Highly Selective Photoelectroreduction of Carbon Dioxide to Ethanol over Graphene/Silicon Carbide Composites

Using sunlight to produce valuable chemicals and fuels from carbon dioxide (CO2), i.e., artificial photosynthesis (AP) is a promising strategy to achieve solar energy storage and a negative carbon cycle. However, selective synthesis of C2 compounds with a high CO2 conversion rate remains challenging for current AP technologies. We performed CO2 photoelectroreduction over a graphene/silicon carbide (SiC) catalyst under simulated solar irradiation with ethanol (C2H5OH) selectivity of>99 % and a CO2 conversion rate of up to 17.1 mmol gcat−1 h−1 with sustained performance. Experimental and theoretical investigations indicated an optimal interfacial layer to facilitate the transfer of photogenerated electrons from the SiC substrate to the few‐layer graphene overlayer, which also favored an efficient CO2 to C2H5OH conversion pathway. The interfacial layer in the graphene/silicon carbide composite allows the facile transfer of photogenerated electrons from the silicon carbide substrate to the active sites of graphene, resulting in efficient CO2 activation and C−C coupling for ethanol production. This catalyst showed a near‐perfect ethanol selectivity of>99 % at an exceedingly high CO2 conversion rate of 17.1 mmol gcat−1 h−1 and stability in ambient CO2 photoelectroreduction.