Tin-copper co-doped porous carbon as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of carbon materials, and provides tin-copper co-doped porous carbon and a preparation method and application thereof.The preparation method comprises the steps that A, raw materials are mixed, a hydrochloric acid solution is added to adjust the pH of a system to 5-6, stirring and cooling are conducted to the room temperature, then standing is conducted to form wet gel, freeze drying is conducted, and gel is obtained; wherein the raw materials comprise 0.8 g to 1.2 g of copper acetylacetonate, 4 g to 6 g of 2-aminobenzaldehyde, 4 g to 6 g of melamine phosphate, 4 g to 6 g of resorcinol and 8 ml to 12 ml of a formaldehyde solution with the concentration being 30 wt%; b, carbonizing the gel in inert protective gas to obtain copper-doped porous carbon; c, tin powder and the copper-doped porous carbon obtained in the step B are subjected to ball milling and mixing according to the mass ratio of 2: (7-12), then the mixture is placed in inert protective gas to be carbonized, and the tin-copper co-doped porous carbon is obtained. The prepared porous carbon material is high in CO2 electrocatalytic activity and has a wide application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon materials, and relates to a tin-copper co-doped porous carbon and its preparation method and application. Background Art

[0002] Electrocatalytic reduction of CO2 has been widely concerned due to its advantages such as greenness, energy conservation, and reusability. Currently, there are mainly two types of electrocatalysts for catalytic conversion of carbon dioxide. One is a bioelectrocatalyst, which has high selectivity and a reversible reaction path, but low productivity. In addition to bioelectrocatalysts, metal electrodes have been widely used in the research of electrocatalytic reduction of CO2, but there are the following problems: traditional doping methods (such as impregnation method) are prone to cause metal agglomeration and uneven distribution of active sites; among metal electrodes, copper metal electrodes are the most widely used, but using only copper element doping as a catalytic electrode has an overly wide selectivity distribution and insufficient stability. At the same time, the occurrence of hydrogen evolution reaction will lead to a decrease in the overall reaction efficiency and selectivity. In order to develop electrode materials with high catalytic activity, the prior art uses multi-metal catalysts. For example, Chinese Patent Publication No. CN 112176359A discloses a multi-metal catalyst prepared from one of silver, copper, nickel, bismuth, zinc, iron, indium, cobalt and two metals of gold, which has the defect of high production cost.

[0003] In summary, it is necessary to study catalyst electrode materials with high catalytic activity. Summary of the Invention

[0004] The present invention provides a tin-copper co-doped porous carbon and its preparation method and application. The porous carbon material has strong electrocatalytic activity for CO2 and has broad application prospects.

[0005] The technical solution of the present invention is realized as follows: A preparation method of a tin-copper co-doped porous carbon, comprising the following steps: A. Mix the raw materials, add hydrochloric acid solution to adjust the pH of the system to 5-6, stir, let it stand at room temperature to form a wet gel, and then freeze-dry to obtain a gel; wherein, the raw materials include 0.8-1.2 g of copper acetylacetonate, 4-6 g of 2-aminobenzaldehyde, 4-6 g of melamine phosphate, 4-6 g of resorcinol, and 8-12 ml of 30 wt% formaldehyde solution; B. Carbonize the gel in an inert protective gas to obtain copper-doped porous carbon, and cool it to room temperature; C. Ball-mill and mix tin powder with the copper-doped porous carbon obtained in step B in a mass ratio of 2:7-12, and then carbonize it in an inert protective gas to obtain tin-copper co-doped porous carbon.

[0006] Preferably, the raw materials include 1 g of copper acetylacetonate, 4 - 6 g of 2-aminobenzaldehyde, 5 g of melamine phosphate, 5 g of resorcinol, and 8 - 12 ml of 30 wt% formaldehyde solution.

[0007] Preferably, the addition amount of the hydrochloric acid solution is 180 - 220 ml.

[0008] Preferably, in step A, the mixing temperature is 45 - 55 °C; the stirring rate is 80 - 120 rpm, and the stirring time is 0.5 - 1.5 h.

[0009] Preferably, the freeze-drying includes the following steps: freeze-drying at -60 to -100 °C for 20 - 36 h, and then vacuum drying for 36 - 72 h.

[0010] Preferably, in step B, the carbonization temperature is 850 - 950 °C, the carbonization time is 1.5 - 3 h, and during the carbonization process, the temperature is raised at a rate of 5 - 15 °C / min.

[0011] Preferably, in step C, the rotation speed of the ball milling and mixing is 250 - 350 revolutions per minute, and the ball milling time is 1.5 - 2.5 h.

[0012] Preferably, in step C, the carbonization temperature is 550 - 650 °C, and the carbonization time is 1.5 - 3 h.

[0013] The present invention also provides a tin and copper co-doped porous carbon obtained by the method as described above.

[0014] The present invention also provides an application of the tin and copper co-doped porous carbon as described above in the field of electrocatalytic conversion of carbon dioxide.

[0015] Preferably, the tin and copper co-doped porous carbon is used to prepare a catalytic electrode.

[0016] The working principle and beneficial effects of the present invention are as follows: 1. The preparation method provided by the present invention is not only simple to operate, has a wide range of raw material sources, is simple and easy to obtain, and saves costs; moreover, the prepared material shows a high carbon dioxide adsorption amount when applied to carbon dioxide adsorption, and at the same time has good CO2 electrocatalytic activity, having good practical prospects.

[0017] 2. In the present invention, each component of the raw materials interacts through a synergistic mechanism. Among them, copper acetylacetonate can participate in the polymerization and be uniformly doped into the gel system; 2-aminobenzaldehyde, resorcinol, formaldehyde, and melamine phosphate can polymerize to form a cross-linked structure in an acidic system, and the free radicals formed during the polymerization process can react with the carbonyl group on acetylacetone to uniformly dope copper ions into the system. Melamine phosphate also participates in the polymerization, and phosphorus elements are uniformly doped into the porous carbon; tin powder can form tin vapor at high temperatures, which can penetrate into the porous carbon and form an alloy with copper. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0019] Figure 1 TEM morphology diagram of the porous carbon material prepared in Example 1 of the present invention.

[0020] Figure 2 Carbon dioxide adsorption diagram of the porous carbon material prepared in Example 1 of the present invention.

[0021] Figure 3 Polarization curve diagram of the porous carbon material prepared in Example 1 of the present invention; test conditions: a three-electrode system is adopted, 1M sodium bicarbonate solution is used as the electrolyte, a saturated calomel electrode is used as the reference electrode, a carbon paper is used as the counter electrode, and the polarization curve diagram is obtained by smearing the active substance on the glassy carbon electrode for testing. SPECIFIC EMBODIMENTS

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0023] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments, and are not intended to limit the present invention.

[0024] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below in conjunction with the accompanying drawings and embodiments, but they should not be construed as limiting the protection scope of the present invention. The production processes, experimental methods or detection methods involved in the embodiments of the present invention are all conventional methods in the prior art without special instructions, and their names and / or abbreviations are all conventional names in the art, which are very clear and definite in the relevant application fields. Those skilled in the art can understand the conventional process steps according to the names and apply the corresponding equipment, and implement them under conventional conditions or the conditions recommended by the manufacturer.

[0025] There are no special restrictions on the sources of various instruments, equipment, raw materials or reagents used in the embodiments of the present invention. They are all conventional products that can be obtained through regular commercial channels, and can also be prepared according to the conventional methods well-known to those skilled in the art.

[0026] Example 1 A preparation method of tin-copper co-doped porous carbon includes the following steps: A. Mix 1.0 g of copper acetylacetonate, 5 g of 2-aminobenzaldehyde, 5 g of melamine phosphate (CAS No. 20208-95-1), 5 g of resorcinol, and 10 ml of 30 wt% formaldehyde solution. After mixing, add the mixture to a 250 ml single-neck flask, add 200 ml of hydrochloric acid solution to adjust the pH of the system to 5, then place it in a 50 °C water bath and stir magnetically for 1 h at a stirring rate of 100 rpm. After cooling, pour it into a beaker and let it stand for 24 h to form a wet gel, and then place it in a freeze dryer for freeze-drying to obtain a gel; the freeze-drying includes the following steps: freeze-dry at -80 °C for 24 h, and then vacuum-dry for 48 h; B. Heat the gel in a nitrogen furnace at a rate of 10 °C / min to 900 °C and carbonize it at 900 °C for 2 h to obtain copper-doped porous carbon; C. Mix 2 g of tin powder and 10 g of copper-doped porous carbon by ball milling at a rotation speed of 300 revolutions per minute for 2 h. After ball milling and mixing, place it in a nitrogen furnace and carbonize it at 600 °C at high temperature to obtain tin-copper co-doped porous carbon.

[0027] Microscopic characterization was performed on the obtained porous carbon material, and the results are as Figure 1 shown; CO2 adsorption tests were performed on the obtained porous carbon material, and the results are as Figure 2 shown; the polarization curve of the obtained porous carbon material was measured, as Figure 3 shown.

[0028] Example 2 A preparation method of tin-copper co-doped porous carbon includes the following steps: A. Mix 1.2 g of copper acetylacetonate, 4 g of 2-aminobenzaldehyde, 6 g of melamine phosphate, 6 g of resorcinol, and 8 ml of 30 wt% formaldehyde solution. After mixing, add the mixture to a 250-ml single-necked flask, add 180 ml of hydrochloric acid solution to adjust the pH of the system to 6, then place it in a water bath at 55 °C and stir magnetically for 1.5 h at a stirring rate of 80 rpm. After cooling, pour it into a beaker and let it stand for 24 h to form a wet gel, and then place it in a freeze dryer for freeze-drying to obtain a gel; the freeze-drying includes the following steps: freeze-dry at -60 °C for 30 h, and then vacuum-dry for 60 h; B. Heat the gel in a nitrogen furnace at a rate of 5 °C / min to 950 °C and carbonize it at 950 °C for 2 h to obtain copper-doped porous carbon; C. Ball-mill and mix 2 g of tin powder with 7 g of copper-doped porous carbon balls at a rotation speed of 350 revolutions per minute for 1.5 h. After ball-milling and mixing, place it in a nitrogen furnace and carbonize it at 650 °C at high temperature to obtain tin-copper co-doped porous carbon.

[0029] Example 3 A method for preparing tin-copper co-doped porous carbon includes the following steps: A. Mix 0.8 g of copper acetylacetonate, 6 g of 2-aminobenzaldehyde, 4 g of melamine phosphate, 4 g of resorcinol, and 12 ml of 30 wt% formaldehyde solution. After mixing, add the mixture to a 250-ml single-necked flask, add 220 ml of hydrochloric acid solution to adjust the pH of the system to 5, then place it in a water bath at 45 °C and stir magnetically for 0.5 h at a stirring rate of 120 rpm. After cooling, pour it into a beaker and let it stand for 24 h to form a wet gel, and then place it in a freeze dryer for freeze-drying to obtain a gel; the freeze-drying includes the following steps: freeze-dry at -100 °C for 20 h, and then vacuum-dry for 36 h; B. Heat the gel in a nitrogen furnace at a rate of 15 °C / min to 850 °C and carbonize it at 850 °C for 2 h to obtain copper-doped porous carbon; C. Ball-mill and mix 2 g of tin powder with 12 g of copper-doped porous carbon balls at a rotation speed of 250 revolutions per minute for 2.5 h. After ball-milling and mixing, place it in a nitrogen furnace and carbonize it at 550 °C at high temperature to obtain tin-copper co-doped porous carbon.

[0030] Example 4 A method for preparing tin-copper co-doped porous carbon includes the following steps: A. Mix 1.0 g of copper acetylacetonate, 5.5 g of 2-aminobenzaldehyde, 5 g of melamine phosphate, 5 g of resorcinol, and 10 ml of 30 wt% formaldehyde solution. After mixing, add the mixture to a 250-ml single-necked flask, add 200 ml of hydrochloric acid solution to adjust the pH of the system to 5, then place it in a water bath at 50 °C and stir magnetically for 1 h at a stirring rate of 100 rpm. After cooling, pour it into a beaker and let it stand for 24 h to form a wet gel, and then place it in a freeze dryer for freeze-drying to obtain a gel; the freeze-drying includes the following steps: freeze-dry at -80 °C for 24 h, and then vacuum-dry for 48 h; B. Heat the gel in a nitrogen furnace at a rate of 10 °C / min to 900 °C and carbonize it at 900 °C for 2 h to obtain copper-doped porous carbon; C. Ball-mill 2 g of tin powder and 11 g of copper-doped porous carbon at a rotation speed of 300 revolutions per minute for 2 h. After ball-milling and mixing, place it in a nitrogen furnace and carbonize it at 600 °C at high temperature to obtain tin-copper co-doped porous carbon.

[0031] Example 5 A method for preparing tin-copper co-doped porous carbon includes the following steps: A. Mix 1.0 g of copper acetylacetonate, 5 g of 2-aminobenzaldehyde, 4.5 g of melamine phosphate, 5.5 g of resorcinol, and 10 ml of 30 wt% formaldehyde solution. After mixing, add the mixture to a 250-ml single-necked flask, add 200 ml of hydrochloric acid solution to adjust the pH of the system to 5, then place it in a water bath at 50 °C and stir magnetically for 1 h at a stirring rate of 100 rpm. After cooling, pour it into a beaker and let it stand for 24 h to form a wet gel, and then place it in a freeze dryer for freeze-drying to obtain a gel; the freeze-drying includes the following steps: freeze-dry at -80 °C for 24 h, and then vacuum-dry for 48 h; B. Heat the gel in a nitrogen furnace at a rate of 10 °C / min to 900 °C and carbonize it at 900 °C for 2 h to obtain copper-doped porous carbon; C. Ball-mill 2 g of tin powder and 10 g of copper-doped porous carbon at a rotation speed of 300 revolutions per minute for 2 h. After ball-milling and mixing, place it in a nitrogen furnace and carbonize it at 600 °C at high temperature to obtain tin-copper co-doped porous carbon.

[0032] Comparative Example 1 A method for preparing a carbon material includes the following steps: A. Mix 1.0 g of copper acetylacetonate, 5 g of 2-aminobenzaldehyde, 2.82 g of melamine, 5 g of resorcinol, and 10 ml of 30 wt% formaldehyde solution. After mixing, add the mixture to a 250-ml single-necked flask, add 200 ml of hydrochloric acid solution to adjust the pH of the system to 5, then place it in a 50°C water bath and stir magnetically for 1 h at a stirring rate of 100 rpm. After cooling, pour it into a beaker and let it stand for 24 h to form a wet gel, and then place it in a freeze dryer for freeze-drying to obtain a gel; the freeze-drying includes the following steps: freeze-dry at -80°C for 24 h, and then vacuum-dry for 48 h; B. Heat the gel in a nitrogen furnace at a rate of 10°C / min to 900°C and carbonize it at 900°C for 2 h to obtain carbon material-a; C. Ball-mill and mix 2 g of tin powder with 10 g of carbon material-a at a rotation speed of 300 revolutions per minute for 2 h. After ball-milling and mixing, place it in a nitrogen furnace for high-temperature carbonization at 600°C to obtain carbon material-A.

[0033] Comparative Example 2 A method for preparing a carbon material, comprising the following steps: A. Mix 1.0 g of copper acetylacetonate, 5 g of 2-aminobenzaldehyde, 5 g of melamine phosphate, 5 g of resorcinol, and 10 ml of 30 wt% formaldehyde solution. After mixing, add the mixture to a 250-ml single-necked flask, add 200 ml of hydrochloric acid solution to adjust the pH of the system to 5, then place it in a 50°C water bath and stir magnetically for 1 h at a stirring rate of 100 rpm. After cooling, pour it into a beaker and let it stand for 24 h to form a wet gel, and then place it in a freeze dryer for freeze-drying to obtain a gel; the freeze-drying includes the following steps: freeze-dry at -80°C for 24 h, and then vacuum-dry for 48 h; B. Heat the gel in a nitrogen furnace at a rate of 10°C / min to 900°C and carbonize it at 900°C for 2 h to obtain carbon material-B.

[0034] Comparative Example 3 A method for preparing a carbon material, comprising the following steps: A. Mix 5 g of 2-aminobenzaldehyde, 5 g of melamine phosphate, 5 g of resorcinol, and 10 ml of 30 wt% formaldehyde solution. After mixing, add the mixture to a 250-ml single-necked flask, add 200 ml of hydrochloric acid solution to adjust the pH of the system to 5, then place it in a 50°C water bath and stir magnetically for 1 h at a stirring rate of 100 rpm. After cooling, pour it into a beaker and let it stand for 24 h to form a wet gel, and then place it in a freeze dryer for freeze-drying to obtain a gel; the freeze-drying includes the following steps: freeze-dry at -80°C for 24 h, and then vacuum-dry for 48 h; B. Heat the gel in a nitrogen furnace at a rate of 10°C / min to 900°C and carbonize it at 900°C for 2 h to obtain carbon material-c; C. Mix 2 g of tin powder with 10 g of carbon material - C by ball milling at a rotation speed of 300 revolutions per minute for 2 h. After ball milling and mixing, place it in a nitrogen furnace for carbonization at 600 °C to obtain carbon material - C.

[0035] Comparative Example 4 A method for preparing a carbon material, comprising the following steps: A. Mix 1.0 g of copper acetylacetonate, 5 g of 4 - aminobenzaldehyde, 5 g of melamine phosphate, 5 g of resorcinol, and 10 ml of 30 wt% formaldehyde solution. After mixing, add it to a 250 - ml single - necked flask, add 200 ml of hydrochloric acid solution to adjust the system pH to 5, then place it in a 50 °C water bath and stir magnetically for 1 h at a stirring rate of 100 rpm. After cooling, pour it into a beaker and let it stand for 24 h to form a wet gel, and then place it in a freeze - dryer for freeze - drying to obtain a gel; the freeze - drying includes the following steps: freeze - dry at - 80 °C for 24 h, and then vacuum - dry for 48 h; B. Heat the gel in a nitrogen furnace from room temperature to 900 °C at a rate of 10 °C / min and carbonize it at 900 °C for 2 h to obtain carbon material - d; C. Mix 2 g of tin powder with 10 g of carbon material - d by ball milling at a rotation speed of 300 revolutions per minute for 2 h. After ball milling and mixing, place it in a nitrogen furnace for carbonization at 600 °C to obtain carbon material - D.

[0036] Comparative Example 5 A method for preparing a carbon material, comprising the following steps: A. Mix 1.0 g of copper 8 - hydroxyquinoline, 5 g of 2 - aminobenzaldehyde, 5 g of melamine phosphate, 5 g of resorcinol, and 10 ml of 30 wt% formaldehyde solution. After mixing, add it to a 250 - ml single - necked flask, add 200 ml of hydrochloric acid solution to adjust the system pH to 5, then place it in a 50 °C water bath and stir magnetically for 1 h at a stirring rate of 100 rpm. After cooling, pour it into a beaker and let it stand for 24 h to form a wet gel, and then place it in a freeze - dryer for freeze - drying to obtain a gel; the freeze - drying includes the following steps: freeze - dry at - 80 °C for 24 h, and then vacuum - dry for 48 h; B. Heat the gel in a nitrogen furnace from room temperature to 900 °C at a rate of 10 °C / min and carbonize it at 900 °C for 2 h to obtain carbon material - e; C. Mix 2 g of tin powder with 10 g of carbon material - e by ball milling at a rotation speed of 300 revolutions per minute for 2 h. After ball milling and mixing, place it in a nitrogen furnace for carbonization at 600 °C to obtain carbon material - E.

[0037] Comparative Example 6 A method for preparing a carbon material, comprising the following steps: A. Mix 1.0 g of copper acetylacetonate, 5 g of melamine phosphate, 5 g of resorcinol, and 10 ml of 30 wt% formaldehyde solution. After mixing, add the mixture to a 250-ml single-neck flask, add 200 ml of hydrochloric acid solution to adjust the pH of the system to 5, then place it in a 50°C water bath and stir magnetically for 1 h at a stirring rate of 100 rpm. After cooling, pour it into a beaker and let it stand for 24 h to form a wet gel, and then freeze-dry it in a freeze-dryer to obtain a gel; the freeze-drying includes the following steps: freeze-dry at -80°C for 24 h, and then vacuum-dry for 48 h; B. Heat the gel in a nitrogen furnace at a rate of 10°C / min to 900°C and carbonize it at 900°C for 2 h to obtain carbon material - f; C. Ball-mill 2 g of tin powder and 10 g of carbon material - f at a rotation speed of 300 revolutions per minute for 2 h. After ball-milling and mixing, place it in a nitrogen furnace and carbonize it at 600°C at high temperature to obtain carbon material - F.

[0038] Test Example 1. Determination of the catalytic performance of the carbon materials prepared in the examples and comparative examples Preparation of a tin-copper co-doped porous carbon catalytic electrode: Weigh 10 mg of the above-mentioned porous carbon and add it to 1.0 ml of absolute ethanol, then add 100 μl of nafio membrane solution. After ultrasonic mixing, take out 10 μl of the above mixture and drop it onto a glassy carbon electrode with a diameter of 6 mm, and let it dry naturally. The catalytic performance is tested using a three-electrode system. In the three-electrode system, use 1.0 M potassium bicarbonate as the electrolyte to test the catalytic performance of the material. During the test, introduce carbon dioxide gas into the reaction cell at a gas flow rate of 5 mL / min; the counter electrode is a hydrophobic carbon cloth, and the reference electrode is a saturated calomel electrode. The voltage range for the polarization curve test is set to -0.8 to -1.6 V, and the scanning rate is 5 mV / s. The results of the carbon dioxide catalytic overpotential are shown in Table 1.

[0039] 2. Measure the specific surface area (m 2 / g), micropore ratio (%), pore diameter (nm), and carbon dioxide adsorption capacity (mmol / g) of the carbon materials prepared in the above examples and comparative examples. The results are shown in Table 1 below.

[0040] Table 1 The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing tin-copper co-doped porous carbon, characterized in that: The steps include: The raw materials are mixed, a hydrochloric acid solution is added to adjust the pH value of the system to 5-6, the mixture is stirred, cooled to room temperature, and then allowed to stand to form a wet gel, and freeze-dried to obtain a gel; wherein the raw materials include 0.8-1.2 g of copper acetylacetonate, 4-6 g of 2-aminobenzaldehyde, 4-6 g of melamine phosphate, 4-6 g of resorcinol, and 8-12 ml of a 30 wt% formaldehyde solution; B. Carbonizing the gel in an inert protective gas to obtain copper-doped porous carbon, and cooling to room temperature; C. Ball-milling the tin powder with a mass ratio of 2:7-12 and the copper-doped porous carbon obtained in step B, and then carbonizing the mixture in an inert protective gas to obtain tin-copper co-doped porous carbon.

2. The method for preparing tin-copper co-doped porous carbon according to claim 1, characterized in that: The raw materials include 1g of copper acetylacetonate, 4-6g of 2-aminobenzaldehyde, 5g of melamine phosphate, 5g of resorcinol and 8-12ml of 30wt% formaldehyde solution.

3. The method for preparing tin-copper co-doped porous carbon according to claim 1, characterized in that: The mixing temperature in step A is 45-55° C.; the stirring rate is 80-120 rpm, and the stirring time is 0.5-1.5 h.

4. The method for preparing tin-copper co-doped porous carbon according to claim 1, characterized in that: The freeze drying comprises the following steps: freeze drying at -60 to -100°C for 20 to 36 hours, and then vacuum drying for 36 to 72 hours.

5. The method for preparing tin-copper co-doped porous carbon according to claim 1, characterized in that: The carbonization temperature in step B is 850-950° C., the carbonization time is 1.5-3 hours, and during the carbonization process, the temperature is increased at a rate of 5-15° C. / min.

6. The method for preparing tin-copper co-doped porous carbon according to claim 1, characterized in that: The rotation speed of the ball milling mixture in step C is 250-350 rpm, and the ball milling time is 1.5-2.5 h.

7. The method for preparing tin-copper co-doped porous carbon according to claim 1, characterized in that: The carbonization temperature in step C is 550-650° C., and the carbonization time is 1.5-3 hours.

8. A tin-copper co-doped porous carbon obtained by the method according to any one of claims 1 to 7.

9. Use of the tin-copper co-doped porous carbon as claimed in claim 8 in the field of carbon dioxide electrocatalytic conversion.

10. The use according to claim 9, characterized in that: The tin-copper co-doped porous carbon is used to prepare a catalytic electrode.

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