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

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.