First-principle study on the conversion of CO2 to value-added C1 products using single-atom cocatalysts on ZnS

Photocatalytic CO2 reduction reaction (CO2RR) offers a sustainable solution to alleviate the greenhouse effect, and produce various chemical products and fuels. This study investigated the structural stability, electronic structure, catalytic activity, and selectivity of M/ZnS (M = Pd, Ag, Pt, Au, Al, Ga, In, Sn and Cu) photocatalysts based on the density functional theory (DFT) under the first-principle framework. The results suggested that all nine metal elements preferred substitution at the outmost surface site. Among these photocatalysts, four (Al/ZnS, Ga/ZnS, In/ZnS, and Sn/ZnS) are more favorable to conduct CO2RR than hydrogen evolution reaction (HER) in aqueous phase. This study explored the potential generation of various C1 products (such as HCOOH, CH3OH, and CH4) on these four single-atom metals and revealed that M/ZnS (M = Al, Ga, and In) are more likely to selectively produce CH3OH/CH4, while Sn/ZnS is more inclined to produce HCOOH. The other five M/ZnS (M = Pd, Ag, Pt, Au, Cu) can induce a severe HER competition, which may be inhibited by using non-aqueous system. This study provides valuable theoretical guidance for the screening and development of high-performance photocatalysts for CO2RR.