S-scheme carrier kinetic pathway constructed by covalent-anion channels in self-assembled cadmium/rhenium sulfide hybrids for efficient Cr(VI) reduction

Abstract

Exploring photocatalysts to accelerate heavy metal Cr(VI) photoreduction is of great significance. Different from traditional strategies, this work proposes a simple and feasible strategy to construct cadmium/rhenium sulfide (CdS/ReS2) S-scheme heterojunctions for enhancing carrier separation through a covalent-anion-driven self-assembling approach. Herein, the construction of internal electric field induced by an atomic-hybridization at CdS/ReS2 interface drives the photoexcited electrons from one-dimensional CdS nanowires to two-dimensional ReS2 nanosheets upon light irradiation, resulting in the formation of an S-scheme carrier kinetic pathway, which enables the separation of electron-hole pairs to accelerate Cr(VI) photoreduction. As a result, the reduction reaction of CdS/ReS2 heterojunction is increased about 11.4 and 24.3 times compared to pristine CdS and ReS2. Our findings provide a new insight in regulating carrier transfer pathway and designing new-type photocatalysts.