One-Step Fabricated Sn Particle on S-Vacancies SnS to Accelerate Photoelectron Transfer for Sterling Photocatalytic CO Reduction in Pure Water Vapor Environment.

Promoting the proton-coupled electron transfer process in order to solve the sluggish carrier migration dynamics is an efficient way to accelerate the photocatalytic CO reduction (PCR) process. Herein, through the reduction of Sn by amino and sulfhydryl groups, Sn particles are lodged in S-vacancies SnS nanosheets. The high conductance of Sn particles expedites the collection and transport of photogenerated electrons, activating the surrounding surface of unsaturated sulfur (S ) and thus lowering the energy barrier for generation of *COOH. Meanwhile, S-vacancies boost H O adsorption while S increases CO adsorption, as demonstrated by density functional theory (DFT), obtaining a selectivity of 97.88% CO and yield of 295.06 µmol g h without the addition of co-catalysts and sacrificial agents. This work provides a new approach to building a fast electron transfer interface between metal particles and semiconductors, which works in tandem with S-vacancies and S to boost the efficiency of photocatalytic CO reduction to CO in pure water vapor environment.