Enhancing Photocatalytic Activity of Au-Capped CdS-PbS Heterooctahedrons by Morphology Control

摘要

We report the preparation of Au-capped CdS-PbS heterooctahedrons of Au@CdS-PbS with controlled morphology for enhanced photocatalytic H-2 generation. Au@CdS-PbS heteronanostructures possess three advantages: (1) CdS-PbS octahedrons form a p-n heterojunction with built-in field for efficient separation of photoexcited charge carriers. (2) Au nanocups exhibit strong light-harvesting capability in broadband spectrum across the visible and near-infrared region induced by the electric quadrupole and magnetic dipole plasmon modes. (3) Due to the higher permittivity of PbS compared with CdS, the intense scattering of PbS dielectric antenna and large local field of Au plasmonic antenna could both lead to the enhanced optical absorption and generation of e/h pairs. By optimizing the morphology of Au@CdS-PbS, the largest normalized photocatalytic H-2 generation rate of 400.6 mu mol/g/h is obtained, which is 6.33 times that of the sum of pure CdS-PbS and standalone Au nanocups. This study provides the essential advantages of p-n heterojunction as well as magnetic plasmon resonance and dielectric antenna effect for the application of highly efficient photocatalysis.