Gas diffusion electrode for electrocatalytic co 2 reduction to co, preparation method and use

Abstract

The present application provides a preparation method for a gas diffusion electrode for electrocatalytic CO2 reduction to CO, comprising: mixing a conductive polymer monomer solution and a metal salt solution at a molar ratio of 100:1 to 1:100 and adding a dispersant to form a mixed solution; and transferring the mixed solution onto a substrate, and reacting at a temperature ranging from -30°C to 50°C for 1-48 h to obtain a gas diffusion electrode. According to the present application, a metal-conductive polymer gas diffusion electrode is formed by means of in-situ growth of conductive polymer monomers self-initiated by metal ions; due to the characteristics of the conductive polymer, the gas diffusion electrode can provide more nucleation sites, reducing the usage amount of metal while achieving similar catalytic effects; secondly, the special structure of the conductive polymer improves the electron transfer rate and the CO2 adsorption capacity on the electrode surface, helping to improve the product selectivity; and finally, the conductive polymer is an organic macromolecular long-chain structure, and the substrate, metal particles and metal-ligand complex to which the conductive polymer is bound can be stabilized by means of cross-linking, thereby improving the stability of the electrode.

Description

Gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO, preparation method and application Technical Field

[0001] The present application relates to the technical field of electrocatalytic CO2 reduction, and in particular to a method for preparing a gas-phase diffusion electrode for electrocatalytic CO2 reduction to produce CO, a gas-phase diffusion electrode for electrocatalytic CO2 reduction to produce CO, and applications thereof. Background Art

[0002] With atmospheric CO2 concentrations increasing dramatically from 270 ppm in the early 19th century to 420 ppm in 2023, recycling CO2 waste gas is becoming increasingly urgent. As a major CO2 emitter, China is actively fulfilling its responsibilities as a major country, proposing "dual carbon" goals and fully promoting carbon emission reductions among businesses.

[0003] New clean energy technologies, such as solar, wind, and nuclear, are developing rapidly. While they are not yet sufficient to replace fossil fuels, obtaining renewable electricity through inexpensive and efficient means has become a reality. Against this backdrop, electrocatalytic CO2 reduction, as a clean and controllable energy conversion technology, is emerging as an effective solution for CO2 emissions reduction.

[0004] The development prospects of electrocatalytic CO2 reduction are very broad, but also extremely challenging. From the perspective of reaction mechanism, CO2 is very chemically inert, so CO2 reduction is very challenging in terms of thermodynamics. On the other hand, the reaction involves a large number of basic steps, reactants and intermediates, which is also very challenging in terms of kinetics. From a production perspective, water is currently usually used as a hydrogen source for electrocatalytic CO2 reduction. On the one hand, the solubility of CO2 in water is very low, and on the other hand, the competition of the hydrogen evolution reaction (HER) inhibits the selectivity of CO2 reduction. Therefore, in order to promote the industrialization of electrochemical reduction of CO2, it is necessary to design electrodes with higher conductivity, better catalytic effect and stronger stability.

[0005] Traditional catalysts for electrocatalytic CO2 reduction are metal-based catalysts, which are classified according to their composition into three main categories: monometallic catalysts, multimetallic catalysts, and modified metal composite catalysts. The selectivity of monometallic catalyst products is closely related to the metal size, morphology, and exposed crystal faces, while the selectivity of multimetallic catalyst products is also closely related to the metal type, ratio, and valence state. These two types of catalysts have high requirements for the preparation process and are relatively expensive. Metal composite catalysts are relatively inexpensive and have relatively low preparation requirements, but the modified substances are often insulating materials, resulting in poor catalyst conductivity and the need for the addition of conductive carbon black.

[0006] The traditional electrode preparation method for electrocatalytic CO2 reduction is to first synthesize a powder catalyst and then load it onto the substrate surface by scraping, dripping or spin coating. The adhesion between the catalyst and the substrate is poor, and the overall stability is poor.

[0007] Summary of the Invention

[0008] In view of this, it is necessary to provide a method for preparing a gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO, as well as a gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO and its application, which has low cost, high selectivity, good conductivity and excellent stability, in order to address the defects of traditional electrodes in electrocatalytic CO2 reduction to CO, such as low selectivity, poor stability and poor conductivity.

[0009] To solve the above problems, this application adopts the following technical solutions:

[0010] One of the purposes of this application is to provide a method for preparing a gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO, comprising the following steps:

[0011] A conductive polymer monomer solution and a metal salt solution in a molar ratio of 100:1 to 1:100 are mixed and a dispersant is added to form a mixed solution.

[0012] The mixed solution is transferred to a substrate and reacted at a temperature of -30°C to 50°C for 1-48 hours to obtain a metal-conductive polymer composite gas phase diffusion electrode for electrocatalytic CO2 reduction to CO.

[0013] In some embodiments, before the step of mixing the conductive polymer monomer solution with the metal salt solution and adding a dispersant to form a mixed solution, the following step is also included: pre-temperature-treating the conductive polymer monomer solution and the metal salt solution at 30°C to -18°C.

[0014] In some embodiments, the conductive polymer monomer solution is prepared by the following method: adding the conductive polymer monomer to the acidic solution and mixing them uniformly to obtain the conductive polymer monomer solution, wherein the molar ratio of the conductive polymer monomer to the acidic solution is 50:1-1:50.

[0015] In some embodiments, the conductive polymer monomer is one or more of aniline, pyrrole, thiophene, indole, pyridine, carbazole, dopamine, and p-phenylene vinyl monomers.

[0016] In some embodiments, the solute of the acidic solution includes one or more of hydrochloric acid, sulfuric acid, nitric acid, formic acid, acetic acid, dodecylbenzenesulfonic acid, p-toluenesulfonic acid, and camphorsulfonic acid; the solvent of the acidic solution is one or more of water, methanol, ethanol, isopropanol, acetonitrile, ethyl acetate, chloroform, dichloromethane, acetone, N-methylpyrrolidone, dimethylformamide, and dimethyl sulfoxide.

[0017] In some embodiments, the metal salt includes one or more of silver nitrate, silver hypochlorite, silver chlorate, silver perchlorate, silver fluoride, silver acetate, silver trifluoroacetate, silver trifluoromethanesulfonate, silver methanesulfonate, silver p-toluenesulfonate, chloroauric acid, zinc nitrate, zinc hypochlorite, zinc chlorate, zinc perchlorate, palladium nitrate, palladium hypochlorite, palladium chlorate, palladium perchlorate, and gallium nitrate.

[0018] In some embodiments, the dispersant is one or more of isopropanol, methanol, ethanol, ethyl acetate, acetonitrile, N-methylpyrrolidone, and dimethylformamide.

[0019] In some embodiments, before transferring the mixed solution to a substrate and reacting it at a temperature of -30°C to 50°C for 1-48 hours to obtain a metal-conductive polymer composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO, the following step is also included: cleaning the surface of the substrate with a hydrated organic solvent.

[0020] In some embodiments, the step of cleaning the substrate surface with a hydrated organic solvent specifically includes: coating the substrate surface with an ionic polymer solution and allowing it to air dry naturally, wherein the amount of the ionic polymer is 0-1 mg / cm 2 between.

[0021] In some embodiments, the substrate materials include polytetrafluoroethylene membrane, polyvinylidene fluoride membrane, polytetrafluoroethylene carbon membrane, polyethylene membrane, non-woven fabric, cellulose membrane film and modified substrate materials thereof.

[0022] In some embodiments, in the step of transferring the mixed solution onto a hydrophobic film substrate and reacting at a temperature of -30°C to 50°C for 1-48 hours to obtain a metal-conductive polymer composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO, the transferring includes one of drop coating, spray coating, blade coating, and spin coating.

[0023] The second purpose of this application is to provide a gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO, which is prepared by the preparation method.

[0024] The third purpose of this application is to provide an application of the gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO in the CO2 electrocatalytic reduction reaction.

[0025] This application adopts the above technical solution, and its beneficial effects are as follows:

[0026] The present application provides a method for preparing a gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO, comprising mixing a conductive polymer monomer solution with a molar ratio of 100:1 to 1:100 with a metal salt solution and adding a dispersant to form a mixed solution, transferring the mixed solution to a substrate, and reacting the mixture at a temperature of -30°C to 50°C for 1-48 hours to obtain a metal-conductive polymer composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO. The present application provides a method for preparing a gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO, wherein a metal ion self-initiates in-situ growth of a conductive polymer monomer to form a metal. The metal-conductive polymer integrated composite is used for a gas-phase diffusion electrode for the electrocatalytic reduction of CO2 to CO. Due to the characteristics of the conductive polymer, the gas-phase diffusion electrode for the electrocatalytic reduction of CO2 to CO can provide more nucleation sites, thereby reducing the amount of metal used while achieving a similar catalytic effect; secondly, the special structure of the conductive polymer increases the electron transfer rate and the amount of CO2 adsorbed on the electrode surface, which is beneficial to improving product selectivity; finally, the conductive polymer is an organic macromolecular long-chain structure, which can stabilize the substrate, metal particles and metal-ligand complex to which it is bound through cross-linking, thereby improving the stability of the electrode.

[0027] In addition, the preparation method of the gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO in the present invention has the characteristics of simple preparation, low price, environmental friendliness, high efficiency and stability, and has the prospect of large-scale industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0029] FIG1 is a flow chart showing the steps of a method for preparing a gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO provided in this embodiment.

[0030] FIG2 is a SEM schematic diagram of a gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO based on a metal-conductive polymer composite in Example 1.

[0031] FIG3 is a bar graph showing the selectivity of catalytic reduction of CO using a metal-conductive polymer composite electrode at different currents in Example 1. DETAILED DESCRIPTION

[0032] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0033] In the description of this application, it should be understood that the terms "upper", "lower", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on this application.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0035] In order to make the purpose, technical solutions and advantages of this application more clear, this application is further described in detail below with reference to the accompanying drawings and embodiments.

[0036] Please refer to FIG1 , which is a flowchart of the steps of the method for preparing a gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO provided in this embodiment, including the following steps S110 to S120 . The implementation method of each step is described in detail below.

[0037] Step S110: mixing a conductive polymer monomer solution and a metal salt solution at a molar ratio of 100:1 to 1:100 and adding a dispersant to form a mixed solution.

[0038] In this embodiment, before the step of mixing the conductive polymer monomer solution with the metal salt solution and adding a dispersant to form a mixed solution, the following step is also included: pre-temperature-treating the conductive polymer monomer solution and the metal salt solution at 30°C to -18°C to reduce the reaction rate and improve the uniformity of the electrode.

[0039] In this embodiment, the conductive polymer monomer solution is prepared by the following method: adding the conductive polymer monomer to the acidic solution and mixing them uniformly to obtain the conductive polymer monomer solution, wherein the molar ratio of the conductive polymer monomer to the acidic solution is 50:1-1:50.

[0040] In this embodiment, the conductive polymer monomer is one or more of aniline, pyrrole, thiophene, indole, pyridine, carbazole, dopamine, and p-phenylene vinyl monomers.

[0041] In this embodiment, the solute of the acidic solution includes one or more of hydrochloric acid, sulfuric acid, nitric acid, formic acid, acetic acid, dodecylbenzenesulfonic acid, p-toluenesulfonic acid, and camphorsulfonic acid; the solvent of the acidic solution is one or more of water, methanol, ethanol, isopropanol, acetonitrile, ethyl acetate, chloroform, dichloromethane, acetone, N-methylpyrrolidone, dimethylformamide, and dimethyl sulfoxide.

[0042] In this embodiment, the metal salt includes one or more of silver nitrate, silver hypochlorite, silver chlorate, silver perchlorate, silver fluoride, silver acetate, silver trifluoroacetate, silver trifluoromethanesulfonate, silver methanesulfonate, silver p-toluenesulfonate, chloroauric acid, zinc nitrate, zinc hypochlorite, zinc chlorate, zinc perchlorate, palladium nitrate, palladium hypochlorite, palladium chlorate, palladium perchlorate, and gallium nitrate.

[0043] In this embodiment, the dispersant is one or more of isopropyl alcohol, methanol, ethanol, ethyl acetate, acetonitrile, N-methylpyrrolidone, and dimethylformamide.

[0044] The main chain of the conductive polymer provided in this embodiment generally has a conjugated structure, and its polymerization process is mostly oxidative coupling of monocyclic precursors. Therefore, an oxidizing metal salt can be used instead of an initiator to initiate polymerization in situ, and the catalytic selectivity and stability can be improved by designing a metal-conductive polymer composite electrode; the conductive polymer is an organic macromolecular long-chain structure, and its bound substrate, metal particles, and metal-ligand complex can be stabilized by cross-linking, thereby improving the stability of the electrode.

[0045] Step S120: transferring the mixed solution onto a substrate, reacting at a temperature of -30°C to 50°C for 1-48 hours, and obtaining a metal-conductive polymer composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO.

[0046] In this embodiment, before transferring the mixed solution to a substrate and reacting it at a temperature of -30°C to 50°C for 1-48 hours to obtain a metal-conductive polymer composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO, the following step is also included: cleaning the surface of the substrate with a hydrated organic solvent.

[0047] In this embodiment, the step of using a hydrated organic solvent to clean the substrate surface specifically includes: coating an ionic polymer solution on the substrate surface and allowing it to air dry naturally, wherein the amount of the ionic polymer used is 0-1 mg / cm 2 between.

[0048] In this embodiment, the substrate materials include polytetrafluoroethylene film, polyvinylidene fluoride film, polytetrafluoroethylene carbon film, polyethylene film, non-woven fabric, cellulose film and modified base materials thereof.

[0049] In this embodiment, in the step of transferring the mixed solution onto a hydrophobic film substrate and reacting at a temperature of -30°C to 50°C for 1-48 hours to obtain a metal-conductive polymer composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO, the transfer includes one of drip coating, spray coating, blade coating, and spin coating.

[0050] The metal-conductive polymer composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO provided by the present invention can be applied to a reaction system for electrocatalytic CO2 reduction to CO.

[0051] The gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO prepared in the above embodiments of the present application forms a metal-conductive polymer integrated composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO by a method of in-situ growth of conductive polymer monomers initiated by metal ions. Due to the characteristics of the conductive polymer, the gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO can provide more nucleation sites, while achieving similar catalytic effects, reducing the amount of metal used; the gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO prepared in the above embodiments of the present application can be applied to the reaction system of CO2 electrocatalytic reduction to CO, which can increase the CO2 adsorption amount on the catalyst surface. At the same time, the special structure of the conductive polymer improves the electron conduction rate, increases the chance of electron reduction of CO2 or intermediates, improves the selectivity of CO2 reduction to CO, and realizes the circular economic utilization and conversion of carbon dioxide.

[0052] The following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0053] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application.

[0054] Example 1

[0055] This embodiment provides a gas-phase diffusion electrode for electrocatalytic reduction of CO2 to produce CO, comprising the following steps:

[0056] (1) Prepare aniline monomer solution (Solution A): Take 0.8 mmol of acetic acid solution, add 0.4 mmol of aniline, and then add 200 μL of isopropanol, stir and mix well, and pre-cool for 2 hours;

[0057] (2) Prepare silver nitrate solution (Solution B): Take 0.1 mmol of silver nitrate solution, add 100 μL of isopropanol, and pre-cool for 2 h;

[0058] (3) Solution A and solution B in Example 1 were uniformly mixed and rapidly added dropwise to the surface of the PTFE carbon membrane for metal ion self-initiated in situ polymerization reaction. The reaction temperature was 0°C and the reaction time was 12 h to prepare a silver-polyaniline composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO, which was labeled as AgNO3(1)-PANI(4)-nafion0-PTFE(C) composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO.

[0059] Table 1 Electrocatalytic performance of the catalyst samples prepared in Example 1 at different currents.

[0060] Please refer to Figure 2, which is a SEM schematic diagram of the gas-phase diffusion electrode based on the metal-conductive polymer composite for electrocatalytic CO2 reduction to CO in Example 1. Figure 3 is a bar graph of the selectivity of CO production by catalytic reduction using the metal-conductive polymer composite electrode at different currents in Example 1.

[0061] Example 2

[0062] This embodiment provides a gas-phase diffusion electrode for electrocatalytic reduction of CO2 to produce CO, comprising the following steps:

[0063] (1) Prepare aniline monomer solution (Solution A): Take 0.8 mmol of acetic acid solution, add 0.4 mmol of aniline, and then add 200 μL of isopropanol, stir and mix well, and pre-cool for 2 hours;

[0064] (2) Prepare silver nitrate solution (Solution B): Take 0.1 mmol of silver nitrate solution, add 100 μL of isopropanol, and pre-cool for 2 h;

[0065] (3) Prepare Nafion solution: Disperse 30 μL of Nafion in 1000 μL of isopropanol and add it dropwise to a 4×4 cm 2 On PTFE carbon film substrate;

[0066] (4) Solution A and solution B in Example 2 were uniformly mixed and rapidly added dropwise to the surface of the PTFE carbon membrane for metal ion self-initiated in situ polymerization reaction. The reaction temperature was 0°C and the reaction time was 12 h to prepare a silver-polyaniline composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO, which was labeled as AgNO3(1)-PANI(4)-nafion30-PTFE(C) composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO.

[0067] Table 2 Electrocatalytic performance of the catalyst samples prepared in Example 2 at different currents.

[0068] Example 3

[0069] This embodiment provides a gas-phase diffusion electrode for electrocatalytic reduction of CO2 to produce CO, comprising the following steps:

[0070] (1) Prepare aniline monomer solution (Solution A): Take 0.8 mmol of acetic acid solution, add 0.4 mmol of aniline, and then add 200 μL of isopropanol, stir and mix well, and pre-cool for 2 hours;

[0071] (2) Prepare silver nitrate solution (Solution B): Take 0.1 mmol of silver nitrate solution, add 100 μL of isopropanol, and pre-cool for 2 h;

[0072] (3) Prepare Nafion solution: Disperse 10 μL of Nafion in 1000 μL of isopropanol and add it dropwise to a 4×4 cm 2 On PTFE carbon film substrate;

[0073] (4) Solution A and solution B in Example 3 were uniformly mixed and rapidly added dropwise to the surface of the PTFE carbon membrane for metal ion self-initiated in situ polymerization reaction. The reaction temperature was 0°C and the reaction time was 12 h to prepare a silver-polyaniline composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO, which was labeled as AgNO3(1)-PANI(4)-nafion10-PTFE(C) composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO.

[0074] Table 3 Electrocatalytic performance of the catalyst samples prepared in Example 3 at different currents.

[0075] Example 4

[0076] This embodiment 4 provides a gas-phase diffusion electrode for electrocatalytic reduction of CO2 to produce CO, comprising the following steps:

[0077] (1) Prepare aniline monomer solution (Solution A): Take 0.8 mmol of acetic acid solution, add 0.4 mmol of aniline, and then add 200 μL of isopropanol, stir and mix well, and pre-cool for 2 hours;

[0078] (2) Prepare silver trifluoromethanesulfonate solution (Solution B): Take 0.1 mmol of silver trifluoromethanesulfonate solution, add 100 μL of isopropanol, and pre-cool for 2 h;

[0079] (3) Solution A and solution B in Example 4 were uniformly mixed and rapidly added dropwise to the surface of the PTFE carbon membrane for metal ion self-initiated in situ polymerization reaction. The reaction temperature was 0°C and the reaction time was 12 h to prepare a silver-polyaniline composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO, which was labeled as AgOTf(1)-PANI(4)-nafion0-PTFE(C) composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO.

[0080] Table 4 Electrocatalytic performance of the catalyst samples prepared in Example 4 at different currents.

[0081] Example 5

[0082] This embodiment provides a gas-phase diffusion electrode for electrocatalytic reduction of CO2 to produce CO, comprising the following steps:

[0083] (1) Prepare aniline monomer solution (Solution A): Take 0.8 mmol of acetic acid solution, add 0.4 mmol of aniline, and then add 200 μL of isopropanol, stir and mix well, and pre-cool for 2 hours;

[0084] (2) Prepare silver nitrate solution (Solution B): Take 0.0625 mmol of silver nitrate solution, add 100 μL of isopropanol, and pre-cool for 2 h;

[0085] (3) Solution A and solution B in Example 5 were uniformly mixed and rapidly added dropwise to the surface of the PTFE carbon membrane for metal ion self-initiated in situ polymerization reaction. The reaction temperature was 0°C and the reaction time was 12 h to prepare a silver-polyaniline composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO, which was labeled as AgNO3(1)-PANI(64)-nafion0-PTFE(C) composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO.

[0086] Table 5 Electrocatalytic performance of the catalyst samples prepared in Example 5 at different currents

[0087] Comparative Example 1

[0088] Take 0.8mmol acetic acid solution, 0.4mmol polyaniline, 0.1mmol AgNO3 and 10μL Nafion solution, disperse them in 1000μL isopropanol, and add them dropwise on a 4×4cm 2 On a PTFE carbon film substrate, an ex-situ polymerized silver-polyaniline composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO was obtained, and its performance was evaluated in the same electrolytic cell under the same operating conditions.

[0089] Since the ex-situ polymerized silver-polyaniline composite catalyst has poor adhesion to the substrate, experiments cannot be carried out in a gas-phase diffusion electrolysis cell.

[0090] Effect verification

[0091] The performance of the metal-conductive polymer composite electrodes of Examples 1-5 and Comparative Example 1 of the present invention was evaluated using a gas phase diffusion electrolytic cell as a CO2 catalytic reduction reaction device. The specific measurement conditions were:

[0092] CO was detected by online gas chromatography (GC2014, Shimadzu, Japan) with a sampling interval of 40 min.

[0093] Gas phase diffusion electrolytic cell CO2 electroreduction performance test:

[0094] (1) Reference electrode: mercury-mercury oxide electrode;

[0095] (2) Counter electrode: platinum electrode;

[0096] (3) Working electrode: Metal-conductive polymer composite electrode (1×1 cm 2 );

[0097] (4) Electrolyte: 1 M KOH solution;

[0098] (5) Ion exchange membrane: Fumasep FAA-3-PK-130;

[0099] (6) CO2 flow rate: 20 sccm;

[0100] Faraday efficiency (FE) calculation:

[0101] For gaseous products, we usually use gas chromatograph for quantitative analysis. The Faraday efficiency calculation formula is: in:

[0102] In the formula, z is the number of transferred electrons; F is the Faraday constant (96485C·mo1 -1 ); C is the concentration of the product (ppm×10 -6 ); v is the gas flow rate into the chromatogram (m 3 ·s -1 ); P is the pressure of the chromatographic injection loop (Pa); j is the current density (A); R is the ideal gas constant (8.314 J·mol -1 ·K -1 ); T is the temperature of the chromatographic injection loop (K).

[0103] It can be seen from Examples 1-5 and Comparative Example 1 that when the metal-conductive polymer composite electrode provided by the present invention is used in the electrocatalytic CO2 to CO process, the reaction selectivity and the stability of the electrode are greatly improved.

[0104] It can be understood that the various technical features of the above-described embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0105] The above are merely preferred embodiments of the present application and only specifically describe the technical principles of the present application. These descriptions are intended only to explain the principles of the present application and should not be construed in any way as limiting the scope of protection of the present application. Based on the explanations herein, any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present application, as well as other specific implementations of the present application that can be conceived by those skilled in the art without inventive effort, shall be included within the scope of protection of the present application.

Claims

1. A method for preparing a gas phase diffusion electrode for electrocatalytic CO2 reduction to CO, characterized in that: The steps include: Mixing a conductive polymer monomer solution and a metal salt solution at a molar ratio of 100:1 to 1:100 and adding a dispersant to form a mixed solution; The mixed solution is transferred to a substrate, and reacted at a temperature of -30°C to 50°C for 1 to 48 hours to obtain a metal-conductive polymer composite gas phase diffusion electrode for electrocatalytic CO2 reduction to produce CO.

2. The method for preparing a gas phase diffusion electrode for electrocatalytic CO2 reduction to CO as claimed in claim 1, characterized in that: Before the step of mixing the conductive polymer monomer solution with the metal salt solution and adding a dispersant to form a mixed solution, the method further includes the following step: pre-thermalizing the conductive polymer monomer solution and the metal salt solution at 30°C to -18°C.

3. The method for preparing a gas phase diffusion electrode for electrocatalytic CO2 reduction to CO as claimed in claim 1, characterized in that: The conductive polymer monomer solution is prepared by the following method: adding the conductive polymer monomer into the acidic solution and mixing them uniformly to obtain the conductive polymer monomer solution, wherein the molar ratio of the conductive polymer monomer to the acidic solution is 50:1-1:

50.

4. The method for preparing a gas phase diffusion electrode for electrocatalytic CO2 reduction to CO as claimed in claim 3, characterized in that: The conductive polymer monomer is one or more of aniline, pyrrole, thiophene, indole, pyridine, carbazole, dopamine, and p-phenylene vinylene monomers.

5. The method for preparing a gas phase diffusion electrode for electrocatalytic CO2 reduction to CO as claimed in claim 3, characterized in that: The solute of the acidic solution includes one or more of hydrochloric acid, sulfuric acid, nitric acid, formic acid, acetic acid, dodecylbenzenesulfonic acid, p-toluenesulfonic acid, and camphorsulfonic acid; the solvent of the acidic solution is one or more of water, methanol, ethanol, isopropanol, acetonitrile, ethyl acetate, chloroform, dichloromethane, acetone, N-methylpyrrolidone, dimethylformamide, and dimethyl sulfoxide.

6. The method for preparing a gas phase diffusion electrode for electrocatalytic CO2 reduction to CO as claimed in claim 1, characterized in that: The metal salt includes one or more of silver nitrate, silver hypochlorite, silver chlorate, silver perchlorate, silver fluoride, silver acetate, silver trifluoroacetate, silver trifluoromethanesulfonate, silver methanesulfonate, silver p-toluenesulfonate, chloroauric acid, zinc nitrate, zinc hypochlorite, zinc chlorate, zinc perchlorate, palladium nitrate, palladium hypochlorite, palladium chlorate, palladium perchlorate, and gallium nitrate.

7. The method for preparing a gas phase diffusion electrode for electrocatalytic CO2 reduction to CO as claimed in claim 1, characterized in that: The dispersant is one or more of isopropanol, methanol, ethanol, ethyl acetate, acetonitrile, N-methylpyrrolidone and dimethylformamide.

8. The method for preparing a gas phase diffusion electrode for electrocatalytic CO2 reduction to CO as claimed in claim 1, characterized in that: Before the step of transferring the mixed solution to a substrate and reacting it at a temperature of -30°C to 50°C for 1-48h to obtain a metal-conductive polymer composite gas-phase diffusion electrode for electrocatalytic CO2 reduction to CO, the method also includes the following step: cleaning the surface of the substrate with a hydrated organic solvent.

9. The method for preparing a gas phase diffusion electrode for electrocatalytic CO2 reduction to CO as claimed in claim 8, characterized in that: The step of using a hydrated organic solvent to clean the substrate surface specifically includes: coating an ionic polymer solution on the substrate surface and air-drying the solution naturally, wherein the amount of the ionic polymer is 0-1 mg / cm 2 between.

10. The method for preparing a gas phase diffusion electrode for electrocatalytic CO2 reduction to CO as claimed in claim 1 or 8, characterized in that: The invention comprises polytetrafluoroethylene film, polyvinylidene fluoride film, polytetrafluoroethylene carbon film, polyethylene film, non-woven fabric, cellulose film and modified base materials thereof.

11. The method for preparing a gas phase diffusion electrode for electrocatalytic CO2 reduction to CO as claimed in claim 1, characterized in that: In the step of transferring the mixed solution onto a hydrophobic film substrate and reacting at a temperature of -30°C to 50°C for 1-48 hours to obtain a metal-conductive polymer composite gas phase diffusion electrode for electrocatalytic CO2 reduction to CO, the transfer includes one of drip coating, spray coating, scraping coating, and spin coating.

12. A gas phase diffusion electrode for electrocatalytic CO2 reduction to CO, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 11.

13. Use of the gas phase diffusion electrode for electrocatalytic reduction of CO2 to produce CO as claimed in claim 12 in a CO2 electrocatalytic reduction reaction.

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