The enhanced local CO concentration for efficient CO2 electrolysis towards C2 products on tandem active sites

Electrochemical reduction of CO2 to C2 products on Cu-based catalysts provides a promising approach for controlling the global carbon balance and restoring renewable surplus electricity. The enhanced CO2 adsorption and CO local concentration are beneficial for CO2 conversion and C2 intermediates formation, promoting the progress of CO2 utilization. Here, we report a bimetallic MOF-derived Co3O4-CuOx/C (M-CuCo/C) catalyst constructed with Co3O4 and CuOx sites wrapped in the carbon skeleton, achieving efficient CO2 activation and C2 generation under low overpotential. The optimized M-CuCo/C catalyst (Cu/Co ratio of 1:2) exhibits a total current density of 19.28 mA/cm2 at −1.05 (V vs. RHE), which is 8.60 times than that on MOF-derived CuOx/C (M-Cu/C). The highest C2 faradic efficiency (FE) reaches 79.2% (-0.75 V vs. RHE), accompany with a C2 production rate of 275.6 μmol/(g·h). The special nanorods-like morphology assembled by dual sites significantly increases electrochemical surface area and electron transmission rate during eCO2RR. The local CO intermediates under real-time electrochemical environment are monitored via rotation ring disk electrode (RRDE) techniques. Combined with in situ infrared measurements and DFT studies, it's demonstrated that CO2 could be efficiently converted to CO under low overpotential on Co3O4 sites, forming local CO-enriched environment around neighboring CuOx sites and further accelerating the process of C2 formation.