Method of electrochemically catalyzing conversion of carbon dioxide to multi-carbon products and composite electrode

Abstract

The application discloses a method for electrochemically catalytically converting carbon dioxide into multi-carbon products and a composite electrode. The application discloses a preparation method of a copper-based catalyst / gas diffusion electrode composite electrode modified by a p-block metal element, and the method comprises the following steps: 1) adding an auxiliary water solution, a copper salt water solution and a p-block metal salt water solution into water to obtain a mixed solution; 2) sequentially adding an alkali solution and a reducing agent water solution into the mixed solution to obtain a precipitate; 3) sequentially washing and drying the precipitate to obtain a solid powder; 4) modifying the solid powder on a gas diffusion electrode to obtain a catalytic electrode; and 5) assembling the catalytic electrode into a gas diffusion flow electrolysis cell, and performing in-situ electrochemical reduction on the catalytic electrode by taking carbon dioxide as raw material, and thus the composite electrode is obtained. Compared with a copper-based catalyst without modification, the composite electrode improves the selectivity of electrochemically catalytically converting carbon dioxide into multi-carbon products, and simultaneously has excellent electrochemical catalytic conversion stability under the condition of a large current density.

Description

Technical Field

[0001] This invention belongs to the field of green chemistry and chemical engineering technology, specifically relating to a method for electrochemical catalytic conversion of carbon dioxide to synthesize multi-carbon products and a composite electrode. Background Technology

[0002] Electrochemical catalytic conversion of carbon dioxide can effectively utilize clean electrical energy to convert water and carbon dioxide into higher-value chemicals or fuels at room temperature, while also enabling efficient storage of renewable energy. The products of carbon dioxide electrochemical catalytic conversion are widely distributed. Compared to single-carbon products (formic acid, carbon monoxide), multi-carbon products (acetic acid, ethylene, ethanol, propanol, etc.) have higher energy density and added value. However, the formation of multi-carbon products involves multi-electron and multi-proton coupling processes, and their reaction intermediates are very complex. The key to the electrocatalytic conversion of carbon dioxide to synthesize multi-carbon products lies in the development of highly efficient electrocatalysts. Copper-based catalysis is currently the only metal-based catalyst discovered capable of producing multi-carbon products, mainly prepared through hydrothermal methods, precipitation methods, electrodeposition methods, and vapor deposition methods. The carbon-carbon coupling steps generally have high reaction energy barriers, meaning that the catalytic system for the electroreduction of carbon dioxide to produce multi-carbon products is still limited by factors such as low product selectivity at high current densities and poor catalytic electrode stability, making it difficult to meet the needs of current commercial applications. Therefore, developing highly selective, efficient, and stable electrochemical catalytic conversion systems for the synthesis of multi-carbon products remains a significant challenge. Summary of the Invention

[0003] The purpose of this invention is to provide a method and composite electrode for the electrochemical catalytic conversion of carbon dioxide to synthesize multi-carbon products. This method uses a copper-based catalyst / gas diffusion electrode composite electrode modified with p-region metal elements as the cathode working electrode. Compared with unmodified copper-based catalysts, it improves catalytic activity and selectivity for the electrochemical catalytic conversion of carbon dioxide to synthesize multi-carbon products. At the same time, it has excellent electrochemical catalytic conversion stability under high current density conditions and has good commercial application value.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] In a first aspect, the present invention provides a method for preparing a copper-based catalyst / gas diffusion electrode composite electrode modified with p-region metal elements, comprising the following steps:

[0006] 1) Add the aqueous solution of the auxiliary agent, the aqueous solution of the copper salt, and the aqueous solution of the p-block metal salt to water to obtain a mixed solution;

[0007] 2) Add alkali solution and reducing agent aqueous solution to the mixture in sequence to obtain a precipitate;

[0008] 3) The precipitate is washed and dried sequentially to obtain a solid powder;

[0009] 4) The solid powder is modified onto a gas diffusion electrode to obtain a catalytic electrode;

[0010] 5) The catalytic electrode is assembled into a gas diffusion flow electrolysis cell and in-situ electrochemical reduction is performed using carbon dioxide as raw material to obtain the copper-based catalyst / gas diffusion electrode composite electrode modified with the p-region metal element.

[0011] In the above-mentioned method for preparing a copper-based catalyst / gas diffusion electrode composite electrode modified with p-block metal elements, the volume ratio of the auxiliary aqueous solution, the copper salt aqueous solution, the p-block metal salt aqueous solution, the water, the alkaline solution, and the reducing agent aqueous solution is 2:1:1:150:1:1;

[0012] The auxiliary agent in the aqueous solution is sodium citrate;

[0013] The concentration of the aqueous solution of the auxiliary agent is 0.5–1.5 M, specifically 0.9 M;

[0014] The copper salt in the copper salt aqueous solution is at least one of copper sulfate, copper chloride, and copper nitrate and their hydrates, specifically CuSO4·5H2O;

[0015] The concentration of the copper salt aqueous solution is 0.1–1.5 M, specifically 1.2 M;

[0016] The p-block metal salt in the aqueous solution of the p-block metal salt is at least one of gallium nitrate, aluminum nitrate, germanium chloride, and antimony chloride and their hydrates, such as Ga(NO3)3;

[0017] The molar ratio of the copper salt to the p-block metal salt can be (100-2):1, specifically 10:1. In a specific embodiment of the present invention, the concentration of the aqueous solution of the p-block metal salt is 0.12M.

[0018] The alkaline solution is an aqueous solution of NaOH or KOH.

[0019] The concentration of the alkaline solution can be 1–10 M, specifically 4.8 M;

[0020] The method includes a step of first stirring the mixture after adding the alkali solution, wherein the first stirring speed is 300 RPM and the time is 10 minutes;

[0021] The reducing agent in the reducing agent aqueous solution is L-(+)-ascorbic acid;

[0022] The concentration of the reducing agent aqueous solution can be 0.1–1.5 M, such as 0.5–1.5 M, specifically 1.2 M;

[0023] The method includes a second stirring step after adding the reducing agent aqueous solution, wherein the second stirring speed is 300 RPM and the time is 30 minutes;

[0024] The precipitate is separated from the mixed system by centrifugation. The centrifugation time can be 5 to 60 minutes (e.g., 15 minutes), and the centrifugation speed can be 3000 to 12000 RPM (e.g., 8000 RPM).

[0025] The washing solvent is selected from at least one of water, acetone, ethanol and methanol, for example, washing with water and acetone alternately;

[0026] The drying temperature can be 60-120℃, specifically 60℃, and the time can be 6-24 hours, specifically 6 hours.

[0027] In the above-mentioned method for preparing a copper-based catalyst / gas diffusion electrode composite electrode modified with p-block metal elements, the modification includes the following steps: drop-coating a dispersion composed of the solid powder, organic solvent and binder onto a gas diffusion electrode to obtain the catalyst electrode;

[0028] Preferably, the organic solvent may be at least one selected from acetone, isopropanol, ethanol, and methanol;

[0029] Preferably, the ratio of the solid powder to the organic solvent can be 5-50 mg: 1 mL, specifically 5 mg: 1 mL;

[0030] Preferably, the ratio of the binder to the solid powder can be 10-50 μL: 10 mg (e.g., 40 μL: 10 mg), and the binder is a 5 wt.% Nafion D-521 dispersion;

[0031] Preferably, the gas diffusion electrode is one of carbon fiber paper, carbon cloth, carbon black cloth, and PTFE film;

[0032] Preferably, the catalyst loading in the catalytic electrode is 1 mg / cm³. 2 ;

[0033] Preferably, the dispersion is prepared by ultrasonically dispersing the solid powder, the organic solvent and the binder, with an ultrasonic power of 100W to 500W and a time of 20 to 60 minutes, specifically 200W for 30 minutes.

[0034] In the above-mentioned method for preparing a copper-based catalyst / gas diffusion electrode composite electrode modified with p-region metal elements, in the in-situ electrochemical reduction step, the electrolyte can be one of NaOH aqueous solution, KOH aqueous solution, RbOH aqueous solution and CsOH aqueous solution, and the electrolyte concentration can be 0.01-10M, specifically 1M;

[0035] In the in-situ electrochemical reduction step, nickel foam is used as the counter electrode and mercury oxide electrode is used as the reference electrode.

[0036] In the in-situ electrochemical reduction step, the current density can be 50–500 mA / cm². 2 Specifically, it can be 400mA / cm 2 The restoration time can be 5 to 60 minutes, specifically 10 minutes.

[0037] In a second aspect, the present invention provides a copper-based catalyst / gas diffusion electrode composite electrode modified with p-region metal elements prepared by any of the above-described preparation methods.

[0038] Thirdly, the present invention provides an electrochemical catalytic conversion system, comprising the aforementioned copper-based catalyst / gas diffusion electrode composite electrode modified with p-region metal elements, an electrolyte, and a gas diffusion type flow electrolytic cell.

[0039] In the above-mentioned electrochemical catalytic conversion system, the electrolyte can be one of NaOH aqueous solution, KOH aqueous solution, RbOH aqueous solution and CsOH aqueous solution;

[0040] The concentration of the electrolyte is 0.01 to 10 M, specifically 1 M.

[0041] Fourthly, the present invention provides the application of the copper-based catalyst / gas diffusion electrode composite electrode modified with p-region metal elements or the electrochemical catalytic conversion system described above in the preparation of multi-carbon products.

[0042] Fifthly, the present invention provides a method for synthesizing multi-carbon products by electrochemical catalytic conversion of carbon dioxide, comprising the following steps: in the electrochemical catalytic system, carbon dioxide is used as a raw material for in-situ electrochemical reduction, and multi-carbon products are synthesized by reaction in a gas diffusion type flow electrolytic cell through the action of electrodes and electrolyte.

[0043] In the above-mentioned method for electrochemical catalytic conversion of carbon dioxide to synthesize multi-carbon products, in the in-situ electrochemical reduction step, nickel foam is used as the counter electrode and mercury oxide electrode is used as the reference electrode.

[0044] In the in-situ electrochemical reduction step, the current density can be 0.1–1.5 A / cm². 2 Specifically, it can be 0.3 to 1.1 A / cm. 2Preferably, the concentration is 0.5–1.1 A / cm. 2 0.7~1.1A / cm 2 More preferably 0.9A / cm 2 (Voltage is -1.07V vs. RHE);

[0045] The multicarbon products are ethylene, ethanol, acetic acid, and propanol.

[0046] The present invention has the following beneficial effects:

[0047] The composite electrode of this invention is prepared using a simple two-step method: the first step involves the wet synthesis of a catalyst precursor, and the second step involves in-situ electroreduction. The preparation method of the catalytic material is simple, low-cost, highly reproducible, and environmentally friendly, laying a solid foundation for industrial development. The preparation method described in this invention is unique and ingenious, utilizing the pd hybridization effect between p-block metal elements and copper-based materials to regulate the electronic structure of the copper-based materials, ultimately achieving the goal of highly efficient electrochemical catalytic conversion of carbon dioxide into multi-carbon products. This represents a significant breakthrough in the field of carbon dioxide electrocatalytic conversion. This method for the electrochemical catalytic conversion of carbon dioxide into multi-carbon products has important practical application value for the efficient resource utilization of carbon dioxide. This invention uses a copper-based catalyst / gas diffusion electrode composite electrode modified with p-block metal elements as the cathode working electrode. Compared to unmodified copper-based catalysts, it improves catalytic activity and selectivity in the electrochemical catalytic conversion of carbon dioxide into multi-carbon products, while exhibiting excellent electrochemical catalytic conversion stability under high current density conditions, demonstrating good commercial application value. Attached Figure Description

[0048] To illustrate the core solutions of the embodiments of the present invention and the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 The image shows a transmission electron microscope (TEM) image of the copper-gallium catalyst in Example 1 of this invention.

[0050] Figure 2 This is an elemental distribution diagram of the copper-gallium catalyst in Example 1 of the present invention;

[0051] Figure 3 The image shows the X-ray diffraction (XRD) image of the composite electrode in Embodiment 1 of the present invention.

[0052] Figure 4 The figures show the current and voltage of the two composite electrodes used in Example 1 and Comparative Example 1 of this invention for the electrochemical reduction of carbon dioxide.

[0053] Figure 5 This is a distribution diagram of the electrochemical reduction of carbon dioxide products of the copper-gallium catalyst / gas diffusion electrode composite electrode in Example 1 of the present invention;

[0054] Figure 6 This is a distribution diagram of the electrochemical reduction of carbon dioxide products of the copper catalyst / gas diffusion electrode composite electrode in Comparative Example 1 of this invention;

[0055] Figure 7 To assess the stability of the electrochemical catalytic conversion synthesis of multi-carbon products using the copper-gallium catalyst / gas diffusion electrode composite electrode in Example 1 of this invention, a current density of 0.9 A / cm² was used for testing. 2 The left vertical axis represents voltage, and the right vertical axis represents the Faraday efficiency of the multi-carbon products. Detailed Implementation

[0056] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative and not intended to limit the scope of the invention. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0057] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; and the materials and reagents used are commercially available unless otherwise specified.

[0058] Example 1: Preparation of a copper-gallium catalyst / gas diffusion electrode composite electrode

[0059] The copper-gallium catalyst / gas diffusion electrode composite electrode was prepared according to the following steps:

[0060] a. 2 mL of 0.9 M sodium citrate aqueous solution, 1 mL of 1.2 M CuSO4·5H2O aqueous solution and 1 mL of 0.12 M Ga(NO3)3 aqueous solution were added sequentially to 150 mL of deionized water and stirred to form a solution.

[0061] b. Next, add 1 mL of 4.8 M NaOH aqueous solution to the above solution, stir at 300 RPM for 10 minutes, then quickly add 1 mL of 1.2 M L-(+)-ascorbic acid aqueous solution, and continue stirring for 30 minutes to obtain a precipitate.

[0062] c. The above precipitate was separated by centrifugation at 8000 RPM for 15 minutes, with alternating washing with water and acetone during the process, and finally dried in an oven at 60°C for 6 hours.

[0063] d. Weigh 10 mg of the dried product obtained above and disperse it in 2 mL of acetone. Then add 40 μL of 5 wt% Nafion D-521 dispersion (solvents: water and 1-propanol), and sonicate for 30 minutes (power: 200 W) to obtain a catalyst precursor dispersion. Next, drop-coat this dispersion onto a gas diffusion electrode, ensuring a concentration of 1 mg / cm³. 2 Catalyst loading.

[0064] e. Assemble the above electrodes into a gas diffusion flow cell for in-situ electrochemical reduction. The electrolyte is 1 MkOH, the counter electrode is nickel foam, and the reference electrode is a mercury oxide electrode. Carbon dioxide passes through the gas chamber of the flow cell during the electrochemical reduction process, and the current density for electrochemical reduction is 0.4 A / cm². 2 After 10 minutes of reduction, a copper-gallium catalyst / gas diffusion electrode composite electrode can be obtained.

[0065] The final transmission electron microscope image of the copper-gallium catalyst is shown below. Figure 1 See element distribution map. Figure 2 See X-ray diffraction pattern. Figure 3 .from Figure 1 It can be seen that the final copper-gallium catalyst was formed by the self-assembly of nanoparticles. From Figure 2 It can be seen that copper and gallium are uniformly distributed in the catalyst. From Figure 3 As can be seen, the in-situ electroreduction copper-gallium catalyst is supported on a gas diffusion electrode and exhibits the crystal form of metallic copper. Combined with the elemental distribution diagram, we can confirm that gallium exists in a doped form, which is conducive to strong electronic interactions between the two elements and exhibits higher catalytic activity.

[0066] Comparative Example 1: Preparation of a copper catalyst / gas diffusion electrode composite electrode

[0067] In Comparative Example 1, without using Ga(NO3)3 solution, the copper catalyst / gas diffusion electrode composite electrode can be obtained by applying the same steps.

[0068] Example 2: Electrochemical catalytic conversion of carbon dioxide to synthesize multi-carbon products

[0069] All electrochemical catalytic conversion experiments were performed on an electrochemical workstation. The carbon dioxide reduction experiment was conducted at room temperature. The electrochemical reduction performance of the p-region metal element-modified copper-based catalyst / gas diffusion electrode composite electrode of this invention was tested using a three-electrode system: the reference electrode was a calomel electrode, the counter electrode was nickel foam, and the working electrode was the copper-gallium catalyst / gas diffusion electrode composite electrode finally prepared in Example 1. The tests were conducted in a gas diffusion flow electrolyzer, with both the cathode and anolyte being 1 mol / L potassium hydroxide solution. Carbon dioxide gas was continuously introduced into the gas chamber of the flow cell during the test. For the carbon dioxide electrochemical reduction performance of the copper-gallium catalyst / gas diffusion electrode composite electrode in Example 1, please refer to [link to Example 1]. Figure 4 See the electrochemical reduction product distribution diagrams for Example 1 and Comparative Example 1. Figure 5 and Figure 6 As can be seen from the figure, the distribution of carbon dioxide reduction products changes significantly with the change of current density, especially at 0.9 A / cm². 2 At a given current density, the Faradaic efficiency of the copper-gallium catalyst / gas diffusion electrode composite electrode for multi-carbon products can reach 81.5%, requiring only -1.07 V vs. RHE. In contrast, the Faradaic efficiency of the copper catalyst / gas diffusion electrode composite electrode for multi-carbon products is only 52.9%, requiring -1.31 V vs. RHE. This demonstrates that the p-region gallium-modified copper-based catalyst / gas diffusion electrode composite electrode exhibits significantly improved catalytic activity compared to the unmodified copper-based catalyst. This improvement is attributed to the pd orbital hybridization effect between gallium and copper, which optimizes the electronic structure of the catalyst and enhances the selectivity for the electrochemical catalytic conversion of carbon dioxide into multi-carbon products.

[0070] Example 3: Catalytic stability study of the composite electrode

[0071] At 0.9A / cm 2 The long-term stability of the composite electrode can be evaluated by conducting the reaction at a current density for 12 hours. We found that after 12 hours of testing, neither the voltage nor the Faradaic efficiency of the multi-carbon products changed significantly. Figure 7 This indicates that the catalyst composite electrode exhibits excellent electrochemical catalytic conversion stability under high current density conditions, and has good commercial application value.

[0072] The present invention has been described in detail above. Those skilled in the art will recognize that the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope. While specific embodiments have been provided, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including modifications made using conventional techniques known in the art that depart from the scope disclosed herein.

Claims

1. A method for preparing a copper-based catalyst gas diffusion electrode composite electrode modified with p-block metal elements, comprising the following steps: 1) Add the aqueous solution of the auxiliary agent, the aqueous solution of the copper salt, and the aqueous solution of the p-block metal salt to water to obtain a mixed solution; The auxiliary agent in the aqueous solution is sodium citrate; The concentration of the aqueous solution of the auxiliary agent is 0.5~1.5M; The concentration of the copper salt aqueous solution is 0.1~1.5M; The molar ratio of the copper salt to the p-region metal salt is (100~2):1; The p-region metal salt in the p-region metal salt aqueous solution is gallium nitrate; 2) Add an alkaline solution and a reducing agent aqueous solution to the mixture in sequence to obtain a precipitate; The volume ratio of the aqueous solution of the auxiliary agent, the aqueous solution of the copper salt, the aqueous solution of the p-block metal salt, the water, the alkaline solution, and the aqueous solution of the reducing agent is 2:1:1:150:1:1; The concentration of the alkaline solution is 1~10M; The reducing agent in the reducing agent aqueous solution is L-(+)-ascorbic acid; The concentration of the reducing agent aqueous solution is 0.1~1.5M; 3) The precipitate is washed and dried sequentially to obtain a solid powder; 4) The solid powder is modified onto a gas diffusion electrode to obtain a catalytic electrode; 5) The catalytic electrode is assembled into a gas diffusion flow electrolysis cell and in-situ electrochemical reduction is performed using carbon dioxide as raw material to obtain the copper-based catalyst gas diffusion electrode composite electrode modified with the p-region metal element.

2. The method for preparing the p-block metal element-modified copper-based catalyst gas diffusion electrode composite electrode according to claim 1, characterized in that: The copper salt in the copper salt aqueous solution is at least one of copper sulfate, copper chloride, and copper nitrate and their hydrates; The alkaline solution is an aqueous solution of NaOH or KOH. The method includes a step of first stirring the mixture after adding the alkali solution, wherein the first stirring speed is 300 RPM and the time is 10 minutes; The method includes a second stirring step after adding the reducing agent aqueous solution, wherein the second stirring speed is 300 RPM and the time is 30 minutes; The precipitate was separated from the mixed system by centrifugation for 5 to 60 minutes at a speed of 3000 to 12000 RPM. The washing solvent is selected from at least one of water, acetone, ethanol and methanol; The drying temperature is 60~120℃, and the time is 6~24 hours.

3. The method for preparing the copper-based catalyst gas diffusion electrode composite electrode modified with p-block metal elements according to claim 1 or 2, characterized in that: The modification includes the following steps: dropwise coating a dispersion consisting of the solid powder, organic solvent and binder onto a gas diffusion electrode to obtain the catalytic electrode.

4. The method for preparing the p-block metal element-modified copper-based catalyst gas diffusion electrode composite electrode according to claim 3, characterized in that: The organic solvent is at least one of acetone, isopropanol, ethanol, and methanol.

5. The method for preparing the p-block metal element-modified copper-based catalyst gas diffusion electrode composite electrode according to claim 3, characterized in that: The ratio of the solid powder to the organic solvent is 5~50 mg:1 mL.

6. The method for preparing the p-block metal element-modified copper-based catalyst gas diffusion electrode composite electrode according to claim 3, characterized in that: The ratio of the binder to the solid powder is 10~50μL:10mg, and the binder is a 5wt.% Nafion D-521 dispersion.

7. The method for preparing the p-block metal element-modified copper-based catalyst gas diffusion electrode composite electrode according to claim 3, characterized in that: The gas diffusion electrode is one of carbon fiber paper, carbon cloth, carbon black cloth, and PTFE film.

8. The method for preparing the p-block metal element-modified copper-based catalyst gas diffusion electrode composite electrode according to claim 3, characterized in that: The catalyst loading in the catalytic electrode is 1 mg / cm³. 2 .

9. The method for preparing the p-block metal element-modified copper-based catalyst gas diffusion electrode composite electrode according to claim 3, characterized in that: The dispersion is prepared by ultrasonic dispersion of the solid powder, the organic solvent and the binder, with an ultrasonic power of 100W~500W and a time of 10~60 minutes.

10. The method for preparing the copper-based catalyst gas diffusion electrode composite electrode modified with p-block metal elements according to any one of claims 1-2, characterized in that: In the in-situ electrochemical reduction step, the electrolyte is one of NaOH aqueous solution, KOH aqueous solution, RbOH aqueous solution and CsOH aqueous solution, and the electrolyte concentration is 0.01~10M; In the in-situ electrochemical reduction step, nickel foam is used as the counter electrode and mercury oxide electrode is used as the reference electrode. In the in-situ electrochemical reduction step, the current density is 50~500 mA / cm². 2 The restoration time is 5 to 60 minutes.

11. The copper-based catalyst gas diffusion electrode composite electrode modified with p-region metal elements prepared by the preparation method of any one of claims 1-10.

12. An electrochemical catalytic conversion system, comprising the copper-based catalyst gas diffusion electrode composite electrode modified with p-block metal elements as described in claim 11, an electrolyte, and a gas diffusion type flow electrolytic cell.

13. The electrochemical catalytic conversion system according to claim 12, characterized in that: The electrolyte is one of NaOH aqueous solution, KOH aqueous solution, RbOH aqueous solution and CsOH aqueous solution; The concentration of the electrolyte is 0.01~10M.

14. The application of the copper-based catalyst gas diffusion electrode composite electrode modified with p-block metal elements as described in claim 11 or the electrochemical catalytic conversion system as described in claim 12 or 13 in the preparation of multi-carbon products.

15. A method for synthesizing multi-carbon products by electrochemical catalytic conversion of carbon dioxide, comprising the following steps: in the electrochemical catalytic system of claim 12 or 13, in-situ electrochemical reduction of carbon dioxide as raw material, and synthesis of multi-carbon products by reaction in a gas diffusion type flow electrolytic cell through the action of electrodes and electrolyte.

16. The method for electrochemical catalytic conversion of carbon dioxide to synthesize multi-carbon products according to claim 15, characterized in that: In the in-situ electrochemical reduction step, nickel foam is used as the counter electrode and mercury oxide electrode is used as the reference electrode. In the in-situ electrochemical reduction step, the current density is 0.1~1.5 A / cm². 2 ; The multicarbon products are ethylene, ethanol, acetic acid, and propanol.

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