Enhanced visible-light-driven photocatalysis from WS2 quantum dots coupled to BiOCl nanosheets: synergistic effect and mechanism insight

Abstract

Quantum dots (QDs) derived from two-dimensional (2D) nanosheets (NSs), especially ultrathin transition metal dichalcogenide (TMD, e.g. WS₂, WSe₂, MoS₂, MoSe₂) NSs, have attracted great attention due to their broad band absorption and high charge mobility. Herein, WS₂ QDs, one of the emerging extraordinary zero-dimensional (0D) TMD materials, were applied to the preparation of novel 0D/2D heterojunctions of WS₂ QDs/BiOCl nanosheets. The obtained WS₂/BiOCl composites exhibited significantly enhanced visible-light-driven photocatalytic activity as compared with pure BiOCl. The results indicated that the holes (h⁺) and O₂˙⁻ are the main active species generated by the catalysts under visible light irradiation. The enhanced photocatalytic performance could be due to the broad band absorption and up-conversion properties of the WS₂ QDs as well as the band alignment and the strong coupling between the WS₂ QDs and BiOCl NSs, leading to a broadened light absorption range and enhanced efficiency for electron–hole pair production and separation. These findings offer exciting opportunities using the extraordinary 2D TMD material-derived quantum dots for the fabrication of novel 0D/2D composites and may provide new insights into the application of the novel 0D/2D composites in catalysis.