Novel dual-layer photoelectrode prepared by RF magnetron sputtering for photocatalytic water splitting

Visible-light absorbing TiO2 and WO3 photocatalytic thin films were prepared by radio-frequency (RF) magnetron sputtering. The effects of sputtering condition on the structural, optical, as well as photocatalytic properties of the prepared thin films were explored. In addition, a novel dual-layer photocatalytic thin film that combines both visible-light TiO2 and WO3 was prepared by the same deposition technique to further enhance the photocatalytic performance. Instrumental analyses such as XRD, SEM-EDX, and UV–visible absorption spectrometry were performed to reveal the crystallinity, surface morphology, chemical composition, and light absorption of the prepared photocatalytic thin films. The activities of the prepared photocatalytic thin films under both UV and visible-light irradiations were evaluated by conducting photovoltammetry and water-splitting reaction in an H-type reactor. The enhanced photocurrent of dual-layer photocatalytic thin film was proved to be resulted from the improved charge separation of the dual-layer structure. The H2 and O2 yields obtained from the water-splitting reactions were consistent with the photocurrent results, showing dual-layer photocatalyst with higher photoactivity than mono-layer photocatalyst.