Nature inspired ZnO/ZnS nanobranch-like composites, decorated with Cu(OH)2 clusters for enhanced visible-light photocatalytic hydrogen evolution

Abstract

In this study, ZnO/ZnS hierarchical nanobranch like composite with Cu(OH)2 clusters were designed via a simple facile hydrothermal process followed by precipitation reaction. Anchoring Cu(OH)2 clusters on the ZnO/ZnS composite surface can shorten the charge migration distance, providing abundant active sites and extend the visible-light absorption. The effects of Cu(OH)2 clusters loading on the photocatalytic application were investigated. The photocatalytic activities for hydrogen production were evaluated under visible-light (λ > 400 nm) irradiation. It was found that coupling suitable weight ratio of Cu(OH)2 cluster over the ZnO/ZnS nanobranches will enhance the photocatalytic hydrogen evolution by 46.5 and 13.7 times higher than pure Zn5(CO3)2(OH)6 and ZnO/ZnS, nanobranches respectively and an apparent quantum efficiency of 11.5% at λ = 420 nm, and 14.7% under monochromatic LED light irradiation of 520 nm wavelength was achieved. This results show that construction of ZnO/ZnS nanobranches decorated with Cu(OH)2 clusters can effectively improve the charge transfer and enhance the photocatalytic hydrogen production. The as-prepared ZnO/ZnS nanobranches decorated with Cu(OH)2 clusters exhibits outstanding stability and recyclability. The mechanism for the enhanced hydrogen evolution is also discussed.