Atomic-level insights into surface engineering of semiconductors for photocatalytic CO₂ reduction

Photocatalytic conversion of CO₂ into solar fuels provides a bright route for the green and sustainable development of human society. However, the realization of efficient photocatalytic CO₂ reduction reaction (CO₂RR) is still challenging owing to the sluggish kinetics or unfavorable thermodynamics for basic chemical processes of CO₂RR, such as adsorption, activation, conversion and product desorption. To overcome these shortcomings, recent works have demonstrated that surface engineering of semiconductors, such as introducing surface vacancy, surface doping, and cocatalyst loading, serves as effective or promising strategies for improved photocatalytic CO₂RR with high activity and selectivity. The essential reason lies in the activation and reaction pathways can be optimized and regulated through the reconstruction of surface atomic and electronic structures. Herein, in this review, we focus on recent research advances about rational design of semiconductor surface for photocatalytic CO₂RR. The surface engineering strategies for improved CO₂ adsorption, activation, and product selectivity will be reviewed. In addition, theoretical calculations along with in situ characterization techniques will be in the spotlight to clarify the kinetics and thermodynamics of the reaction process. The aim of this review is to provide deep understanding and rational guidance on the design of semiconductors for photocatalytic CO₂RR.