A non-metal doped copper-based catalytic material for electrocatalytic reduction of carbon dioxide, its preparation method and application

Abstract

The present invention discloses a non-metal doped copper-based catalytic material for electrocatalytic reduction of carbon dioxide, its preparation method and application. The preparation method of the catalytic material comprises the following steps: synthesizing cuprous oxide as a precursor; activating the cuprous oxide; performing plasma non-metal element doping on the activated cuprous oxide, and finally obtaining a copper-based electrocatalytic material with precisely regulated Cu 0 / Cu + valence and non-metal element doping. The copper-based electrocatalyst with valence regulation and non-metal element doping provided by the present invention exhibits excellent performance in the selectivity of electrocatalytic conversion of CO2 to C2H4.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst preparation, and particularly relates to a non-metal doped copper-based catalytic material for electrocatalytic reduction of carbon dioxide, a preparation method thereof, and an application thereof. Background Art

[0002] With the rapid development of the economic society and the improvement of human productivity, the consumption of fossil energy is increasing continuously. At the same time, the emissions of CO2 are also increasing continuously. And CO2 is the main gas causing the greenhouse effect. Therefore, how to reduce CO2 is an urgent problem to be solved. The existing technologies mainly use the method of catalytic reduction to convert CO2 into CO or other high-value hydrocarbon products, such as formic acid, ethylene, ethanol, etc. In this way, both the greenhouse effect caused by too high CO2 concentration and the problem of energy scarcity are solved. Among them, the market value of ethylene is extremely high (>1000 US dollars / ton). Therefore, the technology of catalytic CO2 conversion to ethylene (C2H4) has attracted particular attention.

[0003] The electrocatalytic reduction of CO2 reaction has the advantages of mild conditions, controllable potential, less consumption of chemicals, less wastewater discharge, etc., and has become the most popular CO2 reduction technology in research. In addition, the combination of renewable energy power generation such as solar energy and wind energy and electrocatalytic CO2 reduction will help to establish a carbon neutral process. Currently, the most studied CO2 electroreduction catalysts are metal catalysts, and different metal types have a huge difference in the selectivity of products. Among them, the copper-based catalyst has relatively moderate binding energies for both adsorbed CO and adsorbed H, which is very conducive to C-C coupling and hydrogenation to produce hydrocarbons and C 2+ products. It should be noted that the valence state of the copper-based catalyst is another key variable for its efficient reduction of C 2+ products. The synergistic effect between high-active valence states (such as Cu 0 and Cu + ) significantly improves the kinetics and thermodynamics of CO2 activation and C-C coupling, while suppressing the C1 product conversion pathway. However, the high-active valence state copper from 0 to +1 is very unstable, which also leads to low selectivity and conversion efficiency of the copper-based catalyst.

[0004] Therefore, inventing a new preparation method of an electrocatalytic material for improving the selectivity and conversion rate of the copper-based catalyst for C 2+ products is extremely important for solving the problem of unstable high-active valence state copper in the process of electrocatalytic CO2. The present invention adjusts the valence state of copper by non-metal doping and helps copper stabilize its high-active valence state (Cu 0 and Cu + ), increases the electron density of the active site, promotes the electron transfer rate, and reduces the formation barrier of the intermediate, greatly improving the activity and selectivity of the catalyst. Summary of the Invention

[0005] The object of the present invention is to address the technical problems of low catalytic activity, high potential, poor Faraday efficiency, and low current efficiency of existing copper-based catalysts. A non-metal doped copper-based catalytic material for electrocatalytic reduction of carbon dioxide, its preparation method, and application are proposed. Based on cuprous oxide, the valence state ratio of copper and the non-metal content are precisely regulated through activation and non-metal plasma doping processes to obtain electrocatalytic materials with different Cu 0 / Cu + and doping amounts.

[0006] To achieve the above technical objectives, the technical solution adopted by the present invention is as follows:

[0007] A preparation method of a non-metal doped copper-based catalytic material for electrocatalytic reduction of carbon dioxide, comprising the following steps:

[0008] 1) Slowly and dropwise add a sodium hydroxide solution to a copper salt solution, heat it in a water bath and continuously stir for a certain time. Then, slowly and dropwise add an ascorbic acid solution thereto, heat it in a water bath and continuously stir for a certain time. After centrifugal separation, wash it with water 1 - 3 times and with alcohol 1 - 3 times, and then dry it to obtain precipitated cuprous oxide;

[0009] 2) Put the precipitated cuprous oxide obtained in step 1) into a vacuum furnace, evacuate it, and raise the temperature to a certain temperature. After maintaining for a period of time, then cool it to room temperature with the furnace to obtain activated cuprous oxide;

[0010] 3) Put the activated cuprous oxide obtained in step 2) into a plasma vapor deposition device, evacuate it, introduce argon gas, raise the temperature to a certain temperature, then switch the gas to argon containing a small amount of ammonia gas, and perform plasma treatment to obtain the non-metal doped copper-based catalytic material.

[0011] Furthermore, in step 1), the concentration of the sodium hydroxide solution is 1 - 3 mol / L, the concentration of the copper salt solution is 0.001 - 0.1 mol / L, preferably 0.005 - 0.01 mol / L;

[0012] In step 1), the volume ratio of the sodium hydroxide solution to the copper salt solution is 1:8 - 12, preferably 1:10;

[0013] In step 1, the concentration of the ascorbic acid solution is 0.2 - 1 mol / L, and the volume ratio of the ascorbic acid solution to the copper salt solution is 1:8 - 12, preferably 1:10.

[0014] Furthermore, in step 1), the stirring time after adding the sodium hydroxide solution to the copper salt solution is 0.3 - 3 h, and the hydrothermal temperature is 40 - 60 °C.

[0015] Further, after dropping the ascorbic acid solution in step 1), the stirring time is 1 - 3 h, the hydrothermal temperature is 40 - 60 °C, and the alcohol used for alcohol washing is one or more of ethanol, methanol, and isopropanol.

[0016] Further, in step 2), the heating rate is 1 - 5 °C / min, heating from room temperature to the activation temperature of 60 - 100 °C, and then maintaining for 4 - 8 h at the activation temperature.

[0017] Further, in step 3), the heating rate is 1 - 15 °C / min, heating from room temperature to 200 - 600 °C, and performing plasma treatment at this temperature; the power of the plasma treatment is 100 - 300 W, and the treatment time is 10 - 30 min.

[0018] Further, the argon containing a small amount of ammonia in step 3) is a 1 - 5% volume fraction ammonia / argon mixture.

[0019] The non-metal doped copper-based catalytic material prepared by the present invention for electrocatalytic reduction of carbon dioxide, the Cu of this catalytic material 0 / Cu + The mass percentage value is 0.1 - 15, and the relative atomic percentage value of the non-metal doping element N / Cu is 0.2 - 0.7.

[0020] The non-metal doped copper-based catalytic material prepared by the present invention for electrocatalytic reduction of carbon dioxide can be well applied to electrocatalytic conversion of CO2 to produce C2H4.

[0021] The beneficial effects obtained by the present invention are as follows:

[0022] The present invention provides a copper-based redox electrocatalytic material and a preparation method thereof. Nitrogen doping is carried out by using a plasma deposition device, and the Cu that can be accurately regulated 0 / Cu + For the material, because the copper with a valence state between 0 and +1 is more active, it can inhibit the C1 pathway, is beneficial to the production of C2 products, and at the same time improves the selectivity and Faraday efficiency of C2H4. The experimental results show that the CO2 electrocatalytic reduction material prepared by the present invention can be stably tested for 2 h at -1.0 vs RHE potential, and the Faraday efficiency of CO2 reduction to C2H4 reaches about 24.5%. The Faraday efficiency of the nitrogen-doped material for reducing C2H4 is about 14% higher than that of pure cuprous oxide. Description of the Drawings

[0023] Figure 1 It is a comparison diagram of SEM scanning electron microscope images of the samples prepared in the control example and Examples 1 - 3.

[0024] Figure 2XRD comparison diagram of the samples prepared in the control example and Examples 1-3.

[0025] Figure 3 is the Cu of cubic cuprous oxide with plasma nitrogen doping under different conditions 0 / Cu + mass percentage value. Specific embodiments

[0026] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0027] Control example

[0028] The control example is pure cuprous oxide. Weigh 171 mg of copper chloride dihydrate, prepare 100 mL of 0.01 mol / L copper chloride solution and pour it into a beaker, heat it in a water bath at 55 °C and continuously stir to dissolve it. Weigh 800 mg of sodium hydroxide to prepare 10 mL of 2.0 mol / L sodium hydroxide aqueous solution, and slowly drop it into the above solution drop by drop. After continuously stirring for 0.5 h, weigh 1.056 g of ascorbic acid to prepare 10 mL of 0.6 mol / L solution, and slowly drop it into the above solution drop by drop. Continue to stir at 55 °C for 3 h and then stop stirring. The dark red precipitate obtained after centrifugal washing twice with distilled water and once with ethanol is dried in an oven at 55 °C to obtain pure cuprous oxide.

[0029] The material prepared in the control example was analyzed by SEM. As Figure 1 shown in (a), the cuprous oxide has a uniform cubic structure, a smooth surface, and a particle size of about 1 μm. Then the sample was analyzed by XRD. As Figure 2 it can be seen that the diffraction peaks of the prepared product correspond to the standard diffraction peaks of cuprous oxide, and no impurity peaks of other products are found. The XRD data was semi-quantitatively analyzed by the relative intensity ratio method. The Cu 0 / Cu + mass percentage value is 0.02, and according to the characterization results of XPS, the N / Cu relative atomic percentage value is 0.

[0030] The electrocatalytic performance of the material prepared in the control example was tested as follows:

[0031] Weigh 10 mg of the material and put it into a vial, add 960 μL of isopropanol and 40 μL of nafion solution (the mass fraction of the Nafion solution is 5%), and ultrasonicate for 2 hours until the catalyst is completely dispersed to obtain a uniform catalyst ink.

[0032] 300 μL of the catalyst ink with the above configuration was removed, uniformly applied to a 1 cm × 3 cm carbon paper, and dried to serve as the working electrode. A nickel foam was used as the anode, and an Ag / AgCl electrode was used as the reference electrode. The catalytic performance test was carried out using a CS2350H electrochemical workstation from Wuhan Kest, in a flow cell of a three-electrode system. The electrolyte was 0.5 mol / L aqueous KHCO3 solution. Before the test, CO2 was passed for 1 h to saturate the CO2 in the electrolyte. The electrochemical workstation applied a potential of -1.64 V (vs Ag / AgCl) for polarization. After the current stabilized, the products were collected for 15 s and introduced into the gas phase. The Faraday efficiency was calculated based on the peak area concentration of ethylene measured in the gas phase. The electrocatalytic performance of the material in the control example could be stably tested for 2 h, with a total current density of 32.1 mA; the Faraday efficiency of ethylene was 10.4%, and the partial current density was 3.3 mA; C 2+ The Faraday efficiency of the product was 26%, and the partial current density was 8 mA.

[0033] Example 1

[0034] The cuprous oxide powder obtained in the control example was placed in a vacuum furnace, evacuated, and heated at a heating rate of 1 °C / min to 65 °C, held for 5 h, and then cooled to room temperature with the furnace to obtain activated cuprous oxide (cuprous oxide is easily oxidized, and vacuum heating activation can remove residual water molecules, allowing the material to be stably preserved for a longer time and avoiding oxidation to cupric oxide). 300 mg of the activated cuprous oxide powder was evenly spread in a porcelain boat, and then the porcelain boat was placed in a plasma chemical vapor deposition device. First, three vacuum purges were performed to replace all the gas in the tube with argon, and then the temperature was set to rise to the target temperature of 300 °C at 10 °C / min and maintained at this temperature for 23 minutes. After the temperature reached the target temperature, the gas was changed to a 2% ammonia / argon gas mixture by volume. Then, the power of the plasma generator was set to 100 W and turned on to fill the entire tube with plasma. After 20 min, the plasma generator was turned off, and the ammonia was replaced with argon by repeating the purging operation. After the temperature decreased, the porcelain boat was taken out to obtain the 3C1W material.

[0035] The material prepared in Example 1 was analyzed by SEM. As Figure 1 shown in (b), some dot-like particles adhered to the surface of the cuprous oxide treated by plasma, increasing the roughness of the structure surface. By performing XRD characterization and analyzing the sample, it can be seen that after plasma nitrogen doping treatment, three diffraction peaks of copper appear, indicating that part of the cuprous was reduced to copper. Using the relative intensity ratio method for semi-quantitative analysis of the XRD data, the Cu 0 / Cu + mass percentage value of this material was 0.161. According to the XPS characterization results, the N:Cu relative atomic percentage value was 0.687.

[0036] The catalyst material was prepared according to the method steps of Example 1. When the power of the plasma generator was 100 W and the plasma treatment temperatures were changed to 200 °C, 300 °C, 400 °C, 500 °C, and 600 °C respectively, the mass percentage values of the finally obtained catalyst material Cu 0 / Cu + are summarized in Figure 3 .

[0037] The electrocatalytic performance of the catalyst material prepared in Example 1 was tested as follows:

[0038] Weigh 10 mg of the catalyst material and put it into a vial, add 960 μL of isopropanol and 40 μL of nafion solution (the mass fraction of the Nafion solution is 5%) and mix them. Ultrasonic for 2 hours until the catalyst is completely dispersed to obtain a uniform catalyst ink.

[0039] Remove 300 μL of the above-prepared catalyst ink and evenly smear it on a 1 cm × 3 cm carbon paper. After drying, it is used as the working electrode, with nickel foam as the anode and an Ag / AgCl electrode as the reference electrode. The catalytic performance test was carried out using a CS2350H electrochemical workstation from Wuhan Koster in a flow cell with a three-electrode system. The electrolyte was 0.5 mol / L aqueous KHCO3 solution. Before the test, CO2 was passed for 1 h to saturate the CO2 in the electrolyte. The electrochemical workstation applied a potential of -1.64 V (vs Ag / AgCl) for polarization. After the current was stabilized, the products were collected for 15 s and introduced into the gas phase. The Faraday efficiency was calculated according to the peak area concentration of ethylene measured in the gas phase. The material of Example 1 could be stably tested for 2 h, with a total current density of 67.8 mA; the Faraday efficiency of ethylene was 24.03%, and the partial current density was 16.3 mA; C 2+ The Faraday efficiency of the product was 31.4%, and the partial current density was 21.3 mA.

[0040] Example 2

[0041] Put the cuprous oxide powder obtained in the control example into a vacuum furnace, evacuate the air, and heat it at a heating rate of 1 °C / min to 65 °C, hold for 5 h, and then cool it to room temperature with the furnace to obtain activated cuprous oxide. 300 mg of the activated cuprous oxide powder was evenly spread in a porcelain boat, and then the porcelain boat was placed in a plasma chemical vapor deposition device. First, perform three vacuum purges to replace all the gas in the tube with argon, and then set the temperature to rise to the target temperature of 300 °C at 10 °C per minute and maintain this temperature for 23 minutes. After the temperature reaches the target temperature, change the gas to a 2% ammonia / argon gas mixture by volume. Then set the power of the plasma generator to 200 W and turn it on to fill the entire tube with plasma. After 20 min, turn off the plasma generator and repeat the purging operation to change the ammonia back to argon. After the temperature drops, take out the porcelain boat to obtain the 3C2W material.

[0042] Perform SEM analysis on the catalyst material prepared in Example 2. As Figure 1 shown in (c), some flaky particles much larger than those in Example 1 adhered to the surface of the cuprous oxide treated by plasma, and the surface roughness of the structure also increased slightly. The XRD data was semi-quantitatively analyzed by the relative intensity ratio method, and it can be obtained that the mass percentage value of Cu 0 / Cu + of this material is 0.429. According to the XPS characterization results, the relative atomic percentage value of N:Cu is 0.5.

[0043] Prepare the catalyst material according to the method steps of Example 2. When the plasma treatment temperature is changed to 200 °C, 300 °C, 400 °C, 500 °C, and 600 °C under the plasma generator power of 200 W, the mass percentage values of Cu 0 / Cu + of the finally prepared catalyst materials at different plasma treatment temperatures are summarized in Figure 3 .

[0044] The electrocatalytic performance of the catalyst material prepared in Example 2 was tested as follows:

[0045] Weigh 10 mg of the catalyst material and put it into a vial, add 960 μL of isopropanol and 40 μL of nafion solution (the mass fraction of the Nafion solution is 5%), and ultrasonicate for 2 hours until the catalyst is completely dispersed to obtain a uniform catalyst ink.

[0046] 300 μL of the catalyst ink with the above configuration was removed, evenly applied on a 1 cm × 3 cm carbon paper, and after drying, it was used as the working electrode, with nickel foam as the anode and Ag / AgCl electrode as the reference electrode. The catalytic performance test was carried out using a CS2350H electrochemical workstation from Wuhan Koster in a flow cell with a three-electrode system. The electrolyte was 0.5 mol / L KHCO3 aqueous solution. Before the test, CO2 was bubbled for 1 h to saturate the CO2 in the electrolyte. The electrochemical workstation applied a potential of -1.64 V (vs Ag / AgCl) for polarization. After the current stabilized, the products were collected for 15 s and introduced into the gas phase. The Faraday efficiency was calculated based on the peak area concentration of ethylene measured in the gas phase. The materials in Example 2 could be stably tested for 2 h, with a total current density of 45.7 mA; the Faraday efficiency of ethylene was 24.5%, and the partial current density was 11.2 mA; C 2+ The Faraday efficiency of the product was 32.7%, and the partial current density was 14.9 mA.

[0047] Example 3

[0048] The cuprous oxide powder obtained in the control example was put into a vacuum furnace, evacuated, and heated to 65 °C at a heating rate of 1 °C / min, held for 5 h, and then cooled to room temperature with the furnace to obtain activated cuprous oxide. 300 mg of the activated cuprous oxide powder was evenly spread in a porcelain boat, and then the porcelain boat was placed in a plasma chemical vapor deposition device. First, three vacuum replacements were performed to replace all the gas in the tube with argon, and then it was set to heat to the target temperature of 300 °C at 10 degrees per minute and maintain this temperature for 23 minutes. After the temperature reached the target temperature, the gas was changed to a 2% volume fraction ammonia / argon mixture. Then the power of the plasma generator was set to 300 W and turned on to fill the entire tube with plasma. After 20 min, the plasma generator was turned off, and the ammonia was replaced back with argon by repeating the gas replacement operation. After the temperature decreased, the porcelain boat was taken out to obtain the 3C3W material.

[0049] SEM analysis was performed on the catalyst material prepared in Example 3, as Figure 1 shown in (d). Many large flaky particles adhered to the surface of the cuprous oxide treated by plasma, and the surface of the structure was very rough. The XRD data was semi-quantitatively analyzed by the relative intensity ratio method, and it could be obtained that the Cu 0 / Cu + mass percentage value of this material was 0.732. According to the XPS characterization results, the N:Cu relative atomic percentage value was 0.222.

[0050] Prepare the catalyst material according to the method steps of Example 3. When the power of the plasma generator is 300 W and the plasma treatment temperature is changed to 200 °C, 300 °C, 400 °C, 500 °C, and 600 °C respectively, the mass percentage values of the finally obtained catalyst material Cu 0 / Cu + are summarized in Figure 3 .

[0051] The electrocatalytic performance of the catalyst material prepared in Example 3 was tested as follows:

[0052] Weigh 10 mg of the catalyst material and put it into a vial. Add 960 μL of isopropanol and 40 μL of nafion solution (the mass fraction of the Nafion solution is 5%) and mix them. Ultrasonic for 2 hours until the catalyst is completely dispersed to obtain a uniform catalyst ink.

[0053] Remove 300 μL of the prepared catalyst ink and evenly coat it on a 1 cm × 3 cm carbon paper. After drying, it is used as the working electrode, with nickel foam as the anode and Ag / AgCl electrode as the reference electrode. The catalytic performance test was carried out using a CS2350H electrochemical workstation from Wuhan Kest. It was carried out in a flow cell with a three-electrode system. The electrolyte was 0.5 mol / L KHCO3 aqueous solution. Before the test, CO2 was passed for 1 h to saturate the CO2 in the electrolyte. The electrochemical workstation applied a potential of -1.64 V (vs Ag / AgCl) for polarization. After the current was stable, the product was collected for 15 s and introduced into the gas phase. The Faraday efficiency was calculated according to the peak area concentration of ethylene measured in the gas phase. The material of Example 3 could be stably tested for 2 h, the total current density was 62.8 mA; the Faraday efficiency of ethylene was 18.78%, and the partial current density was 11.8 mA; C 2+ The Faraday efficiency of the product was 31.5%, and the partial current density was 19.8 mA.

[0054] Example 4

[0055] Put the cuprous oxide powder obtained from the control example into a vacuum furnace, evacuate the air, and heat it up to 65 °C at a heating rate of 1 °C / min, hold for 5 h, and then cool it to room temperature with the furnace to obtain activated cuprous oxide. 300 mg of the activated cuprous oxide powder is evenly spread in a porcelain boat, and then the porcelain boat is placed in a plasma chemical vapor deposition device. First, perform three vacuum purges to replace all the gas in the tube with argon, and then set the temperature to rise to the target temperature of 400 °C at 10 °C per minute and maintain this temperature for 23 minutes. After the temperature reaches the target temperature, change the gas to a 2% ammonia / argon gas mixture by volume. Then set the power of the plasma generator to 200 W and turn it on to fill the entire tube with plasma. After 20 min, turn off the plasma generator, and repeat the purging operation to change the ammonia back to argon. After the temperature drops, take out the porcelain boat to obtain the 3C3W material.

[0056] Perform SEM analysis on the catalyst material prepared in Example 4. Many large blocky flaky particles are attached to the surface of the cuprous oxide treated by plasma, and the surface of the structure is very rough. Use the relative intensity ratio method to perform semi-quantitative analysis on the XRD data, and it can be concluded that the Cu 0 / Cu + mass percentage value is 1.763. According to the XPS characterization results, the N:Cu relative atomic percentage value is 0.175.

[0057] The electrocatalytic performance test of the catalyst material prepared in Example 4 is as follows:

[0058] Weigh 10 mg of the catalyst material and put it into a small bottle, add 960 μL of isopropanol and 40 μL of nafion solution (the mass fraction of the Nafion solution is 5%), and ultrasonicate for 2 h until the catalyst is completely dispersed to obtain a uniform catalyst ink.

[0059] Transfer 300 μL of the above-prepared catalyst ink and evenly coat it on a 1 cm × 3 cm carbon paper. After drying, it serves as the working electrode, with nickel foam as the anode and an Ag / AgCl electrode as the reference electrode. The catalytic performance test is carried out using a CS2350H electrochemical workstation from Wuhan Kest, in a flow cell with a three-electrode system. The electrolyte is a 0.5 mol / L KHCO3 aqueous solution. Before the test, first pass CO2 for 1 h to saturate the CO2 in the electrolyte. The electrochemical workstation applies a potential of -1.64 V (vs Ag / AgCl) for polarization. After the current stabilizes, collect the products for 15 s and introduce them into the gas phase. Calculate the Faraday efficiency according to the peak area concentration of ethylene measured in the gas phase. The material of Example 4 can be stably tested for 2 h, the total current density is 52.2 mA; the ethylene Faraday efficiency is 17.93%, and the partial current density is 9.36 mA; C 2+The product Faraday efficiency is 27.88%, and the partial current density is 14.6 mA.

[0060] The content described in this specification is only a list of the implementation forms of the inventive concept, and the protection scope of the present invention should not be regarded as limited to the specific forms stated in the embodiments.

Claims

1. A preparation method of a non-metal doped copper-based catalytic material for electrocatalytic reduction of carbon dioxide, characterized in that It includes the following steps: 1) Slowly and dropwise add the sodium hydroxide solution into the copper salt solution, heat it in a water bath and continuously stir for a certain period of time. Then, slowly and dropwise add the ascorbic acid solution into it, heat it in a water bath and continuously stir for a certain period of time. After centrifugal separation, wash it with water 1 - 3 times and with alcohol 1 - 3 times, and then dry it to obtain the precipitate cuprous oxide. 2) Put the cuprous oxide precipitate obtained in step 1) into a vacuum furnace, evacuate it, and heat it to a certain temperature. After maintaining for a period of time, then cool it to room temperature with the furnace to obtain the activated cuprous oxide. 3) Put the activated cuprous oxide obtained in step 2) into a plasma chemical vapor deposition device, evacuate it, introduce argon gas, heat it to a certain temperature, and then switch the gas to argon gas containing a small amount of ammonia. After plasma treatment, the non - metal - doped copper - based catalytic material is obtained. In step 2), the heating rate is 1 - 5 °C / min, heat it from room temperature to the activation temperature of 60 - 100 °C, and then maintain it at the activation temperature for 4 - 8 h. In step 3), the heating rate is 1 - 15 °C / min, heat it from room temperature to 200 - 400 °C, and perform plasma treatment at this temperature; the power of the plasma treatment is 100 - 300 W, and the treatment time is 10 - 30 min. In step 3), the argon gas containing a small amount of ammonia is an ammonia / argon gas mixture with a volume fraction of 1 - 5%. Cu of the catalytic material 0 / Cu + The mass percentage value is 0.1 - 1.

763.

2. The preparation method of a non-metal doped copper-based catalytic material for electrocatalytic reduction of carbon dioxide according to claim 1, characterized in that In step 1), the concentration of the sodium hydroxide solution is 1 - 3 mol / L, and the concentration of the copper salt solution is 0.001 - 0.1 mol / L. In step 1), the volume ratio of the sodium hydroxide solution to the copper salt solution is 1:8 - 12. In step 1, the concentration of the ascorbic acid solution is 0.2 - 1 mol / L, and the volume ratio of the ascorbic acid solution to the copper salt solution is 1:8 - 12.

3. The preparation method of a non-metal doped copper-based catalytic material for electrocatalytic reduction of carbon dioxide according to claim 2, characterized in that In step 1), the concentration of the copper salt solution is 0.005 - 0.01 mol / L. In step 1), the volume ratio of the sodium hydroxide solution to the copper salt solution is 1:

10. In step 1, the volume ratio of the ascorbic acid solution to the copper salt solution is 1:

10.

4. The preparation method of a non-metal doped copper-based catalytic material for electrocatalytic reduction of carbon dioxide according to claim 1, characterized in that In step 1), after adding the sodium hydroxide solution into the copper salt solution, the stirring time is 0.3 - 3 h, and the hydrothermal temperature is 40 - 60 °C.

5. The preparation method of a non-metal doped copper-based catalytic material for electrocatalytic reduction of carbon dioxide according to claim 1, characterized in that In step 1), after adding the ascorbic acid solution, the stirring time is 1 - 3 h, and the hydrothermal temperature is 40 - 60 °C. The alcohol used for alcohol washing is one or more of ethanol, methanol, and isopropanol.

6. The non - metal - doped copper - based catalytic material for electrocatalytic reduction of carbon dioxide prepared by the method according to any one of claims 1 - 5, and the relative atomic percentage value of the non - metal - doped element N / Cu in this catalytic material is 0.2 - 0.

7.

7. Application of the non - metal - doped copper - based catalytic material for electrocatalytic reduction of carbon dioxide according to claim 6 in electrocatalytic conversion of CO2 to generate C2H4.

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