Electro-catalysis electrode, preparation method thereof and method for preparing methane through electro-catalysis carbon dioxide reduction reaction

Abstract

The invention relates to an electro-catalysis electrode, a preparation method thereof and a method for preparing methane through electro-catalysis carbon dioxide reduction reaction, and the preparation method of the electro-catalysis electrode comprises the following steps: mixing a formamide polymer loaded copper monatomic catalyst, a binder and a solvent to obtain a catalyst dispersion liquid; and coating the catalyst dispersion liquid on the surface of an electrode, and drying to obtain the electro-catalysis electrode. The electrocatalytic electrode is prepared by adopting the specific formamide polymer loaded copper monatomic catalyst, and when the electrode is used for electrocatalytic carbon dioxide reduction reaction, high methane product selectivity is shown.

Description

Technical Field

[0001] The present disclosure relates to the field of electrocatalysis technology, and in particular, to an electrocatalytic electrode and a preparation method thereof, and a method for producing methane by electrocatalytic carbon dioxide reduction reaction. Background Art

[0002] At present, the energy required for various human production activities mainly depends on the combustion of fossil energy. However, the large-scale use of fossil energy brings two major problems. First, the large-scale emission of carbon dioxide exacerbates the greenhouse effect and poses a threat to climate change. Second, although the reserves of fossil energy are huge, as a non-renewable energy, its limited nature is destined to be exhausted in the future. With the increasing severity of global climate change, the demand for clean energy is imminent.

[0003] Wind and solar energy are renewable energy sources with periodicity and volatility. The electrocatalytic conversion of carbon dioxide in power plants and the atmosphere into fuels or high-value-added chemicals such as carbon monoxide, methane, methanol, ethylene and ethanol can not only reduce the concentration of carbon dioxide in the atmosphere, but also efficiently store the electricity generated by renewable energy. Methane is a high-value electrocatalytic carbon dioxide reduction product that can be directly used in the mature natural gas industry. However, the electrocatalytic reduction of carbon dioxide to methane requires 8 electrons, making the process not easily feasible, especially at high current density. It is still a challenging task to achieve efficient and highly selective production of methane. Summary of the invention

[0004] The purpose of the present disclosure is to provide an electrocatalytic electrode and a preparation method thereof, and a method for producing methane by electrocatalytic carbon dioxide reduction reaction, so as to achieve high-selective production of methane.

[0005] In order to achieve the above object, the present disclosure provides a method for preparing an electrocatalytic electrode in a first aspect, the method comprising:

[0006] The copper single atom catalyst supported by the formamide polymer, a binder and a solvent are first mixed to obtain a catalyst dispersion;

[0007] The catalyst dispersion is coated on the electrode surface and dried to obtain an electrocatalytic electrode.

[0008] Optionally, the steps for preparing the formamide polymer-supported copper single atom catalyst include:

[0009] The formamide is mixed with the copper source for a second time and reacted, and the solid product is then isolated.

[0010] Optionally, the molar ratio of the formamide to the copper source is 1:(0.2-1.2);

[0011] The copper source is one or more selected from copper nitrate, copper sulfate, copper chloride and copper acetylacetonate;

[0012] The mixing conditions include: ultrasonic frequency of 20 to 60 kHz, time of 20 to 40 min;

[0013] The reaction conditions include: temperature of 140-220° C. and time of 6-24 h.

[0014] Optionally, the weight ratio of the copper single atom catalyst supported by the formamide polymer, the binder and the solvent is 1:(0.01-0.5):(50-400);

[0015] The first mixing conditions include: ultrasonic frequency of 20 to 60 kHz, and time of 20 to 40 min.

[0016] Optionally, the binder is one or more selected from Nafion solution, Sustainion XA-9 ionomer solution, polytetrafluoroethylene dispersion, polyvinylidene fluoride and sodium alginate.

[0017] Optionally, the solvent is one or more selected from methanol, ethanol, isopropanol and n-propanol.

[0018] Optionally, the electrode is a carbon-based material gas diffusion electrode and / or a polytetrafluoroethylene gas diffusion electrode.

[0019] Optionally, 1 cm 2 The surface area of ​​the electrode is used as a reference, and the amount of the catalyst dispersion liquid used is 40 to 200 μL.

[0020] In a second aspect of the present disclosure, there is provided an electrocatalytic electrode prepared by the method described in the first aspect of the present disclosure.

[0021] In a third aspect of the present disclosure, a method for producing methane by electrocatalytic reduction of carbon dioxide is provided, the method comprising:

[0022] A working electrode is placed in an electrolytic cell and carbon dioxide is introduced into the electrolytic cell to perform an electrocatalytic reduction reaction; wherein the working electrode is the electrocatalytic electrode described in the second aspect of the present disclosure.

[0023] Through the above technical scheme, the present invention adopts a specific formamide polymer-loaded copper single-atom catalyst to prepare an electrocatalytic electrode. Using this electrode for the electrocatalytic carbon dioxide reduction reaction is beneficial to inhibiting side reactions and promoting the deep hydrogenation of carbon monoxide intermediates produced in the reaction process, thereby showing a higher methane product selectivity. It has the characteristics of mild reaction conditions, cheap and easy preparation of catalysts, high reaction efficiency, etc., and has good prospects for industrial application.

[0024] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0026] Figure 1 is a scanning electron microscope image of the copper single atom catalyst supported by the formamide polymer used in Example 1;

[0027] Figure 2 This is a high-angle annular dark field image of the copper single-atom catalyst supported by the formamide polymer used in Example 1;

[0028] Figure 3 This is the XRD spectrum of the copper single atom catalyst supported by the formamide polymer used in Example 1. DETAILED DESCRIPTION

[0029] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0030] In a first aspect of the present disclosure, a method for preparing an electrocatalytic electrode is provided, the method comprising the following steps S1 to S2:

[0031] S1, first mixing the copper single atom catalyst supported by the formamide polymer, a binder and a solvent to obtain a catalyst dispersion;

[0032] S2. Applying the catalyst dispersion on the electrode surface and drying it to obtain an electrocatalytic electrode.

[0033] The electrocatalytic electrode disclosed in the present invention uses copper single atoms supported by formamide polymer as a catalyst, wherein the formamide polymer used as a carrier is not only cheap and easily available, but also has excellent conductivity, dispersibility and stability under alkaline conditions. The use of this catalyst is beneficial to improving the catalytic efficiency and target product selectivity of the electrocatalytic electrode.

[0034] According to the present disclosure, in step S1, the chemical formula of the copper single atom supported by the formamide polymer is Cu x CHO(CNH) n NH 2 , the structural formula is shown in Formula 1 below,

[0035]

[0036] Among them, 1 < x < 100, 50 < n < 10,000, copper atoms are in a single-atom state in the formamide polymer, and the particle size of the copper single atoms supported by the formamide polymer can be 50 - 500 nm.

[0037] In one embodiment, the preparation steps of the copper single-atom catalyst supported by the formamide polymer include: secondarily mixing formamide with a copper source and reacting them, and then separating the solid product.

[0038] Among them, the chemical formula of formamide is CH 3 NO, and the CAS number is 75 - 12 - 7; the copper source can be one or more selected from copper nitrate, copper sulfate, copper chloride, and copper acetylacetonate, preferably copper nitrate and / or copper sulfate.

[0039] The molar ratio of the formamide to the copper source can be 1:(0.2 - 1.2), preferably 1:(0.4 - 0.8); the second mixing is preferably ultrasonic mixing. Specifically, the conditions of the second mixing can include: ultrasonic frequency of 20 - 60 kHz and time of 20 - 40 min; the conditions of the reaction can include: temperature of 140 - 220 °C and time of 6 - 24 h. Further, after separating the solid product, the solid product can be washed and dried to obtain the copper single-atom catalyst supported by the formamide polymer; among them, the conditions of the drying can include: temperature of 40 - 80 °C and time of 8 - 16 h.

[0040] According to the present disclosure, in step S1, the weight ratio of the copper single-atom catalyst supported by the formamide polymer, the binder, and the solvent can be 1:(0.01 - 0.5):(50 - 400), preferably 1:(0.1 - 0.4):(100 - 300), and more preferably 1:(0.1 - 0.2):(150 - 250).

[0041] Among them, the binder can be one or more selected from Nafion solution, Sustainion XA-9 ionomer solution, polytetrafluoroethylene dispersion, polyvinylidene fluoride, and sodium alginate, preferably one or more selected from Nafion solution, Sustainion XA-9 ionomer solution, and polytetrafluoroethylene dispersion.

[0042] The solvent can be common organic solvents. Specifically, the solvent can be one or more selected from methanol, ethanol, isopropanol, and n-propanol.

[0043] The first mixing is preferably ultrasonic mixing to make the catalyst disperse evenly. Specifically, the conditions of the first mixing can include: ultrasonic frequency of 20 - 60 kHz and time of 20 - 40 min.

[0044] According to the present disclosure, in step S2, the electrode can be any of various electrode types and materials commonly used in the art. In one embodiment, the electrode is a gas diffusion electrode, so that the electrocatalytic electrode is conducive to the electrocatalytic reaction of the gas raw material. Further, the electrode is a carbon-based material gas diffusion electrode and / or a polytetrafluoroethylene gas diffusion electrode.

[0045] In step S2, the amount of the catalyst dispersion can be adjusted within a wide range according to the needs of the catalytic reaction. Specifically, 1 cm 2 Based on the surface area of ​​the electrocatalytic electrode, the amount of the catalyst dispersion can be 40 to 200 μL, preferably 60 to 180 μL, and more preferably 80 to 100 μL.

[0046] The drying conditions may be conventional in the art, for example, the drying conditions may include: a temperature of 60 to 120° C. and a time of 0.1 to 2 h.

[0047] In a second aspect of the present disclosure, there is provided an electrocatalytic electrode prepared by the method described in the first aspect of the present disclosure.

[0048] The catalyst loading of the electrocatalytic electrode can be 0.05 to 5 mg / cm 2 , preferably 0.1 to 3 mg / cm 2 , more preferably 0.2 to 1 mg / cm 2 , for example, 0.36 mg / cm 2 The electrocatalytic electrode can be used for efficient electrocatalytic reduction reaction, and is particularly suitable for the electrocatalytic reduction of carbon dioxide to produce methane.

[0049] In a third aspect of the present disclosure, a method for producing methane by electrocatalytic carbon dioxide reduction reaction is provided, the method comprising: placing a working electrode in an electrolytic cell and introducing carbon dioxide into the electrolytic cell for an electrocatalytic reduction reaction; wherein the working electrode is the electrocatalytic electrode described in the second aspect of the present disclosure.

[0050] According to the present disclosure, the electrolytic cell may be any type of electrocatalytic electrolytic cell commonly used in the art. Specifically, the electrolytic cell may be one or more selected from an H-type electrolytic cell, a flow cell, a membrane battery, and a solid-state electrolytic cell. Further, the electrolytic cell preferably adopts a three-electrode electrochemical system. Specifically, the three-electrode electrochemical system also includes a reference electrode, a counter electrode, a diaphragm, and an electrolyte. Among them, the reference electrode may be one or more selected from a silver / silver chloride electrode, a calomel electrode, and a mercury / mercury oxide electrode. The counter electrode may be one or more selected from a nickel mesh electrode, a platinum mesh electrode, a platinum carbon electrode, a glassy carbon electrode, and a carbon rod electrode. The diaphragm may be a proton exchange membrane and / or an anion exchange membrane. The electrolyte may be a solution selected from KOH, NaOH, KHCO 3 Solution, NaHCO 3 Solution, K 2 CO 3 Solution, Na 2 CO 3 solution, KCl solution, NaCl solution, K 2 SO 4 Solution and Na 2 SO 4 One or more of the solutions.

[0051] The electrocatalytic reduction reaction can be carried out by constant current method or constant potential method. Specifically, the conditions of the constant potential method may include: the potential is -0.1V to -2V, preferably -0.5V to -1.5V, for example -1V. The conditions of the constant current method may include: the current density is 1 to 1000mA / cm 2 , preferably 10 to 800 mA / cm 2 , more preferably 50 to 600 mA / cm 2 , more preferably 100 to 400 mA / cm 2 , more preferably 200 to 300 mA / cm 2 .

[0052] The method for preparing methane by electrocatalytic carbon dioxide reduction reaction provided by the present disclosure uses carbon dioxide as a carbon source and uses a specific copper single atom catalyst as a working electrode catalyst. The isolation of the copper active site can inhibit the carbon-carbon coupling process in the electrocatalytic carbon dioxide reduction process and reduce the generation of multi-carbon products. In addition, the copper single atom active site has a strong adsorption capacity for the carbon monoxide intermediates produced in the electrocatalytic carbon dioxide reduction process, which can promote the deep hydrogenation process of the carbon monoxide intermediates, thereby showing a higher selectivity for the target product methane. Specifically, when the electrolytic cell is a flow cell, at 50 mA / cm 2 Up to 600mA / cm 2The current density range can achieve a methane product Faradaic efficiency of more than 58%, preferably more than 75%, and the methane product current density can reach 170mA / cm 2 above.

[0053] The present disclosure is further described below in conjunction with specific embodiments, which are only part of the embodiments of the present disclosure, rather than all of the embodiments. Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present disclosure can be purchased from the market or prepared by existing methods.

[0054] In the examples, a Zeiss Supra 40 scanning electron microscope was used to measure the morphology and size of the copper single atom catalyst supported on the formamide polymer, and the test condition was 5 kV. A Themis Z high-resolution transmission electron microscope was used to measure the state of copper atoms in the catalyst, and the test condition was 300 keV.

[0055] Example 1

[0056] (1) Preparation of formamide polymer-supported copper single atom catalyst

[0057] 1.2 mmol (290 mg) of copper nitrate trihydrate was added to 60 mL of formamide liquid (the molar ratio of formamide to copper nitrate was 1:0.8), and then the copper nitrate trihydrate was fully dissolved by intense ultrasonication at a frequency of 40 kHz for 30 min. The resulting solution was added to a 100 mL polytetrafluoroethylene liner and then placed in a hydrothermal kettle and sealed, and then heated from room temperature to 180 ° C for 12 h. The resulting black solid product was centrifuged, washed with deionized water and centrifuged, and dried in a vacuum oven at 60 ° C overnight to obtain a copper single atom catalyst supported by a formamide polymer, whose chemical formula is Cu 50 CHO(CNH) 1000 NH 2 .

[0058] Figure 1 This is a scanning electron microscope image of the copper single atom catalyst supported by the formamide polymer, and it can be seen that the catalyst size is 50 to 500 nm; Figure 2 This is a high-angle annular dark field image of the copper single atom catalyst supported by the formamide polymer. It can be seen that compared with carbon and nitrogen atoms, the contrast of copper atoms is higher. The scattered bright spots in the image are isolated copper atoms. It can be seen that the copper atoms are in a single-atom state in the formamide polymer; the XRD spectrum of the copper single atom catalyst supported by the formamide polymer is shown in Figure 3 .

[0059] (2) Preparation of electrocatalytic electrodes

[0060] 8 mg of the catalyst obtained in step (1) was added to 1.97 mL of isopropanol solution, and then 30 μL of Sustainion XA-9 ionomer solution (5 wt%) was added, the weight ratio of catalyst, Sustainion XA-9 ionomer solution and isopropanol was 1:0.1875:193, and then ultrasonically mixed at 40 kHz ultrasonic frequency for 30 min to obtain a uniform catalyst dispersion; 200 μL of the above catalyst dispersion was drop-coated on a 1.5 cm×1.5 cm polytetrafluoroethylene gas diffusion electrode (the amount of catalyst dispersion was 88.9 μL / cm 2 ), and then placed under an infrared lamp and baked at 90°C for 1 hour to obtain an electrocatalytic electrode with a catalyst loading of 0.36 mg / cm 2 .

[0061] Example 2

[0062] The electrocatalytic electrode was prepared according to the method of Example 1, except that in step (1), the amount of copper nitrate trihydrate used was 0.6 mmol (the molar ratio of formamide to copper nitrate was 1:0.4). Figure 1 Similarly, the high-angle annular dark field image is Figure 2 Similarly, the XRD pattern is Figure 3 similar.

[0063] The catalyst loading of the electrocatalytic electrode prepared in this example is 0.36 mg / cm 2 .

[0064] Example 3

[0065] The electrocatalytic electrode was prepared according to the method of Example 1, except that in step (1), the amount of copper nitrate trihydrate used was 0.3 mmol (the molar ratio of formamide to copper nitrate was 1:0.2). The scanning electron micrograph of the obtained catalyst was Figure 1 Similarly, the high-angle annular dark field image is Figure 2 Similarly, the XRD pattern is Figure 3 similar.

[0066] The catalyst loading of the electrocatalytic electrode prepared in this example is 0.36 mg / cm 2 .

[0067] Example 4

[0068] The electrocatalytic electrode was prepared according to the method of Example 1, except that in step (1), the amount of copper nitrate trihydrate used was 1.8 mmol (the molar ratio of formamide to copper nitrate was 1:1.2). The scanning electron micrograph of the obtained catalyst was Figure 1 Similarly, the high-angle annular dark field image is Figure 2Similarly, the XRD pattern is Figure 3 similar.

[0069] The catalyst loading of the electrocatalytic electrode prepared in this example is 0.36 mg / cm 2 .

[0070] Example 5

[0071] An electrocatalytic electrode was prepared according to the method of Example 1, except that in step (2), 30 μL Nafion solution was used instead of Sustainion XA-9 ionomer solution, and solvent ethanol was used instead of isopropanol solution, and the weight ratio of catalyst, Nafion solution and solvent ethanol was 1:0.19:194.

[0072] The catalyst loading of the electrocatalytic electrode prepared in this example is 0.36 mg / cm 2 .

[0073] Example 6

[0074] An electrocatalytic electrode was prepared according to the method of Example 1, except that in step (2), the weight ratio of the catalyst, the Sustainion XA-9 ionomer solution and the isopropanol was 1:0.38:190.

[0075] The catalyst loading of the electrocatalytic electrode prepared in this example is 0.36 mg / cm 2 .

[0076] Example 7

[0077] An electrocatalytic electrode was prepared according to the method of Example 1, except that in step (2), the weight ratio of the catalyst, the Sustainion XA-9 ionomer solution and the isopropanol was 1:0.09:195.

[0078] The catalyst loading of the electrocatalytic electrode prepared in this example is 0.36 mg / cm 2 .

[0079] Example 8

[0080] The electrocatalytic electrode was prepared according to the method of Example 1, except that in step (2), the amount of catalyst dispersion was 44.4 μL / cm 2 .

[0081] The catalyst loading of the electrocatalytic electrode prepared in this example is 0.18 mg / cm 2 .

[0082] Example 9

[0083] The electrocatalytic electrode was prepared according to the method of Example 1, except that in step (2), the amount of catalyst dispersion was 177.8 μL / cm 2 .

[0084] The catalyst loading of the electrocatalytic electrode prepared in this example is 0.71 mg / cm 2 .

[0085] Comparative Example 1

[0086] The electrocatalytic electrode was prepared according to the method of Example 1, except that in step (1), no copper nitrate trihydrate was added, that is, the amount of copper nitrate trihydrate was 0 mmol, and formamide polymer was used as a catalyst to prepare the electrocatalytic electrode. The catalyst loading of the electrocatalytic electrode was 0.36 mg / cm 2 .

[0087] Comparative Example 2

[0088] CuCl 2 ·2H 2 O (0.17 g) and glucose (2.44 g) were dissolved in 80 mL of water to obtain a mixed solution (CuCl 2 ·2H 2 O and glucose concentrations are both 12.5mM), XC-72 carbon powder (64mg) is added in a copper-carbon mass ratio of 1:1, and stirred vigorously for 5h. During this process, hexadecylamine (1.44g) is slowly added. After forming a light blue emulsion, it is poured into a high-pressure reactor and stirred and heated at 120°C in an oil bath for 2h. After cooling to room temperature, it is repeatedly washed with deionized water, ethanol, and n-hexane, and then the resulting precipitate is heated and stirred at 60°C for 4h in 100wt% acetic acid for acid pickling and etching; finally, the acetic acid is washed away to obtain a copper single atom catalyst. Then, an electrocatalytic electrode is prepared according to the method of step (2) of Example 1, and the catalyst loading of the obtained electrocatalytic electrode is 0.36mg / cm 2 .

[0089] Test Case

[0090] The electrocatalytic electrodes prepared in the examples and comparative examples were used as working electrodes to carry out electrocatalytic carbon dioxide reduction reaction to produce methane. The active area of ​​the working electrode was 1 cm 2A flow cell was used to separate the cathode chamber from the anode chamber using an anion exchange membrane, with a silver / silver chloride electrode as the reference electrode and nickel foam as the counter electrode. A 1.0 M (mol / L) KOH solution was used as the electrolyte in the cathode chamber and the anode chamber, and a peristaltic pump was used to continuously flow the electrolyte at a flow rate of 10 mL / min. High-purity carbon dioxide was continuously introduced into the back of the gas diffusion electrode in the cathode chamber at a flow rate of 50 sccm. The electrocatalytic carbon dioxide reduction reaction was carried out using a constant current method, and the constant current was set to 300 mA.

[0091] The gas phase products of the electrocatalytic carbon dioxide reduction products were detected by gas chromatography, and the detection conditions were: Agilent7890B GC, Ar carrier gas, FID detector, capillary column, column temperature 60°C. The liquid phase products were detected by nuclear magnetic resonance spectrometer, and the detection conditions were: 400 MHz, 64 times of water pressure peak; according to the amount of the product obtained by the measurement, the Faraday efficiency of the methane product and the current density of the methane part were calculated according to the following formula. The results are shown in Table 1.

[0092] Methane product Faraday efficiency = amount of methane × 8 × Faraday constant / (total current density × time)

[0093] Methane product current density = methane product Faraday efficiency × total current density

[0094] Table 1

[0095]

[0096] As can be seen from Table 1, the electrocatalytic electrode disclosed in the present invention has a higher Faraday efficiency and current density for methane product in the electrocatalytic carbon dioxide reduction reaction, indicating that the electrocatalytic electrode disclosed in the present invention can significantly improve methane selectivity and catalytic activity.

[0097] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0098] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0099] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for preparing an electrocatalytic electrode, characterized in that: The method includes: The copper single atom catalyst supported by the formamide polymer, a binder and a solvent are first mixed to obtain a catalyst dispersion; The catalyst dispersion is coated on the electrode surface and dried to obtain an electrocatalytic electrode.

2. The method according to claim 1, wherein: The preparation steps of the formamide polymer-supported copper single-atom catalyst include: The formamide is mixed with the copper source for a second time and reacted, and the solid product is then isolated.

3. The method according to claim 2, wherein: The molar ratio of the formamide to the copper source is 1:(0.2-1.2); The copper source is one or more selected from copper nitrate, copper sulfate, copper chloride and copper acetylacetonate; The second mixing conditions include: ultrasonic frequency of 20 to 60 kHz, time of 20 to 40 min; The reaction conditions include: temperature of 140-220° C. and time of 6-24 h.

4. The method according to claim 1, wherein: The weight ratio of the copper single atom catalyst supported by the formamide polymer, the binder and the solvent is 1: (0.01-0.5): (50-400); The first mixing conditions include: ultrasonic frequency of 20 to 60 kHz, and time of 20 to 40 min.

5. The method according to claim 1 or 4, wherein: The binder is one or more selected from Nafion solution, Sustainion XA-9 ionomer solution, polytetrafluoroethylene dispersion, polyvinylidene fluoride and sodium alginate.

6. The method according to claim 1 or 4, wherein: The solvent is one or more selected from methanol, ethanol, isopropanol and n-propanol.

7. The method according to claim 1, wherein: The electrode is a carbon-based material gas diffusion electrode and / or a polytetrafluoroethylene gas diffusion electrode.

8. The method according to claim 1, wherein: 1cm 2 The surface area of ​​the electrode is used as a reference, and the amount of the catalyst dispersion liquid used is 40 to 200 μL.

9. An electrocatalytic electrode prepared by the method according to any one of claims 1 to 8.

10. A method for preparing methane by electrocatalytic reduction of carbon dioxide, characterized in that: The method includes: The working electrode is placed in an electrolytic cell and carbon dioxide is introduced into the electrolytic cell to perform an electrocatalytic reduction reaction; wherein the working electrode is the electrocatalytic electrode according to claim 9.

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