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

Abstract

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 (C2 H5 OH) 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 C2 H5 OH conversion pathway.