Hierarchically CdS Decorated 1D ZnO Nanorods-2D Graphene Hybrids: Low Temperature Synthesis and Enhanced Photocatalytic Performance

A simple, low-temperature synthesis approach is reported for planting CdS-sensitized 1D ZnO nanorod arrays on the 2D graphene (GR) sheet to obtain the ternary hierarchical nanostructures, during which graphene oxide (GO) as the precursor of GR acts as a flexible substrate for the formation of ZnO nanorod arrays. The hierarchical CdS-1D ZnO-2D GR hybrids can serve as an efficient visible-light-driven photocatalyst for selective organic transformations. The fast electron transport of 1D ZnO nanorods, the well-known electronic conductivity of 2D GR, the intense visible-light absorption of CdS, the unique hierarchical structure, and the matched energy levels of CdS, ZnO and GR efficiently boost the photogenerated charge carriers separation and transfer across the interfacial domain of hierarchical CdS-1D ZnO-2D GR hybrids under visible light irradiation via three-level electron transfer process. Furthermore, the superior reusability of ternary hybrids is achieved by controlling the reaction parameters, i.e., using visible light irradiation and holes scavenger to prevent ZnO and CdS from photocorrosion. This work demonstrates a facile way of fabricating hierarchical CdS-1D ZnO-2D GR hybrids in a controlled manner and highlights a promising scope of adopting integrative photosensitization and co-catalyst strategy to design more efficient semiconductor-based composite photocatalysts toward solar energy capture and conversion.