Hybrid metal-dual sulfide core–shell nanostructures with enhanced photocatalytic properties

In this study, we report a facile cation-exchange method to synthesize three different metal@dual sulfide hybrid nanostructures with enhanced photocatalytic properties. Starting from clusters of Au@Ag 2 S with a poorly crystalline shell, excess amounts of Cd 2+ , Zn 2+ and Pb 2+ are used to promote the thermodynamically unfavored cation-exchange under elevated temperature. The change of shell compositions accompanies the disassembly of Au@Ag 2 S clusters into monodisperse ternary core–shell nanostructures with modulated optical properties. Interestingly, it is found that Au@Ag 2 S–CdS outperforms Au@Ag 2 S–ZnS and Au@Ag 2 S–PbS in the visible-light-driven photodegradation of methylene blue, which can be largely attributed to the improved shell crystallinity, enhanced visible light absorption and appropriate band alignment for charge transfer.