A visible-light active TiO2 photocatalyst multilayered with WO3
Sputter-deposited TiO2 films with high visible-light photocatalytic activity were successfully realized by a hybrid TiO2/Pt/WO3 film structure with Pt nanoparticles uniformly distributed at the interface of the TiO2 and WO3 films. The TiO2/Pt/WO3 hybrid films enable the complete decomposition of CH3CHO under visible-light irradiation. The water contact angle of the TiO2/Pt/WO3 hybrid films reaches below 5° under visible-light irradiation. Pt nanoparticles are considered to act as a cocatalyst to improve the electron–hole separation efficiency. We demonstrate that the photogenerated holes in WO3 are transferred to the surface of the TiO2 film with less hole-trapping and induce high visible-light photocatalytic activity and hydrophilic behavior, and the photogenerated electrons are accumulated in the Pt nanoparticles. The highly hydrophilic thin films with high visible-light photocatalytic activity can be applied to various indoor products possessing self-cleaning and antifogging properties.