Enhanced Photoelectrochemical Activities of ZnO Nanorod Arrays After a Modification of ZnS or ZnIn2S4

Highly ordered ZnO nanorod arrays (NRAs) were prepared via a facile ion-exchange route for the photoelectrochemical (PEC) application. Then, ZnO NRAs were modified with ZnS and ZnIn 2 S 4 , respectively, through using a hydrothermal treatment method again. It was found that both the ZnS and ZnIn 2 S 4 modifications were in favor of enhancing the PEC activity of ZnO NRAs, although there were no obvious enhancements in the visible-light absorption. Thus, the enhancement was attributed to both the efficient charge separation and excellent electrocatalytic activity of ZnIn 2 S 4 . The Mott–Schottky (M–S) plots of two samples were compared and analyzed for clarifying the intrinsic mechanism. A schematic band model has also been proposed for clarifying the charge transfer process in a heterojunction.