Promoted photoelectrocatalytic hydrogen evolution of a type II structure via an AlO recombination barrier layer deposited using atomic layer deposition.

Constructing a semiconductor type II structure is an effective way to enhance the photogenerated charge separation efficiency. The separation and migration of interfacial photogenerated carriers is a key factor, which influences the photocatalytic activity. In this study, a conformal AlO recombination barrier layer was introduced at the interface between TiO nanowires and CdSe nanoparticles, and the application of this composite in photoelectrocatalytic (PEC) hydrogen production was explored. Under visible-light irradiation, the photocurrent response and PEC hydrogen evolution performance increased step-by-step from TiO to the AlO/TiO and CdSe/AlO/TiO nanowire arrays. Moreover, the H evolution rate of CdSe/AlO/TiO was much higher than that of a different configuration, AlO/CdSe/TiO. The enhanced PEC hydrogen evolution performance was attributed to the prevention of the interfacial charge recombination caused by the AlO recombination barrier layer. Our results may shed new light on developing novel and highly efficient photocatalysts using rational interface design.