Electrocatalytic material for efficiently preparing ethylene by using oxyphilic metal doped Cu-based catalyst as well as preparation method and application of electrocatalytic material

Abstract

The preparation method comprises the following steps: preparing an ice-cold acidic aqueous solution of a bivalent copper salt, mixing the ice-cold acidic aqueous solution of the bivalent copper salt with an oxyphilic metal acidic ice-cold aqueous solution to obtain an ice-cold mixed solution, and carrying out ultrasonic treatment on the ice-cold mixed solution of the bivalent copper salt and the oxyphilic metal to obtain the electrocatalytic material for efficiently preparing ethylene by using an oxyphilic metal-doped Cu-based catalyst. Adding the mixed solution into a sodium borohydride ice-cold aqueous solution, maintaining an ice bath and continuously stirring in the process of adding the mixed solution, then carrying out a reaction for a certain period of time, and carrying out post-treatment after the reaction, thereby obtaining the product. According to the method, under the acidic condition, in the process of synthesizing the bimetallic copper-based catalyst material through a coprecipitation method, the type and proportion of oxyphilic metal doping are regulated and controlled, and the copper-based electro-catalysis material with the optimized Cu site electron density is obtained. The oxyphilic metal doped copper-based electrocatalyst provided by the invention can be used for directionally electrocatalytically converting CO2 into C2H4, so that key regulation and control of a key intermediate reaction path are realized, and high selectivity is kept in a wide current window.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst preparation, and in particular relates to an electrocatalytic material for efficiently producing ethylene using an oxophilic metal-doped Cu-based catalyst, as well as a preparation method and application thereof. Background Art

[0002] Carbon utilization technology is crucial to reducing the cost of CCUS implementation, and it can be divided into geological, chemical, mineralization and biological utilization. Compared with the long time required for mineralization and low-quality storage, chemical utilization can achieve rapid conversion of CO2 in a shorter time. Electrochemical carbon dioxide reduction reaction (eCO2RR) provides a promising way to achieve sustainable utilization of CO2 and convert it into high-value-added chemicals. Copper (Cu)-based catalysts are the main eCO2RR electrocatalysts because their unique properties allow the production of multi-carbon (C 2+ ) products, such as ethylene (C2H4) and ethanol (C2H5OH). In the past decade, eCO2RR has made significant breakthroughs in the selective production of single-carbon (C1) products and in the production of more valuable multi-carbon (C 2+ ) products have also made some progress. Compared with C1 products, C 2+ The products (such as ethylene, ethanol, acetic acid and n-propanol) have higher energy density and economic value and can be further used as raw materials for synthesizing long-chain hydrocarbon fuels. 2+ However, the existing technology system faces two core bottlenecks: First, the electrocatalytic reaction involves complex proton-coupled electron transfer (PCET) mechanism and multi-intermediate reaction, which makes it difficult to achieve C 2+ The high selectivity of the product is much more challenging than that of the C1 product. In addition, there are problems in the kinetics such as high CC coupling energy barrier and serious competitive hydrogen evolution reaction, which leads to the selectivity of high-value products generally being less than 50%. At present, it is mainly believed that the dimerization of adsorbed CO (*CO) and *CHO after hydrogenation of *CO is the main method to achieve C 2+ The main CC coupling pathway of product evolution, while the single C 2+ The rate-determining step of product synthesis can be attributed to efficient CC coupling and the regulation of its subsequent directed reaction pathway, which provides a key regulatory target for catalyst design.

[0003] Traditional catalyst research and development mostly relies on empirical trial and error, and it is difficult to cope with scientific challenges such as the interweaving of multiple electron transfer pathways and the complex distribution of intermediate adsorption energy during the electrocatalytic reduction of CO2. In particular, there are significant shortcomings in high-value product selectivity and reaction stability. To address this core issue, we have constructed a three-in-one rational catalyst design paradigm of "theoretical calculation-experimental verification-mechanism exploration". By deeply analyzing the kinetic bottlenecks and thermodynamic limitations of the reaction pathway, focusing on the electronic structure optimization and microenvironmental regulation of copper-based catalysts, we can achieve precise design from the atomic scale to macroscopic performance. Studies have found that bimetallic Cu-based catalysts can effectively improve *CO coverage and promote CC coupling because of their asymmetric arrangement M-Cu structure with rich heterogeneous interfaces. The *CO coverage on the Cu active center is strongly affected by the second metal, and most of the *CO migrates from the second metal center to avoid poisoning of the Cu site. High *CO coverage can not only ensure the supply of *CO, but also, especially in the efficient conversion of CO2 to C 2+ At low product reaction rates, the barrier to CC coupling can be effectively lowered. Furthermore, due to the electronegativity difference between the metals, the second metal can effectively modulate the electronic state and microenvironment of the Cu active center. Therefore, this type of catalyst has great potential for the preparation of efficient eCO₂RR. However, the rational design of bimetallic interfaces, excellent catalytic performance, and in-depth research on mechanisms beyond the cascade effect are still limited, which seriously hinders the understanding of the mechanism and catalyst design. Summary of the Invention

[0004] The purpose of the present invention is to provide a catalyst for the catalytic conversion of existing copper-based catalysts to C 2+ In order to solve the technical problems such as low product selectivity, unsatisfactory selectivity for single product, and low current efficiency, an electrocatalytic material for efficiently producing ethylene with an oxophilic metal-doped Cu-based catalyst and its preparation method and application are proposed.

[0005] Based on theoretically guided screening, this invention discovered that regulating the electronic structure of the Cu site can directionally drive the subsequent reaction path. The oxophilic metal-Cu-based catalyst designed and synthesized using this electronic structure rearrangement strategy can effectively improve the selectivity of the C2H4 product. Through oxophilic metal doping and regulation, the present invention optimizes the electron cloud density of the Cu site, promotes the transfer of secondary metal electrons to the Cu atom, effectively stabilizes the Cu-O bond, reduces the barrier to ethylene formation from the key intermediate, and exhibits a low desorption energy for ethylene, significantly improving the catalyst's activity and selectivity for ethylene.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A method for preparing an electrocatalytic material for efficiently producing ethylene using an oxophilic metal-doped Cu-based catalyst is as follows: a certain molar amount of a divalent copper nitrate salt and an oxophilic metal salt are weighed, dissolved in an ice-cold acidic aqueous solution, mixed evenly, and then added to an aqueous sodium borohydride solution, maintained in an ice bath throughout the entire process; and during the co-precipitation synthesis of a bimetallic copper-based catalyst material, the type and ratio of the oxophilic metal doping are regulated to select one or more of Ce, Ga, and Sm, thereby obtaining a copper-based electrocatalytic material with optimized Cu site electron density.

[0008] The method for preparing an electrocatalytic material for efficiently producing ethylene using an oxophilic metal-doped Cu-based catalyst specifically comprises the following steps: preparing an ice-cold acidic aqueous solution of a divalent copper salt, mixing the solution with an ice-cold acidic aqueous solution of the oxophilic metal to obtain a mixed solution, then adding the mixed solution to an aqueous sodium borohydride solution, maintaining an ice bath and continuously stirring at a high speed during the addition of the mixed solution, then reacting for a certain period of time, and performing post-treatment after the reaction to obtain the electrocatalytic material for efficiently producing ethylene using an oxophilic metal-doped Cu-based catalyst.

[0009] More preferably, an ice-cold aqueous solution of an acidic divalent copper salt is prepared and mixed with a certain proportion of an ice-cold acidic aqueous solution of an oxophilic metal to obtain an ice-cold mixed solution. The mixed solution is then rapidly added dropwise to a sodium borohydride solution while stirring continuously for a certain period of time while maintaining an ice bath. The mixture is then centrifuged, washed with water, and washed with alcohol several times to obtain a copper-based electrocatalytic material with an optimized Cu electron cloud density. Furthermore, the oxophilic metal is one or more of Ce, Ga, and Sm, with a doping molar ratio of 5 to 50%.

[0010] Furthermore, the divalent copper salt is dissolved in an ice-cold aqueous solution of dilute hydrochloric acid to obtain an ice-cold acidic solution of the divalent copper salt; the pH of the acidic solution of the divalent copper salt is 0.5 to 2. The concentration of the divalent copper salt aqueous solution is 0.01-1.0 mol / L, preferably 0.05 to 0.5 mol / L;

[0011] The ice-cold oxophilic metal acidic solution is prepared by dissolving an oxophilic metal salt in an ice-cold dilute hydrochloric acid solution to obtain an ice-cold oxophilic metal acidic solution; the pH of the oxophilic metal acidic solution is 0.5-2; the oxophilic metal in the oxophilic metal salt is one or more of Ce, Ga, and Sm. The concentration of the oxophilic metal acidic solution is 0.001-0.5 mol / L, and more preferably, the oxophilic metal doping concentration is 0.005-0.5 mol / L, preferably 0.01-0.25 mol / L.

[0012] Furthermore, the volume ratio of the mixed solution to the sodium borohydride aqueous solution is 1.5-2.5:1. The ice-cold mixed metal aqueous solution is quickly added within 3-10 minutes.

[0013] Furthermore, the concentration of the sodium borohydride solution is 0.1-2 mol / L, the dropping rate is 1-5 mL / min, and the stirring time after dropping is 0.5-3 h.

[0014] Furthermore, the number of water washings is 1-5 times, and the number of alcohol washings is 1-3 times, and the alcohol is one or more of ethanol, methanol, and isopropanol.

[0015] The electrocatalytic material for efficiently producing ethylene using an oxophilic metal-doped Cu-based catalyst provided by the present invention can be well applied to the electrocatalytic conversion of CO2 to a C2H4 product. The electrocatalytic material for efficiently producing ethylene using an oxophilic metal-doped Cu-based catalyst is used as a catalyst in converting carbon dioxide to ethylene via an electrolytic reaction. The application method comprises the following steps: the carbon dioxide electrocatalytic material is dried and then prepared into an ink solution, which is evenly applied to carbon paper using an air spray gun and used as a working electrode. A platinum sheet is used as an anode, a saturated Ag / AgCl electrode is used as a reference electrode, and a 0.1-1 mol / L KOH aqueous solution is used as an electrolyte. The electrolyte is aerated with CO2 to saturate it. The reaction is carried out in a three-electrode system including a gas diffusion electrode (GDE). The cathode and anode electrolytes are separated by an anion exchange membrane, and the cathode and anode electrolytes flow in and out continuously. The working electrode is activated before testing, and then the CO2 is converted to a C2H4 product via an electrolytic reaction.

[0016] Compared with the prior art, the present invention has the following beneficial effects: the present invention proposes an electrocatalytic material for the efficient production of ethylene by an oxophilic metal-doped Cu-based catalyst, which can effectively change the electron delocalization of the Cu site, thereby promoting the dynamic adsorption of CC coupling intermediates and facilitating the C 2+ The product is generated while guiding subsequent reactions toward the ethylene pathway, significantly improving the selectivity and current density of C2H4. Experimental results show that the CO2 electrocatalytic reduction material prepared by this invention can be stably tested for 20 hours, and the C2H4 product can maintain a good and stable output. The Faradaic efficiency of the CO2 electrolysis reaction to C2H4 reached approximately 70.3%. The optimized material increased the Faradaic efficiency of C2H4 reduction by approximately 35.2% compared to the unmodified Cu-based catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the SEM scanning electron microscope image of the electrocatalytic material sample prepared in the control example.

[0018] Figure 2 This is a SEM image of the electrocatalytic material sample prepared in the example.

[0019] Figure 3 The following are the XRD pattern comparison results of the electrocatalytic material samples prepared in the control example and the embodiment.

[0020] Figure 4 The XPS graph comparison results of the electrocatalytic material samples prepared in the examples are shown. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.

[0022] Control Example

[0023] The control example is an unmodified Cu-based catalyst. Weigh 241.6 mg of copper nitrate trihydrate, add it to 10 mL of dilute hydrochloric acid solution (pH is 1), and configure it into a 0.1 mol / L copper nitrate acidic solution named A solution (10 mL). Weigh 188.8 mg of sodium borohydride to configure it into 5 mL of 1.0 mol / L sodium borohydride aqueous solution, named B solution. Quickly add solution A dropwise to solution B, maintain an ice bath and stir continuously during the whole process, the dropwise addition rate is 2 mL / min, and the dropwise addition time is 5 min. After the dropwise addition, keep the ice bath and continue stirring for 1.0 h, wash with distilled water, centrifuge 4 times, wash with ethanol, centrifuge 2 times, and then treat to obtain a black precipitate, which is dried at 60 ° C in a vacuum drying oven for 12 h to obtain an unmodified Cu-based catalyst material (named CuO x ).

[0024] CuO prepared in the control example x The materials were subjected to SEM analysis, such as Figure 1 The unmodified Cu-based catalyst is in the form of nanoparticles with a particle size of about 100 nm. Figure 3 It can be seen that the diffraction peaks of the unprepared product are only those of Cu and Cu oxide, and no diffraction peaks of other metals are found.

[0025] CuO prepared in the control example x The material was used for CO2 electrolysis reaction, and its electrocatalytic performance was tested as follows:

[0026] 10 mg of electrocatalytic material was weighed and placed in a vial, and 960 uL of isopropanol and 40 uL of nafion solution (5% wt) were added and mixed. The mixture was ultrasonicated for 1 hour to completely disperse the catalyst and obtain a uniform catalyst ink.

[0027] Use an air spray gun to apply the ink prepared above on a 1cm*3cm carbon paper with a loading of 0.6-0.7mg / cm 2, after drying, it was used as the working electrode, with the platinum sheet as the anode and the saturated Ag / AgCl electrode as the reference electrode. The electrocatalytic performance test was carried out using the BioLogic-VMP electrochemical workstation. The CO2 electrolysis reaction was carried out in a three-electrode system (flow cell) containing a gas diffusion electrode GDE. The electrolyte continuously flowed in and out of the flow cell. The cathode and anode electrolytes were separated by an anion exchange membrane. The cathode liquid flow rate was 5mL / min, and the anode liquid flow rate was 5mL / min. The electrolyte was a 0.5mol / LKOH aqueous solution. Before the test, the electrolyte was aerated with CO2 to saturate it. Before the CO2 electrolysis reaction was reduced to produce ethylene, a constant potential was applied to activate the working electrode, and then the electrochemical workstation was operated at -100 to -450mA / cm 2 (at 50mA / cm 2 The electrolysis reaction of CO2 to produce ethylene was carried out at a current density of -200mA / cm 2 Under C, the Faraday efficiency of ethylene is 35.1%; 2+ The product Faradaic efficiency is 45.3%, and it can be stably tested for 3 hours.

[0028] Example 1

[0029] Weigh 241.6 mg of copper nitrate trihydrate and add it to 5 mL of dilute hydrochloric acid solution (0°C) to prepare a 0.2 mol / L copper nitrate acidic solution (pH 1); then weigh 43.4 mg of cerium nitrate hexahydrate and add it to 5 mL of dilute hydrochloric acid solution (0°C) to obtain a 0.02 mol / L cerium metal acidic solution (pH 1) with a Ce / Cu molar ratio of 10%. Mix the two and name it Solution A (10 mL). Weigh 188.8 mg of sodium borohydride and prepare it into 5 mL of a 1.0 mol / L sodium borohydride aqueous solution, named Solution B. Quickly add Solution A dropwise to Solution B, maintaining an ice bath and stirring continuously throughout the process, with a dropwise acceleration rate of 2 mL / min and a dropwise addition time of 5 minutes. After the addition, the mixture was kept in an ice bath and stirred for 1.0 h. The mixture was washed with distilled water and centrifuged 4 times and washed with ethanol and centrifuged 2 times to obtain a black precipitate. The black precipitate was dried in a vacuum drying oven at 60 ° C for 12 h to obtain the electrocatalytic material (named Ce1CuO x ).

[0030] Ce1CuO prepared in Example 1 x The materials were subjected to SEM analysis, such as Figure 2 The Ce-modified Cu-based catalyst is in the form of nanoparticles with a particle size of about 50 nm. Figure 3 It can be seen that the diffraction peaks of the unprepared product are only those of Cu and Cu oxide, and no diffraction peak of Ce metal is found. Figure 4 The XPS results confirmed the presence of Ce species and confirmed the atomic-level dispersion of Ce elements.

[0031] Example 1 Preparation of Ce1CuO x The electrocatalytic performance of the materials was tested as follows:

[0032] 10 mg of electrocatalytic material was weighed and placed in a vial, and 960 uL of isopropanol and 40 uL of nafion solution (5% wt) were added and mixed. The mixture was ultrasonicated for 1 hour to completely disperse the catalyst and obtain a uniform catalyst ink.

[0033] Use an air spray gun to apply the ink prepared above on a 1cm*3cm carbon paper with a loading of 0.6-0.7mg / cm 2 , after drying, it was used as the working electrode, with the platinum sheet as the anode and the saturated Ag / AgCl electrode as the reference electrode. The electrocatalytic performance test was carried out using the BioLogic-VMP electrochemical workstation. The CO2 electrolysis reaction was carried out in a three-electrode system (flow cell) containing a gas diffusion electrode GDE. The electrolyte continuously flowed in and out of the flow cell. The cathode and anode electrolytes were separated by an anion exchange membrane. The cathode liquid flow rate was 5mL / min, and the anode liquid flow rate was 5mL / min. The electrolyte was a 0.5mol / LKOH aqueous solution. Before the test, the electrolyte was aerated with CO2 to saturate it. Before the CO2 electrolysis reaction was reduced to produce ethylene, a constant potential was applied to activate the working electrode, and then the electrochemical workstation was operated at -100 to -450mA / cm 2 (at 50mA / cm 2 The electrocatalytic performance was tested at a current density of -350 mA / cm 2 Under C, the Faraday efficiency of ethylene is 70.3%; 2+ The product Faradaic efficiency is 85.5% and can be stably tested for 20 hours.

[0034] Example 2

[0035] Weigh 241.6 mg of copper nitrate trihydrate and add it to 5 mL of dilute hydrochloric acid solution (0°C) to prepare a 0.2 mol / L copper nitrate acidic solution (pH 1); then weigh 86.8 mg of cerium nitrate hexahydrate and add it to 5 mL of dilute hydrochloric acid solution (0°C) to obtain a 0.04 mol / L cerium metal acidic solution (pH 1) with a Ce / Cu molar ratio of 20%. Mix the two and name it Solution A (10 mL). Weigh 188.8 mg of sodium borohydride and prepare it into 5 mL of a 1.0 mol / L sodium borohydride aqueous solution, named Solution B. Quickly add Solution A dropwise to Solution B, maintaining an ice bath and stirring continuously throughout the process, with a dropwise acceleration rate of 2 mL / min and a dropwise addition time of 5 minutes. After the addition, the mixture was kept in an ice bath and stirred for 1.0 h. The mixture was washed with distilled water and centrifuged 4 times and washed with ethanol and centrifuged 2 times to obtain a black precipitate. The black precipitate was dried in a vacuum drying oven at 60 ° C for 12 h to obtain the electrocatalytic material (named Ce2CuO x ).

[0036] Ce2CuO prepared in Example 2 x The materials were subjected to SEM analysis, such as Figure 2 The Ce-modified Cu-based catalyst is in the form of nanoparticles with a particle size of about 50 nm. Figure 3 It can be seen that the diffraction peaks of the unprepared product are only those of Cu and Cu oxide, and no diffraction peak of Ce metal is found. Figure 4 The XPS results confirmed the presence of Ce species and confirmed the atomic-level dispersion of Ce elements.

[0037] Ce2CuO prepared in Example 2 x The electrocatalytic performance of the materials was tested as follows:

[0038] 10 mg of electrocatalytic material was weighed and placed in a vial, and 960 uL of isopropanol and 40 uL of nafion solution (5% wt) were added and mixed. The mixture was ultrasonicated for 1 hour to completely disperse the catalyst and obtain a uniform catalyst ink.

[0039] Use an air spray gun to apply the ink prepared above on a 1cm*3cm carbon paper with a loading of 0.6-0.7mg / cm 2, after drying, it was used as the working electrode, with the platinum sheet as the anode and the saturated Ag / AgCl electrode as the reference electrode. The electrocatalytic performance test was carried out using the BioLogic-VMP electrochemical workstation. The CO2 electrolysis reaction was carried out in a three-electrode system (flow cell) containing a gas diffusion electrode GDE. The electrolyte continuously flowed in and out of the flow cell. The cathode and anode electrolytes were separated by an anion exchange membrane. The cathode liquid flow rate was 5mL / min, and the anode liquid flow rate was 5mL / min. The electrolyte was a 0.5mol / LKOH aqueous solution. Before the test, the electrolyte was aerated with CO2 to saturate it. Before the CO2 electrolysis reaction was reduced to produce ethylene, a constant potential was applied to activate the working electrode, and then the electrochemical workstation was operated at -100 to -450mA / cm 2 (at 50mA / cm 2 The electrocatalytic performance was tested at a current density of -350 mA / cm 2 Under C, the Faraday efficiency of ethylene is 56.9%; 2+ The product Faradaic efficiency is 75.3% and can be stably tested for 20 hours.

[0040] Example 3

[0041] Weigh 241.6 mg of copper nitrate trihydrate and add it to 5 mL of dilute hydrochloric acid solution (0°C) to prepare a 0.2 mol / L copper nitrate acidic solution (pH 1); then weigh 25.5 mg of hydrated gallium nitrate and add it to 5 mL of dilute hydrochloric acid solution (0°C) to obtain a 0.02 mol / L gallium metal acidic solution (pH 1) with a Ga / Cu molar ratio of 10%. Mix the two and name it solution A (10 mL). Weigh 188.8 mg of sodium borohydride and prepare 5 mL of a 1.0 mol / L sodium borohydride aqueous solution, named solution B. Solution A was quickly added dropwise to solution B, maintaining an ice bath and stirring continuously throughout the process. The drop rate was 2 mL / min and the dropwise addition time was 5 min. After the dropwise addition, keep the ice bath and continue stirring for 1.0 h. After washing with distilled water, centrifuge 4 times and wash with ethanol and centrifuge 2 times, the black precipitate was obtained and dried in a vacuum drying oven at 60°C for 12 h to obtain the electrocatalytic material (named GaCuO x ).

[0042] GaCuO prepared in Example 3 x The materials were subjected to SEM analysis, such as Figure 2 The unmodified Cu-based catalyst is in the form of nanoparticles with a particle size of about 50 nm. Figure 3 It can be seen that the diffraction peaks of the unprepared product are only those of Cu and Cu oxide, and no diffraction peaks of Ga metal are found. Figure 4The XPS results confirmed the presence of Ga species and confirmed the atomic-level dispersion of Ga elements.

[0043] Example 3 Preparation of GaCuO x The electrocatalytic performance of the materials was tested as follows:

[0044] 10 mg of electrocatalytic material was weighed and placed in a vial, and 960 uL of isopropanol and 40 uL of nafion solution (5% wt) were added and mixed. The mixture was ultrasonicated for 1 hour to completely disperse the catalyst and obtain a uniform catalyst ink.

[0045] Use an air spray gun to apply the ink prepared above on a 1cm*3cm carbon paper with a loading of 0.6-0.7mg / cm 2 , after drying, it was used as the working electrode, with the platinum sheet as the anode and the saturated Ag / AgCl electrode as the reference electrode. The electrocatalytic performance test was carried out using the BioLogic-VMP electrochemical workstation. The CO2 electrolysis reaction was carried out in a three-electrode system (flow cell) containing a gas diffusion electrode GDE. The electrolyte continuously flowed in and out of the flow cell. The cathode and anode electrolytes were separated by an anion exchange membrane. The cathode liquid flow rate was 5mL / min, and the anode liquid flow rate was 5mL / min. The electrolyte was a 0.5mol / LKOH aqueous solution. Before the test, the electrolyte was aerated with CO2 to saturate it. Before the CO2 electrolysis reaction was reduced to produce ethylene, a constant potential was applied to activate the working electrode, and then the electrochemical workstation was operated at -100 to -450mA / cm 2 (at 50mA / cm 2 The electrocatalytic performance was tested at a current density of -350 mA / cm 2 Under C, the Faraday efficiency of ethylene is 50.6%; 2+ The product Faradaic efficiency is 69.9% and can be stably tested for 20 hours.

[0046] Example 4

[0047] Weigh 241.6 mg of copper nitrate trihydrate and add it to 5 mL of dilute hydrochloric acid solution (0°C) to prepare a 0.2 mol / L copper nitrate acidic solution (pH 1). Then weigh 44.4 mg of samarium nitrate hexahydrate and add it to 5 mL of dilute hydrochloric acid solution (0°C) to obtain a 0.02 mol / L samarium metal acidic solution (pH 1) with a Sm / Cu molar ratio of 10%. Mix the two and designate them as Solution A (10 mL). Weigh 188.8 mg of sodium borohydride and prepare them into 5 mL of a 1.0 mol / L sodium borohydride aqueous solution, designated Solution B. Rapidly add Solution A dropwise to Solution B, maintaining an ice bath and stirring continuously throughout the process, at a rate of 2 mL / min, for 5 minutes. After the addition, the mixture was kept in an ice bath and stirred for 1.0 h. The mixture was washed with distilled water and centrifuged 4 times and washed with ethanol and centrifuged 2 times to obtain a black precipitate. The black precipitate was dried in a vacuum drying oven at 60 °C for 12 h to obtain the electrocatalytic material (named SmCuO x ).

[0048] Example 4 Preparation of SmCuO x The materials were subjected to SEM analysis, such as Figure 2 The unmodified Cu-based catalyst is in the form of nanoparticles with a particle size of about 50 nm. Figure 3 It can be seen that the diffraction peaks of the unprepared product are only those of Cu and Cu oxide, and no diffraction peaks of Sm metal are found. Figure 4 The XPS results confirmed the presence of Sm species and confirmed the atomic-level dispersion of Sm elements.

[0049] SmCuO prepared in Example 4 x The electrocatalytic performance of the materials was tested as follows:

[0050] 10 mg of electrocatalytic material was weighed and placed in a vial, and 960 uL of isopropanol and 40 uL of nafion solution (5% wt) were added and mixed. The mixture was ultrasonicated for 1 hour to completely disperse the catalyst and obtain a uniform catalyst ink.

[0051] Use an air spray gun to apply the ink prepared above on a 1cm*3cm carbon paper with a loading of 0.6-0.7mg / cm 2, after drying, it was used as the working electrode, with the platinum sheet as the anode and the saturated Ag / AgCl electrode as the reference electrode. The electrocatalytic performance test was carried out using the BioLogic-VMP electrochemical workstation. The CO2 electrolysis reaction was carried out in a three-electrode system (flow cell) containing a gas diffusion electrode GDE. The electrolyte continuously flowed in and out of the flow cell. The cathode and anode electrolytes were separated by an anion exchange membrane. The cathode liquid flow rate was 5mL / min, and the anode liquid flow rate was 5mL / min. The electrolyte was a 0.5mol / LKOH aqueous solution. Before the test, the electrolyte was aerated with CO2 to saturate it. Before the CO2 electrolysis reaction was reduced to produce ethylene, a constant potential was applied to activate the working electrode, and then the electrochemical workstation was operated at -100 to -450mA / cm 2 (at 50mA / cm 2 The electrocatalytic performance was tested at a current density of -400 mA / cm 2 Under C, the Faraday efficiency of ethylene is 57.6%; 2+ The product Faradaic efficiency is 78.3% and can be stably tested for 20 hours.

[0052] The contents described in this specification are merely an enumeration of implementation forms of the inventive concept, and the protection scope of the present invention should not be considered as being limited to the specific forms described in the embodiments.

Claims

1. A method for preparing an electrocatalytic material for efficiently producing ethylene using an oxophilic metal-doped Cu-based catalyst, characterized in that: The following steps are involved: A divalent copper salt is dissolved in an ice-cold acidic aqueous solution to obtain an acidic solution of the divalent copper salt, which is then mixed with a prepared oxophilic metal acidic solution to obtain a mixed solution. The mixed solution is then added to a prepared sodium borohydride aqueous solution. During the addition of the mixed solution, an ice bath is maintained and the reaction is continuously stirred. After the reaction, post-treatment is performed to obtain an electrocatalytic material for efficiently producing ethylene using an oxophilic metal-doped Cu-based catalyst.

2. The preparation method according to claim 1, characterized in that Dissolve a divalent copper salt in an ice-cold acidic aqueous solution, specifically: A divalent copper salt is weighed and dissolved in an ice-cold acidic aqueous solution to obtain an acidic aqueous solution of the divalent copper salt.

3. The preparation method according to claim 1, characterized in that The pH of the acidic solution of the divalent copper salt is 0.5-2; The temperature of the acidic aqueous solution does not exceed 0°C; The ice-cold acidic aqueous solution is an acidic aqueous solution containing one or more of HCl, H2SO4, and HNO3.

4. The preparation method according to claim 1, characterized in that Prepare an oxophilic metal acidic solution, specifically comprising: dissolving an oxophilic metal salt in an acidic ice-cold aqueous solution to obtain an oxophilic metal acidic solution; The pH of the oxophilic metal acidic solution is 0.5 to 2; The temperature of the acidic ice-cold aqueous solution does not exceed 0°C; The acidic ice-cold aqueous solution is an acidic aqueous solution containing one or more of HCl, H2SO4, and HNO3; The oxophilic metal in the oxophilic metal salt is one or more of Ce, Ga, and Sm.

5. The preparation method according to claim 1, characterized in that The stirring speed of the stirring reaction is 1000-1500 rpm; The stirring reaction time is 0.5-3h.

6. The preparation method according to claim 1, characterized in that The concentration of the divalent copper salt acidic solution is 0.01-1.0 mol / L, and the concentration of the oxophilic metal acidic solution is 0.001-0.5 mol / L.

7. The preparation method according to claim 1, characterized in that The concentration of the sodium borohydride aqueous solution is 0.1-2 mol / L; The volume ratio of the mixed solution to the sodium borohydride aqueous solution is 1.5-2.5:

1.

8. The preparation method according to claim 1, characterized in that The mixed solution was quickly added to the prepared sodium borohydride aqueous solution over a period of 3 to 10 minutes.

9. An electrocatalytic material for efficiently producing ethylene using an oxophilic metal-doped Cu-based catalyst prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the electrocatalytic material for efficiently producing ethylene using an oxophilic metal-doped Cu-based catalyst according to claim 9 as a catalyst in converting carbon dioxide into ethylene via an electrolysis reaction.

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