Oxygen-deficient bismuth tungstate and bismuth oxide composite photoanode with improved photostability

A homogeneous layer of Bi₂O₃-Bi₁₄WO₂₄ composite (BWO/Bi₂O₃) thin film was fabricated using a combination of electrodeposition and thermal treatment. The evenly distributed Bi₁₄WO₂₄ component within the Bi₂O₃ layer was found to be important in stabilising the photoelectrochemical performances of Bi₂O₃ photoanode by promoting the photoelectron transport. The unmodified Bi₂O₃ suffered from severe photocorrosion as proven by X-ray diffraction (XRD) and inductively coupled plasma (ICP) analyses while the composite thin film was active without noticeable activity decay for at least 3 h of illumination. This strategy might be applicable to other photocatalysts with stability issues.