An electrocatalyst for vanadium oxide-modified bismuth-tin alloy, its preparation method and application

Abstract

This invention provides an electrocatalyst for vanadium oxide-modified bismuth-tin alloy, its preparation method, and its application. The electrocatalyst is BiSn(VO₂)₂. x The material exhibits a two-dimensional nanosheet morphology, wherein the BiSn is an alloy, and VO x BiSn(VO) is modified on the surface of BiSn nanosheets in a cluster form, and BiSn(VO) x The lattice spacing corresponds to the (012) plane of Bi. This invention directly prepares BiSn(VO) with high selectivity and high activity via a one-step electrodeposition method. x The electrocatalyst, through vanadium oxide modification and tin alloying, significantly enhances the electrocatalytic activity of bismuth-based materials. Within a wide potential window, the electrocatalyst achieves a formate faradaic efficiency exceeding 90% and exhibits good stability in cycling tests. Furthermore, this electrocatalyst demonstrates excellent performance in rechargeable Zn-CO2 battery systems and co-electrolysis systems.

Description

Technical Field

[0001] This invention relates to the fields of nanomaterials and electrocatalysis, specifically to an electrocatalyst for vanadium oxide-modified bismuth-tin alloy, its preparation method, and its application. Background Technology

[0002] With the rapid development of technology, the consumption of fossil fuels has increased dramatically, leading to a rise in atmospheric carbon dioxide concentration. Electrochemical carbon dioxide reduction (CO2RR) converts carbon dioxide into value-added chemicals or fuels, representing a promising strategy to mitigate the excessive burning of fossil fuels and the greenhouse effect. In aqueous solution, the electrochemical reduction of carbon dioxide can yield various products. Formate, as a low-toxicity and energy-intensive electrochemical carbon dioxide reduction product, has broad application prospects in energy and industrial fields. However, the electrochemical reduction of carbon dioxide to formate faces bottlenecks such as low selectivity and limited production efficiency, and also involves competing reactions with hydrogen evolution. Therefore, developing highly efficient catalysts with high activity, high selectivity, and long-term stability is crucial for the large-scale practical application of formate. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] To address the shortcomings of existing technologies, this invention provides an electrocatalyst for vanadium oxide-modified bismuth-tin alloys, its preparation method, and its application. By modifying the surface of bismuth-tin alloy nanosheets with abundant active sites with vanadium oxide clusters, a highly active electrocatalyst is constructed to solve the problems mentioned in the background art.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] According to a first aspect of the present invention, an electrocatalyst for vanadium oxide-modified bismuth-tin alloy is provided, wherein the electrocatalyst is BiSn(VO₂O₃)₂O₃. x The material exhibits a two-dimensional nanosheet morphology, wherein the BiSn is an alloy, and VO x BiSn(VO) is modified on the surface of BiSn nanosheets in a cluster form, and BiSn(VO) x The lattice spacing corresponds to the (012) plane of Bi.

[0008] Preferably, the electrocatalyst has a nanosheet structure with a size of 200–500 nm.

[0009] According to a second aspect of the present invention, a method for preparing an electrocatalyst of vanadium oxide modified bismuth-tin alloy is provided, comprising the following steps:

[0010] (1) Dissolve bismuth nitrate, tin chloride and ammonium metavanadate in hydrochloric acid solution and stir until homogeneous to obtain electrolyte;

[0011] (2) Using the electrolyte from step (1), a three-electrode electrolytic cell is constructed. Carbon cloth is used as the working electrode, saturated Ag / AgCl electrode is used as the reference electrode, and platinum sheet is used as the counter electrode. A constant current density is applied to perform electrochemical deposition to obtain an electrocatalyst.

[0012] (3) The electrocatalyst is washed alternately with water and ethanol and dried under vacuum to obtain the vanadium oxide modified bismuth tin electrocatalyst.

[0013] Preferably, in step (1), the molar ratio of tin chloride, bismuth nitrate and ammonium metavanadate is 1:11-12:3-6;

[0014] The concentration of the hydrochloric acid solution is 0.1–1 M, and the amount of hydrochloric acid solution added is 50 mL.

[0015] More preferably, the molar ratio of tin chloride, bismuth nitrate and ammonium metavanadate is 1:11:4;

[0016] The concentration of the hydrochloric acid solution is 0.5M.

[0017] Preferably, in step (2), during the electrochemical deposition process, the constant current density is -5 to -50 mA / cm². 2 The electrochemical deposition time is 200–600 s.

[0018] More preferably, in step (2), during the electrochemical deposition process, the constant current density is -25 mA / cm². 2 The electrochemical deposition time was 400 s.

[0019] Preferably, in step (3), the electrocatalyst is washed with water and ethanol alternately 3 to 5 times;

[0020] The vacuum drying temperature is 60–80°C, and the vacuum drying time is 6–8 hours.

[0021] According to a third aspect of the present invention, an electrocatalyst of vanadium oxide modified bismuth-tin alloy or an electrocatalyst of vanadium oxide modified bismuth-tin alloy obtained according to the above preparation method is provided for use in a carbon dioxide electroreduction reaction.

[0022] Preferably, in a flow electrolytic cell, the vanadium oxide-modified bismuth-tin alloy electrocatalyst maintains a formate efficiency (FE) of over 90% in a potential range of -0.5 to -1.3 V (vs. RHE).

[0023] According to a fourth aspect of the present invention, an electrocatalyst of vanadium oxide modified bismuth-tin alloy or an electrocatalyst of vanadium oxide modified bismuth-tin alloy obtained according to the above preparation method is provided for use in a reversible zinc-carbon dioxide battery.

[0024] Preferably, using the vanadium oxide-modified bismuth-tin alloy electrocatalyst as the cathode and zinc foil as the anode, and testing under specific electrolyte conditions, specifically, the cathode electrolyte is 0.5M potassium bicarbonate, and the anode electrolyte is a mixture of 6M potassium hydroxide and 0.2M zinc acetate. The maximum power density of the battery can reach 3.8 mW / cm³. 2 .

[0025] According to a fifth aspect of the present invention, an electrocatalyst of vanadium oxide modified bismuth-tin alloy or an electrocatalyst of vanadium oxide modified bismuth-tin alloy obtained according to the above preparation method is provided for use in a carbon dioxide reduction reaction system assisted by ethylene glycol oxidation.

[0026] Preferably, BiSn(VO) is used. x The NiCoLDH electrode combination achieves a Faraday efficiency of 182% formate at 0.6V.

[0027] (III) Beneficial Effects

[0028] This invention provides an electrocatalyst for vanadium oxide-modified bismuth-tin alloy, its preparation method, and its application. It offers the following advantages:

[0029] (1) This solution provides an electrocatalyst for vanadium oxide-modified bismuth-tin alloy. The introduction of tin alloying can promote the adsorption and activation of carbon dioxide molecules, while the surface-modified vanadium oxide (VOC) x This can accelerate water dissociation, thereby providing an ample supply of hydrogen protons (H*), which in turn improves the formation of subsequent *OCHO species. Based on this, the catalyst exhibits high selectivity, high activity, and good stability in the electrocatalytic carbon dioxide reduction reaction.

[0030] (2) The method provided in this scheme for preparing an electrocatalyst of vanadium oxide modified bismuth-tin alloy can be synthesized by a one-step deposition method, which is easy to produce on a large scale, improves production efficiency, and is environmentally friendly.

[0031] (3) The vanadium oxide modified bismuth-tin alloy electrocatalyst provided in this scheme exhibits excellent performance in the process of carbon dioxide electroreduction to formate, and has important application value in energy storage and carbon dioxide resource utilization. Attached Figure Description

[0032] Figure 1 This is a schematic diagram illustrating the synthesis of an electrocatalyst for vanadium oxide-modified bismuth-tin alloy according to the present invention.

[0033] Figure 2 The electrocatalyst BiSn(VO2) prepared in Example 1 of this invention x X-ray diffraction pattern of )

[0034] Figure 3 The electrocatalyst BiSn(VO2) prepared in Example 1 of this invention x Transmission electron micrographs of (a) and (b) are shown in the following figures: (a) is a TEM image and (b) is a HRTEM image.

[0035] Figure 4 The electrocatalyst BiSn(VO2) prepared in Example 1 of this invention x XPS spectra before and after argon ion etching, where (a) is the Bi 4f XPS spectrum, (b) is the Sn 3d XPS spectrum, and (c) is the V2p XPS spectrum.

[0036] Figure 5 The electrocatalyst BiSn(VO2) prepared in Example 1 of this invention x LSV curves obtained by flow cell testing in an electrolyte saturated with CO2 and Ar;

[0037] Figure 6 The electrocatalyst BiSn(VO2) prepared in Example 1 of this invention x Faraday efficiency plots of H2, CO, and formate products in a flow cell;

[0038] Figure 7 The electrocatalyst BiSn(VO2) prepared in Example 1 of this invention x Stability test diagram in flow cell;

[0039] Figure 8 The electrocatalyst BiSn(VO2) prepared in Example 1 of this invention x Discharge polarization curves and power density curves in Zn-CO2 batteries;

[0040] Figure 9 The electrocatalyst BiSn(VO2) prepared in Example 1 of this invention x LSV curve in a carbon dioxide reduction reaction system assisted by ethylene glycol oxidation;

[0041] Figure 10 The electrocatalyst BiSn(VO2) prepared in Example 1 of this invention x The formate Faraday efficiency at different voltages in a carbon dioxide reduction reaction system assisted by ethylene glycol oxidation.

[0042] Figure 11 This is a comparison chart of the LSV curves of the electrocatalysts prepared in Comparative Example 1, Comparative Example 2 and Example 1 of the present invention. Detailed Implementation

[0043] To better illustrate the content of this invention, the following description is provided in conjunction with specific embodiments.

[0044] Example 1

[0045] A method for preparing an electrocatalyst of vanadium oxide modified bismuth-tin alloy, such as... Figure 1 As shown, it includes the following steps:

[0046] Step 1: Accurately weigh 55 mmol of Bi(NO3)3·5H2O, 5 mmol of SnCl4·5H2O and 20 mmol of NH4VO3, dissolve them in 50 ml of 0.5 M HCl solution, stir for 20 minutes until the solution is homogeneous, and obtain the electrolyte.

[0047] Step two: Use a 1cm × 2cm carbon cloth as the working electrode, a saturated Ag / AgCl electrode as the reference electrode, and a platinum sheet as the counter electrode. Apply a constant current density of -25mA / cm². 2 The electrodeposition method was used to deposit BiSn(VO) in the above electrolyte for 400 s to obtain BiSn(VO) x Electrocatalyst;

[0048] Step 3: Wash the prepared electrocatalyst three times alternately with water and ethanol, and then dry it in a vacuum oven at 60°C for 6 hours to obtain the vanadium oxide modified bismuth-tin alloy electrocatalyst.

[0049] Example 2

[0050] Step 1: Accurately weigh 55 mmol of Bi(NO3)3·5H2O, 4 mmol of SnCl4·5H2O and 20 mmol of NH4VO3, dissolve them in 50 ml of 0.5 M HCl solution, stir for 20 minutes until the solution is homogeneous, and obtain the electrolyte.

[0051] Step two: Use a 1cm × 2cm carbon cloth as the working electrode, a saturated Ag / AgCl electrode as the reference electrode, and a platinum sheet as the counter electrode. Apply a constant current density of -25mA / cm². 2 The electrodeposition method was used to deposit BiSn(VO) in the above electrolyte for 400 s to obtain BiSn(VO) x Electrocatalyst;

[0052] Step 3: Wash the prepared electrocatalyst three times alternately with water and ethanol, and then dry it in a vacuum oven at 60°C for 6 hours to obtain the vanadium oxide modified bismuth-tin alloy electrocatalyst.

[0053] Example 3

[0054] Step 1: Accurately weigh 55 mmol of Bi(NO3)3·5H2O, 6 mmol of SnCl4·5H2O and 20 mmol of NH4VO3, dissolve them in 50 ml of 0.5 M HCl solution, stir for 20 minutes until the solution is homogeneous, and obtain the electrolyte.

[0055] Step two: Use a 1cm × 2cm carbon cloth as the working electrode, a saturated Ag / AgCl electrode as the reference electrode, and a platinum sheet as the counter electrode. Apply a constant current density of -25mA / cm². 2 The electrodeposition method was used to deposit BiSn(VO) in the above electrolyte for 400 s to obtain BiSn(VO) x Electrocatalyst;

[0056] Step 3: Wash the prepared electrocatalyst three times alternately with water and ethanol, and then dry it in a vacuum oven at 60°C for 6 hours to obtain the vanadium oxide modified bismuth-tin alloy electrocatalyst.

[0057] Example 4

[0058] Step 1: Accurately weigh 55 mmol of Bi(NO3)3·5H2O, 5 mmol of SnCl4·5H2O and 15 mmol of NH4VO3, dissolve them in 50 ml of 0.5 M HCl solution, stir for 20 minutes until the solution is homogeneous, and obtain the electrolyte.

[0059] Step two: Use a 1cm × 2cm carbon cloth as the working electrode, a saturated Ag / AgCl electrode as the reference electrode, and a platinum sheet as the counter electrode. Apply a constant current density of -25mA / cm². 2 The electrodeposition method was used to deposit BiSn(VO) in the above electrolyte for 400 s to obtain BiSn(VO) x Electrocatalyst;

[0060] Step 3: Wash the prepared electrocatalyst three times alternately with water and ethanol, and then dry it in a vacuum oven at 60°C for 6 hours to obtain the vanadium oxide modified bismuth-tin alloy electrocatalyst.

[0061] Example 5

[0062] Step 1: Accurately weigh 55 mmol of Bi(NO3)3·5H2O, 5 mmol of SnCl4·5H2O and 30 mmol of NH4VO3, dissolve them in 50 ml of 0.5 M HCl solution, stir for 20 minutes until the solution is homogeneous, and obtain the electrolyte.

[0063] Step two: Use a 1cm × 2cm carbon cloth as the working electrode, a saturated Ag / AgCl electrode as the reference electrode, and a platinum sheet as the counter electrode. Apply a constant current density of -25mA / cm².2 The electrodeposition method was used to deposit BiSn(VO) in the above electrolyte for 400 s to obtain BiSn(VO) x Electrocatalyst;

[0064] Step 3: Wash the prepared electrocatalyst three times alternately with water and ethanol, and then dry it in a vacuum oven at 60°C for 6 hours to obtain the vanadium oxide modified bismuth-tin alloy electrocatalyst.

[0065] Example 6

[0066] Step 1: Accurately weigh 55 mmol of Bi(NO3)3·5H2O, 5 mmol of SnCl4·5H2O and 20 mmol of NH4VO3, dissolve them in 50 ml of 0.1 M HCl solution, stir for 20 minutes until the solution is homogeneous, and obtain the electrolyte.

[0067] Step two: Use a 1cm × 2cm carbon cloth as the working electrode, a saturated Ag / AgCl electrode as the reference electrode, and a platinum sheet as the counter electrode. Apply a constant current density of -25mA / cm². 2 The electrodeposition method was used to deposit BiSn(VO) in the above electrolyte for 400 s to obtain BiSn(VO) x Electrocatalyst;

[0068] Step 3: Wash the prepared electrocatalyst three times alternately with water and ethanol, and then dry it in a vacuum oven at 60°C for 6 hours to obtain the vanadium oxide modified bismuth-tin alloy electrocatalyst.

[0069] Example 7

[0070] Step 1: Accurately weigh 55 mmol of Bi(NO3)3·5H2O, 5 mmol of SnCl4·5H2O and 20 mmol of NH4VO3, dissolve them in 50 ml of 1.0 M HCl solution, stir for 20 minutes until the solution is homogeneous, and obtain the electrolyte.

[0071] Step two: Use a 1cm × 2cm carbon cloth as the working electrode, a saturated Ag / AgCl electrode as the reference electrode, and a platinum sheet as the counter electrode. Apply a constant current density of -25mA / cm². 2 The electrodeposition method was used to deposit BiSn(VO) in the above electrolyte for 400 s to obtain BiSn(VO) x Electrocatalyst;

[0072] Step 3: Wash the prepared electrocatalyst three times alternately with water and ethanol, and then dry it in a vacuum oven at 60°C for 6 hours to obtain the vanadium oxide modified bismuth-tin alloy electrocatalyst.

[0073] Example 8

[0074] Step 1: Accurately weigh 55 mmol of Bi(NO3)3·5H2O, 5 mmol of SnCl4·5H2O and 20 mmol of NH4VO3, dissolve them in 50 ml of 0.5 M HCl solution, stir for 20 minutes until the solution is homogeneous, and obtain the electrolyte.

[0075] Step two: Use a carbon cloth with an area of ​​1cm × 2cm as the working electrode, a saturated Ag / AgCl electrode as the reference electrode, and a platinum sheet as the counter electrode. Use a constant current density of -50mA / cm². 2 The electrodeposition method was used to deposit BiSn(VO) in the above electrolyte for 400 s to obtain BiSn(VO) x Electrocatalyst;

[0076] Step 3: Wash the prepared electrocatalyst three times alternately with water and ethanol, and then dry it in a vacuum oven at 60°C for 6 hours to obtain the vanadium oxide modified bismuth-tin alloy electrocatalyst.

[0077] Example 9

[0078] Step 1: Accurately weigh 55 mmol of Bi(NO3)3·5H2O, 5 mmol of SnCl4·5H2O and 20 mmol of NH4VO3, dissolve them in 50 ml of 0.5 M HCl solution, stir for 20 minutes until the solution is homogeneous, and obtain the electrolyte.

[0079] Step two: Use a carbon cloth with an area of ​​1cm × 2cm as the working electrode, a saturated Ag / AgCl electrode as the reference electrode, and a platinum sheet as the counter electrode. Use a constant current density of -5mA / cm². 2 The electrodeposition method was used to deposit BiSn(VO) in the above electrolyte for 400 s to obtain BiSn(VO) x Electrocatalyst;

[0080] Step 3: Wash the prepared electrocatalyst three times alternately with water and ethanol, and then dry it in a vacuum oven at 60°C for 6 hours to obtain the vanadium oxide modified bismuth-tin alloy electrocatalyst.

[0081] Example 10

[0082] Step 1: Accurately weigh 55 mmol of Bi(NO3)3·5H2O, 5 mmol of SnCl4·5H2O and 20 mmol of NH4VO3, dissolve them in 50 ml of 0.5 M HCl solution, stir for 20 minutes until the solution is homogeneous, and obtain the electrolyte.

[0083] Step two: Use a 1cm × 2cm carbon cloth as the working electrode, a saturated Ag / AgCl electrode as the reference electrode, and a platinum sheet as the counter electrode. Apply a constant current density of -25mA / cm².2 The electrodeposition method was used to deposit BiSn(VO) in the above electrolyte for 200 s to obtain BiSn(VO) x Electrocatalyst;

[0084] Step 3: Wash the prepared electrocatalyst three times alternately with water and ethanol, and then dry it in a vacuum oven at 60°C for 6 hours to obtain the vanadium oxide modified bismuth-tin alloy electrocatalyst.

[0085] Example 11

[0086] Step 1: Accurately weigh 55 mmol of Bi(NO3)3·5H2O, 5 mmol of SnCl4·5H2O and 20 mmol of NH4VO3, dissolve them in 50 ml of 0.5 M HCl solution, stir for 20 minutes until the solution is homogeneous, and obtain the electrolyte.

[0087] Step two: Use a 1cm × 2cm carbon cloth as the working electrode, a saturated Ag / AgCl electrode as the reference electrode, and a platinum sheet as the counter electrode. Apply a constant current density of -25mA / cm². 2 The electrodeposition method was used to deposit BiSn(VO) in the above electrolyte for 600 s to obtain BiSn(VO) x Electrocatalyst;

[0088] Step 3: Wash the prepared electrocatalyst three times alternately with water and ethanol, and then dry it in a vacuum oven at 60°C for 6 hours to obtain the vanadium oxide modified bismuth-tin alloy electrocatalyst.

[0089] Comparative Example 1

[0090] A method for preparing a bismuth metal catalyst (Bi) includes the following steps:

[0091] Step 1: Accurately weigh 55 mmol of Bi(NO3)3·5H2O and dissolve it in 50 ml of 0.5 M HCl solution. Stir for 20 minutes until the solution is homogeneous to obtain the electrolyte.

[0092] Step two: Use a 1cm × 2cm carbon cloth as the working electrode, a saturated Ag / AgCl electrode as the reference electrode, and a platinum sheet as the counter electrode. Apply a constant current density of -25mA / cm². 2 The electrodeposition method was used to deposit metallic Bi in the above electrolyte for 400 s;

[0093] Step 3: Wash the prepared metallic Bi with water and ethanol three times alternately, and then dry it in a vacuum oven at 60°C for 6 hours to obtain the metallic Bi electrocatalyst.

[0094] Comparative Example 2

[0095] A method for preparing a bismuth-tin alloy catalyst (BiSn) includes the following steps:

[0096] Step 1: Accurately weigh 55 mmol of Bi(NO3)3·5H2O and 5 mmol of SnCl4·5H2O, dissolve them in 50 ml of 0.5 M HCl solution, stir for 20 minutes until the solution is homogeneous, and obtain the electrolyte.

[0097] Step two: Use a 1cm × 2cm carbon cloth as the working electrode, a saturated Ag / AgCl electrode as the reference electrode, and a platinum sheet as the counter electrode. Apply a constant current density of -25mA / cm². 2 The BiSn alloy was obtained by electrodeposition in the above electrolyte for 400 s.

[0098] Step 3: Wash the prepared BiSn alloy three times alternately with water and ethanol, and then dry it in a vacuum oven at 60°C for 6 hours to obtain the BiSn alloy catalytic electrode.

[0099] Performance testing

[0100] BiSn(VO) prepared in Example 1 x XRD analysis of electrocatalysts, such as Figure 2 As shown, the X-ray diffraction pattern indicates that the synthesized BiSn(VO) x The electrocatalyst phase is still elemental Bi, corresponding to the standard spectrum of Bi JCPDS#85-1329.

[0101] BiSn(VO) prepared in Example 1 x Electrocatalysts were analyzed by TEM, such as Figure 3 As shown, according to Figure 3 From figures a and b, we can see that BiSn(VO x The material exhibits a nanosheet morphology, BiSn(VO) x The lattice spacing of ) corresponds to the (012) plane of Bi.

[0102] BiSn(VO) prepared in Example 1 x X-ray photoelectron spectroscopy analysis of electrocatalysts, such as... Figure 4 As shown, the changes before and after argon ion etching confirm that BiSn(VO) x The electrocatalyst contains bismuth and tin in alloy form, while vanadium exists in the form of vanadium oxide, forming a bismuth-tin alloy material modified with vanadium oxide.

[0103] BiSn(VO) prepared in Example 1 x The performance of the electrocatalyst was tested in a flow electrolyzer, such as... Figure 5As shown, the electrolytes are 1M potassium hydroxide solutions saturated with CO2 and Ar, respectively. The BiSn(VO2)2 solution... x The catalyst exhibits a higher current density in a CO2-saturated electrolyte, demonstrating the material's intrinsically high CO2 reduction performance.

[0104] BiSn(VO) prepared in Example 1 x The performance of the electrocatalyst was tested in a flow electrolyzer, such as... Figure 6 As shown, within the potential range of -0.5V to -1.3V (vs. RHE), the formate Faradaic efficiency exhibits a trend of first increasing and then decreasing. At a potential of -0.6V vs. RHE, the highest formate Faradaic efficiency can reach 98%, and the formate Faradaic efficiency consistently remains above 90%, demonstrating that the prepared BiSn(VO x The electrocatalyst exhibits high selectivity for formate.

[0105] In order to evaluate the BiSn(VO x The stability of the electrocatalyst during long-term cycling tests and its ability to continuously produce formate were evaluated. Figure 7 BiSn(VO) prepared in Example 1 x The electrocatalyst was electrolyzed in 1M potassium hydroxide electrolyte using a flow cell at a constant potential of -0.6V vs. RHE for 100h. The chronoamperometry curves and the Faradaic efficiency of the formate electrolysis product were obtained. The test results show that the BiSn(VO4)2 prepared by this method... x Electrocatalysts have excellent stability and great market application prospects.

[0106] Figure 8 It is the BiSn(VO) synthesized in Example 1 x The performance of the electrocatalyst in a rechargeable Zn-CO2 battery was investigated. The assembled Zn-CO2 battery exhibited excellent rechargeability and discharge performance at 4 mA / cm². 2 Peak power can reach 3.8mW / cm². 2 .

[0107] Figure 9 Using NiCo LDH sample as the anode catalyst, and BiSn(VO2) prepared in Example 1 of this invention... x An electrocatalyst was used as the cathode in a co-electrolysis system, where the cathode electrolyte was 1M potassium hydroxide and the anode electrolyte was 1M potassium hydroxide + 1M ethylene glycol. Results confirmed that the electrolyzer constructed using the ethylene glycol oxidation reaction as the anode exhibited a higher current density.

[0108] Figure 10Using NiCo LDH sample as the anode catalyst, and BiSn(VO2) prepared in Example 1 of this invention... x The catalyst was used as the cathode to form a co-electrolysis system, and the results showed that the total Faraday efficiency of the formate in the electrolyzer could reach 182% at a voltage of 0.6V.

[0109] Figure 11 The polarization curves of BiSn(VOx) and BiSn and Bi catalysts prepared in the comparative example are compared in a flow electrolyzer. The results show that Sn alloying helps to improve the electrocatalytic CO2 reduction performance of Bi materials, while surface modification of VOx clusters can further improve the performance of BiSn materials, thereby achieving performance optimization.

[0110] Based on the above performance tests, it can be seen that the vanadium oxide-modified bismuth-tin alloy electrocatalyst, its preparation method, and its applications provided by this invention exhibit a nanosheet structure, good crystallinity, and stability. When applied to the electrocatalytic reduction of carbon dioxide to formate, it demonstrates high activity and excellent stability. Within a wide potential window, the catalyst achieves a formate Faradaic efficiency exceeding 90% and exhibits good stability in cycling tests. Furthermore, this electrocatalyst exhibits high power density and excellent co-electrolysis performance in a rechargeable Zn-CO2 battery system, demonstrating its potential application value in energy storage and conversion.

[0111] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An electrocatalyst for vanadium oxide-modified bismuth-tin alloy, characterized in that: The electrocatalyst is BiSn(VO₂)₂ x The material exhibits a two-dimensional nanosheet morphology, wherein the BiSn is an alloy, and VO x BiSn(VO) is modified on the surface of BiSn nanosheets in a cluster form, and BiSn(VO) x The lattice spacing corresponds to the (012) plane of Bi.

2. The electrocatalyst for vanadium oxide-modified bismuth-tin alloy according to claim 1, characterized in that: The electrocatalyst has a nanosheet structure with a size of 200–500 nm.

3. A method for preparing an electrocatalyst of vanadium oxide modified bismuth-tin alloy as described in claim 1 or 2, characterized in that: Includes the following steps: (1) Dissolve bismuth nitrate, tin chloride and ammonium metavanadate in hydrochloric acid solution and stir until homogeneous to obtain electrolyte; (2) Using the electrolyte from step (1), a three-electrode electrolytic cell is constructed. Carbon cloth is used as the working electrode, saturated Ag / AgCl electrode is used as the reference electrode, and platinum sheet is used as the counter electrode. A constant current density is applied to perform electrochemical deposition to obtain an electrocatalyst. (3) The electrocatalyst is washed alternately with water and ethanol and dried under vacuum to obtain the vanadium oxide modified bismuth-tin alloy electrocatalyst.

4. The method for preparing an electrocatalyst of vanadium oxide modified bismuth-tin alloy according to claim 3, characterized in that: In step (1), the molar ratio of tin chloride, bismuth nitrate and ammonium metavanadate is 1:11-12:3-6; The concentration of the hydrochloric acid solution is 0.1–1 M, and the amount of hydrochloric acid solution added is 50 mL.

5. The method for preparing an electrocatalyst of vanadium oxide modified bismuth-tin alloy according to claim 3, characterized in that: In step (2), during the electrochemical deposition process, the constant current density is -5 to -50 mA / cm². 2 The electrochemical deposition time is 200–600 s.

6. The method for preparing an electrocatalyst of vanadium oxide modified bismuth-tin alloy according to claim 3, characterized in that: In step (3), the electrocatalyst is washed with water and ethanol alternately 3 to 5 times; The vacuum drying temperature is 60–80°C, and the vacuum drying time is 6–8 hours.

7. The application of an electrocatalyst of vanadium oxide modified bismuth-tin alloy according to claim 1 or 2, or an electrocatalyst of vanadium oxide modified bismuth-tin alloy obtained by the preparation method according to any one of claims 3 to 6, in the electroreduction reaction of carbon dioxide.

8. The application of an electrocatalyst of vanadium oxide modified bismuth-tin alloy according to claim 1 or 2, or an electrocatalyst of vanadium oxide modified bismuth-tin alloy obtained by the preparation method according to any one of claims 3 to 6, in a reversible zinc-carbon dioxide battery.

9. The application of an electrocatalyst of vanadium oxide modified bismuth-tin alloy according to claim 1 or 2, or an electrocatalyst of vanadium oxide modified bismuth-tin alloy obtained by the preparation method according to any one of claims 3 to 6, in a carbon dioxide reduction reaction system assisted by ethylene glycol oxidation.

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