A Ni-VC single-atom alloy electrocatalytic CO2 reduction material and its preparation method

Abstract

The present invention discloses a Ni-VC single-atom alloy electrocatalytic CO2 reduction material and a preparation method thereof, belonging to the technical field of composite material preparation. In the present invention, a nanofiber membrane containing nickel salt and vanadium salt is prepared by electrospinning, and then a Ni-VC / CNFs electrocatalytic material is prepared by pre-oxidation and high-temperature carbonization methods. The present invention prepares a Ni-VC single-atom alloy structure, and the electrospun nanofibers provide a nanoreactor for the formation of the Ni-VC single-atom alloy structure. VC is beneficial to the distribution orientation of Ni atoms, so that nickel is distributed on the surface of VC nanoparticles in an atomic state. This Ni-VC nanoalloy structure is conducive to optimizing the electronic structure of Ni atoms and improving the utilization efficiency of Ni atoms, effectively promoting its catalytic activity and selectivity in the electrocatalytic CO2 reduction reaction. In a wide voltage range (-0.78 to -1.18 V vs. RHE), the Faraday efficiency of its CO product can approach 100%.

Description

Technical Field

[0001] The present invention relates to a Ni-VC single-atom alloy electrocatalytic CO2 reduction material and a preparation method thereof, belonging to the technical field of composite material preparation. Background Art

[0002] Currently, in order to inhibit the deterioration of climate conditions, new technologies for reducing carbon dioxide emissions in the atmosphere are encouraged to limit / eliminate the negative impact of excessive carbon dioxide emissions on the global climate. Among the numerous ways to reduce the CO2 content, the CO2 electroreduction reaction (CO2RR) has received extensive attention and research due to its mild reaction conditions and high energy efficiency. Carbon monoxide (CO), as a CO2RR reduction product with high commercial value, is an important raw material for the production of hydrocarbon chemicals and is also the chemical closest to commercial application among numerous CO2RR products.

[0003] Nickel (Ni)-based catalysts have been widely used in the research of the reduction product CO due to their low preparation cost and rich reserves. Although the currently reported Ni-based catalysts all show certain catalytic activities, the utilization efficiency of their Ni active sites still needs to be improved urgently. At the same time, how to simply and efficiently optimize the electronic structure regulation of Ni active sites still needs to be further studied in depth. Therefore, exploring a simple and efficient method for preparing Ni-based CO2 reduction materials with excellent CO activity and selectivity has very important practical application significance. Summary of the Invention

[0004] Technical Problem:

[0005] The present invention provides a Ni-based catalyst for efficiently catalyzing the reduction of CO2 to CO, avoiding the problem of excessive competitive product H2 during the reaction process and improving the utilization rate of its active sites, and selecting a suitable method to optimize its catalytic performance.

[0006] Technical Solution:

[0007] To solve the above problems, the present invention provides a single-atom alloy (Ni-VC SAA) catalyst with Ni element atomically dispersed on VC (vanadium carbide) nanoparticles by using an electrospun nanofiber as a nano-reactor and utilizing the high-temperature thermal driving effect for use in an efficient electrocatalytic CO2 reduction material. The Ni element in the nanofiber is converted from nano-scale dispersion to atomic-scale dispersion on the surface of VC nanoparticles by using the simple and efficient high-temperature thermal driving effect, and a Ni-VC single-atom alloy electrocatalytic CO2 reduction material is prepared. This catalyst is cheap and easy to prepare, and for the obtained Ni-VC SAA electrocatalytic CO2 reduction material in a wide voltage test range (-0.78~-1.18V vs. RHE), the Faraday efficiency of its product CO can reach nearly 100%.

[0008] The first object of the present invention is to provide a method for preparing a Ni-VC SAA electrocatalytic CO2 reduction material, and the preparation method includes the following steps:

[0009] (1) Uniformly disperse nickel salt, vanadium salt and nanofiber precursor in an organic solvent to obtain an electrospinning solution; then use electrospinning to obtain a nanofiber membrane containing nickel salt and vanadium salt;

[0010] (2) Pre-oxidize the nanofiber membrane prepared in step (1), and then perform high-temperature carbonization treatment in an inert gas atmosphere to obtain a Ni-VC / CNFs electrocatalytic material.

[0011] In one embodiment of the present invention, the nanofiber precursor in step (1) is at least one of polyvinylpyrrolidone, polyvinyl alcohol, and polyacrylonitrile.

[0012] In one embodiment of the present invention, the nickel salt in step (1) is at least one of nickel chloride, nickel nitrate, nickel acetate, and nickel acetylacetonate.

[0013] In one embodiment of the present invention, the vanadium salt in step (1) is at least one of vanadium acetylacetonate, vanadium chloride, and vanadyl acetylacetonate.

[0014] In one embodiment of the present invention, the organic solvent in step (1) is at least one of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, ethanol, and water.

[0015] In one embodiment of the present invention, the molar ratio of nickel salt to vanadium salt in the electrospinning solution in step (1) is (0.5-3):1. Preferably 1:1.

[0016] In one embodiment of the present invention, the molar concentration of the metal salt in the electrospinning solution in step (1) is 20-50 mol%.

[0017] In one embodiment of the present invention, the mass concentration of the metal salt in the electrospinning solution in step (1) is 15-30%.

[0018] In one embodiment of the present invention, the conditions of electrospinning in step (1) are: the positive voltage of electrospinning is 10-25 kV, the distance between the receiver and the needle is 10-25 cm, and the solution flow rate is 0.10-0.25 mL / min.

[0019] In one embodiment of the present invention, in the pre-oxidation process of step (2), the heating rate is 2-30 °C / min, the constant temperature is 200-280 °C, and the constant temperature time is 0.5-3 h.

[0020] In one embodiment of the present invention, the conditions for the high-temperature carbonization treatment in step (2) are as follows: the heating rate is 2 - 30 °C / min, the constant temperature is 800 - 1200 °C, and the constant temperature time is 0.5 - 3 h.

[0021] In one embodiment of the present invention, the temperature of the high-temperature carbonization treatment is preferably 1100 °C.

[0022] In one embodiment of the present invention, the preparation method specifically includes the following steps:

[0023] (1) Nickel nitrate, vanadium acetylacetonate, and polyvinylpyrrolidone are added to N,N-dimethylformamide. After magnetic stirring evenly, the solution is electrospun using electrospinning technology to obtain a nanofiber membrane containing nickel salt and vanadium salt.

[0024] (2) The nanofiber membrane containing nickel salt and vanadium salt prepared in step (1) is heat-treated. In an air atmosphere, it is first heated to 200 - 280 °C at a heating rate of 2 - 30 °C / min, and then kept at a constant temperature for 0.5 - 3 h for pre-oxidation treatment; after the pre-oxidation ends, the gas atmosphere is changed to an inert gas, and the temperature is continuously raised to 800 - 1200 °C at a heating rate of 5 - 30 °C / min using a tube furnace and kept at a constant temperature for 0.5 - 3 h for high-temperature carbonization treatment; after the constant temperature ends, the tube furnace is naturally cooled to room temperature in an inert gas atmosphere, and the Ni-VC SAA electrocatalytic CO2 reduction material is obtained.

[0025] In one embodiment of the present invention, in step (2), the high-temperature carbonization treatment is to sandwich the nanofiber membrane between graphite sheets and place it in the middle position of the tube furnace for treatment.

[0026] The second object of the present invention is to provide a Ni-VC SAA electrocatalytic CO2 reduction material using the above method.

[0027] In one embodiment of the present invention, the nickel element exists in the form of single atoms in the electrocatalytic CO2 reduction material.

[0028] In one embodiment of the present invention, the vanadium element exists in the form of VC nanoparticles in the electrocatalytic CO2 reduction material.

[0029] The third object of the present invention is to apply the above electrocatalytic CO2 reduction material to the catalytic production of carbon monoxide products from CO2.

[0030] The fourth object of the present invention is to provide a method for electrocatalytic CO2 reduction to produce carbon monoxide products, and the method uses the above electrocatalytic CO2 reduction material as a catalyst.

[0031] In one embodiment of the present invention, within a relatively wide voltage test range (-0.78 to -1.18 V vs. RHE), the Faradaic efficiency of the product carbon monoxide of the electrocatalytic CO2 reduction material is nearly 100%.

[0032] Beneficial effects:

[0033] The present invention utilizes a thermal driving effect to atomically anchor nickel elements on the surface of vanadium carbide nanoparticles, simply and efficiently preparing a Ni-VC SAA electrocatalytic CO2 reduction material. This method is simple and reproducible.

[0034] The Ni-VC SAA electrocatalytic CO2 reduction material prepared by the present invention has very excellent catalytic performance due to its unique single-atom alloy structure. The Faradaic efficiency of its reduction product carbon monoxide is nearly 100%, and the product selectivity is very good. Description of the drawings

[0035] Figure 1 is the microscopic morphology diagram of the Ni-VC SAA electrocatalytic CO2 reduction material; among them, (a) is the transmission electron microscope image of the Ni-VC SAA electrocatalytic CO2 reduction material; (b) is the aberration-corrected electron microscope image and element distribution map of the Ni-VC SAA electrocatalytic CO2 reduction material.

[0036] Figure 2 is the X-ray diffraction pattern of the Ni-VC SAA electrocatalytic CO2 reduction material.

[0037] Figure 3 is the product Faradaic efficiency diagram of the Ni-VC SAA electrocatalytic CO2 reduction material.

[0038] Figure 4 is the product Faradaic efficiency diagram of the Ni-VC SAA-800 electrocatalytic CO2 reduction material.

[0039] Figure 5 is the product Faradaic efficiency diagram of the Ni1-VC2 SAA electrocatalytic CO2 reduction material.

[0040] Figure 6 is the product Faradaic efficiency diagram of the Ni SA electrocatalytic CO2 reduction material.

[0041] Figure 7 is the product Faradaic efficiency diagram of the VC electrocatalytic CO2 reduction material.

[0042] Figure 8 is the product Faradaic efficiency diagram of the Ni SA-VC electrocatalytic CO2 reduction material. Detailed implementation manners

[0043] To better understand the present invention, the content of the present invention will be further clarified below in conjunction with examples, but the content of the present invention is not limited to the examples listed below.

[0044] Example 1:

[0045] (1) Take 0.4 mmol of nickel chloride, 0.4 mmol of vanadyl acetylacetonate, and 4 g of polyvinylpyrrolidone and add them to 20 mL of N,N-dimethylformamide solution. Under room temperature conditions, stir magnetically for 12 h to obtain a homogeneous and transparent spinning solution. Then, use electrospinning technology to spin the solution. Set the positive voltage of the spinning electrode to 18 kV, the distance between the receiver and the spinning needle to 20 cm, and the solution flow rate to 0.2 mL / min to obtain a nanofiber membrane containing nickel salt and vanadium salt.

[0046] (2) Cut the above nanofiber membrane into a rectangle of 5 cm × 2 cm, and then sandwich it between graphite sheets and place it in the middle of a tube furnace. Under an air atmosphere, first heat it to 220 °C at a heating rate of 10 °C / min, and then keep it at a constant temperature for 1 h for pre-oxidation treatment; after the pre-oxidation is completed, change the gas atmosphere to an argon atmosphere with a flow rate set to 100 mL / min, and continue to use the tube furnace to heat it to 1100 °C at a heating rate of 10 °C / min and keep it at a constant temperature for 2 h for high-temperature heat-driven treatment; after the constant temperature is completed, naturally cool the tube furnace to room temperature under an inert gas atmosphere to obtain the Ni-VC SAA electrocatalytic CO2 reduction material.

[0047] Use transmission electron microscopy and aberration-corrected electron microscopy to study the microscopic morphology of the Ni-VC SAA catalyst. Figure 1 (a) is the transmission electron microscopy image of Ni-VC SAA. From Figure 1 (a), it can be observed that Ni-VC SAA nanocrystals are uniformly distributed on the surface of three-dimensional network-like carbon nanofibers. The diameter of the nanocrystals is about 10 - 20 nm, and the diameter of the carbon fibers is about 100 - 200 nm. Figure 1 (b) is the high-angle annular dark-field scanning transmission electron microscopy image and element distribution map of Ni-VC SAA. From Figure 1 (b), it can be observed that atomically dispersed Ni single atoms are anchored on the surface of VC nanocrystals. In addition, the element distribution map further shows the atomic-level distribution state of Ni.

[0048] Perform X-ray diffraction characterization on the prepared Ni-VC SAA electrocatalytic CO2 reduction material. Figure 2 is the X-ray diffraction pattern of Ni-VC SAA. From Figure 2It can be seen that the Ni-VC SAA only produces diffraction peaks at 37.8°, 43.6°, 63.2°, 75.6°, and 79.4°. The above diffraction peaks correspond to the fcc-phase VC nanocrystals. No relevant diffraction peaks of the Ni element were observed, indicating the atomic-level distribution of the Ni element.

[0049] The electrocatalytic carbon dioxide reduction performance test was analyzed using an electrochemical workstation at room temperature. The prepared Ni-VC / CNFs was cut into a regular square of 0.8×0.8 cm 2 and, due to its self-supporting property, it can be directly used as the working electrode. Using an H-type electrolytic cell, an Ag / AgCl electrode as the reference electrode, and a Pt wire as the counter electrode, the three form a standard three-electrode system. 0.1M KHCO3 was used as the electrolyte, and during the test, CO2 gas with a purity of 99.999% was continuously introduced, and the gas flow rate was set at 20 mL / min. Using an electrochemical workstation, the catalytic activity of the Ni-VC SAA electrocatalytic CO2 reduction material was tested.

[0050] Figure 3 It is the Faraday efficiency diagram of the products of the Ni-VC SAA electrocatalytic CO2 reduction material. The Faraday efficiency values of the products of the catalyst at different voltages were calculated through relevant formulas, as Figure 3 shown. In the voltage range (-0.78~-1.18V vs. RHE), the Faraday efficiency of the product carbon monoxide of the catalyst exceeded 98%. When the voltage was -0.98V, the Faraday efficiency of the product carbon monoxide reached the optimal value of 99.6%. Even when the voltage increased (≥-1.08V), the catalyst could still effectively inhibit the hydrogen evolution competing reaction, and the Faraday efficiency of the product carbon monoxide still exceeded 98%. Generally speaking, the catalyst showed very excellent carbon dioxide reduction activity and carbon monoxide selectivity.

[0051] Example 2:

[0052] Compared with Example 1, the high-temperature heat-driven temperature is different:

[0053] 0.4 mmol of nickel chloride, 0.4 mmol of vanadyl acetylacetonate, and 4 g of polyvinylpyrrolidone were added to 20 mL of N,N-dimethylformamide solution. At room temperature, a homogeneous and transparent spinning solution was prepared by magnetic stirring for 12 h, and then the solution was spun using electrospinning technology. The spinning positive electrode voltage was set at 18 kV, the distance between the receiver and the spinning needle was 20 cm, and the solution flow rate was 0.2 mL / min to obtain a nanofiber membrane containing nickel salt and vanadium salt.

[0054] The above nanofiber membrane was cut into a rectangle of 5 cm × 2 cm, and then clamped between graphite sheets and placed in the middle of a tubular furnace. Under an air atmosphere, it was first heated to 220 °C at a heating rate of 10 °C / min, and then held at a constant temperature for 1 h for pre-oxidation treatment; after the pre-oxidation was completed, the gas atmosphere was changed to an argon atmosphere with a flow rate set to 100 mL / min, and the tubular furnace was continued to be heated to 800 °C at a heating rate of 10 °C / min and held at a constant temperature for 2 h for high-temperature thermal driving treatment; after the constant temperature was completed, the tubular furnace was naturally cooled to room temperature under an inert gas atmosphere, and the Ni-VC SAA electrocatalytic CO2 reduction material was obtained.

[0055] Test the catalytic performance of the Ni-VC SAA electrocatalytic CO2 reduction material according to the method in Example 1.

[0056] Figure 4 It is the product Faraday efficiency diagram of the Ni-VC SAA electrocatalytic CO2 reduction material. The product Faraday efficiency values of the catalyst at different voltages were calculated through relevant formulas, as Figure 4 shown. In the voltage range (-0.78~-1.18 V vs. RHE), the product carbon monoxide Faraday efficiency of the catalyst is 52.6~76.8%, and when the voltage is -0.98 V, the Faraday efficiency of the product carbon monoxide reaches the optimal value of 76.8%. As the voltage increases (-1.18 V), the catalyst cannot efficiently inhibit the hydrogen evolution competitive reaction, and the product carbon monoxide Faraday efficiency is 52.6%.

[0057] Similarly, referring to Example 1, only the high-temperature thermal driving temperature was changed and replaced with 900, 1000, 1200, and 1500 °C respectively. The catalytic performances of the corresponding prepared electrocatalytic materials are shown in Table 1.

[0058] Table 1

[0059]

[0060]

[0061] Example 3:

[0062] Compared with Example 1, the amount of metal salt used is different:

[0063] Take 0.2 mmol of nickel chloride, 0.4 mmol of vanadium acetylacetonate, and 4 g of polyvinylpyrrolidone and add them to 20 mL of N,N-dimethylformamide solution. At room temperature, a homogeneous and transparent spinning solution was prepared by magnetic stirring for 12 h, and then the solution was spun by electrospinning technology. The spinning positive electrode voltage was set to 18 kV, the distance between the receiver and the spinning needle was 20 cm, and the solution flow rate was 0.2 mL / min to obtain a nanofiber membrane containing nickel salt and vanadium salt.

[0064] The above nanofiber membrane was cut into a rectangle of 5 cm × 2 cm, and then clamped between graphite sheets and placed in the middle of a tube furnace. Under an air atmosphere, it was first heated to 220 °C at a heating rate of 10 °C / min, and then kept at a constant temperature for 1 h for pre-oxidation treatment; after the pre-oxidation was completed, the gas atmosphere was changed to an argon atmosphere with a flow rate set at 100 mL / min, and the tube furnace was continued to be heated to 1100 °C at a heating rate of 10 °C / min and kept at a constant temperature for 2 h for high-temperature heat-driven treatment; after the constant temperature was completed, the tube furnace was naturally cooled to room temperature under an inert gas atmosphere, and the Ni-VC SAA electrocatalytic CO2 reduction material was thus prepared.

[0065] The catalytic performance of the Ni-VC SAA electrocatalytic CO2 reduction material was tested according to the method in Example 1.

[0066] Figure 5 It is the product Faraday efficiency diagram of the Ni-VC SAA electrocatalytic CO2 reduction material. The product Faraday efficiency values of the catalyst at different voltages were calculated through relevant formulas, as Figure 5 shown. In the voltage range (-0.78~-1.18 V vs. RHE), the Faraday efficiency of the product carbon monoxide of the catalyst was only 68.2~86.4%, and when the voltage was -0.98 V, the Faraday efficiency of the product carbon monoxide reached the optimal value of 86.4%. When the voltage decreased (-0.78 V), the catalyst could not effectively inhibit the hydrogen evolution competitive reaction, the Faraday efficiency of the product carbon monoxide was only 68.2%, and the Faraday efficiency of the competitive product hydrogen reached 31.8%.

[0067] Similarly, referring to Example 1, only the amount of metal salt was changed, and they were respectively replaced with 0.1, 0.8, and 1.2 mmol of nickel chloride, and the catalytic performances of the prepared electrocatalytic materials are shown in Table 2.

[0068] Table 2

[0069] Usage amount of nickel chloride (mmol) Ni:V molar ratio Faraday efficiency (-0.78~-1.18V) 0.2 (Example 3) 0.5:1 68.2～86.4％ 0.4 (Example 1) 1:1 98.2～99.6％ 0.8 2:1 40.4～48.4％ 1.2 3:1 32.8～40.5％

[0070] Comparative Example 1:

[0071] 0.4 mmol of nickel chloride and 4 g of polyvinylpyrrolidone were added to 20 mL of N,N-dimethylformamide solution, and under room temperature conditions, a homogeneous and transparent spinning solution was prepared by magnetic stirring for 12 h. Then, electrospinning technology was used to spin the solution, with the spinning positive electrode voltage set at 18 kV, the distance between the receiver and the spinning needle head at 20 cm, and the solution flow rate at 0.2 mL / min, to obtain a nanofiber membrane containing nickel salt.

[0072] The above-mentioned nanofiber membrane was cut into a rectangle of 5 cm×2 cm, and then sandwiched between graphite sheets and placed in the middle of a tube furnace. Under an air atmosphere, it was first heated to 220 °C at a heating rate of 10 °C / min, and then kept at a constant temperature for 1 h for pre-oxidation treatment; after the pre-oxidation was completed, the gas atmosphere was changed to an argon atmosphere with a flow rate set at 100 mL / min, and the tube furnace was continued to be heated to 1100 °C at a heating rate of 10 °C / min and kept at a constant temperature for 2 h for high-temperature heat-driven treatment; after the constant temperature was completed, the tube furnace was naturally cooled to room temperature under an inert gas atmosphere to obtain a Ni nanoparticle catalyst; and then pickling was carried out with nitric acid with a concentration of 30%, thus obtaining a Ni SA electrocatalytic CO2 reduction material.

[0073] The catalytic performance of the Ni-VC SAA electrocatalytic CO2 reduction material was tested according to the method in Example 1.

[0074] Figure 6 It is a Faraday efficiency diagram of the products of the Ni SA electrocatalytic CO2 reduction material. The Faraday efficiency values of the products of the catalyst at different voltages were calculated through relevant formulas, as Figure 6 shown. In the voltage range (-0.78~-1.18 V vs. RHE), the Faraday efficiency of the product carbon monoxide of the catalyst was only 40.4~51.2%, and the Faraday efficiency of the competing product hydrogen was relatively high, indicating that the activity and carbon monoxide selectivity of the Ni SA electrocatalytic CO2 reduction material were poor.

[0075] Similarly, referring to Example 1, the vanadium salt was omitted, and the dosage of nickel chloride was adjusted to 0.8 mmol, and the others remained unchanged to obtain the corresponding catalytic material. The results of its catalytic performance were as follows: in the voltage range (-0.78~-1.18 V vs. RHE), the Faraday efficiency of the product carbon monoxide of the catalyst was 59.4~68.6%.

[0076] Comparative Example 2:

[0077] 0.4 mmol of vanadyl acetylacetonate and 4 g of polyvinylpyrrolidone were added to 20 mL of N,N-dimethylformamide solution, and under room temperature conditions, a homogeneous and transparent spinning solution was prepared by magnetic stirring for 12 h, and then the solution was spun by electrospinning technology. The spinning positive electrode voltage was set at 18 kV, the distance between the receiver and the spinning needle was 20 cm, and the solution flow rate was 0.2 mL / min to obtain a nanofiber membrane containing nickel salt and vanadium salt.

[0078] The above nanofiber membrane was cut into a rectangle of 5 cm × 2 cm, and then clamped between graphite sheets and placed in the middle of a tubular furnace. Under an air atmosphere, it was first heated to 220 °C at a heating rate of 10 °C / min, and then kept at a constant temperature for 1 h for pre-oxidation treatment; after the pre-oxidation was completed, the gas atmosphere was changed to an argon atmosphere with a flow rate set at 100 mL / min, and the tubular furnace was continued to be heated to 1100 °C at a heating rate of 10 °C / min and kept at a constant temperature for 2 h for high-temperature heat-driven treatment; after the constant temperature was completed, the tubular furnace was naturally cooled to room temperature under an inert gas atmosphere, and the VC electrocatalytic CO2 reduction material was obtained.

[0079] The catalytic performance of the Ni-VC SAA electrocatalytic CO2 reduction material was tested according to the method in Example 1.

[0080] Figure 7 It is the product Faraday efficiency diagram of the VC electrocatalytic CO2 reduction material. The product Faraday efficiency values of the catalyst at different voltages were calculated through relevant formulas, as Figure 7 shown. In the voltage range (-0.78~-1.18 V vs. RHE), the Faraday efficiency of the product carbon monoxide of the catalyst was only 5.6~9.4%, and the catalyst could not effectively inhibit the hydrogen evolution competitive reaction, and the Faraday efficiency of the competitive product hydrogen exceeded 90%. Generally speaking, the catalyst showed poor carbon dioxide reduction activity and carbon monoxide selectivity.

[0081] Similarly, referring to Example 1, the nickel salt was omitted, and the dosage of vanadyl acetylacetonate was adjusted to 0.8 mmol, and the others remained unchanged to obtain the corresponding catalytic material. The results of its catalytic performance were: in the voltage range (-0.78~-1.18 V vs. RHE), the Faraday efficiency of the product carbon monoxide of the catalyst was 8.2~10.6%.

[0082] Comparative Example 3:

[0083] Weighed 1.5 mg of Ni SA prepared in Comparative Example 1 and 1.5 mg of the VC catalyst prepared in Comparative Example 2 with a balance, ground and mixed them evenly with a grinder, and then dispersed them in 2 mL of ethanol. Subsequently, 100 μL of Nafion117 solution was added to the above solution and sonicated for 30 min. After the solution was evenly dispersed, the above solution was evenly sprayed on the carbon paper (2×2 cm 2 ) by a spray gun, and it was placed under an infrared lamp for solvent evaporation to obtain the Ni SA-VC working electrode.

[0084] The catalytic performance of the Ni-VC SAA electrocatalytic CO2 reduction material was tested according to the method in Example 1.

[0085] Figure 8It is the Faraday efficiency diagram of the products of the Ni SA-VC electrocatalytic CO2 reduction material. The Faraday efficiency values of the products of the catalyst at different voltages are calculated through relevant formulas, as Figure 8 shown. In the voltage range (-0.78~-1.18V vs. RHE), the Faraday efficiency of the product carbon monoxide of the catalyst is only 16.6~26.4%, and the catalyst cannot effectively inhibit the hydrogen evolution competitive reaction, and the Faraday efficiency of the competitive product hydrogen exceeds 70%. Generally speaking, the catalyst exhibits poorer CO2 reduction activity and CO selectivity than Example 1.

Claims

1. A method for preparing Ni-VC SAA electrocatalytic CO2 reduction material, characterized in that, The preparation method comprises the following steps: (1) Uniformly disperse nickel salt, vanadium salt and nanofiber precursor in an organic solvent to obtain an electrospinning solution; subsequently, prepare a nanofiber membrane containing nickel salt and vanadium salt by electrospinning; the molar ratio of nickel salt to vanadium salt in the electrospinning solution is 1:1; (2) Perform pre-oxidation treatment on the nanofiber membrane prepared in step (1), and then perform high-temperature carbonization treatment in an inert gas atmosphere to obtain a Ni-VC / CNFs electrocatalytic material; the conditions for the high-temperature carbonization treatment are: the heating rate is 2-30 °C / min, the constant temperature is 1100 °C, and the constant temperature time is 0.5-3 h.

2. The method according to claim 1, characterized in that, The molar concentration of the metal salt in the electrospinning solution described in step (1) is 20-50 mol%.

3. The method according to claim 1, wherein The nanofiber precursor described in step (1) is at least one of polyvinylpyrrolidone, polyvinyl alcohol, and polyacrylonitrile.

4. The method according to claim 1, wherein The conditions for the electrospinning described in step (1) are: the positive voltage for electrospinning is 10-25 kV, the distance between the receiver and the needle is 10-25 cm, and the solution flow rate is 0.10-0.25 mL / min.

5. The method according to claim 1, characterized in that In the pre-oxidation process described in step (2), the heating rate is 2-30 °C / min, the constant temperature is 200-280 °C, and the constant temperature time is 0.5-3 h.

6. A Ni-VC SAA electrocatalytic CO2 reduction material prepared by the method according to any one of claims 1-5.

7. Use of the Ni-VC SAA electrocatalytic CO2 reduction material according to claim 6 in the catalytic production of carbon monoxide products from CO2.

8. A method for electrocatalytic reduction of CO2 to produce carbon monoxide products, characterized in that, The method uses the above electrocatalytic CO2 reduction material as a catalyst.

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