Insight into enhanced visible-light-driven Cr(VI) reduction with ZnO/ZnSe hierarchical n-p heterojunction

Abstract A series of novel porous center-hollow ZnO/ZnSe microspheres were synthesized via two-step hydrothermal and ion-exchange method. It is found the load of ZnSe improves photocatalytic activity of the nanocomposites and ZSe-3 sample shows the most prominent performance, 88.8% of Cr(VI) can be reduced in 60 min under the irradiation of visible light (λ > 420 nm). ZnSe nanoparticles can be used to sensitize the ZnO microspheres and further extend the visible light response range. The n-p heterojunction formed at the interface between ZnO and ZnSe can also contribute to improve the separation and transfer properties of charge carriers in ZnO.