First-Principles Study of Single Atom Catalyzed Photoelectrochemical Reduction of CO$_{\mathrm{2}}$*

Production of synthetic chemical fuels from solar energy is critical for us to meet the globally growing need of energy as the fossil fuels are depleting fast. The greenhouse gas CO$_{\mathrm{2}}$, as the major product of consumption of both fossil fuels and solar fuels, can be used as the feedstock for solar fuels, thereby providing a sustainable way of closing the carbon cycle. The conversion rate of CO$_{\mathrm{2}}$ to fuels is, however, still too low to be practical besides the poor selectivity of products. In this study, we have investigated the use of single metal atoms supported on graphene sheets as catalysts for the photoelectrochemical reduction of CO$_{\mathrm{2}}$ using the first-principles approach. Reaction pathways to produce a variety of products such as CO, HCOOH, HCHO, CH$_{\mathrm{3}}$OH and CH$_{\mathrm{4}}$ will be presented to demonstrate the differences in metals with a focus on their efficiency and selectivity. Potential candidates of better catalytic performance for production of fuels are identified through computational screening.