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

Abstract

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.