Oxygen-doped MoS2 nanospheres/CdS quantum dots/g-C3N4 nanosheets are synthetized through hydrothermal and chemical bath deposition-calcination processes. The prepared materials are characterized by X-ray diffraction transient-state photoluminescence spectra, transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and electrochemical experiment. These results show that the ternary composite material has longer lifetime of photogenerated carriers and more active sites, thereby enhancing photocatalytic performance. CdS quantum dots act as a bridge between the intermediate transport charges in the ternary composite. The oxygen defect engineering prolongs the lifetime of carriers obviously, which is confirmed by transient-state photoluminescence. Moreover, the photocatalytic H2 evolution and photodegradation of bisphenol A for MoS2/CdS/g-C3N4 is up to 956 μmol h-1 g-1 and 95.2% under visible-light irradiation, respectively. Furthermore, excellent photocatalytic activity can be ascribed to the synergistic effect of defect engineering and formation of ternary heterostructures, which is with broad-spectrum response, longer lifetime of photo-induced electron-holes, and more surface active sites.
Keywords: MoS2 nanosphere; g-C3N4; heterojunction; photocatalysis; quantum dot.