Preparation method and application of a carambola-shaped CuO / Cu-MOF electrocatalyst

Abstract

The application relates to a preparation method and application of a citron-shaped CuO / Cu-MOF electrocatalyst. The application aims to solve the problem of the existing C2H4 selectivity limitation of CuO. The method comprises the following steps: 1, preparing a precursor solution; 2, hydrothermal reaction; 3, calcination; and 4, in-situ conversion. Application: the citron-shaped CuO / Cu-MOF electrocatalyst is used as a raw material to prepare a gas diffusion electrode, and is used for electrocatalytic CO2 reduction. The application is used for the preparation and application of the citron-shaped CuO / Cu-MOF electrocatalyst.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation method and application of an electrocatalyst. BACKGROUND

[0002] The electrocatalytic CO2 reduction technology can convert CO2 into valuable chemicals and energy (such as methane, ethylene, methanol, etc.) through an electrochemical reaction, and effectively recycle carbon dioxide. This process can be directly driven by renewable electricity (such as wind energy and solar energy), avoiding carbon emissions caused by traditional fossil fuels.

[0003] Metal oxide materials have wide application prospects in the field of electrocatalysis, especially in CO2 reduction reactions. By changing the surface morphology, lattice defects or doping of metal oxides, the catalytic performance can be optimized. Cu is currently the only known electrocatalyst that can reduce CO2 to C2 products, and CuO exhibits good selectivity in CO2 reduction, especially in the reduction of hydrocarbons such as methane and ethylene. However, the C2H4 selectivity of single metal oxide is still limited. SUMMARY

[0004] The present application aims to solve the problem of limited C2H4 selectivity of existing CuO, and further provides a preparation method and application of a carambola-shaped CuO / Cu-MOF electrocatalyst.

[0005] A preparation method of a carambola-shaped CuO / Cu-MOF electrocatalyst, which is carried out according to the following steps:

[0006] I. Preparation of precursor solution:

[0007] Under stirring conditions, copper salt is added to water to dissolve and obtain a copper salt solution. Then, under stirring conditions, a precipitating agent is added to the copper salt solution and mixed uniformly. Finally, under room temperature, the mixture is stirred for 5 min to 80 min to obtain a precursor solution;

[0008] II. Hydrothermal reaction:

[0009] The precursor solution is subjected to a hydrothermal reaction, then cooled to room temperature, and finally subjected to separation, washing and drying in sequence to obtain a precursor;

[0010] III. Calcination:

[0011] The precursor is calcined in an air or oxygen atmosphere at a temperature of 200℃ to 600℃ for 1h to 4h to obtain a precursor CuO;

[0012] IV. In-situ conversion:

[0013] The precursor CuO is added to a mixed solution of organic solvent and water to dissolve, then the trimesic acid is added to stir for 10min-60min, and finally the hydrothermal reaction is carried out at the temperature of 100 DEG C-180 DEG C for 12h-36h, so as to obtain the carambola-shaped CuO / Cu-MOF electrocatalyst.

[0014] The application of the carambola-shaped CuO / Cu-MOF electrocatalyst, the carambola-shaped CuO / Cu-MOF electrocatalyst is used as a raw material to prepare a gas diffusion electrode, and is used for electrocatalytic CO2 reduction.

[0015] The carambola-shaped CuO / Cu-MOF electrocatalyst prepared by the application has the advantages that:

[0016] The carambola-shaped CuO / Cu-MOF electrocatalyst prepared by the application has excellent electrocatalytic CO2 reduction performance, when the adding ratio of the prepared CuO precursor and the trimesic acid is 3:1, and the activation time is 20min, the working current density is 300mA·cm -2 The selectivity of the produced C2H4 reaches 48%.

[0017] The carambola-shaped CuO / Cu-MOF electrocatalyst prepared by the application has the advantages that the process is simple, has good scalability, and can realize large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The XRD images of the precursor CuO prepared in step three of the embodiment and the carambola-shaped CuO / Cu-MOF electrocatalyst prepared in step four;

[0019] Figure 2 The scanning electron microscope image of the carambola-shaped CuO / Cu-MOF electrocatalyst prepared in the embodiment one;

[0020] Figure 3 The curve of the selectivity of the CO2 reduction product of the carambola-shaped CuO / Cu-MOF electrocatalyst prepared in the embodiment one with the applied current density. DETAILED DESCRIPTION

[0021] Specific embodiment one: the preparation method of the carambola-shaped CuO / Cu-MOF electrocatalyst in the embodiment is as follows:

[0022] I. Preparation of the precursor solution:

[0023] Under the stirring condition, the copper salt is added to water to dissolve, so as to obtain a copper salt solution, then the precipitating agent is added to the copper salt solution to mix uniformly under the stirring condition, and finally the stirring reaction is carried out at room temperature for 5min-80min, so as to obtain the precursor solution;

[0024] II. Hydrothermal reaction:

[0025] The precursor solution is subjected to hydrothermal reaction, then cooled to room temperature, and finally subjected to separation, washing and drying in sequence to obtain the precursor;

[0026] III. Calcination:

[0027] The precursor is calcined in air or oxygen atmosphere at a temperature of 200-600℃ for 1-4h to obtain the precursor CuO.

[0028] IV. In-situ transformation:

[0029] The precursor CuO is dissolved in a mixed solution of organic solvent and water, then trimesic acid is added and stirred for 10-60min, and finally subjected to hydrothermal reaction at a temperature of 100-180℃ for 12-36h to obtain the CuO / Cu-MOF electrocatalyst in the form of carambola.

[0030] The present embodiment combines metal oxides with organic materials to form organic-inorganic hybrid catalysts. The CuO / Cu-MOF has a highly adjustable pore structure and abundant coordination active sites. The Cu-MOF material provides abundant reaction sites, optimizing the adsorption and activation process of CO2 molecules. By combining CuO with Cu-MOF, the selectivity of the catalyst for CO2 reduction can be improved.

[0031] The present embodiment has the following advantages:

[0032] The carambola-shaped CuO / Cu-MOF electrocatalyst prepared in the present embodiment exhibits excellent electrocatalytic CO2 reduction performance. When the addition ratio of the prepared CuO precursor to trimesic acid is 3:1 and the activation time is 20min, the selectivity of the prepared CuO / Cu-MOF electrocatalyst for CO2 reduction reaches 48% at a working current density of 300mA·cm -2 The selectivity of the prepared CuO / Cu-MOF electrocatalyst for CO2 reduction reaches 48% at a working current density of 300mA·cm

[0033] The carambola-shaped CuO / Cu-MOF electrocatalyst prepared in the present embodiment has a simple process and good scalability, and can be produced on a large scale.

[0034] Specific embodiment two: The difference between the present embodiment and specific embodiment one is that the copper salt in step one is copper nitrate, copper chloride, copper sulfate or copper acetate; and the precipitating agent in step one is urea, sodium carbonate, sodium hydroxide, potassium hydroxide or hexamethylenetetramine. The rest is the same as specific embodiment one.

[0035] Specific embodiment three: the difference between this embodiment and one of the specific embodiments one or two is that in step one, the copper salt is added to water to dissolve under the condition of stirring speed of 200 r / min-2000 r / min to obtain a copper salt solution, then the precipitant is added to the copper salt solution to mix uniformly under the condition of stirring speed of 200 r / min-2000 r / min, finally, the reaction is stirred for 5 min-80 min under the condition of room temperature and stirring speed of 200 r / min-2000 r / min to obtain the precursor solution; the stirring speed in step four is 200 r / min-2000 r / min. The others are the same as specific embodiment one or two.

[0036] Specific embodiment four: the difference between this embodiment and one of the specific embodiments one to three is that the concentration of the copper salt in the copper salt solution in step one is 1 mM-1 M; the molar ratio of the copper salt to the precipitant in step one is 1:(1-10). The others are the same as specific embodiment three.

[0037] Specific embodiment five: the difference between this embodiment and one of the specific embodiments one to four is that the hydrothermal reaction in step two is specifically carried out under the condition of temperature of 100℃-180℃ for 12 h-36 h. The others are the same as specific embodiment one to four.

[0038] Specific embodiment six: the difference between this embodiment and one of the specific embodiments one to five is that the separation, washing and drying in step two are specifically carried out as follows: centrifugation is carried out under the condition of rotation speed of 4000 rpm-9000 rpm for 2 min-10 min to obtain the particles, then the particles are washed to neutral with anhydrous ethanol and water as the washing liquid, finally, the washed particles are dried under the condition of temperature of 40℃-100℃ for 12 h-24 h. The others are the same as specific embodiment one to five.

[0039] Specific embodiment seven: the difference between this embodiment and one of the specific embodiments one to six is that the mass of the precursor CuO to the volume of the mixed solution of the organic solvent and water in step four is 1 g:(150-400) mL; the molar ratio of the precursor CuO to the trimesic acid in step four is (1-5):1; the volume ratio of the organic solvent to water in the mixed solution of the organic solvent and water in step four is 1:(0.1-10), and the organic solvent is methanol, ethanol, propanol or isopropanol. The others are the same as specific embodiment one to six.

[0040] Specific embodiment eight: the application of the citron-shaped CuO / Cu-MOF electrocatalyst, the citron-shaped CuO / Cu-MOF electrocatalyst is used as a raw material to prepare a gas diffusion electrode, which is used for electrocatalytic reduction of CO2.

[0041] Specific embodiment nine: the difference between this embodiment and specific embodiment eight is that the gas diffusion electrode is prepared according to the following steps:

[0042] ① The carambola-shaped CuO / Cu-MOF electrocatalyst is added to a mixed solution of Nafion and isopropanol, and ultrasonic mixing is carried out at a power of 100 W to 500 W for 10 min to 60 min to obtain a catalyst ink;

[0043] The volume ratio of the Nafion solution to isopropanol in the mixed solution is 1:(10-30); and the concentration of the carambola-shaped CuO / Cu-MOF electrocatalyst in the catalyst ink is 3 mg / mL to 10 mg / mL;

[0044] ② The catalyst ink is sprayed onto carbon paper at a temperature of 35°C to 65°C according to a loading amount of the carambola-shaped CuO / Cu-MOF electrocatalyst of 0.5 mg / cm 2 to 2.0 mg / cm 2 , and finally dried to obtain a gas diffusion electrode. The other steps are the same as in specific embodiment eight.

[0045] The gas diffusion electrode prepared in this embodiment is simple to operate, and the carambola-shaped CuO / Cu-MOF electrocatalyst does not need to be pretreated. CuO / Cu-MOF is an organic-inorganic interface material of stable oxide and stable MOF, which stably exists in an air atmosphere without considering the problem of air oxidation.

[0046] Specific embodiment ten: the difference between this embodiment and one of specific embodiments eight or nine is that the electrocatalytic CO2 reduction is carried out according to the following steps:

[0047] ① Assembly: a gas diffusion electrode is arranged between a CO2 gas flow chamber and a cathode chamber, and an anion exchange membrane is arranged between the cathode chamber and an anode chamber by using a flow-type electrolytic cell; a counter electrode is arranged in the anode chamber, a reference electrode is arranged in the cathode chamber, and a cathode liquid flow tank is connected to the cathode chamber through a conduit, and an anode liquid flow tank is connected to the anode chamber through a conduit; electrolyte is poured into the cathode liquid flow tank and the anode liquid flow tank, and finally a positive electrode of a power supply is connected to the counter electrode, and a negative electrode of the power supply is connected to the gas diffusion electrode;

[0048] ② Electro-catalytic activation: CO2 gas is introduced into the CO2 gas flow chamber at a flow rate of 1 mL / min to 50 mL / min, and the CO2 is continuously introduced; and the catalyst is activated at a potential of -1.0 V to -3.0 V vs Ag / AgCl applied to the gas diffusion electrode for 5 min to 60 min;

[0049] ③ Electro-catalytic reduction of CO2: CO2 gas is introduced into a CO2 gas flow chamber at a flow rate of 1 mL / min to 50 mL / min, and electro-catalytic reduction of CO2 is carried out under the condition that the current density of the gas diffusion electrode is 50 mA·cm -2 ~ 900 mA·cm -2 , the gas product is collected, the electrolyte after the reaction is separated and purified, and the electro-catalytic reduction of CO2 is completed.

[0050] The electrolyte in step ① is KOH electrolyte with a concentration of 0.5 M to 5 M; the material of the CO2 gas flow chamber in step ① is stainless steel; the counter electrode in step ① is a foam Ni, a Pt-coated titanium felt, or an IrO2-coated titanium felt; and the reference electrode in step ① is an Ag / AgCl electrode. The other aspects are the same as those in Embodiment 8 or 9.

[0051] The beneficial effects of the present application are verified by the following embodiments:

[0052] Embodiment 1:

[0053] A preparation method of a papaya-shaped CuO / Cu-MOF electro-catalyst, which is carried out according to the following steps:

[0054] I. Preparation of a precursor solution:

[0055] Under the condition that the stirring speed is 800 r / min, copper salt is added to water to be dissolved to obtain a copper salt solution, then under the condition that the stirring speed is 800 r / min, a precipitating agent is added to the copper salt solution to be mixed uniformly, and finally under the condition that the stirring speed is 800 r / min at room temperature, the reaction is stirred for 20 min to obtain a precursor solution.

[0056] II. Hydrothermal reaction:

[0057] Under the condition that the temperature is 100℃, the precursor solution is subjected to hydrothermal reaction for 12 h, then the temperature is lowered to room temperature, and finally separation, washing, and drying are sequentially performed to obtain a precursor.

[0058] III. Calcination:

[0059] Under the condition that the temperature is 300℃ in an air atmosphere, the precursor is calcined for 3 h to obtain a precursor CuO.

[0060] IV. In-situ conversion:

[0061] The precursor CuO is added to a mixed solution of an organic solvent and water to be dissolved, then trimesic acid is added, under the condition that the stirring speed is 800 r / min, the mixture is stirred for 30 min, and finally under the condition that the temperature is 120℃, hydrothermal reaction is carried out for 24 h to obtain a papaya-shaped CuO / Cu-MOF electro-catalyst.

[0062] The copper salt in step one is copper chloride; the precipitant in step one is sodium hydroxide.

[0063] The concentration of the copper salt in the copper salt solution in step one is 5mM; the molar ratio of the copper salt to the precipitant in step one is 1:1.

[0064] The separation, washing and drying in step two are specifically performed as follows: centrifugation at a speed of 4000rpm for 2min to obtain the particles, then washing the particles to neutral with anhydrous ethanol and water as the washing liquid, and finally drying the washed particles at a temperature of 60℃ for 12h.

[0065] The mass of the precursor CuO to the volume of the mixed solution of the organic solvent and water in step four is 1g:280mL; the molar ratio of the precursor CuO to the trimesic acid in step four is 3:1; the volume ratio of the organic solvent to water in the mixed solution of the organic solvent and water in step four is 1:1, and the organic solvent is ethanol.

[0066] The application of the prepared carambola-like CuO / Cu-MOF electrocatalyst nanocatalyst, the carambola-like CuO / Cu-MOF electrocatalyst as a raw material for preparing a gas diffusion electrode, is used for electrocatalytic reduction of CO2;

[0067] The gas diffusion electrode is specifically prepared as follows:

[0068] ①The carambola-like CuO / Cu-MOF electrocatalyst is added to a mixed solution of Nafion and isopropanol, ultrasonic mixing is performed at a power of 300W for 20min to obtain a catalyst ink;

[0069] The volume ratio of the Nafion solution to isopropanol in the mixed solution of Nafion and isopropanol is 1:30; the concentration of the carambola-like CuO / Cu-MOF electrocatalyst in the catalyst ink is 8mg / mL;

[0070] ②The loading amount of the carambola-like CuO / Cu-MOF electrocatalyst is 1.0mg / cm 2 , the catalyst ink is sprayed onto carbon paper at a temperature of 55℃, and finally dried to obtain a gas diffusion electrode;

[0071] The carbon paper is 28BC;

[0072] The electrocatalytic reduction of CO2 is specifically performed as follows:

[0073] ① Assembling: using a flow-type electrolytic cell, a gas diffusion electrode is arranged between the CO2 gas flow chamber and the cathode chamber, an anion exchange membrane is arranged between the cathode chamber and the anode chamber; a counter electrode is arranged in the anode chamber, a reference electrode is arranged in the cathode chamber, and a cathode liquid flow cell is connected to the cathode chamber through a conduit, and an anode liquid flow cell is connected to the anode chamber through a conduit; electrolyte is poured into the cathode liquid flow cell and the anode liquid flow cell, and finally the positive electrode of the power supply is connected to the counter electrode, and the negative electrode of the power supply is connected to the gas diffusion electrode;

[0074] The electrolyte is a KOH electrolyte with a concentration of 1M; the material of the CO2 gas flow chamber is stainless steel; the counter electrode in step ① is a foam Ni; the reference electrode is an Ag / AgCl electrode; and the anion exchange membrane is fumasep FAA-3-PK-130;

[0075] ② Electro-catalytic activation: CO2 gas is introduced into the CO2 gas flow chamber at a flow rate of 30mL / min, CO2 is continuously introduced, and the catalyst is activated for 20min under the condition that an electric potential of-2.0V vs Ag / AgCl is applied to the gas diffusion electrode;

[0076] ③ Electro-catalytic reduction of CO2: CO2 gas is introduced into the CO2 gas flow chamber at a flow rate of 30mL / min, CO2 is continuously introduced, and the electro-catalytic reduction of CO2 is carried out under the condition that the current density of the gas diffusion electrode is 50mA·cm -2 ~500mA·cm -2 , the gas products are collected, the electrolyte after the reaction is separated and purified, and the electro-catalytic reduction of CO2 is completed.

[0077] Example Two: The difference between this example and Example One is that the molar ratio of the copper salt to the precipitant in step one is 1:3. The others are the same as in Example One.

[0078] Example Three: The difference between this example and Example One is that the organic solvent in step four is methanol. The others are the same as in Example One.

[0079] Example Four: The difference between this example and Example One is that the volume ratio of the organic solvent to water in the mixed solution of the organic solvent and water in step four is 1:3. The others are the same as in Example One.

[0080] Example Five: The difference between this example and Example One is that the molar ratio of the trimesic acid to the precursor CuO in step four is 5:1. The others are the same as in Example One.

[0081] Figure 1XRD images of the precursor CuO prepared in step three and the CuO / Cu-MOF electrocatalyst prepared in step four of Example One; as can be seen from the figure, the system without the addition of trimesic acid only shows the relevant diffraction peaks of CuO. The system with the addition of trimesic acid shows the relevant diffraction peaks of Cu-MOF in addition to the relevant diffraction peaks of CuO, indicating that CuO / Cu-MOF is formed after the addition of trimesic acid.

[0082] Figure 2 Scanning electron microscope image of the CuO / Cu-MOF electrocatalyst prepared in Example One; as can be seen from the figure, the prepared CuO / Cu-MOF presents a carambola-like morphology.

[0083] Figure 3 Curve of the selectivity of the CO2 reduction product of the carambola-like CuO / Cu-MOF electrocatalyst prepared in Example One with the applied current density; as can be seen from the figure, as the applied current density gradually increases, the main product of the electrocatalytic CO2 reduction of the CuO / Cu-MOF nanocatalyst in most of the applied current density range is C2H4, and in the gaseous product of the CO2 reduction reaction, the C2H4 selectivity at a low current density (<150 mA / cm 2 ) is lower than that at a high current density (150 mA / cm 2 ~ 500 mA / cm 2 ), and reaches 48% at 300 mA / cm 2 . According to the relevant research on the reaction mechanism of the CO2 reduction reaction, the *CO molecule adsorbed on the Cu surface is the key intermediate product for the formation of C2H4. As the current density gradually increases, the CO selectivity gradually decreases, meaning that more *CO undergoes C-C coupling to form C2H4. At the same time, as the current density gradually increases, the H2 selectivity presents a trend of first decreasing and then increasing, indicating that at a high current density, it is not conducive to the formation of C2H4.

Claims

1. A method for preparing a carambola-like CuO / Cu-MOF electrocatalyst, characterized by It is carried out according to the following steps: I. Preparation of precursor solution: Under stirring, the copper salt is added into water to dissolve, to obtain a copper salt solution, then under stirring, the precipitant is added into the copper salt solution to mix uniformly, finally under room temperature, stirring reaction is carried out for 5 min to 80 min, to obtain the precursor solution; II. Hydrothermal reaction: The precursor solution is subjected to hydrothermal reaction, then cooled to room temperature, finally separation, washing and drying are carried out in sequence, to obtain the precursor; III. Calcination: Under the condition of air or oxygen atmosphere, temperature of 200℃ to 600℃, the precursor is calcined for 1h to 4h, to obtain the precursor CuO; IV. In-situ conversion: The precursor CuO is added into the mixed solution of organic solvent and water to dissolve, then the trimesic acid is added to stir for 10 min to 60 min, finally under the condition of temperature of 100℃ to 180℃, hydrothermal reaction is carried out for 12h to 36h, to obtain the carambola-shaped CuO / Cu-MOF electrocatalyst.

2. The method according to claim 1, wherein the method for preparing a carambola-like CuO / Cu-MOF electrocatalyst is characterized by The copper salt in step I is copper nitrate, copper chloride, copper sulfate or copper acetate; the precipitant in step I is urea, sodium carbonate, sodium hydroxide, potassium hydroxide or hexamethylenetetramine.

3. The method according to claim 1, wherein the method is characterized by In step I, under the condition of stirring speed of 200r / min to 2000r / min, the copper salt is added into water to dissolve, to obtain a copper salt solution, then under the condition of stirring speed of 200r / min to 2000r / min, the precipitant is added into the copper salt solution to mix uniformly, finally under the condition of room temperature and stirring speed of 200r / min to 2000r / min, stirring reaction is carried out for 5 min to 80 min, to obtain the precursor solution; The stirring speed in step IV is 200r / min to 2000r / min.

4. The method according to claim 1, wherein the method for preparing a carambola-like CuO / Cu-MOF electrocatalyst is characterized by The concentration of copper salt in the copper salt solution in step I is 1mM to 1M; the molar ratio of copper salt to precipitant in step I is 1:(1-10).

5. The method of claim 1, wherein the CuO / Cu-MOF electrocatalyst is prepared by the following steps: (1) preparing a Cu-MOF precursor; (2) preparing a CuO / Cu-MOF precursor; (3) preparing a CuO / Cu-MOF electrocatalyst. The hydrothermal reaction in step II is specifically carried out under the condition of temperature of 100℃ to 180℃, for 12h to 36h.

6. The method for preparing a starfruit-shaped CuO / Cu-MOF electrocatalyst according to claim 1, characterized in that... The separation, washing and drying in step II are specifically carried out according to the following steps: under the condition of rotation speed of 4000rpm to 9000rpm, centrifugation is carried out for 2 min to 10 min, to obtain particles, then the particles are washed to neutral with anhydrous ethanol and water as washing liquid, finally the washed particles are dried at temperature of 40℃ to 100℃ for 12h to 24h.

7. The method according to claim 1, wherein the method is characterized by The mass of the precursor CuO to the volume of the mixed solution of organic solvent and water in step IV is 1g:(150-400)mL; the molar ratio of the precursor CuO to the trimesic acid in step IV is (1-5):1; the volume ratio of the organic solvent to water in the mixed solution of organic solvent and water in step IV is 1:(0.1-10), and the organic solvent is methanol, ethanol, propanol or isopropanol.

8. Use of a carambola-like CuO / Cu-MOF electrocatalyst prepared according to claim 1, characterized in that The carambola-shaped CuO / Cu-MOF electrocatalyst is used as raw material to prepare a gas diffusion electrode for electrocatalytic reduction of CO2.

9. Use of a carambola-like CuO / Cu-MOF electrocatalyst according to claim 8, characterized in that The gas diffusion electrode is specifically prepared according to the following steps: The CuO / Cu-MOF electrocatalyst in the shape of a carambola is added to a mixed solution of Nafion and isopropyl alcohol, and under the condition of a power of 100 W-500 W, ultrasonic mixing is carried out for 10 min-60 min to obtain a catalyst ink; The volume ratio of the Nafion solution to the isopropyl alcohol in the mixed solution is 1:(10-30); and the concentration of the CuO / Cu-MOF electrocatalyst in the shape of a carambola in the catalyst ink is 3 mg / mL-10 mg / mL; (ii) The loading amount of the CuO / Cu-MOF electrocatalyst in the shape of a carambola is 0.5 mg / cm 2 ~ 2.0 mg / cm 2 The catalyst ink is sprayed onto the carbon paper at a temperature of 35°C to 65°C, and finally dried to obtain a gas diffusion electrode.

10. Use of a carambola-like CuO / Cu-MOF electrocatalyst according to claim 9, characterized in that The electrocatalytic CO2 reduction is specifically carried out by the following steps: ① Assembly: a gas diffusion electrode is arranged between a CO2 gas flow chamber and a cathode chamber, and an anion exchange membrane is arranged between the cathode chamber and an anode chamber by using a flow-type electrolytic cell; a counter electrode is arranged in the anode chamber, a reference electrode is arranged in the cathode chamber, and a cathode liquid flow pool is connected to the cathode chamber through a conduit, and an anode liquid flow pool is connected to the anode chamber through a conduit; electrolyte is poured into the cathode liquid flow pool and the anode liquid flow pool, and finally, a positive electrode of a power supply is connected to the counter electrode, and a negative electrode of the power supply is connected to the gas diffusion electrode; ② Electro-catalytic activation: CO2 gas is introduced into the CO2 gas flow chamber at a flow rate of 1 mL / min-50 mL / min, and the CO2 is continuously introduced; under the condition that an electric potential of-1.0 V--3.0 V vs Ag / AgCl is applied to the gas diffusion electrode, the catalyst is activated for 5 min-60 min; ③Electrocatalytic reduction of CO2: CO2 gas is passed into the CO2 gas flow chamber at a flow rate of 1 mL / min to 50 mL / min, and the CO2 is continuously passed in, and the electrocatalytic reduction of CO2 is carried out under the condition that the current density of the gas diffusion electrode is 50 mA·cm -2 ~900 mA·cm -2 , the gas product is collected, the electrolyte after the reaction is separated and purified, and the electrocatalytic reduction of CO2 is completed. The electrolyte in step ① is KOH electrolyte with a concentration of 0.5 M-5 M; the material of the CO2 gas flow chamber in step ① is stainless steel; the counter electrode in step ① is a foam Ni, a Pt-coated titanium felt or an IrO2-coated titanium felt; and the reference electrode in step ① is an Ag / AgCl electrode.

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