, and can detect the liquid phase products by using a liquid nuclear magnetic method.

[0051] The application is further illustrated by the following examples.

[0052] The application is further illustrated by combining the following drawings, examples and comparative examples. The examples of the application are only used to explain the application, and do not limit the application in any way.

[0053] Example 1

[0054] As Figure 1 shown, the present embodiment provides a preparation method of a silver-doped cupric oxide catalytic electrode, and the preparation method is as follows:

[0055] (1) First, the carbon-based gas diffusion electrode (size 2.5 cm x 2.5 cm) was placed in a magnetron sputtering vacuum chamber, using a high-purity copper target (purity 99.99%) as the sputtering source, setting the vacuum degree to 5 Torr, and the sputtering time to 12 minutes. The copper catalyst thickness of the sputter-prepared copper electrode (Cu electrode) was 200 nm.

[0056] (2) A 30 mL silver nitrate aqueous solution with a concentration of 1 mmol L -1 was configured in a polytetrafluoroethylene (PTFE) liner, and the sputter-prepared copper electrode was placed in the PTFE liner with one side facing down. The PTFE liner was then placed in a high-pressure reaction kettle, and the high-pressure reaction kettle was then placed in a high-temperature oven.

[0057] (3) The high-temperature oven temperature was set to 160°C, and the reaction time was 8 h. After the reaction was completed, the electrode was removed after the reaction kettle was lowered to 25°C, and the electrode was rinsed with deionized water for more than 5 minutes. The prepared electrode was further air-dried to obtain a silver-doped copper oxide catalytic electrode (denoted as Ag-CuO-1).

[0058] Example 2

[0059] This example provides a method for preparing a silver-doped copper oxide catalytic electrode. The preparation method is similar to that of Example 1, except that the concentration of the silver nitrate aqueous solution used is 0.5 mmol L -1 . The final silver-doped copper oxide catalytic electrode prepared is denoted as Ag-CuO-0.5.

[0060] Example 3

[0061] This example provides a method for preparing a silver-doped copper oxide catalytic electrode. The preparation method is similar to that of Example 1, except that the concentration of the silver nitrate aqueous solution used is 1.5 mmol L -1 . The final silver-doped copper oxide catalytic electrode prepared is denoted as Ag-CuO-1.5.

[0062] Comparative Example 1

[0063] This comparative example provides a method for preparing a catalytic electrode. The preparation method is similar to that of Example 1, except that the Cu electrode after step (1) sputtering is directly used as a catalyst without further treatment.

[0064] The electrode materials prepared in the above examples and comparative examples were subjected to the following performance analysis:

[0065] (1) X-ray crystal diffraction analysis (XRD) test

[0066] The catalytic electrodes prepared in Example 1, Example 2, Example 3 and Comparative Example 1 were subjected to X-ray diffraction tests (e.g. Figure 2 The results show that the XRD pattern of the original copper electrode of Comparative Example 1 mainly shows the diffraction peak of copper, while the XRD patterns of the silver-doped copper oxide electrodes obtained in Examples 1, 2 and 3 mainly show the diffraction peak of copper oxide.

[0067] (2) Scanning tunneling electron microscope (SEM) test

[0068] The catalytic electrodes obtained in Example 1 and Comparative Example 1 were subjected to SEM testing, and the results were as follows: Figure 3 As shown in the figure, the surface of the Cu electrode (ie, the electrode obtained in Comparative Example 1) mainly presents a spherical particle morphology, while the Ag-CuO-1 shows a nanosheet morphology.

[0069] The catalytic electrodes obtained in Example 1, Example 2 and Example 3 of the present invention were subjected to SEM testing, and the results were as follows: Figure 4 As shown in the figure, it can be seen that with the increase of silver nitrate solution, the size of the nanosheets of the catalytic electrode gradually increases, indicating that silver doping is conducive to the morphological growth of the nanosheet catalyst.

[0070] (3) Transmission electron microscopy (TEM) test

[0071] The catalytic electrode (Ag-CuO-1) obtained in Example 1 was subjected to TEM test ( Figure 5 ), the low-magnification transmission image shows that the catalyst has the morphology of nanosheets, the high-resolution transmission image shows that the lattice size of the catalyst is the corresponding lattice of copper oxide crystals, and the element distribution map shows that silver elements are evenly distributed in the catalyst, proving that silver elements are evenly doped into the copper oxide catalyst.

[0072] (4) X-ray photoelectron spectroscopy (XPS) test

[0073] The catalytic electrode (Ag-CuO-1) obtained in Example 1 was subjected to XPS test. The XPS test results showed that the Ag3d spectrum ( Figure 6 ) proved that silver was successfully incorporated into the copper oxide catalyst structure.

[0074] (5) Electron paramagnetic resonance (EPR) test

[0075] Electron paramagnetic resonance (EPR) test was performed on the catalytic electrode (Ag-CuO-1) obtained in Example 1 and the catalytic electrode (Cu) obtained in the comparative example. The EPR test results are compared in the following figure ( Figure 7)It is proved that compared with Cu, Ag-CuO-1 has higher oxygen vacancy concentration, and higher oxygen vacancy concentration will help to promote the adsorption of carbon dioxide, thereby promoting the electrocatalytic reduction reaction of carbon dioxide.

[0076] (6) Test of product distribution (faraday efficiency) of electrocatalytic carbon dioxide reduction reaction

[0077] The test method is as follows:

[0078] In a flow electrolytic cell with a reaction area of 2 cm 2 , under the condition of constant current, the electrocatalytic reduction experiment of carbon dioxide, the cathode electrolyte is 1M KCl solution with pH=2, CO2 gas is filled into the cathode electrolyte, the flow rate of CO2 gas is 30 mL min -1 , the anode electrolyte is H2SO4 solution with pH=2, the anode catalyst is titanium felt, the reaction area is 2 cm 2 . The current density range is 50-600 mA cm 2 .

[0079] The test results are as follows:

[0080] As shown in Figure 8 a, compared with the copper electrode (Cu) of Comparative Example 1, the hydrogen product of the silver-doped copper oxide electrode (Ag-CuO-1) of Example 1 decreased obviously, and in the current range of 50-600 mA cm 2 , the hydrogen product selectivity of the electrode of Example 1 was lower than that of the electrode of Comparative Example 1, which showed that the silver-doped copper oxide electrode could significantly inhibit hydrogen evolution and promote the electrocatalytic reduction reaction of carbon dioxide.

[0081] As shown in Figure 8 b, compared with the copper electrode (Cu) of Comparative Example 1, the silver-doped copper oxide electrode (Ag-CuO-1) of Example 1, in the current range of 50-600 mA cm 2 , the ethylene product selectivity of the electrode of Example 1 was significantly higher than that of the electrode of Comparative Example 1. In 100 mA cm -2 , the ethylene product selectivity of the electrode prepared in Example 1 was close to 50%, which was about 2 times higher than that of the copper electrode, which showed that the silver-doped copper oxide electrode could significantly promote carbon-carbon coupling and the generation of multi-carbon products.

[0082] Table 1 ethylene product selectivity of Example 1, Example 2 and Example 3 (-100 mA cm -2 )

[0083] Silver nitrate solution concentration Ethylene product selectivity Example 1 (Ag-CuO-1) 1 mmol L -1 ]] 48.9％ Example 2 (Ag-CuO-0.5) 0.5 mmol L -1 ]] 39.6％ Example 2 (Ag-CuO-1.5) 1.5 mmol L -1 ]] 23.3％

[0084] As shown in Table 1, the ethylene product test results of the catalysts with different silver doping concentrations show that the catalytic electrode prepared from the 1 mmol L -1 of silver nitrate solution exhibits the highest ethylene product selectivity. By adjusting the doping concentration of silver, the selectivity of the ethylene product can be regulated.

[0085] The silver-doped copper oxide catalytic electrode prepared by the method has high catalytic activity and high multi-carbon product selectivity in the electrocatalytic reduction of acidic carbon dioxide. Silver doping increases the oxygen vacancy concentration of the catalyst and promotes the adsorption of carbon dioxide and the reaction intermediate carbon monoxide, and promotes the carbon-carbon coupling process.

[0086] The above-described embodiments are only a preferred scheme of the present application, and are not intended to limit the present application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, any technical solutions obtained by equivalent replacement or equivalent transformation fall within the scope of the present application.

Claims

1. A method for preparing a silver-doped copper oxide catalytic electrode, characterized in that: The details are as follows: S1: placing a carbon-based gas diffusion electrode in a magnetron sputtering vacuum chamber, using a copper target as a sputtering source, and sputtering a layer of copper on one side of the carbon-based gas diffusion electrode. The resulting electrode is used as the original copper electrode; S2: adding a silver nitrate solution to the polytetrafluoroethylene liner, placing the original copper electrode in a reactor with the copper-sputtered side of the original copper electrode facing downward to be close to the silver nitrate solution, and then placing the entire polytetrafluoroethylene liner in a high-pressure reactor for a hydrothermal reaction; S3: After the hydrothermal reaction is completed, the reactor temperature is cooled to room temperature, the electrode after the reaction is taken out and washed and dried to obtain a silver-doped copper oxide catalytic electrode.

2. The method for preparing a silver-doped copper oxide catalytic electrode according to claim 1, characterized in that: During the sputtering operation of S1, the vacuum degree of the magnetron sputtering vacuum chamber is greater than 5 Torr, and the purity of the copper target is greater than 99%.

3. The method for preparing a silver-doped copper oxide catalytic electrode according to claim 1, characterized in that: In the above-mentioned S1, the thickness of the copper layer on the original copper electrode is 100-500 nm.

4. The method for preparing a silver-doped copper oxide catalytic electrode according to claim 1, characterized in that: In S2, the concentration of the silver nitrate solution is 0.5-5 mmol L -1 .

5. The method for preparing a silver-doped copper oxide catalytic electrode according to claim 1, characterized in that: In the step S2, the temperature of the hydrothermal reaction is 120-200°C, the heating rate is 2-5°C / min, and the reaction time is 6-12h.

6. The method for preparing a silver-doped copper oxide catalytic electrode according to claim 1, characterized in that: In S3, the electrode after the reaction is rinsed with water and then air-dried.

7. A silver-doped copper oxide catalytic electrode obtained by the preparation method according to any one of claims 1 to 6.

8. The silver-doped copper oxide catalytic electrode according to claim 7, characterized in that: The silver-doped copper oxide catalytic electrode has a morphology of a nanosheet with a thickness of 2-20 nm.

9. Use of the silver-doped copper oxide catalytic electrode according to claim 7 in the electrocatalytic reduction reaction of carbon dioxide.

10. Use of the silver-doped copper oxide catalytic electrode in the electrocatalytic reduction reaction of carbon dioxide according to claim 9, characterized in that: The details are as follows: The carbon dioxide electrocatalytic reduction reaction is carried out in a flow electrolysis cell with a built-in membrane electrode device; The reaction area of ​​the flow electrolytic cell is 2-50 cm 2 , the cathode electrolyte is a KCl aqueous solution with a pH of 1-2, the anolyte is a sulfuric acid aqueous solution with a pH of 1-2, the cathode catalyst is a silver-doped copper oxide catalytic electrode, and the anode catalyst is titanium felt; The electrolysis conditions of the carbon dioxide electrocatalytic reduction reaction are: 50-600mA cm 2 Constant current, 5-50ml min -1 The carbon dioxide gas flow rate.

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