Promoted photoelectrocatalytic hydrogen evolution of a type II structure via an Al2O3 recombination barrier layer deposited using atomic layer deposition

Abstract

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 Al₂O₃ recombination barrier layer was introduced at the interface between TiO₂ 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 TiO₂ to the Al₂O₃/TiO₂ and CdSe/Al₂O₃/TiO₂ nanowire arrays. Moreover, the H₂ evolution rate of CdSe/Al₂O₃/TiO₂ was much higher than that of a different configuration, Al₂O₃/CdSe/TiO₂. The enhanced PEC hydrogen evolution performance was attributed to the prevention of the interfacial charge recombination caused by the Al₂O₃ recombination barrier layer. Our results may shed new light on developing novel and highly efficient photocatalysts using rational interface design.