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

A heterojunction photoanode of Fe 2 O 3 loaded on a WO 3 film on a fluorine-doped tin oxide substrate (FTO-WO 3 /Fe 2 O 3 ) 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-WO 3 under simulated sunlight because of the synergistic effect of Fe 2 O 3 and WO 3 . 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 Fe 2 O 3 enhanced the separation and migration efficiencies of the photoinduced electrons and holes, improving the PEC water-splitting properties. The FTO-WO 3 /Fe 2 O 3 photoanode showed a 1.25 times enhancement in photocurrent density compared with FTO-WO 3 . This result suggests that facile chemical vapor deposition growth is an effective way to fabricate heterojunctions and improve the properties of WO 3 photoanodes for PEC water-splitting applications.