Controlled growth of Cu2−xS sheet-like nanoshells and Cu2−xS–CdS p–n junctions on Au nanorods with coupled plasmon resonances and enhanced photocatalytic activities

Abstract

In this study, we propose an approach to grow Cu_2−xS sheet-like nanoshells on Au nanorods with the aid of Ag₂S auxiliary templates. The Ag₂S semi-shells are first grown on the side-surface of the Au nanorods and then, the Cu_2−xS sheet-like nanoshells are selectively grown on the opposite side, which is beneficial for improving the controllability of the growth sites of the Cu_2−xS sheet-like nanoshells. The Cu_2−xS–CdS p–n junctions grown on Au nanorods are produced by replacing Ag⁺ with Cd²⁺ in the as-prepared Au/(Cu_2−xS–Ag₂S), so that Au/(Cu_2−xS–CdS) heterorods with non-central symmetric shells of Cu_2−xS–CdS p–n junctions are formed. By carefully adjusting the effective thickness of the Cu_2−xS–CdS junctions, the optimized photocatalytic activity of the Au/(Cu_2−xS–CdS) heterorods is obtained, and it is about 1.62 and 1.22-fold that of Au/Cu_2−xS and Au/CdS, respectively. The improved photocatalytic performance of the Au/(Cu_2−xS–CdS) heterorods is attributed to the effective charge carriers at the interfaces of CdS–Au, Cu_2−xS–Au and the Cu_2−xS–CdS p–n junction. Our findings provide a strategy for the optimal design of plasmon–exciton heterostructures with improved photocatalytic activity.