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

A heterojunction photoanode of FeOloaded on a WOfilm on a fluorine-doped tin oxide substrate(FTO-WO/FeO)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-WOunder simulated sunlight because of the synergistic effect of FeOand WO.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 FeOenhanced the separation and migration efficiencies of the photoinduced electrons and holes,improving the PEC water-splitting properties.The FTO-WO/FeOphotoanode showed a 1.25 times enhancement in photocurrent density compared with FTO-WO.This result suggests that facile chemical vapor deposition growth is an effective way to fabricate heterojunctions and improve the properties of WOphotoanodes for PEC water-splitting applications.