摘要
A series of ZnO-CdS-Ag 2 S ternary nanostructures with different amounts of Ag 2 S were prepared using simple and low-cost successive ionic layer adsorption and reaction (SILAR) and a chemical precipitation method. The ZnO nanowires, with a diameter of ∼100 nm and a length of ∼1 μm, were modified by coating CdS and Ag 2 S. CdS has a high absorption coefficient and can efficiently match with the energy levels of ZnO, which can enhance the light absorption ability of the nanostructures. In addition, Ag 2 S with a narrow band gap was used as the main light absorber and played an important role in increasing the light absorption in the visible light region. The photocatalytic activity of the ZnO-CdS-Ag 2 S ternary nanostructures was investigated using the degradation of methyl orange (MO) in an aqueous solution under visible light. The ZnO-CdS-Ag 2 S ternary nanostructures were found to be more efficient than ZnO nanowires, ZnO-CdS nanowires, and ZnO-Ag 2 S nanowires. There is 7.68 times more photocatalytic activity for MO degradation in terms of the rate constant for ZnO-CdS-Ag 2 S 15-cycle ternary nanostructure compared to the as-grown ZnO. Furthermore, the effect of the amount of Ag 2 S and CdS on the ZnO surface on the photocatalytic activity was analyzed. The superior photo-absorption properties and photocatalytic performance of the ZnO-CdS-Ag 2 S ternary nanostructures can be ascribed to the heterostructure, which enhanced the separation of the photo-induced electron-hole pairs. In addition, visible light could be absorbed by ZnO-CdS-Ag 2 S ternary nanostructures rather than by ZnO.