A device and method for reducing carbon dioxide to prepare multi-carbon products by connecting a low-temperature plasma in series with an electrolytic cell

Abstract

The present invention discloses a device and method for reducing carbon dioxide to prepare multi-carbon products by connecting a low-temperature plasma in series with an electrolytic cell. After the catalyst is synthesized, it is modified by using low-temperature plasma technology to improve the efficiency of the Cu-based catalyst in catalyzing the electro-reduction of carbon dioxide. Compared with the direct electro-catalytic reduction of carbon dioxide gas into a membrane electrode assembly MEA to synthesize multi-carbon products, the present invention passes carbon dioxide gas through a self-made corona low-temperature plasma reactor to achieve excitation and activation of the inert carbon dioxide gas, and the plasma after the corona reaction is passed into the catalyst layer of the cathode reaction chamber of the membrane electrode assembly MEA to promote the electro-reduction of carbon dioxide into multi-carbon products. The present invention effectively solves the problem that inert carbon dioxide is difficult to activate and convert in traditional electrolytic cells, and realizes the new plasma technology and electrocatalytic CO 2 The cross-coupling of the reduction process provides a new process for the electro-reduction of carbon dioxide gas into liquid fuel, solving the current problems of carbon dioxide emissions and energy shortages.

Description

Technical Field

[0001] The present invention belongs to the technical field of low-temperature plasma technology and electrocatalytic carbon dioxide, and in particular relates to a device and method for reducing carbon dioxide to prepare multi-carbon products by connecting a low-temperature plasma in series with an electrolytic cell. The device and method combine plasma technology and electrocatalytic technology to efficiently promote the conversion of carbon dioxide gas into multi-carbon products. Background Art

[0002] Currently, the main methods involved in CO2 conversion include photocatalysis, thermal catalysis and electrocatalysis. If CO2 can be converted into multi-carbon compounds that we can use, it will not only solve the environmental pollution problem caused by CO2, but also solve the energy shortage problem currently facing the world.

[0003] Electrocatalytic CO2 conversion has many advantages, such as low requirements for reaction conditions, fast reaction rate, and easy adjustment of the reaction process, so it has attracted much attention. At present, the research technology based on Cu-based catalysts to catalyze the conversion of CO2 to multi-carbon products is relatively mature. By adjusting the valence state of different Cu elements, the surface structure and composition of Cu-based catalysts, and introducing other metal elements, the electrocatalytic reduction of CO2 to multi-carbon products can be promoted or changed. However, since CO2 is an inert gas, its C=O double bond has high stability. In the electrocatalytic process, high energy is required to break its C=O double bond (803kJ / mol) to activate it. In addition, the traditional electrocatalytic process is carried out in a liquid electrolyte, and the strong hydrogen evolution reaction will also inhibit the conversion of CO2, resulting in low energy utilization efficiency. Therefore, the electrocatalytic conversion of CO2 to multi-carbon products still faces problems such as difficult synthesis of multi-carbon products and low yield.

[0004] Low-temperature plasma technology mainly uses high-voltage discharge technology to activate inert gas molecules under normal temperature and pressure. The high-voltage power supply provides electrical energy to excite inert CO2 gas molecules, and the generated high-energy electrons collide at high frequencies to form a series of activated components such as ions, free radicals, and excited molecules. Therefore, the use of low-temperature plasma technology to activate CO2 gas molecules, after the CO2 molecules are excited to an activated state, and then through electrocatalytic technology, it will be more conducive to the generation of multi-carbon compounds. In addition, low-temperature plasma technology has the advantages of simple equipment and easy operation.

[0005] Converting CO2 into multi-carbon organic matter is one of the current research hotspots. In the face of the continuous consumption of fossil energy, it is urgent to find new alternative energy sources. Multi-carbon compounds will regenerate CO2 gas during use. The technology of recycling CO2 gas is very promising. Therefore, the combination of low-temperature plasma technology and electrocatalytic CO2 reduction technology can generate green energy, and then renewable energy can be used as the energy supply for low-temperature plasma technology and electrocatalytic process, which can form a truly green, pollution-free, zero-emission renewable energy recycling system.

[0006] Therefore, the present invention is expected to change the current difficulties of CO2 conversion and low product selectivity by coupling low-temperature plasma technology with CO2 electrocatalysis technology, thereby synthesizing multi-carbon products with better application prospects. Summary of the invention

[0007] The present invention is based on the problem that the current CO2 electrocatalysis has low efficiency and low selectivity of multi-carbon target products, and proposes a device and method for promoting the conversion of CO2 to multi-carbon target products. The activation state of CO2 molecules is stimulated by low-temperature plasma technology, thereby promoting the efficient conversion of CO2 jet plasma gas in the membrane electrode assembly MEA. The method has the advantages of simple process flow, low working requirements, high practical value of products, environmental friendliness, and flexible reaction operation.

[0008] The object of the present invention is achieved through the following technical scheme: a device for reducing carbon dioxide to prepare multi-carbon products by connecting a low-temperature plasma in series with an electrolytic cell, the device comprising a jet plasma array and a membrane electrode assembly MEA connected in series;

[0009] The jet plasma array contains six high-voltage electrodes connected in series and evenly arranged, which increases the residence time of carbon dioxide gas being activated, promotes more inert carbon dioxide gas to be converted into a plasma state, and the carbon dioxide gas in an excited state is introduced into the catalyst layer of the cathode reaction chamber of the membrane electrode assembly MEA and is reduced to a multi-carbon product;

[0010] The membrane electrode assembly MEA adopts a Cu-based catalyst, and the Cu-based catalyst is treated by low-temperature plasma technology. The catalyst surface and the carbon paper surface are physically modified by plasma treatment, so that the catalyst and the carbon paper surface have a hydrophobic effect, thereby inhibiting the hydrogen evolution reaction (HER). The electrolyte of the anode reaction chamber of the membrane electrode assembly MEA adopts a potassium chloride solution, in which the chloride ions interact with the electron cloud of the electrons of the Cu-based catalyst metal atoms, and are chemically modified to change the charge density of the CO2 electroreduction process and improve the selectivity of multi-carbon products.

[0011] Furthermore, the outermost layer of the jet plasma array is sealed by insulating sealing material, and the high-voltage electrode is fixed in the sealed cavity by insulating screws. The entire sealed cavity is 280 mm in length, 60 mm in height, and 100 mm in width. The entire jet plasma array is in a sealed state and can work at normal temperature and pressure.

[0012] Furthermore, the high-voltage electrode has a height of 80 mm and a diameter of 2 mm, and the interval between each high-voltage electrode is 40 mm.

[0013] Furthermore, the high voltage electrode is provided with electric energy by a high voltage power supply.

[0014] Furthermore, the Cu-based catalyst is selected from CuPd, CuFe, CuAg, and CuNi bimetallic catalysts.

[0015] Furthermore, a carbon dioxide mass flow meter is installed on the carbon dioxide inlet of the jet plasma array.

[0016] Furthermore, the device also includes an electrochemical workstation, which includes a cathode electrode clamp, a reference electrode clamp and an anode electrode clamp; the membrane electrode assembly MEA includes a CO2 inlet, a gas outlet, an anolyte input port, an anolyte output port, a cathode catalyst layer, an anion exchange membrane, an anode catalyst layer, a cathode working electrode, and an anode working electrode. The two catalyst layers of the membrane electrode assembly MEA are separated by an anion exchange membrane to allow only anions to be exchanged between the two electrodes to prevent cations from affecting the reaction process;

[0017] The cathode electrode clip and anode electrode clip of the electrochemical workstation are connected to the cathode working electrode and anode working electrode of the membrane electrode assembly MEA in sequence, and the anode electrode clip and the reference electrode clip of the electrochemical workstation are short-circuited. After being activated by the jet plasma array, the carbon dioxide gas is introduced into the cathode catalyst layer through the CO2 inlet. The gas products produced by the reaction are detected online by gas chromatography, and the liquid products are collected once in the cathode reaction liquid and then analyzed by nuclear magnetic resonance hydrogen spectrum (NMR).

[0018] On the other hand, the present invention also provides a method for reducing carbon dioxide to prepare multi-carbon products by using a low-temperature plasma in series with an electrolytic cell, the method comprising the following steps:

[0019] (1) By adjusting the parameters of a carbon dioxide mass flow meter, the flow rate of carbon dioxide gas entering the jet plasma array is controlled, the jet plasma array is connected to a high-voltage power supply, and six high-voltage electrodes are used to break down carbon dioxide to generate plasma by glow discharge;

[0020] (2) The carbon dioxide plasma jet gas is introduced into the cathode catalyst layer of the membrane electrode assembly MEA through the CO2 inlet of the membrane electrode assembly MEA. The anode electrolyte is a 0.1 mol / l potassium chloride solution. Before the reaction starts, the carbon dioxide jet plasma gas is introduced for 30 minutes to fully mix the anode electrolyte and the cathode CO2 plasma.

[0021] (3) Weigh 10 mg of the prepared Cu-based catalyst and dissolve it in 1.85 ml of isopropanol and 0.05 ml of a 5% Nafion mixed solution. After ultrasonic vibration for 30 min, take 1.8 ml of the mixed solution and spray it on a 2.5*2.5 cm carbon paper;

[0022] (4) assembling a membrane electrode assembly MEA, placing the carbon paper sprayed with the Cu-based catalyst on the cathode catalyst layer of the membrane electrode assembly MEA, placing the anion exchange membrane between the cathode catalyst layer and the anode catalyst layer, turning on the electrochemical workstation, and pretreating the Cu-based catalyst using cyclic voltammetry (CV). After the current is stabilized, the electrochemical reaction test is performed using the chronoamperometry method;

[0023] (5) collecting gas and liquid products generated in the membrane electrode assembly MEA, analyzing the gas products by gas chromatography, and testing the liquid products by nuclear magnetic resonance hydrogen spectroscopy (NMR);

[0024] (6) The analysis of liquid products requires the use of deuterated DMSO reagent as a standard sample. Take 0.5 ml of the electrolyte solution reacted for one hour and 0.1 ml of the deuterated DMSO solution to prepare the test sample.

[0025] Beneficial effects of the present invention:

[0026] (1) Simple process flow. The device structure of the present invention is relatively simple. It uses low-temperature plasma technology and electrocatalytic CO2 technology to couple, which can stimulate the activated state of carbon dioxide at room temperature and pressure, making it possible to improve the carbon dioxide conversion rate;

[0027] (2) Low working requirements. The device has low requirements for the environment. The energy for the reaction mainly comes from the electricity generated by renewable energy. There are no special requirements for external conditions such as temperature, pressure, and humidity.

[0028] (3) The product has high practical value. The multi-carbon products formed by electrocatalysis of CO2 can solve the current problem of excessive CO2 emissions and the current problem of lack of liquid fuels;

[0029] (4) Environmentally friendly. The cathode products of the reaction are all usable low-carbon gas and high-carbon liquid, which are pollution-free to the environment. The main product of the anode is oxygen, and the electricity required for the reaction also mainly comes from renewable energy. Therefore, the device is very friendly and harmless to environmental conditions.

[0030] (5) Strong operability. The device controls the flow rate of the reaction gas through a CO2 mass flow meter, and can be stopped and started immediately. The reaction parameters are mainly controlled by an electrochemical workstation, which is relatively simple and convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a diagram of a device that uses low-temperature plasma technology to promote the electrocatalytic reduction of carbon dioxide into multi-carbon products.

[0032] In the figure, 1. jet plasma array, 2. carbon dioxide inlet, 3. power supply positive terminal, 4. ground terminal, 5. high voltage electrode, 6. carbon dioxide outlet, 7. high voltage power supply; 8. CO2 gas inlet, 9. gas outlet, 10. anode electrolyte inlet, 11. anode electrolyte outlet, 12. cathode catalyst layer, 13. anion exchange membrane, 14. anode catalyst layer, 15. cathode working electrode, 16. anode working electrode, 17. membrane electrode assembly MEA. DETAILED DESCRIPTION

[0033] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0034] The present invention is mainly based on low-temperature plasma treatment and electrocatalytic CO2 reduction to produce multi-carbon products. Low-temperature plasma technology is used to excite carbon dioxide gas in an inert state, so that the CO2 gas is in an excited activation state, which is convenient for electroreduction reaction in the membrane electrode assembly MEA. By performing electroreduction reaction on a Cu-based catalyst, CO2 gas is converted into multi-carbon compounds currently required by the industry, so as to solve the current environmental governance problems and energy shortage problems caused by CO2 emissions. Figure 1 As shown, the present invention provides a method for promoting the electroreduction of carbon dioxide into multi-carbon compounds. The device of the invention mainly includes the following parts: the device includes a jet plasma array 1, a high-voltage power supply 7, an electrochemical workstation, a membrane electrode assembly MEA17 and a carbon dioxide mass flow meter.

[0035] The jet plasma array 1 includes six evenly distributed high-voltage electrodes 5, which are sealed by an airtight cover. The high-voltage electrodes 5 are powered by a high-voltage power supply 7. The left and right ends of the airtight cover are provided with a carbon dioxide gas inlet 2 and a carbon dioxide outlet 6. A carbon dioxide mass flowmeter is installed on the carbon dioxide inlet 2 of the jet plasma array 1; the carbon dioxide outlet 6 is used to discharge the CO2 jet plasma, and the CO2 jet plasma discharged from the exhaust pipe flows into the membrane electrode assembly MEA17. The electrochemical workstation includes a cathode electrode clamp, a reference electrode clamp and an anode electrode clamp; the membrane electrode assembly MEA17 includes a CO2 inlet 8, a gas outlet 9, an anolyte input port 10, an anolyte output port 11, a cathode The cathode catalyst layer 12, the anion exchange membrane 13, the anode catalyst layer 14, the cathode working electrode 15 and the anode working electrode 16, the anion exchange membrane 13 is used to separate the two catalyst layers between the positive and negative electrodes of the membrane electrode assembly MEA17, and only anions are allowed to pass through, so as to prevent cations and the generated gas from affecting the reaction process; the cathode working electrode 15 and the anode working electrode 16 of the membrane electrode assembly MEA17 are respectively connected to the cathode electrode clamp, the reference electrode clamp and the anode electrode clamp (the reference electrode clamp and the anode electrode clamp are short-circuited) in the electrochemical workstation to form a closed loop of the electroreduction process of CO2; the electrolyte in the membrane electrode assembly MEA17 and the anode electrolysis chamber use a neutral potassium chloride solution;

[0036] The jet plasma array 1 comprises six cylindrical high-voltage electrodes 5 connected in series and arranged evenly, each of which is 80 mm in height and 2 mm in diameter, so as to enhance the residence time of carbon dioxide gas being activated and promote more inert carbon dioxide gas to be converted into a plasma state. The interval between each high-voltage electrode is 40 mm, and each high-voltage electrode 5 has two needle-shaped electrodes for tip discharge, and the needle-shaped electrodes are spaced 20 mm apart. The six high-voltage electrodes 5 are connected in series with the positive electrode of the high-voltage power supply 7, and the other electrode of the plasma reactor is connected to the ground wire. High-purity carbon dioxide gas with a volume fraction of 99.999% in an excited state is introduced into the cathode catalyst layer of the membrane electrode assembly MEA17 and is reduced to a multi-carbon product. The outermost layer of the jet plasma array 1 is sealed by an insulating sealing material, and the high-voltage electrode 5 is fixed in the sealed cavity by insulating screws. The entire sealed cavity is 280 mm in length, 60 mm in height, and 100 mm in width. The entire jet plasma array 1 is in a sealed state and can work at normal temperature and pressure. After being activated by the jet plasma array 1, high-purity carbon dioxide gas is introduced into the catalyst layer of the cathode reaction chamber through the cathode air inlet. The gas products produced by the reaction are detected online by gas chromatography, and the liquid products are collected once in the anode reaction liquid and then analyzed by nuclear magnetic resonance hydrogen spectrum (NMR).

[0037] The improvement of the low-temperature plasma device for preparing multi-carbon products over the traditional plasma device is that the gaseous reactant is only inert CO2 gas, and the low-temperature plasma device is not a reaction device, but a device for generating activated CO2 gas;

[0038] The improvement of the technology for promoting carbon dioxide electroreduction compared to the conventional electrocatalytic carbon dioxide reaction is that the low-temperature plasma technology is combined with the electrocatalytic reduction of CO2 gas. First, high-purity CO2 gas with a volume fraction of 99.999% is introduced into the low-temperature plasma device, and the inert CO2 gas molecules are placed in an excited activation state through the discharge effect of six high-voltage electrodes. Then, the CO2 gas in the jet plasma state is introduced into the cathode catalyst layer in the membrane electrode assembly MEA for electroreduction reaction.

[0039] The electrolyte of the anode of the membrane electrode assembly MEA17 is improved compared with the traditional electrolyte in that the traditional electrolyte anode uses potassium bicarbonate electrolyte, while the present device uses potassium chloride solution instead of potassium bicarbonate solution at the anode, and the positive and negative electrode catalyst layers are separated by an anion exchange membrane. This is because Cl - It will produce adsorption on the Cu-based catalyst and affect the surface structure and state of Cu. The electron cloud between chloride ions and metal atoms will interact with each other, changing the charge density of the CO2 electroreduction process and affecting the adsorption energy of the intermediates produced in the CO2 electrocatalytic reaction, so as to achieve the purpose of improving the selectivity of multi-carbon products.

[0040] The improvement of the Cu-based catalyst (bimetallic catalysts such as CuPd, CuFe, CuAg, CuNi, etc.) prepared by the traditional method is that the obtained Cu-based catalyst materials are pretreated again by low-temperature plasma technology, and the purpose of catalyst modification is achieved by using different treatment times and treatment voltages for the catalyst. The catalyst and carbon paper are treated by low-temperature plasma technology mainly to achieve the purpose of physical modification. The catalyst and carbon paper treated by low-temperature plasma technology can have a physical hydrophobic effect. This hydrophobic effect can have a certain inhibitory effect on the hydrogen evolution reaction (HER) in the electrochemical process, so that the electrocatalytic efficiency and energy conversion flow more to the CO2 electrocatalytic reaction, and the selectivity of multi-carbon products is further improved; finally, the catalyst is loaded on the carbon paper for CO2 electrocatalytic experiments;

[0041] On the other hand, the present invention also provides a device and method for reducing carbon dioxide to prepare multi-carbon products by connecting a low-temperature plasma in series with an electrolytic cell, which mainly comprises the following steps:

[0042] (1) The flow rate of CO2 is regulated to 30 sccm by a carbon dioxide mass flow meter, and the high-voltage electrode of the jet plasma array discharges to excite the CO2 into an activated state, and then passes into the membrane electrode assembly MEA;

[0043] (2) Take 10 mg of the prepared copper-based catalyst, dissolve it in a mixed solution of 1.85 ml of isopropanol and 0.05 ml of 5% Nafion (mass fraction), and ultrasonically vibrate for 30 min. Use a pipette to take 1.8 ml of the mixed solution and spray it on a 2.5*2.5 cm carbon paper. Before use, the carbon paper is treated with low-temperature plasma in an Ar atmosphere and placed in the cathode catalyst layer of the MEA membrane electrode assembly;

[0044] (3) A 0.1 mol / l potassium chloride solution is introduced into the anode reaction chamber of the membrane electrode assembly MEA, and the catalyst layers of the anode and cathode chambers are separated by an anion exchange membrane;

[0045] (4) After CO2 gas was introduced at a rate of 30 sccm for 30 min, electrochemical testing was performed. The electrochemical workstation was turned on, and the catalyst was scanned by cyclic voltammetry to perform the activation process. Then, the electrochemical test experiment was performed by chronoamperometry at different voltages (-1.1 V, -1.2 V, -1.3 V, -1.4 V, -1.5 V) for 60 min, and the gas products of the cathode reaction chamber and the liquid products of the anode reaction chamber in the membrane electrode assembly MEA after the reaction were collected;

[0046] (5) Jet plasma CO2 gas is electro-reduced at the cathode, and the gaseous products include CO, CH4, C2H4, etc., and the liquid products include formic acid, methanol, ethanol, etc.; the gaseous products at the cathode are passed through a polyfluoroethylene tube to an online gas chromatograph for analysis; after the reaction is completed for 60 minutes, 0.5 ml of the anode electrolyte in the membrane electrode assembly MEA is collected, and 0.1 ml of deuterated DMSO is added. The types of liquid products are analyzed by NMR testing, and the corresponding Faraday efficiency is calculated.

[0047] The above embodiments are used to illustrate the present invention rather than to limit the present invention. Any modification and change made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A device for reducing carbon dioxide to prepare multi-carbon products by connecting a low-temperature plasma in series with an electrolytic cell, characterized in that: The device comprises a jet plasma array (1) and a membrane electrode assembly MEA (17) connected in series; The jet plasma array (1) comprises six high-voltage electrodes (5) connected in series and arranged evenly, which increase the residence time of carbon dioxide gas being activated and promote more inert carbon dioxide gas to be converted into a plasma state. The carbon dioxide gas in an excited state is introduced into the cathode catalyst layer of the membrane electrode assembly MEA (17) and is reduced to a multi-carbon product. The left and right ends of the jet plasma array (1) are provided with a carbon dioxide gas inlet (2) and a carbon dioxide outlet (6). The carbon dioxide outlet (6) is used to discharge CO2 jet plasma. The CO2 jet plasma discharged from the exhaust pipe flows into the membrane electrode assembly MEA (17) through the CO2 inlet (8). The membrane electrode assembly MEA (17) uses a Cu-based catalyst, and the Cu-based catalyst is treated by low-temperature plasma technology. The catalyst surface and the carbon paper surface are physically modified by plasma treatment, so that the catalyst and the carbon paper surface have a hydrophobic effect, thereby inhibiting the hydrogen evolution reaction (HER). The electrolyte of the anode reaction chamber of the membrane electrode assembly MEA (17) uses a potassium chloride solution, in which the chloride ions interact with the electron cloud of the electrons of the Cu-based catalyst metal atoms, and are chemically modified to change the charge density of the CO2 electroreduction process and improve the selectivity of multi-carbon products.

2. The device for reducing carbon dioxide to prepare multi-carbon products by connecting a low-temperature plasma in series with an electrolytic cell according to claim 1, characterized in that: The outermost layer of the jet plasma array (1) is sealed by an insulating sealing material, and the high-voltage electrode (5) is fixed in the sealed cavity by insulating screws. The entire sealed cavity is 280 mm in length, 60 mm in height, and 100 mm in width. The entire jet plasma array (1) is in a sealed state and can operate at normal temperature and pressure.

3. The device for reducing carbon dioxide to prepare multi-carbon products by connecting a low-temperature plasma in series with an electrolytic cell according to claim 1, characterized in that: The high-voltage electrode (5) has a height of 80 mm and a diameter of 2 mm, and the interval between each high-voltage electrode is 40 mm.

4. The device for reducing carbon dioxide to prepare multi-carbon products by connecting a low-temperature plasma in series with an electrolytic cell according to claim 1, characterized in that: The high voltage electrode (5) is supplied with electric energy by a high voltage power supply (7).

5. The device for reducing carbon dioxide to prepare multi-carbon products by connecting a low-temperature plasma in series with an electrolytic cell according to claim 1, characterized in that: Cu-based catalysts include CuPd, CuFe, CuAg, and CuNi bimetallic catalysts.

6. The device for reducing carbon dioxide to prepare multi-carbon products by connecting a low-temperature plasma in series with an electrolytic cell according to claim 1, characterized in that: A carbon dioxide mass flow meter is installed on the carbon dioxide inlet (2) of the jet plasma array (1).

7. The device for reducing carbon dioxide to prepare multi-carbon products by connecting a low-temperature plasma in series with an electrolytic cell according to claim 1, characterized in that: The device membrane electrode assembly MEA (17) comprises a CO2 inlet (8), a gas outlet (9), an anode electrolyte input port (10), an anode electrolyte output port (11), a cathode catalyst layer (12), an anion exchange membrane (13), an anode catalyst layer (14), a cathode working electrode (15) and an anode working electrode (16); the two electrodes of the membrane electrode assembly MEA are separated by an anion exchange membrane (13), allowing only anions to be exchanged between the two electrodes, thereby preventing cations from affecting the reaction process; The cathode electrode clamp of the electrochemical workstation is connected to the cathode working electrode (15) of the membrane electrode assembly MEA (17), and the anode electrode clamp is short-circuited with the reference electrode clamp and then connected to the anode working electrode (16) of the membrane electrode assembly MEA (17). After being activated by the jet plasma array (1), the carbon dioxide gas is passed into the cathode catalyst layer (12) of the membrane electrode assembly MEA (17) through the CO2 inlet (8). The gas products generated by the reaction are detected online by gas chromatography, and the liquid products are collected once in the anode electrolyte and then analyzed by nuclear magnetic resonance hydrogen spectrum (NMR).

8. A method for reducing carbon dioxide to prepare multi-carbon products using a low-temperature plasma-connected electrolytic cell based on the device according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: (1) By adjusting the parameters of a carbon dioxide mass flow meter, the flow rate of carbon dioxide gas entering the jet plasma array (1) is controlled, the jet plasma array (1) is connected to a high-voltage power supply (7), and six high-voltage electrodes (5) are used to break down carbon dioxide to generate plasma by glow discharge; (2) The carbon dioxide plasma jet gas is introduced into the cathode catalyst layer (12) of the membrane electrode assembly MEA (17) through the CO2 inlet (8) of the membrane electrode assembly MEA (17), the anode electrolyte is a 0.1 mol / l potassium chloride solution, and the cathode CO2 gas is introduced from the top and discharged from the bottom, while the anode electrolyte is introduced from the bottom and discharged from the top, so that the CO2 gas and the anode electrolyte can be fully mixed and evenly mixed, thereby improving the utilization efficiency of CO2; (3) Weigh 10 mg of the prepared Cu-based catalyst and dissolve it in 1.85 ml of isopropanol and 0.05 ml of a 5% Nafion mixed solution. After ultrasonic vibration for 30 min, take 1.8 ml of the mixed solution and spray it on a 2.5*2.5 cm carbon paper; (4) Assembling the membrane electrode assembly MEA (17): First, commercial yttrium oxide is used as the anode catalyst material, and 3*3 cm of yttrium oxide catalyst is cut and placed on the anode catalyst layer (14) of the membrane electrode assembly MEA (17). Then, the activated anion exchange membrane is rinsed with deionized water and placed on the anode catalyst layer (14). Finally, carbon paper sprayed with a Cu-based catalyst is placed on the cathode catalyst layer (12) of the membrane electrode assembly MEA (17). The electrochemical workstation is turned on and the Cu-based catalyst is pretreated by cyclic voltammetry (CV). After the current is stabilized, the electrochemical reaction test is performed by chronoamperometry. (5) collecting gas and liquid products generated in the membrane electrode assembly MEA (17), analyzing the gas products online by gas chromatography, and testing the liquid products by nuclear magnetic resonance hydrogen spectroscopy (NMR); (6) The analysis of liquid products requires the use of deuterated DMSO as a standard sample. Take 0.5 ml of the electrolyte solution that has been reacted for one hour and 0.1 ml of the deuterated DMSO solution to prepare the test sample.

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