Efficient promotion of charge transfer and separation in hydrogenated TiO2/WO3 with rich surface-oxygen-vacancies for photodecomposition of gaseous toluene.

Oxygen-deficient TiO2/WO3 constructed via the controllable temperature of hydrogen annealing is designed in view of combining the broad visible spectrum absorption with the prominent coupled semiconductor properties. Surface lattice disorder of TiO2/WO3 arises at hydrogen annealing temperature of 200 and 300°C, while critical phase transition from TiO2/WO3 to TiO2/WO2.9 occurs at 400°C, both of which can introduce oxygen vacancies. The hydrogenated TiO2/WO3 with rich surface-oxygen-vacancies exhibits much higher photocatalytic activity for decomposition of gaseous toluene than pristine TiO2/WO3 under visible-light illumination (λ>420nm). The photoelectrochemical analysis shows that the improved electronic properties of oxygen-deficient TiO2/WO3 enable dramatically efficient promotion of photoinduced charge transfer and separation, which is the key factor for the improved photocatalytic activity. It is hoped that the present work could boost ongoing interest for preparing various hydrogenated coupled semiconductors with enhanced activity for diverse photocatalytic applications.