Carbonized Yolk-shell Metal-Organic Frameworks for Electrochemical Conversion of CO2 into Ethylene

With the excessive consumption of fossil fuels and the massive emission of CO2, it has led to a series of environmental crises posing a serious threat to sustainable development. Electrochemical CO2 reduction reaction (CO2RR) to ethylene helps solve these serious environmental crises. Herein, we report the synthesis of a copper-based electrocatalyst by pyrolysis of yolk-shell structured HKUST-1 with partial substitution of trimesic acid by benzimidazole(nitrogen source). The electrocatalyst exhibits an ethylene Faradic efficiency(FE) of 25.8% and a partial ethylene current density of 23.7 mA/cm(2), in addition, the electrocatalyst can maintain stable performance during 10 h of electrolysis, which are all better than those of the electrocatalyst without nitrogen dopant. According to electrochemical measurements and X-ray photoelectron spectroscopy(XPS), we propose that the nitrogen dopant plays an effective role in stabilizing Cu(I) species and promoting CO2 molecules activation, as well as suppressing the reduction of Cu(I) species during electrolysis. Eventually, the performance of the electrocatalyst toward CO2 RR is studied in a flow cell. This work provides a new route for the design of Cu-based electrocatalyst toward electrochemical CO2 conversion into ethylene.