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

Abstract

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.