Investigation of visible light active Ag sensitized mixed phase TiO2 photocatalyst for solar energy application

Visible photo-active anatase and mixed phase Ag/TiO₂ photocatalysts were prepared using sol–gel method with 1.5 wt% Ag concentration. Due to the large band gap, pristine titania (anatase) is mainly active in the UV light and the photoactivity is limited. But in the presence of both anatase (~3.2 eV) and rutile (~3.0 eV) phases in TiO₂, the catalyst is expected to show enhancement in the photoactivity due to mixed phase junction. The Ag particles are used to act as electron sink and to swiftly transport the photo-generated electrons and, consequently, lessen the recombination rate. The synergistic effect of surface plasmon resonance (SPR) enhanced local field due to Ag particles and the existing mixed phase of TiO₂ is expected to provide a boost in its photoactivity in the visible region. In the present work the mixed phase Ag/TiO₂ photocatalyst showed large enhancement in the degradation of methylene blue compared to all the reference systems.