An oxidatively modified cuprous oxide catalyst, a method of preparation and an electrode

Abstract

The application belongs to the technical field of electrocatalysis and electrosynthesis, and discloses an oxidized modified cuprous oxide catalyst, a preparation method and an electrode. The oxidized modified cuprous oxide catalyst is obtained by mixing an oxidizing agent and cuprous oxide particles and reacting under certain conditions. By simply changing the reaction conditions, the morphology, structure and chemical valence state of the cuprous oxide catalyst can be controlled. After pre-reduction reconstruction, the cuprous oxide catalyst with different active sites on the surface is obtained, so that the performance of the catalyst for electrocatalytic reduction of carbon dioxide is controlled and improved. The most preferred oxidized modified cuprous oxide catalyst and electrode of the application are applied to the electrocatalytic reduction of carbon dioxide, and the Faraday efficiency of methane reaches 85.6%, while the Faraday efficiencies of ethylene and hydrogen are as low as 2.6% and 14.4%, respectively. The oxidized modified cuprous oxide catalyst synthesized by the application does not introduce additional elements into the catalyst, the operation process is simple, the preparation conditions are mild, and the catalyst has good industrial application prospect.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalysis and electrosynthesis technology, and particularly relates to an oxidized cuprous oxide catalyst, its preparation method, and its electrode. Background Technology

[0002] Currently, due to the rapid increase in atmospheric carbon dioxide concentration, human society is facing a potential and severe climate crisis. Electrocatalytic carbon dioxide reduction (CO2RR) can utilize (excess) renewable energy to produce high-value-added fuels or chemicals and can achieve a near-closed carbon cycle, which is of great significance for reducing carbon dioxide concentration and achieving sustainable development for human society.

[0003] However, current CO2RR catalysts exhibit poor selectivity, activity, and stability, necessitating the development of new, highly efficient catalysts to improve their catalytic performance. Copper-based catalysts, due to their unique catalytic properties, can convert carbon dioxide into products involving multiple electron steps, such as methane, ethylene, and ethanol, and have attracted widespread attention in electrocatalytic carbon dioxide reduction. Cuprous oxide is a common semiconductor photo / electrocatalyst, in which copper is in a monovalent state. During photo / electrocatalytic conversion, it typically undergoes photocorrosion or preferential reduction, forming an in-situ reconstructed catalyst. The active sites for electrocatalytic carbon dioxide reduction are usually the new phases, grain boundaries, or interfaces formed after reconstruction. Therefore, by altering the morphology, structure, and chemical valence state of the initial cuprous oxide catalyst, the properties of the active sites after in-situ reconstruction can be modulated, thereby improving the electrocatalytic carbon dioxide reduction performance.

[0004] Patent CN 112899709 B discloses a copper-based compound / copper nanoelectrode with interfacial synergistic effects, its preparation, and its application. By pre-reducing and reconstructing the electrode, the synergistic effects of monovalent copper / zero-valent copper, divalent copper / zero-valent copper, and divalent copper / monovalent copper / zero-valent copper are utilized to lower the reaction energy barrier for carbon monoxide dimerization, promoting the formation of multi-carbon products ethylene and ethanol. Patent CN 114959775 A discloses a method for improving the performance of copper-based electrocatalysts and its application. By adding organic molecular additives to the electrolyte, in-situ controllable reconstruction of the catalyst is induced under an electric field, promoting the selectivity and activity of electrocatalytic carbon dioxide reduction.

[0005] Based on the above analysis, the existing technologies have the following problems and shortcomings: the performance of cuprous oxide catalysts for electrocatalytic carbon dioxide reduction still cannot meet the needs of practical applications, and the pre-reduction and reconstruction methods are relatively complex, generally requiring the introduction of other species. There is a lack of a simple and effective modification method to improve its electrocatalytic carbon dioxide reduction performance while inhibiting the hydrogen evolution reaction to meet the needs of industrial applications. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides an oxidized cuprous oxide catalyst and its application in the electrocatalytic carbon dioxide reduction reaction.

[0007] This invention is achieved by using an oxidized cuprous oxide electrocatalyst. Cuprous oxide particles are mixed with an oxidant (such as hydrogen peroxide) and dispersed in a solvent. The mixture reacts under different reaction conditions (such as ultrasound, stirring, or standing) to obtain a modified cuprous oxide catalyst with a roughened surface structure. This modified catalyst is then fabricated into a catalyst electrode. After pre-reduction and reconstruction, the surface of the catalyst electrode is rich in more active sites. When applied to the electrocatalytic carbon dioxide reduction reaction, its selectivity for the electrocatalytic carbon dioxide reduction reaction can be controlled and improved.

[0008] Furthermore, the size of the cuprous oxide particles is 0.1–5000 nm.

[0009] Furthermore, the oxidant is one or more of hydrogen peroxide, oxygen, peracetic acid, sodium dichromate, chromic acid, nitric acid, potassium permanganate, ammonium persulfate, sodium hypochlorite, ammonia, bromine, and iodine.

[0010] Furthermore, the solvent is one or more of ethanol, water, and isopropanol.

[0011] Furthermore, the reaction conditions are ultrasound, stirring, or dispersion followed by standing.

[0012] Furthermore, the preparation process of the catalyst electrode is as follows: the catalyst and binder are dissolved in a solvent, dispersed evenly, drop-coated onto the surface of a conductive substrate, and dried to obtain the catalyst electrode.

[0013] Furthermore, the solvent is ethanol, isopropanol, or n-propanol.

[0014] Furthermore, the binder is a Nafion solution, anion exchange solution, basic ionomer, PVDF, or PTFE.

[0015] Furthermore, the conductive substrate includes carbon paper, carbon cloth, carbon fiber, or glassy carbon electrode.

[0016] Furthermore, the step of applying the oxidically modified catalyst electrode to the electrocatalytic carbon dioxide reduction reaction includes:

[0017] Step 1: Place the above-mentioned oxidized cuprous oxide catalyst electrode in a three-electrode electrolytic cell, introduce high-purity carbon dioxide gas, and perform constant potential pre-reduction reconstruction to obtain the reconstructed electrode.

[0018] Step 2: The reconstructed electrode is left in the electrolytic cell, and high-purity carbon dioxide gas is continuously introduced at a certain flow rate. Different potentials are applied through the electrochemical workstation to carry out the electrocatalytic carbon dioxide reduction reaction.

[0019] Step 3: Connect the exhaust gas from the above reaction to the gas chromatograph inlet, sample and analyze the concentration of the products in the exhaust gas in real time, and calculate the Faraday efficiency of each product in combination with the total amount of electricity applied by the electrochemical workstation.

[0020] Furthermore, the electrolytic cell device mentioned in step two includes one of an H-type electrolytic cell, a gas diffusion flow electrolytic cell, or a membrane electrode electrolytic cell;

[0021] Furthermore, the electrolyte in step one includes one or more of potassium bicarbonate, potassium hydroxide, potassium chloride, potassium bromide, or potassium iodide; the pre-reduction potential is 0 to -2.0V (vs Ag / AgCl), and the pre-reduction time is determined by a time-current curve. The pre-reduction process is considered to be over when the current reaches a stable state.

[0022] Furthermore, the potential range mentioned in step two is 0 to -3.0V (vs Ag / AgCl).

[0023] Furthermore, the Faraday efficiency mentioned in step three is equal to the amount of electricity required for product generation per unit time divided by the total amount of electricity input to the electrochemical workstation per unit time.

[0024] Another objective of this invention is to provide a method for preparing an oxidically modified cuprous oxide catalyst and electrode.

[0025] Another object of the present invention is to provide a catalyst and electrode for electrocatalytic carbon dioxide reduction reaction based on the above-described oxidized cuprous oxide catalyst and electrode.

[0026] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this invention are as follows:

[0027] First, this invention modifies cuprous oxide catalysts with oxidants. By changing the reaction conditions, the morphology, structure, and chemical valence state of the cuprous oxide catalyst can be controlled. After pre-reduction and reconstruction, cuprous oxide catalysts with surfaces rich in different active sites are obtained, thereby regulating and improving their performance in electrocatalytic carbon dioxide reduction. Compared with current literature reports using methods such as doping, alloying, and surface modification, this method does not introduce additional elements into the cuprous oxide catalyst, which is beneficial for a deeper understanding of the catalyst's active sites, thus better guiding catalyst design and improving electrocatalytic performance.

[0028] Secondly, considering the technical solution as a whole or from a product perspective, the technical effects and advantages of the technical solution protected by this invention are specifically described as follows: This invention provides a method for obtaining an oxidized cuprous oxide catalyst by mixing and dispersing an oxidant with cuprous oxide and reacting it chemically under certain conditions. This catalyst is then used to fabricate a catalyst electrode to improve the performance of the electrocatalytic carbon dioxide reduction reaction. This method is simple to operate and the reaction conditions are mild. By simply adjusting the reaction conditions for oxidative modification, the selectivity of the electrocatalytic carbon dioxide reduction products can be changed. The Faradaic efficiency for methane can reach a maximum of 85.6%, while the Faradaic efficiency for hydrogen is as low as 2.6%; the Faradaic efficiency for ethylene can reach a maximum of 41.4%, while the Faradaic efficiency for methane decreases to 18.2%.

[0029] The technical solution of this invention fills a technological gap in the domestic and international industry: This invention uses an oxidant to modify a cuprous oxide catalyst, and controls the surface morphology, structure, and chemical valence state of the cuprous oxide catalyst by simply changing the oxidation reaction conditions. Furthermore, through pre-reduction reconstruction, a cuprous oxide catalyst with a surface rich in different catalytic active sites is obtained, thereby controlling its selectivity for electrocatalytic carbon dioxide reduction. Currently, there are no relevant reports domestically or internationally, filling the technological gap in the application of cuprous oxide catalysts to electrocatalytic carbon dioxide reduction.

[0030] This invention utilizes an oxidant to modify a cuprous oxide catalyst and discovers that by changing the oxidation reaction conditions (such as ultrasound, stirring, or allowing it to stand after uniform dispersion), the selectivity of the catalyst for electrocatalytic carbon dioxide reduction after pre-reduction and reconstruction can be significantly affected. This indicates that common solution dispersion methods may significantly affect the morphology or chemical valence state of the catalyst surface during the oxidation process, thereby affecting the type and number of active sites after pre-reduction and reconstruction. Attached Figure Description

[0031] Figure 1 This is a flow chart of the preparation process of the oxidized cuprous oxide catalyst and electrode provided in Examples 2-6 of the present invention;

[0032] Figure 2 These are scanning electron microscope (SEM) images of the oxidized cuprous oxide catalysts provided in Examples 1-3 and Example 6 of this invention. Example 1 ( Figure 2 a), Example 2 ( Figure 2 b), Example 3 Figure 2 c), Example 6 Figure 2 d);

[0033] Figure 3 The electrodes provided in Examples 1-6 of this invention (Comparative Examples 1-9) correspond to the Faraday efficiencies of electrocatalytic carbon dioxide reduction to hydrogen, methane and ethylene.

[0034] Figure 4 The electrode provided in Example 1 of this invention (Comparative Example 1) is used for the Faraday efficiency-potential diagram of the products of the electrocatalytic carbon dioxide reduction reaction, including four products: hydrogen, carbon monoxide, methane and ethylene.

[0035] Figure 5 The electrode provided in Example 2 of this invention (Comparative Example 2) is used for the Faraday efficiency-potential diagram of the products of the electrocatalytic carbon dioxide reduction reaction, including four products: hydrogen, carbon monoxide, methane and ethylene.

[0036] Figure 6 The electrode provided in Example 3 of this invention (Comparative Example 3) is used for the Faraday efficiency-potential diagram of the products of the electrocatalytic carbon dioxide reduction reaction, including four products: hydrogen, carbon monoxide, methane and ethylene.

[0037] Figure 7 The electrode provided in Example 3 of this invention (Comparative Example 4) is used for the Faraday efficiency-potential diagram of the products of the electrocatalytic carbon dioxide reduction reaction, including four products: hydrogen, carbon monoxide, methane and ethylene.

[0038] Figure 8 The electrode provided in Example 3 of this invention (Comparative Example 5) is used for the Faraday efficiency-potential diagram of the products of the electrocatalytic carbon dioxide reduction reaction, including four products: hydrogen, carbon monoxide, methane and ethylene.

[0039] Figure 9 The electrode provided in Example 6 of this invention (Comparative Example 6) is used for the Faraday efficiency-potential diagram of the products of the electrocatalytic carbon dioxide reduction reaction, including four products: hydrogen, carbon monoxide, methane and ethylene.

[0040] Figure 10 The electrode provided in Example 6 of this invention (Comparative Example 7) is used for the Faraday efficiency-potential diagram of the products of the electrocatalytic carbon dioxide reduction reaction, including four products: hydrogen, carbon monoxide, methane and ethylene.

[0041] Figure 11 The electrode provided in Example 6 of this invention (Comparative Example 8) is used for the Faraday efficiency-potential diagram of the products of the electrocatalytic carbon dioxide reduction reaction, including four products: hydrogen, carbon monoxide, methane and ethylene.

[0042] Figure 12 The electrode provided in Example 6 of this invention (Comparative Example 9) is used for the Faraday efficiency-potential diagram of the products of the electrocatalytic carbon dioxide reduction reaction, including four products: hydrogen, carbon monoxide, methane, and ethylene. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0044] To address the problems existing in the prior art, the present invention provides an oxidized cuprous oxide catalyst and its application in the electrocatalytic carbon dioxide reduction reaction. The present invention will be described in detail below with reference to the accompanying drawings.

[0045] To enable those skilled in the art to fully understand how the present invention is specifically implemented, this section provides an explanatory description of the embodiments that expand upon the technical solutions of the claims.

[0046] like Figure 1 As shown, the preparation process of the oxidized cuprous oxide catalyst and electrode provided in Examples 2-6 of this invention includes the following steps:

[0047] S101: A certain amount of oxidant is mixed with cuprous oxide particles and then added to a solvent and dispersed evenly;

[0048] S102: Place the above mixture in a sealed reagent bottle and carry out a chemical reaction under certain conditions;

[0049] S103: Centrifuge, wash and vacuum dry the mixture after the above reaction to obtain the oxidized cuprous oxide catalyst;

[0050] S104: Dissolve the modified catalyst and binder obtained above in a solvent, disperse them evenly, drop-coat them onto the surface of a conductive substrate, and dry them to obtain the catalyst electrode.

[0051] The chemical reaction conditions provided in this invention example are ultrasonication, stirring or uniform dispersion followed by standing, and are carried out at room temperature and pressure, resulting in mild reaction conditions.

[0052] The oxidants provided in the examples of this invention include, but are not limited to, hydrogen peroxide, oxygen, peracetic acid, sodium dichromate, chromic acid, nitric acid, potassium permanganate, ammonium persulfate, sodium hypochlorite, ammonia, bromine, iodine, etc.

[0053] To demonstrate the inventiveness and technical value of the technical solution of this invention, this section provides specific product or related technology application examples of the technical solution claimed.

[0054] Example 1

[0055] 0.834 g of polyvinylpyrrolidone (PVP, molecular weight 40000) was dissolved in 50 mL of 0.01 M cuprous chloride dihydrate solution. Then, 5 mL of 2 M sodium hydroxide solution was added dropwise to the mixture. The mixture was stirred for 30 minutes, and the solution gradually turned blue-green and then dark brown. Subsequently, 5 mL of 0.6 M ascorbic acid solution was added dropwise to obtain a reddish-brown mixed solution. The mixture was stirred for another 3 hours. The entire reaction was carried out in a water bath at a constant temperature of 55 degrees Celsius. Finally, the mixture was filtered, centrifuged, washed with water and ethanol, and vacuum dried in a 60-degree Celsius oven for 12 hours to obtain truncated cuprous oxide particles. Figure 2 As shown in a.

[0056] Example 2

[0057] Weigh 70 mg of cuprous oxide particles from Example 1 above, add them to 20 ml of deionized water and 10 ml of 30% hydrogen peroxide, mix thoroughly, seal in a reagent bottle, and sonicate at 30% power for 1 hour. During the sonication process, maintain the water temperature at approximately 20 degrees Celsius using ice. Finally, centrifuge the mixture, wash with deionized water and ethanol, and vacuum dry to obtain the oxidized cuprous oxide catalyst. Figure 2 As shown in b.

[0058] Example 3

[0059] Weigh 70 mg of cuprous oxide particles from Example 1 above, add them to 20 ml of deionized water and 10 ml of 30% hydrogen peroxide, mix thoroughly, seal in a reagent bottle, and stir magnetically at room temperature for 1 hour. Finally, centrifuge the mixture, wash with deionized water and ethanol, and vacuum dry to obtain the oxidized cuprous oxide catalyst, as shown below. Figure 2 As shown in c.

[0060] Example 4

[0061] The magnetic stirring time in the steps described in Example 3 was adjusted to 3 hours, while the other steps remained unchanged, to obtain an oxidized cuprous oxide catalyst.

[0062] Example 5

[0063] The magnetic stirring time in the steps described in Example 3 was adjusted to 7 hours, while the other steps remained unchanged, to obtain an oxidized cuprous oxide catalyst.

[0064] Example 6

[0065] Weigh 70 mg of cuprous oxide particles from Example 1 above, add them to 20 ml of deionized water and 10 ml of 30% hydrogen peroxide, mix thoroughly, seal in a reagent bottle, and let stand at room temperature for 2 hours. Finally, centrifuge the mixture, wash with deionized water and ethanol, and vacuum dry to obtain the oxidized cuprous oxide catalyst, as shown below. Figure 2 As shown in d.

[0066] Comparative Examples 1-9

[0067] 2 mg of the oxidized cuprous oxide catalyst described in Examples 1-6 was weighed and added to a mixed solution of 1 ml isopropanol and 50 μL 5% Nafion. The mixture was then sonicated to homogenize the solution and a catalyst ink was prepared. The surface of a 4 mm diameter glassy carbon electrode was polished sequentially with 500 nm, 100 nm and 50 nm alumina powders. The electrode was then cleaned with ethanol and deionized water. A certain amount of the catalyst ink (specific composition shown in Table 1) was pipetted onto the surface of the glassy carbon electrode and allowed to dry naturally to obtain the catalyst electrode.

[0068] Table 1. Catalyst ink droplet amount and catalyst type for Comparative Examples 1-9

[0069] Comparative Example 1 10 Example 1 Comparative Example 2 10 Example 2 Comparative Example 3 10 Example 3 Comparative Example 4 10 Example 4 Comparative Example 5 10 Example 5 Comparative Example 6 5 Example 6 Comparative Example 7 7.5 Example 6 Comparative Example 8 10 Example 6 Comparative Example 9 12.5 Example 6

[0070] The embodiments of the present invention have achieved some positive results during the research and development or use process, and have indeed great advantages compared with the prior art. The following content describes them in conjunction with the data, charts and other information of the experimental process.

[0071] This invention, through experiments, discovered that, firstly, truncated octahedral cuprous oxide (… Figure 2 a) It was mixed with hydrogen peroxide for oxidative modification, and different external conditions were applied. Scanning electron microscopy (SEM) characterization results showed that under ultrasonic conditions ( Figure 2 b) The surface morphology of cuprous oxide changed from the initial granular form to ultrathin nanosheets, while under stirring ( Figure 2 c) and standing ( Figure 2 Under condition d), the overall shape of cuprous oxide remains granular, with only surface roughening and porosity. This is attributed to the larger energy input of ultrasound, resulting in greater morphological changes and an increase in specific surface area.

[0072] The catalyst electrodes described in Comparative Examples 1-9 were placed in an H-type electrolytic cell for electrocatalytic carbon dioxide reduction. First, high-purity argon and carbon dioxide were introduced separately to purge the oxygen from the electrolyte and saturate the dissolved carbon dioxide in the 0.1 mol / L potassium bicarbonate solution. Then, a voltage of -1.2 V (vs Ag / AgCl) was applied to the working electrode via an electrochemical workstation for pre-reduction reconstruction. The reference electrode was a saturated Ag / AgCl electrode, and the counter electrode was a Pt sheet. Time-current curves were recorded until the current reached complete stability, indicating the end of the pre-reduction process. Finally, the applied voltage was varied via the electrochemical workstation to conduct the electrocatalytic carbon dioxide reduction reaction in a constant potential mode at a carbon dioxide flow rate of 30 sccm. The tail gas was fed into a gas chromatograph for product concentration analysis, and the Faradaic efficiency of the corresponding products was calculated. The results are shown in Table 2 and... Figures 3-12 As shown.

[0073] Table 2 shows the Faraday efficiency of carbon dioxide reduction to hydrogen, methane, and ethylene for different catalyst electrodes.

[0074]

[0075] Analysis of the above results shows that the initial cuprous oxide particles have a high Faraday efficiency for methane (47.9%, compared to Comparative Example 1). Figure 3 While ultrasonic oxidation-modified cuprous oxide significantly inhibited methane formation (18.2%, compared to Comparative Example 2), Figure 3 It also greatly promoted the formation of ethylene (41.4%, compared to Comparative Example 2). Figure 3 Furthermore, cuprous oxide modified by stirring and static oxidation significantly inhibited hydrogen generation (8.1% and 11.6%, compared to comparative examples 3 and 8). Figure 3 Meanwhile, the selectivity for methane was further improved to 69% and 57.1% (comparative examples 3 and 8). Figure 3 The selectivity of ethylene changed little. The above results indicate that ultrasonic oxidation modification nano-sized cuprous oxide, increasing the active sites for CC coupling formation, while inhibiting the hydrogenation of *CO. Conversely, stirring and static oxidation modification did not change the active sites for *CO hydrogenation to form methane on the original surface, but significantly inhibited the coupling of *H on the surface to form hydrogen as a byproduct, thus further improving methane selectivity. Among these, the stirred oxidation modification of cuprous oxide showed the highest Faraday efficiency in methane (69%, Comparative Example 3). Figure 3 ).

[0076] Furthermore, the synthesis conditions of cuprous oxide modified by stirring were further optimized by changing the stirring time (1 h, 3 h, and 7 h), as in Examples 3-5. The corresponding catalyst electrodes were then prepared as Comparative Examples 3-5. The electrocatalytic results are shown in Figures 1 and 2. Figures 6-8 As shown, when the stirring time is increased to 7 hours, the Faraday efficiency of methane reaches a maximum of 85.6%, while the Faraday efficiency of ethylene formation decreases to 2.6%, and the Faraday efficiency of hydrogen is 14.4%. This indicates that increasing the stirring time can further increase the active sites for CO hydrogenation to form methane on the cuprous oxide surface.

[0077] Furthermore, the preparation process of the catalyst electrode in Example 6 was optimized by changing the amount of drop-coated catalyst ink, as shown in Comparative Examples 6-9. The electrocatalytic performance results are as follows: Figures 9-12 As shown, insufficient catalyst ink droplets (e.g., Comparative Example 6, 5 μL) resulted in an excessively high hydrogen Faraday efficiency (reaching 36.4%), indicating that insufficient catalyst could not completely cover the glassy carbon electrode surface, leading to a dominant hydrogen evolution reaction and inhibiting the carbon dioxide reduction reaction; while Comparative Examples 7-9, such as... Figures 10-12As shown, increasing the amount of catalyst ink droplets does not significantly change the Faraday efficiency of methane and hydrogen. Most preferably, a catalyst ink droplet amount of 10 μL is the optimal solution of this invention.

[0078] In summary, this invention modifies the cuprous oxide catalyst with an oxidant, allowing for simple adjustment of reaction conditions to control its morphology, structure, and chemical valence state. After pre-reduction and reconstruction, cuprous oxide catalysts with surface rich in different active sites are obtained, thereby regulating and improving their performance in electrocatalytic carbon dioxide reduction. The most preferred application of this oxidized cuprous oxide catalyst in the electrocatalytic carbon dioxide reduction reaction shows a maximum Faraday efficiency of 85.6% for methane, while the Faraday efficiencies for ethylene and hydrogen are as low as 2.6% and 14.4%, respectively. The oxidant-modified cuprous oxide catalyst synthesized in this invention does not introduce any additional elements into the catalyst, has a simple operation process, mild preparation conditions, and shows great promise for industrial applications.

[0079] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing an electrode, characterized in that, Weigh 70 mg of cuprous oxide particles with truncated octahedral morphology, add them to 20 ml of deionized water and 10 ml of 30% hydrogen peroxide, mix them evenly, seal the mixture in a reagent bottle, stir magnetically at room temperature or let it stand at room temperature, centrifuge, wash and vacuum dry the mixture after the reaction to obtain a modified cuprous oxide catalyst with roughened surface structure, and then make it into a catalyst electrode. The catalyst electrode is prepared as follows: 2 mg of the modified cuprous oxide catalyst is weighed and added to a mixed solution of 1 ml isopropanol and 50 μL 5% Nafion and ultrasonically homogenized to prepare catalyst ink. The surface of a 4 mm diameter glassy carbon electrode is polished sequentially with 500 nm, 100 nm and 50 nm alumina powder, and then cleaned with ethanol and deionized water. 7.5, 10 or 12.5 μL of the catalyst ink is pipetted onto the surface of the glassy carbon electrode and naturally dried to obtain the catalyst electrode. The catalyst electrode was placed in a three-electrode electrolytic cell, and high-purity carbon dioxide gas was introduced to perform constant potential pre-reduction reconstruction to obtain the reconstructed electrode. The pre-reduction potential is 0 to -2.0 V, relative to the Ag / AgCl electrode; The pre-reduction time is determined by the time-current curve, and the pre-reduction process is considered to be over when the current reaches a stable level.

2. The electrode prepared by the preparation method according to claim 1.

3. The application of the electrode as described in claim 2 in the electrocatalytic carbon dioxide reduction reaction.

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