Enhanced visible-light photoelectrochemical performance via chemical vapor deposition of Fe2O3 on a WO3 film to form a heterojunction.

A heterojunction photoanode of Fe₂O₃ loaded on a WO₃ film on a fluorine-doped tin oxide substrate (FTO-WO₃/Fe₂O₃) was prepared via a simple hydrothermal and chemical vapor deposition (CVD) growth method. The photoanode showed higher photoelectrochemical (PEC) water-splitting activity than that of the pristine FTO-WO₃ under simulated sunlight because of the synergistic effect of Fe₂O₃ and WO₃. The as-synthesized material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The photocurrent density was estimated by linear sweep voltammetry and further confirmed using intensity-modulated photocurrent spectra. Experiments demonstrated that the coated Fe₂O₃ enhanced the separation and migration efficiencies of the photoinduced electrons and holes, improving the PEC water-splitting properties. The FTO-WO₃/Fe₂O₃ photoanode showed a 1.25 times enhancement in photocurrent density compared with FTO-WO₃. This result suggests that facile chemical vapor deposition growth is an effective way to fabricate heterojunctions and improve the properties of WO₃ photoanodes for PEC water-splitting applications. [ABSTRACT FROM AUTHOR]