Insight into Charge Separation in WO3/BiVO4 Heterojunction for Solar Water Splitting

Recently, the WO 3 /BiVO 4 heterojunction has shown promising photoelectrochemical (PEC) water splitting activity based on its charge transfer and light absorption capability, and notable enhancement of the photocurrent has been achieved via morphological modification of WO 3 . We developed a graft copolymer-assisted protocol for the synthesis of WO 3 mesoporous thin films on a transparent conducting electrode, wherein the particle size, particle shape, and thickness of the WO 3 layer were controlled by tuning the interactions in the polymer/sol–gel hybrid. The PEC performance of the WO 3 mesoporous photoanodes with various morphologies and the individual heterojunctions with BiVO 4 (WO 3 /BiVO 4 ) were characterized by measuring the photocurrents in the absence/presence of hole scavengers using light absorption spectroscopy and intensity-modulated photocurrent spectroscopy. The morpholo…