NxC-Induced Switching of Methane and Ethylene Products’ Selectivity from CO2 Electroreduction over Cu Catalyst

Regulating the electronic properties or morphology feature of CO2 electroreduction catalysts can maintain selectivity toward certain reduction products. Here we report a nitrogen doped carbon (NxC) modification strategy that can switch CH4 and CH2CH2 product selectivity during CO2 electrolysis over the Cu catalyst. The fabricated core–shell Cu@NxC catalyst exhibited good performance in suppressing HER and promoting CO2RR. About 90% FEs was achieved over the Cu@NxC-350 °C (10:4) catalyst, of which the CH2CH2 FEs was 54% at −1.4 V vs RHE. However, the C1 product was the majority over the Cu@NxC-400 °C (10:4) catalyst, and 63% FEs of CH4 was achieved at the same applied potential. The in-depth characterization revealed that the remarkable selectivity switching of CH4 and CH2CH2 products originated from the NxC shell, rather than the change in the electronic feature of the Cu core. The more pyrrolic N contained in the Cu@NxC catalyst tended to form bridge-bonded *CO, leading to a dominant CH4 product, while the more pyridinic N contained in the Cu@NxC catalyst tended to form linearly bonded *CO, which was favorable for C–C coupling to form the CH2CH2 product. Our results provided insights into the role of the chemical environment on CO2 electroreduction processes.