WO₃ as Additive for Efficient Photocatalyst Binary System TiO₂/WO₃

Two different methods of synthesis of TiO₂/WO₃ heterostructures were carried out with the aim to increase photocatalytic activity. In this study, anodic TiO₂ nanotube films were synthesized by electrochemical anodization of titanium foil. WO₃ particles were applied to anodic Ti/TiO₂ samples in two different ways – by electrophoretic deposition (EPD) and insertion during the anodization process. Structural and photocatalytic properties were compared between pristine TiO₂ and TiO₂ with incorporated WO₃ particles. Raman mapping was used to character-ise the uniformity of EPD WO₃ coating and to determine the structural composition. The study showed that deposition of WO₃ onto TiO₂ nanotube layer lowered the band gap of the binary system compared to pristine TiO₂ and WO₃ influence on photo-electrochemical properties of titania. The addition of WO₃ increased charge carrier dynamics but did not increase the measured photo-current response. As the WO₃ undergoes a phase transition from monoclinic to orthorhombic at approximately 320 ℃ proper sequence WO₃ deposition could be beneficial. It was observed that secondary heat treatment of WO₃ lowers the photocurrent.