Construction of CdS/CoOx core-shell nanorods for efficient photocatalytic H2 evolution

Efficient separation of electrons and holes, associated with the reduction or oxidation reactions, is of great significance in a photocatalytic system. In this study, we demonstrate the novel CdS/cobalt oxide core-shell nanorods (CdS/CoOx core-shell NRs) prepared by a facile impregnation-calcination method. The negatively charged surface of CdS induces the in situ growth of CoO and Co3O4 (abbreviated as CoOx here) as the outer shell, which efficiently captures the photogenerated holes and renders drastically improved charge separation efficiency to CdS/CoOx core-shell NRs. Moreover, the intimate interfacial contact between the CdS core and CoOx shell offers rectified charge transfer directions, which further boosts the charge separation. In consequence, the severe photocorrosion is effectively alleviated, and nearly ca. 43-folds higher of H2 production rate is achieved on CdS/CoOx core-shell NRs compared to the pristine CdS NRs. We believe that this work not only provides new approaches toward photocatalysts with steerable charge flows and enhanced photostability, but also contributes to design other efficient photocatalytic systems.