An amorphous polytetrafluoroethylene modified molecular catalyst, its preparation method and application

Abstract

The application discloses an amorphous polytetrafluoroethylene modified molecular catalyst and a preparation method and application thereof, belongs to the technical field of electrocatalysis, and is characterized in that carbon nanotubes and polytetrafluoroethylene are uniformly mixed and high-temperature annealing is performed to obtain a catalyst carrier, the catalyst carrier is mixed with cobalt phthalocyanine in N,N-dimethylformamide, centrifugation, washing and drying are performed to obtain a cobalt phthalocyanine catalyst; the polytetrafluoroethylene hydrophobic immobilized cobalt phthalocyanine can be applied to electrocatalysis of carbon dioxide into carbon monoxide. The application mainly controls the processing temperature, regulates the crystallinity of polytetrafluoroethylene, constructs a micro-hydrophobic environment for cobalt phthalocyanine, and improves the carbon dioxide concentration at a reaction interface, and the prepared catalyst exhibits excellent performance of catalyzing carbon dioxide into carbon monoxide under a large current density.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrocatalysis, and particularly relates to an electrocatalytic carbon dioxide reduction to carbon monoxide catalyst, a preparation method and application thereof. BACKGROUND

[0002] Due to the large consumption of fossil fuels, the amount of carbon dioxide emissions accumulates in the atmosphere year by year. The electrochemical carbon dioxide reduction reaction (CO2RR) is a key technology to realize carbon neutralization and closed-loop carbon cycle. Due to the adjustability and significant electronic structure of molecular catalysts, and the ability to achieve catalytic performance comparable to metal catalysts at significantly lower load levels. Therefore, in recent years, the rational design and optimization of molecular catalysts for application in CO2RR have attracted widespread attention (E. Boutin, M. Wang, J. C. Lin, M. Mesnage, D. Mendoza, B. Lassalle-Kaiser, C. Hahn, T. F. Jaramillo, M. Robert, Aqueous Electrochemical Reduction of Carbon Dioxide and Carbon Monoxide into Methanol with Cobalt Phthalocyanine, Angew. Chem. Int. Ed. 58 (2019) 1433-7851; Z. Jiang, Z. Zhang, H. Li, Y. Tang, Y. Yuan, J. Zao, H. Zheng, Y. Liang, Molecular Catalyst with Near 100% Selectivity for CO2 Reduction in Acidic Electrolytes, Advanced Energy Materials. 13 (2023) 2203603; X. Kong, Y. Liu, P. Li, J. Ke, Z. Liu, F. Ahmad, W. Yan, Z. Li, Z. Geng, J. Zeng, Coordinate Activation in Heterogeneous Carbon Dioxide Reduction on Co-Based Molecular Catalysts, Applied Catalysis B: Environmental. 268 (2020) 118452).

[0003] Research on molecular catalysts can be divided into homogeneous catalysis and heterogeneous catalysis (Y. Wu, Y. Liang, H. Wang, Heterogeneous Molecular Catalysts of Metal Phthalocyanines for Electrochemical CO2 Reduction Reactions, Acc. Chem. Res. 54 (2021) 3149-3159). Compared with homogeneous catalysis in which catalyst molecules shuttle around the electrode, heterogeneous catalysis has faster electron transfer speed (X. Zhang, Y. Wang, M. Gu, M. Wang, Z. Zhang, W. Pan, Z. Jiang, H. Zheng, M. Lucero, H. Wang, G. E. Sterbinsky, Q. Ma, Y.-G. Wang, Z. Feng, J. Li, H. Dai, Y. Liang, Molecular Engineering of Dispersed Nickel Phthalocyanines on Carbon Nanotubes for Selective CO2 Reduction, Nat Energy. 5 (2020) 684-692), higher catalyst spatial density (A. J. Sathrum, C. P. Kubiak, Kinetics and Limiting Current Densities of Homogeneous and Heterogeneous Electrocatalysts, J. Phys. Chem. Lett. 2 (2011) 2372-2379) and lower electrolyzer requirements (T. Burdyny, W. A. Smith, CO2 Reduction on Gas-Diffusion Electrodes and Why Catalytic Performance Must Be Assessed at Commercially-Relevant Conditions, Energy Environ. Sci. 12 (2019) 1442-1453). Therefore, immobilizing molecular catalysts on carbon nanotubes is a common heterogeneous catalysis strategy and exhibits near 100% CO selectivity at low current

[0004] ANMarianov,Y.Jiang,Mechanism-Driven Design of HeterogeneousMolecular Electrocatalysts for CO2 Reduction,Acc.Mater.Res.3(2022)620-633;L.Sun,V.Reddu,S.Xi,C.Dai,Y.Sheng,T.Su,ACFisher,X.Wang,Cobalt QuaterpyridineComplexes for Highly Efficient Heterogeneous CO2 Reduction in Aqueous Media,Advanced Energy Materials.12(2022)2202108; NanotubeHybrid Structures,Nat Commun. 8(2017)14675). However, as the current density increases, protons occupy a large number of active sites, leading to an increase in hydrogen ether reaction (HER) and a decrease in CO selectivity (P. Yue, Q. Fu, J. Li, L. Zhang, L. Xing, Z. Kang, Q. Liao, X. Zhu, Triple-Phase Electrocatalysis for The Enhanced CO2 Reduction to HCOOH on A Hydrophobic Surface, Chemical Engineering Journal. 405(2021)126975). At a current density of 75 mA / cm² 2At present, the CO Faraday efficiency of the immobilized molecular catalyst is less than 80%, which makes it unable to be popularized and applied in industry. A feasible strategy is to inhibit proton transfer by adjusting the hydrophobicity of the active site, increase the local concentration of CO2(J.A.Rabinowitz, D.S.Ripatti, R.G.Mariano, M.W.Kanan, Improving the Energy Efficiency of CO Electrolysis by Controlling Cu Domain Size in Gas Diffusion Electrodes, ACS Energy Lett. 7 (2022) 4098-4105), promote the formation of solid-liquid-gas three-phase interface(L.Xiong, X.Fu, Y.Zhou, P.Nian, Z.Wang, Q.Yue, Precise Site-Hydrophobicity Modulation for Boosting High-Performance CO2 Electroreduction, ACS Catal. (2023) 6652-6660), and finally realize the selective reduction of CO2 to CO.

[0005] Therefore, how to control the key process parameters to adjust the hydrophobic morphology of the molecular catalyst, so as to improve the CO2 concentration at the reaction interface and inhibit the occurrence of hydrogen evolution reaction at high current density, is of great significance and is still a key technical problem to be solved. SUMMARY

[0006] The present application aims to control the hydrophobic morphology of the molecular catalyst, and provides an amorphous polytetrafluoroethylene (PTFE) modified molecular catalyst and its synthesis and application. By controlling the treatment temperature, the crystallinity of PTFE is reduced, the three-dimensional spherical crystal structure of PTFE collapses, and amorphous flaky PTFE is formed. The micrometer flaky catalyst has a certain interception effect on raw gas CO2, which increases the CO2 concentration at the catalytic interface, promotes the transition of the contact interface from the Wenzel state to the Cassie state, and can be well applied in the field of electrocatalytic CO2 reduction.

[0007] The technical purpose of the present application is achieved by the following technical scheme.

[0008] An amorphous polytetrafluoroethylene modified molecular catalyst, which is a hydrophobic immobilized cobalt phthalocyanine catalyst with micrometer flaky polytetrafluoroethylene, is prepared according to the following steps:

[0009] The carbon nanotube hydrophobized by micrometer flaky polytetrafluoroethylene is mixed with cobalt phthalocyanine at a mass ratio of 15:(1-3), and N,N-dimethylformamide is added for acute ultrasonic dispersion, the addition amount of N,N-dimethylformamide is (20-30) milliliters per milligram of cobalt phthalocyanine, centrifugation and removal of supernatant, after washing and drying, an amorphous polytetrafluoroethylene modified molecular catalyst is obtained, wherein:

[0010] After mixing polytetrafluoroethylene and carbon nanotubes, deionized water is added for dispersion to obtain a slurry material, and after drying at room temperature, a powder-like polytetrafluoroethylene hydrophobized carbon nanotube is obtained; the powder-like polytetrafluoroethylene hydrophobized carbon nanotube is heated to 400-450 degrees Celsius at a rate of 5-10 degrees Celsius per minute under an inert protective atmosphere from room temperature 20-30 degrees Celsius, and is kept for 1-3 hours, and then is cooled to room temperature 20-30 degrees Celsius with the furnace, to obtain the carbon nanotube hydrophobized by micrometer flaky polytetrafluoroethylene; after mixing polytetrafluoroethylene and carbon nanotubes, the mass percentage of polytetrafluoroethylene is 10-30 wt%.

[0011] Further, after mixing polytetrafluoroethylene and carbon nanotubes, the mass percentage of polytetrafluoroethylene is 20 wt%.

[0012] Further, the mass ratio of the carbon nanotube hydrophobized by micrometer flaky polytetrafluoroethylene to cobalt phthalocyanine is 15:1.

[0013] Further, the addition amount of N,N-dimethylformamide is (20-25) milliliters per milligram of cobalt phthalocyanine.

[0014] Further, the inert protective atmosphere is nitrogen, argon or helium.

[0015] Further, the powder-like polytetrafluoroethylene hydrophobized carbon nanotube is heated to 400-430 degrees Celsius at a rate of 5-10 degrees Celsius per minute under an inert protective atmosphere from room temperature 20-30 degrees Celsius, and is kept for 2-3 hours, and then is cooled to room temperature 20-30 degrees Celsius with the furnace.

[0016] The application of the amorphous polytetrafluoroethylene modified molecular catalyst in the electrocatalytic reduction of carbon dioxide to carbon monoxide.

[0017] In use, the amorphous polytetrafluoroethylene modified molecular catalyst (i.e. the supported cobalt phthalocyanine catalyst of the application), FAA solution and DMF are mixed into a homogeneous solution, which is sprayed on a gas diffusion electrode as a working electrode (i.e. a catalytic electrode), and the loading is 1-3 mg / cm 2 The iridium oxide loaded foam nickel is used as a counter electrode, and the electrocatalytic reaction is carried out by electrification; the electrolyte is an alkali solution, such as 1 mol / L KOH aqueous solution.

[0018] Compared with the prior art, the specific beneficial effects of the present application are as follows:

[0019] (1) The present application reduces the crystallinity of the hydrophobic agent PTFE through temperature control, and expands from three-dimensional spherical crystals to two-dimensional amorphous state. The change in crystallinity makes the contact between PTFE and CNT better, promotes the further improvement of the hydrophobicity of the catalyst carrier, and at the same time, the conductivity of PTFE rises, so that the cell voltage does not rise too much.

[0020] (2) The present application constructs a microsheet-shaped immobilized molecular catalyst. The microsheet shape forms "air chambers" during CO2RR, has the function of trapping CO2, improves the CO2 concentration at the interface, promotes the transition of the reaction interface from the solid-liquid interface-based Wenzel state to the solid-gas interface-based Cassie state, and realizes 98% CO Faraday efficiency.

[0021] (3) The production route of the HT-PTFE-CoPc / CNT catalyst of the present application is simple, the preparation cost is relatively low, and the reaction conditions are easy to realize. It can maintain high CO selectivity under high current density, and at the same time, it maintains good economic benefits due to low cost, which provides important scientific and technological support for the industrialization of CO2RR technology. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is the synthesis route of HT-PTFE-CoPc / CNT obtained in Example 2.

[0023] Figure 2 is the SEM characterization result graph of HT-PTFE-CoPc / CNT obtained in Example 2.

[0024] Figure 3 is the EDS characterization result graph of HT-PTFE-CoPc / CNT obtained in Example 2.

[0025] Figure 4 is the CLSM characterization result graph of HT-PTFE-CoPc / CNT obtained in Example 1 and Example 2.

[0026] Figure 5 is the XRD characterization result graph of the phthalocyanine cobalt catalyst obtained in Example 1-2.

[0027] Figure 6 is the contact angle test result graph of the phthalocyanine cobalt catalyst obtained in Example 1-2.

[0028] Figure 7 is the Faraday efficiency characterization graph of the product CO of the phthalocyanine cobalt catalyst obtained in Example 1-2 for electrocatalytic CO2 reduction.

[0029] Figure 8is a local current density characterization map of the product CO of the electrocatalytic reduction of CO2 by the phthalocyanine cobalt catalyst obtained in Example 1-2.

[0030] Figure 9 is a Faraday efficiency characterization map of the product CO of the electrocatalytic reduction of CO2 by the phthalocyanine cobalt catalyst obtained in Example 1-4.

[0031] Figure 10 is a stability test characterization map of the product CO of the electrocatalytic reduction of CO2 by the HT-PTFE-CoPc / CNT obtained in Example 2. DETAILED DESCRIPTION

[0032] The application will be further described in detail below through specific examples, which can enable a person skilled in the art to have a more comprehensive understanding of the application, but in no way limit the application.

[0033] It should be noted that the application patent previously applied by the research group, "A high hydrophobicity molecular catalyst and its preparation method and application", application number 2023108872318, application date July 19, 2023 (prior application), uses hydrophobic materials for modification, but the research group failed to control the hydrophobic morphology, and later on the basis of previous research, high temperature treatment was carried out in order to change the hydrophobic morphology; In this application, the basic idea of the prior application is improved, and the unfinished part can refer to the prior application.

[0034] Example 1

[0035] Accurately weigh 15 mg of carbon nanotubes and 1 mg of phthalocyanine cobalt in a beaker, add 20 mL of N,N-dimethylformamide (DMF), ultrasonic treatment for 30 min, centrifuge at 7000 r / min for 3 min, remove the supernatant, and then wash the obtained solid with DMF, ethanol, and deionized water, respectively, and dry in an oven at 80°C for 10 h to obtain a supported phthalocyanine cobalt (CoPc / CNT).

[0036] Example 2

[0037] (1) Accurately weigh 20 mg of carbon nanotubes and spread them in a beaker, take 5.6 μL of PTFE emulsion (i.e. PTFE suspension in aqueous solution) with a mass concentration of 0.9 g / mL and dilute it to 200 μL with deionized water, add the diluted emulsion dropwise to the beaker, ultrasonic treatment for 10 min to mix the emulsion and carbon nanotubes uniformly and form a mud-like state (the mass fraction of PTFE in the solid is 20 wt%, i.e. the mass of PTFE / the sum of the mass of PTFE and the mass of carbon nanotubes).

[0038] (2) The obtained slurry-like mixture was left to stand overnight (8 hours) at room temperature 20-30 degrees Celsius, and dried in an oven at 80 degrees Celsius for 10 hours to obtain PTFE-CNT (20 wt%).

[0039] (3) The obtained PTFE-CNT was heated at a rate of 10 degrees Celsius per minute from room temperature 20-30 degrees Celsius to 400 degrees Celsius in a nitrogen atmosphere, and subjected to high-temperature treatment for 2 hours, and then slowly annealed to room temperature in a tube furnace to obtain HT-PTFE-CNT.

[0040] (4) 15 mg of HT-PTFE-CNT powder and 1 mg of cobalt phthalocyanine were mixed in a beaker, 20 mL of N,N-dimethylformamide (DMF) was added, and ultrasonic treatment was performed for 30 minutes. After centrifugation at a speed of 7000 r / min for 3 minutes, the supernatant was removed, and the obtained solid was sequentially washed with DMF, ethanol, and deionized water, and dried in an oven at 80 degrees Celsius for 10 hours to obtain HT-PTFE-CoPc / CNT.

[0041] Figure 1 is a synthetic route diagram of HT-PTFE-CoPc / CNT obtained in Example 2. Figure 2 is a scanning electron microscope image of HT-PTFE-CoPc / CNT obtained in Example 2, in which PTFE presents a microparticle morphology. Figure 3 is an energy spectrum diagram of HT-PTFE-CoPc / CNT obtained in Example 2, and it can be seen that the F element is uniformly distributed, that is, the PTFE forms an amorphous state and is uniformly dispersed. Figure 4 is a laser confocal scanning electron microscope characterization diagram of HT-PTFE-CoPc / CNT obtained in Examples 1 and 2, and it can be seen that the fluorescence intensity decays slowly, and the contact interface changes from the Wenzel state to the Cassie state, reference Shi, R et al. Efficient Wettability-Controlled Electroreduction of CO2 to CO at Au / C Interfaces. Nat Commun 11, 3028 (2020). Figure 5 is an X-ray diffraction characterization result of the cobalt phthalocyanine catalyst obtained in Examples 1-2, and the peak value of PTFE in Example 2 is lower, indicating that the crystallinity of PTFE decreases after high-temperature annealing and forms an amorphous state. Figure 6 is a contact angle test experimental result of the cobalt phthalocyanine catalyst obtained in Examples 1-2, and the contact angle of Example 2 is significantly greater than that of Example 1, indicating that the amorphous PTFE significantly improves the hydrophobicity of the catalyst.

[0042] Example 3

[0043] (1) Accurately weigh 20 mg of carbon nanotubes into a beaker, take 2.5 μL of PTFE emulsion (i.e. a suspended aqueous solution of PTFE) with a mass concentration of 0.9 g / mL and dilute to 200 μL with deionized water, and add the diluted emulsion dropwise into the beaker, and ultrasonically mix for 10 min to make the emulsion and carbon nanotubes uniformly mixed and in a slurry state (the mass fraction of PTFE in the solid is 10 wt%, i.e. the mass of PTFE / the sum of the mass of PTFE and the mass of carbon nanotubes).

[0044] (2) The obtained slurry-like mixture is left to stand overnight (8 hours) at room temperature of 20-30 degrees Celsius, dried in an oven at 80 degrees Celsius for 10 h, and PTFE-CNT (10 wt%) is obtained.

[0045] (3) The obtained PTFE-CNT is heated at a rate of 10 degrees Celsius per minute to 430 degrees Celsius under a nitrogen atmosphere from room temperature of 20-30 degrees Celsius, and high-temperature treatment is performed for 3 h, and then slowly annealed to room temperature in a tube furnace, and HT-PTFE-CNT (10 wt%) is obtained.

[0046] (4) 15 mg of HT-PTFE-CNT powder and 1 mg of cobalt phthalocyanine are mixed in a beaker, 20 mL of N,N-dimethylformamide (DMF) is added, ultrasonic treatment is performed for 30 min, the supernatant is removed after centrifugation at a speed of 7000 r / min for 3 min, and the obtained solid is sequentially washed with DMF, ethanol, and deionized water, and dried in an oven at 80 degrees Celsius for 10 h, and PTFE-CoPc / CNT (10 wt%) is obtained.

[0047] Example 4

[0048] (1) Accurately weigh 20 mg of carbon nanotubes into a beaker, take 8.6 μL of PTFE emulsion (i.e. a suspended aqueous solution of PTFE) with a mass concentration of 0.9 g / mL and dilute to 200 μL with deionized water, and add the diluted emulsion dropwise into the beaker, and ultrasonically mix for 10 min to make the emulsion and carbon nanotubes uniformly mixed and in a slurry state (the mass fraction of PTFE in the solid is 30 wt%, i.e. the mass of PTFE / the sum of the mass of PTFE and the mass of carbon nanotubes).

[0049] (2) The obtained slurry-like mixture is left to stand overnight (8 hours) at room temperature of 20-30 degrees Celsius, dried in an oven at 80 degrees Celsius for 10 h, and PTFE-CNT (30 wt%) is obtained.

[0050] (3) The obtained PTFE-CNT is heated at a rate of 10 degrees Celsius per minute to 450 degrees Celsius under a nitrogen atmosphere from room temperature of 20-30 degrees Celsius, and high-temperature treatment is performed for 1 h, and then slowly annealed to room temperature in a tube furnace, and HT-PTFE-CNT (30 wt%) is obtained.

[0051] (4) Take 15 mg of HT-PTFE-CNT powder and 1 mg of cobalt phthalocyanine in a beaker, add 20 mL of N,N-dimethylformamide (DMF), ultrasonic treatment for 30 min, remove the supernatant after centrifugation at 7000 r / min for 3 min, sequentially wash the obtained solid with DMF, ethanol and deionized water, and dry in an oven at 80°C for 10 h to obtain PTFE-CoPc / CNT (30 wt%).

[0052] Example 5

[0053] (1) Take 10 mg of cobalt phthalocyanine catalyst prepared in Examples 1-4, 80 μL of FAA solution (purchased from Fuel Cell Store company, mass percentage of 25 wt%), and 10 mL of DMF in a beaker, ultrasonic treatment for 30 min to form a uniform mixed solution. Under the operating conditions of 75°C, the mixed solution is sprayed onto a 2x2 cm 2 gas diffusion electrode using nitrogen as the carrier gas to obtain a catalytic electrode. The mass of the gas diffusion electrode is weighed before and after spraying using an analytical balance to control the solid loading of the electrode to be 1.5 mg / cm 2 .

[0054] (2) The performance of the catalytic electrode is tested using a membrane electrode reactor, which is referred to in Zhang, G. et al. Efficient CO2 Electroreduction on Facet-Selective Copper Films with High Conversion Rate. Nat Commun 12, 5745 (2021). The test electrolyte is 1 mol / L KOH solution, the electrode area is 4 cm 2 , and the products are detected by gas chromatography.

[0055] The CO faradaic efficiency values of the cobalt phthalocyanine catalysts prepared in Examples 1-2 under different test current densities are shown in Figure 7 . It can be seen that the high temperature treatment makes the PTFE and CNT well combined, and the sheet catalyst forms a "gas chamber" to trap CO2 to improve the CO2 concentration at the interface, and the HT-PTFE-CoPc / CNT still maintains high reaction selectivity under high current density. The CO local current density of the cobalt phthalocyanine catalysts prepared in Examples 1-2 under different test current densities is shown in Figure 8 , which has a similar rule as the CO faradaic efficiency change. The CO faradaic efficiency values of the cobalt phthalocyanine catalysts prepared in Examples 1-4 under different test current densities are shown in Figure 9As shown, it can be seen that the optimal content of PTFE in the microsheet-shaped PTFE hydrophobic immobilized phthalocyanine cobalt catalyst is 20wt%, at which the catalyst has the optimal performance. The HT-PTFE-CoPc / CNT prepared in Example 2 can maintain a CO Faraday efficiency of 90% or more and a stability of 3h at a current density of 75mA / cm 2 The stability of the catalyst at a current density of 75mA / cm Figure 10 As shown, it can be seen that the optimal content of PTFE in the microsheet-shaped PTFE hydrophobic immobilized phthalocyanine cobalt catalyst is 20wt%, at which the catalyst has the optimal performance. The HT-PTFE-CoPc / CNT prepared in Example 2 can maintain a CO Faraday efficiency of 90% or more and a stability of 3h at a current density of 75mA / cm

[0056] According to the adjustment of the process parameters according to the content of the present application, the preparation of the amorphous polytetrafluoroethylene modified molecular catalyst in the present application can be realized, which shows basically consistent performance with the present application. Although the preferred embodiments of the present application are described above in combination with the drawings, the present application is not limited to the above specific embodiments, and the above specific embodiments are only illustrative and not limiting. Those skilled in the art can make many specific changes under the guidance of the present application without departing from the purpose of the present application and the scope protected by the claims.

Claims

1. An amorphous polytetrafluoroethylene-modified molecular catalyst, characterized in that, The molecular catalyst is a hydrophobic treatment of microparticle polytetrafluoroethylene immobilized cobalt phthalocyanine catalyst, which is prepared according to the following steps: The carbon nanotubes with hydrophobic treatment of microparticle polytetrafluoroethylene and the cobalt phthalocyanine are mixed in a mass ratio of 15: (1-3), N,N-dimethylformamide is added for ultrasonic dispersion, the addition amount of N,N-dimethylformamide is (20-30) milliliters per milligram of cobalt phthalocyanine, centrifugation and removal of supernatant, after washing and drying, the amorphous polytetrafluoroethylene modified molecular catalyst is obtained, wherein the carbon nanotubes with hydrophobic treatment of microparticle polytetrafluoroethylene are prepared according to the following method: After mixing polytetrafluoroethylene and carbon nanotubes, the mass percentage of polytetrafluoroethylene is 10-30wt%, the mass percentage of polytetrafluoroethylene is the mass of polytetrafluoroethylene / the sum of the mass of polytetrafluoroethylene and the mass of carbon nanotubes, then deionized water is added for dispersion to obtain a mud-like material, after drying at room temperature, the powder-like polytetrafluoroethylene hydrophobic treated carbon nanotubes are obtained; the powder-like polytetrafluoroethylene hydrophobic treated carbon nanotubes are heated to 400-450 degrees Celsius at a rate of 5-10 degrees Celsius per minute under an inert protective atmosphere from room temperature 20-30 degrees Celsius, and are kept for 1-3 hours, then are cooled to room temperature 20-30 degrees Celsius with the furnace, to obtain the carbon nanotubes with hydrophobic treatment of microparticle polytetrafluoroethylene.

2. An amorphous polytetrafluoroethylene-modified molecular catalyst according to claim 1, wherein After mixing polytetrafluoroethylene and carbon nanotubes, the mass percentage of polytetrafluoroethylene is 20wt%.

3. The amorphous polytetrafluoroethylene-modified molecular catalyst according to claim 1, wherein The mass ratio of the carbon nanotubes with hydrophobic treatment of microparticle polytetrafluoroethylene to cobalt phthalocyanine is 15:

1.

4. The amorphous polytetrafluoroethylene-modified molecular catalyst of claim 1, wherein, The addition amount of N,N-dimethylformamide is (20-25) milliliters per milligram of cobalt phthalocyanine.

5. The amorphous polytetrafluoroethylene-modified molecular catalyst of claim 1, wherein, The inert protective atmosphere is nitrogen, argon or helium.

6. The amorphous polytetrafluoroethylene-modified molecular catalyst of claim 1, wherein, The powder-like polytetrafluoroethylene hydrophobic treated carbon nanotubes are heated to 400-430 degrees Celsius at a rate of 5-10 degrees Celsius per minute under an inert protective atmosphere from room temperature 20-30 degrees Celsius, and are kept for 2-3 hours, then are cooled to room temperature 20-30 degrees Celsius with the furnace.

7. A method of preparing an amorphous polytetrafluoroethylene-modified molecular catalyst as claimed in claim 1, characterized by, The molecular catalyst is a hydrophobic treatment of microparticle polytetrafluoroethylene immobilized cobalt phthalocyanine catalyst, which is prepared according to the following steps: The carbon nanotubes with hydrophobic treatment of microparticle polytetrafluoroethylene and the cobalt phthalocyanine are mixed in a mass ratio of 15: (1-3), N,N-dimethylformamide is added for ultrasonic dispersion, the addition amount of N,N-dimethylformamide is (20-30) milliliters per milligram of cobalt phthalocyanine, centrifugation and removal of supernatant, after washing and drying, the amorphous polytetrafluoroethylene modified molecular catalyst is obtained, wherein the carbon nanotubes with hydrophobic treatment of microparticle polytetrafluoroethylene are prepared according to the following method: The polytetrafluoroethylene and the carbon nanotube are mixed, the mass percentage of the polytetrafluoroethylene is 10-30 wt%, the mass percentage of the polytetrafluoroethylene is the mass of the polytetrafluoroethylene / mass of the polytetrafluoroethylene and the carbon nanotube, then deionized water is added for dispersion, to obtain a mud-like material, which is dried at room temperature to obtain a powder-like polytetrafluoroethylene hydrophobic treated carbon nanotube; the powder-like polytetrafluoroethylene hydrophobic treated carbon nanotube is heated to 400-450 degrees Celsius at a speed of 5-10 degrees Celsius per minute from room temperature 20-30 degrees Celsius under an inert protective atmosphere, and is kept for 1-3 hours, then is cooled to room temperature 20-30 degrees Celsius with the furnace, to obtain a micron flake-like polytetrafluoroethylene hydrophobic treated carbon nanotube.

8. The method for preparing an amorphous polytetrafluoroethylene-modified molecular catalyst according to claim 7, characterized in that, The polytetrafluoroethylene and the carbon nanotube are mixed, the mass percentage of the polytetrafluoroethylene is 20 wt%; the mass ratio of the micron flake-like polytetrafluoroethylene hydrophobic treated carbon nanotube to cobalt phthalocyanine is 15:1; the added amount of N,N-dimethylformamide is (20-25) milliliters per milligram of cobalt phthalocyanine; the inert protective atmosphere is nitrogen, argon or helium; the powder-like polytetrafluoroethylene hydrophobic treated carbon nanotube is heated to 400-430 degrees Celsius at a speed of 5-10 degrees Celsius per minute from room temperature 20-30 degrees Celsius under the inert protective atmosphere, and is kept for 2-3 hours, then is cooled to room temperature 20-30 degrees Celsius with the furnace.

9. Use of an amorphous polytetrafluoroethylene modified molecular catalyst according to any one of claims 1-6 in electrocatalytic reduction of carbon dioxide to carbon monoxide.

10. Use of an amorphous polytetrafluoroethylene-modified molecular catalyst according to claim 9 for the electrocatalytic reduction of carbon dioxide to carbon monoxide, characterized in that, In use, the amorphous polytetrafluoroethylene modified molecular catalyst, FAA solution and DMF are mixed into a homogeneous solution, which is sprayed on a gas diffusion electrode as a working electrode, with a loading of 1-3 mg / cm 2 A foam nickel loaded with iridium oxide is used as a counter electrode, and an electric catalytic reaction is carried out by applying electricity; an alkaline solution is used as an electrolyte.

11. Use of an amorphous polytetrafluoroethylene-modified molecular catalyst according to claim 10 for the electrocatalytic reduction of carbon dioxide to carbon monoxide, characterized in that, The alkali solution is 1 mol / L KOH aqueous solution.

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