A CoTNPc / Cu / Cu2O@C electrocatalyst, its preparation method and application

Abstract

This invention discloses a CoTNPc / Cu / Cu2O@C electrocatalyst, its preparation method, and its application, relating to the field of electrochemical CO2 reduction raw material technology. The invention involves mixing and stirring obtained Cu2O powder, solvent, and dopamine hydrochloride, centrifuging, and vacuum drying to obtain Cu2O@DA. The Cu2O@DA is then calcined in an inert atmosphere and cooled to room temperature to obtain a Cu / Cu2O@C precursor. The obtained Cu / Cu2O@C precursor and obtained CoTNPc are separately subjected to ultrasonic treatment in DMF solvent, followed by mixing and stirring to obtain a mixed solution. This solution is then centrifuged, vacuum dried, and the CoTNPc / Cu / Cu2O@C catalyst is obtained. This invention provides an electrocatalyst with uniform morphology, uniform elemental distribution, and excellent electrochemical performance for the efficient electroreduction of carbon dioxide to ethylene. Its preparation method is controllable, uses simple equipment, has high conversion efficiency, and is low in cost.

Description

Technical Field

[0001] This invention relates to the field of electrochemical CO2 reduction material technology, and more specifically, to a CoTNPc / Cu / Cu2O@C electrocatalyst, its preparation method, and its application. Background Technology

[0002] With the expansion of industrial activities, the amount of carbon dioxide emitted from the combustion of fossil fuels continues to rise, leading to a sustained increase in atmospheric carbon dioxide concentration and triggering a severe greenhouse effect. Therefore, developing clean and efficient carbon dioxide reduction technologies has become a critical issue urgently needing to be addressed for sustainable development. Converting carbon dioxide into high-value-added products (such as ethylene, formic acid, methane, and ethanol) is a practical and feasible solution.

[0003] Ethylene is the world's most produced basic chemical raw material, widely used in the production of bulk chemicals such as polyethylene and polyvinyl chloride. Utilizing renewable energy to electrocatalyze the conversion of CO2 into ethylene can reduce atmospheric carbon concentration and mitigate the greenhouse effect, while also replacing traditional petrochemical routes and reducing fossil resource consumption. This technology can also store intermittent renewable electricity, achieving electrochemical energy conversion and supporting distributed production at emission sources, thus contributing to carbon reduction, energy peak shaving, and green manufacturing. Compared to thermal, photocatalytic, and biocatalysis, electrocatalysis offers advantages such as milder conditions, controllable energy, a wide range of raw materials, and a cleaner process.

[0004] The core of electrocatalytic CO2 reduction lies in a complex electrochemical process: driven by electrons provided by an external power source, CO2 molecules are activated and reconstructed on the catalyst surface by combining with protons in the electrolyte, thus converting them into target products (methane, formic acid, ethylene, ethanol, etc.). The catalyst plays a decisive role, dominating the reaction pathway and product selectivity. Its essence lies in utilizing its unique electronic structure and surface geometry to selectively stabilize key intermediates in specific reaction pathways, thereby achieving selective control over the final product.

[0005] Although copper is the only single-metal catalyst that can efficiently electroreduc CO2 into multi-carbon products (such as ethylene), it suffers from insufficient selectivity, poor stability, and intense competition from hydrogen evolution side reactions.

[0006] Therefore, exploring and improving copper-based catalysts to make them highly selective and stable electrocatalysts is the core research direction in the current process of practical application of electrocatalytic CO2 reduction. Summary of the Invention

[0007] In view of this, the present invention provides a CoTNPc / Cu / Cu2O@C electrocatalyst, its preparation method and application.

[0008] A method for preparing a CoTNPc / Cu / Cu2O@C electrocatalyst includes the following steps:

[0009] (1) Mix and grind 4-nitrophthalonitrile, anhydrous cobalt chloride, urea and ammonium molybdate tetrahydrate, then heat to carry out solid-phase reaction, and then successively pass through acid washing, alkali washing, filtration and vacuum drying to obtain cobalt tetranitrophthalocyanine, i.e. CoTNPc; (2) Mix copper acetate monohydrate, solvent, sodium hydroxide and ascorbic acid, heat and stir in a water bath, then centrifuge, wash and vacuum dry to obtain Cu2O powder. (3) The obtained Cu2O powder, solvent and dopamine hydrochloride were mixed and stirred, collected by centrifugation, and dried under vacuum to obtain Cu2O@DA. Cu2O@DA was calcined in an inert atmosphere and cooled to room temperature after calcination to obtain Cu / Cu2O@C precursor. (4) The obtained Cu / Cu2O@C precursor and the obtained CoTNPc were placed in DMF solvent and ultrasonically treated, then mixed and stirred to obtain a mixed solution, collected by centrifugation, and vacuum dried to obtain the CoTNPc / Cu / Cu2O@C catalyst.

[0010] Furthermore, in step (1), the molar ratio of 4-nitrophthalonitrile, anhydrous cobalt chloride, urea and ammonium molybdate tetrahydrate is 20:4:200:1.

[0011] The beneficial effects of adopting the above-mentioned further technical solution are as follows: within this molar ratio range, ammonium molybdate tetrahydrate as a catalyst can effectively promote the solid-phase reaction and improve the yield and purity of cobalt tetranitrophthalocyanine (CoTNPc); at the same time, it avoids excess reactant residue or by-product formation.

[0012] Furthermore, in step (1), the solid-phase reaction temperature is 120-180℃ and the solid-phase reaction time is 3-6h.

[0013] The beneficial effects of adopting the above-mentioned further technical solution are as follows: the temperature and time range ensures that the solid-phase reaction proceeds fully, so that the raw materials are completely converted into the target product, while avoiding the decomposition or carbonization of the phthalocyanine ring due to excessively high temperature or time, thus ensuring the integrity of the product structure.

[0014] Furthermore, in step (1), the acid washing uses a 1.0-2.0 mol / L hydrochloric acid solution; the alkaline washing uses a 0.5-1.0 mol / L sodium hydroxide solution.

[0015] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: acid washing can effectively remove unreacted metal ions and metal oxide impurities, and alkaline washing can remove residual organic impurities and acidic by-products. The combination of the two significantly improves the purity of CoTNPc, and the concentration is moderate, avoiding damage to the phthalocyanine structure.

[0016] Furthermore, in step (1), the vacuum drying temperature is 50-70℃, the vacuum drying time is 12-24h, and the vacuum degree is -0.09MPa.

[0017] The beneficial effects of adopting the above-mentioned further technical solutions are: low-temperature vacuum drying can effectively remove solvents and moisture from the product, while preventing CoTNPc from oxidizing or agglomerating at high temperatures, thus maintaining good dispersibility and chemical stability.

[0018] Furthermore, in step (2), the solvent is distilled water, and the mass-volume ratio of copper acetate monohydrate, distilled water, sodium hydroxide and ascorbic acid is 200mg:45mL:(120-240)mg:(88-264)mg.

[0019] The beneficial effects of adopting the above-mentioned further technical solution are as follows: This ratio can precisely control the nucleation and growth rate of Cu2O, obtaining Cu2O powder with uniform particle size and regular morphology; ascorbic acid, as a reducing agent, can gently reduce Cu2O particles. + Reduced to Cu + To avoid excessive reduction and the formation of elemental copper.

[0020] Furthermore, in step (2), the water bath heating temperature is 50°C and the water bath heating time is 0.5h.

[0021] The beneficial effects of adopting the above-mentioned further technical solution are: the 50℃ water bath provides a uniform and mild reaction environment, and the reaction tends to be complete within 0.5h, which not only ensures the rapid generation of Cu2O, but also prevents particle agglomeration or oxidation caused by prolonged heating.

[0022] Furthermore, in step (3), the mass ratio of Cu2O powder, solvent and dopamine hydrochloride is 10:(5.0-6.0):(15.0-20.0).

[0023] The beneficial effects of adopting the above-mentioned further technical solution are: the mass ratio ensures that dopamine hydrochloride fully polymerizes on the Cu2O surface to form a uniform polydopamine coating layer, which is neither too thin, resulting in an incomplete carbon layer, nor too thick, causing electron transport to be blocked.

[0024] Furthermore, in step (3), the solvent is a mixture of ammonia, anhydrous ethanol and distilled water in a volume ratio of 1:21:7.

[0025] Furthermore, in step (3), the inert gas is argon.

[0026] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: Argon gas, as an inert protective atmosphere, can prevent Cu2O from being further reduced to elemental copper or oxidized to copper oxide during high-temperature calcination, while avoiding carbon layer oxidation and ensuring the stable formation of Cu / Cu2O heterojunction.

[0027] Furthermore, in step (3), the calcination temperature is 300-500℃, the calcination time is 1-4h, and the heating rate is 2-4℃ / min.

[0028] The beneficial effects of adopting the above-mentioned further technical solution are: the temperature range allows polydopamine to be fully carbonized to form a conductive carbon layer, while partially reducing Cu2O to generate Cu elemental substance, forming a Cu / Cu2O heterojunction; the slow heating avoids carbon layer cracking or metal particle agglomeration, maintaining the integrity of the coating structure.

[0029] Furthermore, in step (4), the mass ratio of Cu / Cu2O@C precursor to CoTNPc in the mixed solution is 50:(1-3).

[0030] The beneficial effects of adopting the above-mentioned further technical solution are as follows: This ratio can ensure that CoTNPc is uniformly loaded on the Cu / Cu2O@C surface without agglomeration, forming the best interfacial contact; if it is too low, there will be insufficient active sites, and if it is too high, it may cover the active sites of Cu / Cu2O. This range maximizes the synergistic effect of the two.

[0031] Furthermore, in step (4), the ultrasonic treatment time is 1-3 hours and the ultrasonic power is 100W.

[0032] The present invention also provides a CoTNPc / Cu / Cu2O@C electrocatalyst, which is prepared by the aforementioned preparation method.

[0033] The present invention also provides an application of the CoTNPc / Cu / Cu2O@C electrocatalyst in electrocatalytic carbon dioxide reduction.

[0034] Furthermore, it is used in electrochemical carbon dioxide reduction electrodes; The preparation method of the electrochemical carbon dioxide reduction electrode includes the following steps: The CoTNPc / Cu / Cu2O@C catalyst, isopropanol, deionized water and Nafion solution were mixed evenly and then ultrasonically dispersed to obtain a dispersion. The dispersion was evenly dropped onto carbon paper and allowed to air dry naturally before being used as the working electrode, namely the electrochemical carbon dioxide reduction electrode.

[0035] Furthermore, the mass-to-volume ratio of the CoTNPc / Cu / Cu2O@C catalyst, isopropanol, deionized water, and Nafion solution is (8-10) mg:(700-900) μL:(50-250) μL:50 μL; the ultrasonic dispersion time is 20-30 min, and the ultrasonic power is 100 W; the loading of the CoTNPc / Cu / Cu2O@C catalyst on the working electrode is 0.8-1 mg / cm³. 2 .

[0036] Furthermore, the electrochemical carbon dioxide reduction equipment used in the electrocatalytic carbon dioxide reduction consists of a gas chromatograph, an electrochemical workstation, a current amplifier, an electrolytic cell, a working electrode, a counter electrode, and a reference electrode. The working electrode is the electrochemical carbon dioxide reduction electrode; The reference electrode is a mercury / mercury oxide electrode. The counter electrode is a pure platinum plate, and the proton exchange membrane is a Nafion 117 proton exchange membrane. The electrolyte is a KOH solution; An electrocatalytic carbon dioxide reduction reaction was carried out in an electrochemical workstation using a flow-cell electrolyzer as the reactor.

[0037] Compared with the prior art, the present invention has the following beneficial effects: This invention successfully prepared a carbon-coated Cu / Cu2O catalyst supported on CoTNPc (CoTNPc / Cu / Cu2O@C). This design utilizes the CoTNPc active sites to rapidly convert CO2 into CO and transport it to adjacent Cu2O active sites. By constructing a locally high-concentration CO environment, the energy barrier of CC coupling is effectively reduced, thereby significantly promoting the formation of C2H4.

[0038] 1. The preparation method of this invention includes the synthesis of cobalt tetranitrophthalocyanine and carbon-coated cuprous oxide and copper, as well as the preparation of a supported catalyst of cobalt tetranitrophthalocyanine loaded onto carbon-coated cuprous oxide and copper. Specifically, cobalt tetranitrophthalocyanine is synthesized via a high-temperature solid-state reaction, and carbon-coated cuprous oxide and copper are obtained through high-temperature carbonization. Then, cobalt tetranitrophthalocyanine and carbon-coated cuprous oxide and copper are separately added to an N,N dimethylformamide solution and sonicated, followed by mixing, stirring, centrifugation, and vacuum drying to obtain a solid catalyst powder. This method is simple and easy to implement, and by effectively controlling the synthesis conditions of the catalyst, a CoTNPc / Cu / Cu₂O@C catalyst can be obtained.

[0039] 2. The CoTNPc / Cu / Cu2O@C electrocatalyst synthesized in this invention exhibits a polyhedral structure, with a uniform carbon layer encapsulating cuprous oxide and a uniformly loaded tetranitrophthalocyanine cobalt, which increases the exposed area of ​​the active sites.

[0040] 3. The preparation method of the present invention has the advantages of easy control of reaction conditions, simple equipment, high conversion efficiency and low cost. Attached Figure Description

[0041] Figure 1 The XRD pattern of the CoTNPc / Cu / Cu2O@C electrocatalyst prepared in Example 1; Figure 2 TEM image of the CoTNPc / Cu / Cu2O@C electrocatalyst prepared in Example 1; Figure 3 A physical image of the equipment used for electrochemical CO2 reduction of the CoTNPc / Cu / Cu2O@C electrocatalyst prepared in Example 1; Figure 4 Linear scan curve of the CoTNPc / Cu / Cu2O@C electrocatalyst prepared in Example 1 in CO2-saturated 1M KOH; Figure 5 The image shows the C2H4 Faradaic efficiency of the CoTNPc / Cu / Cu2O@C electrocatalyst prepared in Example 1 at -1.0V (V vs. RHE). Detailed Implementation

[0042] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] In this invention, "room temperature" is defined as 25±2℃.

[0044] Example 1 The preparation method of CoTNPc / Cu / Cu2O@C electrocatalyst specifically includes the following steps: (1) 10 mmol of 4-nitrophthalonitrile, 2 mmol of anhydrous cobalt chloride, 100 mmol of urea and 0.5 mmol of ammonium molybdate tetrahydrate were mixed and ground, and then reacted in a solid-state environment at 160 °C for 5 hours. The product was washed successively with 70 mL of 1 mol / L hydrochloric acid and 70 mL of 1 mol / L sodium hydroxide solution, filtered, and then dried under vacuum at 60 °C for 12 hours at a vacuum degree of -0.9 MPa to obtain cobalt tetranitrophthalocyanine (CoTNPc).

[0045] (2) 2 mmol of copper acetate monohydrate was dispersed in 30 mL of distilled water and sonicated for 30 minutes at a power of 100 W. The mixture was stirred at 400 r / min in a 50 °C water bath, and 40 mL of sodium hydroxide aqueous solution (0.2 mol / L) was rapidly added. Then, 20 mL of ascorbic acid aqueous solution (0.1 mol / L) was slowly and continuously added. After reacting for 0.5 hours, the mixture was centrifuged at 8000 r / min, washed repeatedly with water and anhydrous ethanol, and dried under vacuum at 60 °C for 12 hours at a vacuum of -0.9 MPa to obtain Cu₂O powder.

[0046] (3) Add 2 mL of 25 wt% ammonia solution to a mixture of 40 mL of anhydrous ethanol and 12 mL of water. While stirring at 400 r / min, add 100 mg of Cu2O powder obtained in step (2) and continue stirring for 1 h to obtain a mixed solution. Separately, dissolve 150 mg of dopamine hydrochloride in 2 mL of ethanol and 2 mL of water, mix with the obtained mixed solution, and stir for 2 h. Collect the product by centrifugation at 8000 r / min, and dry under vacuum at 60 °C for 12 h at a vacuum degree of -0.9 MPa to obtain Cu2O@DA. Place it in a tube furnace, heat it to 400 °C at 2 °C / min under argon protection, hold for 1 h, and cool to room temperature to obtain the Cu / Cu2O@C precursor.

[0047] (4) 50 mg of the Cu / Cu2O@C precursor obtained in step (3) and 1 mg of CoTNPc obtained in step (1) were placed in 30 mL of DMF. The mixture was first sonicated for 30 min to achieve uniform dispersion at a power of 100 W, followed by high-energy sonication for 2 h at a power of 120 W. The mixture was then stirred continuously at 400 r / min for 12 h until adsorption equilibrium was reached. The product was collected by centrifugation at 8000 r / min and vacuum dried at 60 °C for 12 h at a vacuum degree of -0.9 MPa to obtain the CoTNPc / Cu / Cu2O@C catalyst.

[0048] Example 2 The preparation method of CoTNPc / Cu / Cu2O@C electrocatalyst specifically includes the following steps: (1) 10 mmol of 4-nitrophthalonitrile, 2 mmol of anhydrous cobalt chloride, 100 mmol of urea and 0.5 mmol of ammonium molybdate tetrahydrate were mixed and ground, and then reacted in a solid-state environment at 160 °C for 5 hours. The product was washed successively with 70 mL of 1 mol / L hydrochloric acid and 70 mL of 1 mol / L sodium hydroxide solution, filtered, and then dried under vacuum at 60 °C for 12 hours at a vacuum degree of 100 W to obtain cobalt tetranitrophthalocyanine (CoTNPc).

[0049] (2) 2 mmol of copper acetate monohydrate was dispersed in 30 mL of distilled water and sonicated for 30 minutes at a power of 100 W. The mixture was stirred at 400 rpm in a 50 °C water bath, and 40 mL of 0.3 mol / L sodium hydroxide aqueous solution was rapidly added. Then, 20 mL of 0.15 mol / L ascorbic acid aqueous solution was slowly and continuously added. After reacting for 1 hour, the mixture was centrifuged at 8000 rpm, washed repeatedly with water and anhydrous ethanol, and dried under vacuum at 60 °C for 12 hours at a vacuum of -0.9 MPa to obtain Cu₂O powder.

[0050] (3) Add 2 mL of 25 wt% ammonia solution to a mixture of 40 mL of anhydrous ethanol and 12 mL of water. While stirring at 400 r / min, add 120 mg of Cu2O powder obtained in step (2) and continue stirring for 1 h to obtain a mixed solution. Separately, dissolve 150 mg of dopamine hydrochloride in 2 mL of ethanol and 2 mL of water, mix with the obtained mixed solution, and stir for 2 h. Collect the product by centrifugation at 8000 r / min, and dry under vacuum at 60 °C for 12 h at a vacuum degree of -0.9 MPa to obtain Cu2O@DA. Place it in a tube furnace, heat it to 400 °C at 2 °C / min under argon protection, hold for 1 h, and cool to room temperature to obtain the Cu / Cu2O@C precursor.

[0051] (4) 50 mg of the Cu / Cu2O@C precursor obtained in step (3) and 1 mg of CoTNPc obtained in step (1) were placed in 30 mL of DMF. The mixture was first sonicated for 30 min to achieve uniform dispersion at a power of 100 W, followed by high-energy sonication for 2 h at a power of 120 W. The mixture was then stirred continuously at 400 r / min for 12 h until adsorption equilibrium was reached. The product was collected by centrifugation at 8000 r / min and vacuum dried at 60 °C for 12 h at a vacuum degree of -0.9 MPa to obtain the CoTNPc / Cu / Cu2O@C catalyst.

[0052] Example 3 The preparation method of CoTNPc / Cu / Cu2O@C electrocatalyst specifically includes the following steps: (1) 10 mmol of 4-nitrophthalonitrile, 2 mmol of anhydrous cobalt chloride, 100 mmol of urea and 0.5 mmol of ammonium molybdate tetrahydrate were mixed and ground, and then reacted in a solid-state environment at 160 °C for 5 hours. The product was washed successively with 70 mL of 1 mol / L hydrochloric acid and 70 mL of 1 mol / L sodium hydroxide solution, filtered, and then dried under vacuum at 60 °C for 12 hours at a vacuum degree of -0.9 MPa to obtain cobalt tetranitrophthalocyanine (CoTNPc).

[0053] (2) 2 mmol of copper acetate monohydrate was dispersed in 30 mL of distilled water and sonicated for 30 minutes at a power of 100 W. The mixture was stirred at 400 r / min in a 50 °C water bath, and 40 mL of sodium hydroxide aqueous solution (0.15 mol / L) was rapidly added. Then, 20 mL of 0.05 mol / L ascorbic acid aqueous solution was slowly and continuously added. After reacting for 0.5 hours, the mixture was centrifuged at 8000 r / min, washed repeatedly with water and anhydrous ethanol, and dried under vacuum at 60 °C for 12 hours at a vacuum degree of -0.9 MPa to obtain Cu₂O powder.

[0054] (3) Add 2 mL of 25 wt% ammonia solution to a mixture of 40 mL of anhydrous ethanol and 12 mL of water. While stirring at 400 r / min, add 100 mg of Cu2O powder obtained in step (2) and continue stirring for 1 h to obtain a mixed solution. Separately, dissolve 200 mg of dopamine hydrochloride in 2 mL of ethanol and 2 mL of water, mix with the obtained mixed solution, and stir for 2 h. Collect the product by centrifugation at 8000 r / min, and dry under vacuum at 60 °C for 12 h at a vacuum degree of -0.9 MPa to obtain Cu2O@DA. Place it in a tube furnace, heat it to 400 °C at 2 °C / min under argon protection, hold for 1 h, and cool to room temperature to obtain the Cu / Cu2O@C precursor.

[0055] (4) 50 mg of the Cu / Cu2O@C precursor obtained in step (3) and 3 mg of the CoTNPc obtained in step (1) were placed in 30 mL of DMF. The mixture was first sonicated for 30 min to achieve uniform dispersion at a power of 100 W, followed by high-energy sonication for 2 h at a power of 120 W. The mixture was then stirred continuously at 400 r / min for 12 h until adsorption equilibrium was reached. The product was collected by centrifugation at 8000 r / min and vacuum dried at 60 °C for 12 h at a vacuum degree of -0.9 MPa to obtain the CoTNPc / Cu / Cu2O@C catalyst.

[0056] Comparative Example 1 The CoTNPc electrocatalyst was prepared using the same method as in Example 1, except that it only included step (1).

[0057] Comparative Example 2 The Cu2O electrocatalyst was prepared using the same method as in Example 1, except that it only included step (2).

[0058] Comparative Example 3 The Cu / Cu2O@C electrocatalyst was prepared using the same method as in Example 1, except that step (4) was not included.

[0059] Comparative Example 4 The CoTNPc / Cu2O electrocatalyst is prepared in the same way as in Example 1, except that step (3) is not included and the precursor in step (4) is replaced with cuprous oxide.

[0060] Comparative Example 5 The CoTNPc / Cu / Cu2O@C electrocatalyst was prepared in the same way as in Example 1, except that the loading of CoTNPc in step (4) was 5 mg.

[0061] Performance testing: 1. XRD and TEM characterization: Depend on Figure 1 As can be seen, Example 1 successfully synthesized the CoTNPc / Cu / Cu2O@C electrocatalyst.

[0062] Depend on Figure 2 It can be seen that the morphology of the CoTNPc / Cu / Cu2O@C electrocatalyst is a polyhedral structure, with the carbon layer uniformly encapsulating cuprous oxide.

[0063] 2. Electrochemical CO2 reduction experiment: The CoTNPc / Cu / Cu2O@C working electrode material prepared in Example 1 was used in electrochemical CO2 reduction.

[0064] like Figure 3 As shown, the electrochemical CO2 reduction equipment mainly adopts a three-electrode system, consisting of an electrochemical workstation, a current amplifier, an electrolytic cell, a gas chromatograph, a working electrode, a counter electrode, and a reference electrode; it uses a pure platinum plate (1.5 cm²). 2 The Hg / HgO electrode (V vs. SHE 0.098 V) was used as the reference electrode. The working electrode was carbon paper coated with the CoTNPc / Cu / Cu2O@C catalyst prepared in Example 1. Specifically: (1) 10 mg of the CoTNPc / Cu / Cu2O@C electrocatalyst prepared in Example 1 was mixed evenly with 800 μL isopropanol, 150 μL deionized water and 50 μL Nafion solution (5 wt%), and ultrasonically dispersed for 30 min at 100 W to obtain a dispersion; (2) 100 μL of the dispersion was evenly dropped three times in a 4:3:3 ratio onto a 1×1 cm² plate. 2 The catalyst was placed on carbon paper and air-dried naturally before being used as the working electrode, with a catalyst loading of 1 mg / cm³. 2 (area 1cm² immersed in electrolyte) 2 The electrolyte was a KOH solution with a concentration of 1 mol / L, and pure CO2 was bubbled through it to saturate the solution for 40 minutes.

[0065] The main method for testing the electrochemical CO2 reduction performance is the linear sweep voltammetry, with the following detection parameters: settling time is 10s, scan rate is 5mV / s, and scan range is -2.0 to 0V (V vs. RHE).

[0066] The results are as follows Figure 4-5 As shown.

[0067] Depend on Figure 4 It can be seen that the CoTNPc / Cu / Cu2O@C electrocatalyst prepared in Example 1 has an initial potential of only -0.5V (V vs. RHE) for CO2, and a local current density of -843.6mA / cm² at a voltage of -2.0V (V vs. RHE). 2 It exhibits high electrochemical activity.

[0068] Depend on Figure 5 It can be seen that the CoTNPc / Cu / Cu2O@C electrocatalyst prepared in Example 1 has a Faraday efficiency of 55.6% for C2H4 at a voltage of -1.0V (V vs. RHE), exhibiting high C2H4 conversion activity.

[0069] Examples 1-3 and Comparative Examples 1-5 were tested according to the above method, and their performance is shown in Table 1.

[0070] Table 1

[0071] Conclusion: Through comparative experiments with varying content and loading conditions, the CoTNPc / Cu / Cu2O@C catalyst proposed in this invention exhibits significant advantages. Its core lies in the synergistic tandem catalytic mechanism: the CoTNPc molecular layer can efficiently reduce CO2 to a high-concentration CO intermediate, thereby synergistically interacting with the adjacent Cu / Cu2O interface, utilizing suitable... CO binding effectively promotes CC coupling, thereby significantly improving ethylene selectivity and reducing reaction overpotential. Simultaneously, the external carbon layer provides stabilizing confinement for the Cu / Cu₂O nanoparticles, maintaining the key Cu... + The presence of species can prevent particle aggregation and excessive reduction, significantly enhancing the long-term operational stability of the catalyst.

[0072] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a CoTNPc / Cu / Cu2O@C electrocatalyst, characterized in that, Includes the following steps: (1) Mix and grind 4-nitrophthalonitrile, anhydrous cobalt chloride, urea and ammonium molybdate tetrahydrate, then heat to carry out solid-phase reaction, and then successively pass through acid washing, alkali washing, filtration and vacuum drying to obtain cobalt tetranitrophthalocyanine, i.e. CoTNPc; (2) Mix copper acetate monohydrate, solvent, sodium hydroxide and ascorbic acid, heat and stir in a water bath, then centrifuge, wash and vacuum dry to obtain Cu2O powder. (3) The obtained Cu2O powder, solvent and dopamine hydrochloride were mixed and stirred, collected by centrifugation, and dried under vacuum to obtain Cu2O@DA. Cu2O@DA was calcined in an inert atmosphere and cooled to room temperature after calcination to obtain Cu / Cu2O@C precursor. (4) The obtained Cu / Cu2O@C precursor and the obtained CoTNPc were placed in DMF solvent and ultrasonically treated, then mixed and stirred to obtain a mixed solution, collected by centrifugation, and vacuum dried to obtain the CoTNPc / Cu / Cu2O@C catalyst.

2. The preparation method of the CoTNPc / Cu / Cu2O@C electrocatalyst according to claim 1, characterized in that, In step (1), the molar ratio of 4-nitrophthalonitrile, anhydrous cobalt chloride, urea and ammonium molybdate tetrahydrate is 20:4:200:

1.

3. The preparation method of the CoTNPc / Cu / Cu2O@C electrocatalyst according to claim 1, characterized in that, In step (2), the solvent is distilled water, and the mass-volume ratio of copper acetate monohydrate, distilled water, sodium hydroxide and ascorbic acid is 200mg:45mL:(120-240)mg:(88-264)mg.

4. The preparation method of the CoTNPc / Cu / Cu2O@C electrocatalyst according to claim 1, characterized in that, In step (3), the mass ratio of Cu2O powder, solvent and dopamine hydrochloride is 10:(5.0-6.0):(15-20).

5. The preparation method of the CoTNPc / Cu / Cu2O@C electrocatalyst according to claim 1, characterized in that, In step (3), the solvent is a mixture of ammonia, anhydrous ethanol and distilled water in a volume ratio of 1:21:

7.

6. The preparation method of the CoTNPc / Cu / Cu2O@C electrocatalyst according to claim 1, characterized in that, In step (3), the calcination temperature is 300-500℃, the calcination time is 1-4h, and the heating rate is 2-4℃ / min.

7. The preparation method of the CoTNPc / Cu / Cu2O@C electrocatalyst according to claim 1, characterized in that, In step (4), the mass ratio of Cu / Cu2O@C precursor to CoTNPc in the mixed solution is 50:(1-3).

8. A CoTNPc / Cu / Cu2O@C electrocatalyst, characterized in that, It is prepared by the preparation method described in any one of claims 1-7.

9. The application of the CoTNPc / Cu / Cu2O@C electrocatalyst according to claim 8 in electrocatalytic carbon dioxide reduction.

10. The application of the CoTNPc / Cu / Cu2O@C electrocatalyst according to claim 9 in the electrocatalytic reduction of carbon dioxide, characterized in that, Used in electrochemical carbon dioxide reduction electrodes; The method for preparing the electrochemical carbon dioxide reduction electrode, Includes the following steps: The CoTNPc / Cu / Cu2O@C catalyst, isopropanol, deionized water and Nafion solution were mixed evenly and then ultrasonically dispersed to obtain a dispersion. The dispersion was evenly dropped onto carbon paper and allowed to air dry naturally before being used as the working electrode, namely the electrochemical carbon dioxide reduction electrode.

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