Enhanced charge separation of NiO/ZnO P-N heterojunction nanorod arrays for photoelectrochemical water splitting

Abstract

In pursuing efficient photoelectrochemical (PEC) water splitting, core-shell heterojunction nanowire arrays photoanode have emerged as a promising candidate. This study presents the successful design and construction of a NiO/ZnO p-n heterojunction nanowire array, which facilitates the separation and transmission of charge, effectively suppresses photo corrosion of the photoanode, and showcases remarkable PEC water splitting performance. Specifically, the optimized NiO/ZnO core-shell photoanode exhibited a remarkable 10.5-fold increase in photoelectric conversion efficiency and a 6.6-fold increase in photocurrent density at 1.23 V relative to pure ZnO. Furthermore, an in-depth analysis of the band structure and the PEC water splitting mechanism of the NiO/ZnO photoanode elucidated the advantages of the p-n heterojunction in effectively separating photo-induced carriers. This work introduces a novel concept for the design and optimization of the core-shell structure of efficient solar fuel production, contributing to the development of renewable energy technology.