Dual-plasmon-induced photocatalytic performance enhancement in Au-PbS-CdS nanodumbbells with double Au caps on the ends

Abstract

In this paper, Au-PbS-CdS nanodumbbells (NDs) with double Au caps on the ends have been synthesized by a simple three-step wet-chemical method. The results show that, a L-SPR induced lateral electric field distribution around this hybrid can be tactfully achieved by adjusting the size of Au caps and their distance, and the dual-plasmon-induced wide spectral coupling between metal and semiconductor can also be observed. Also, the intimate and multi-interface contacts (such as PbS-CdS, Au-PbS and Au-CdS) in these heterostructures provide multiple channels for high-speed photogenerated charge carrier transfer. These will provide a new possibility for high efficiency utilization of solar energy. Subsequently, we have further evaluated the photocatalytic performance of the designed Au-PbS-CdS ND photocatalysts through photocatalytic H2 generation and degradation tests of rhodamine B. The H2 generation rate of the photocatalyst was measured to be 6.31 times higher than that of the mixture of nanoparticles (NPs) (nearly 1.34 times that of core-shell nanorod (NRs) structures). The corresponding rate constant of RhB photodegradation is respectively about 2.35 and 6.41 times that of the NRs and mixture of pure semiconductor NPs. Specifically, the photocatalytic activities of Au-PbS-CdS ND photocatalysts increase with Au caps enlarging. Our results demonstrate that Au-PbS-CdS NDs with double Au caps on the end possess more outstanding visible/NIR-light-driven photocatalytic actives.