Preparation and characterization of silver and indium vanadate co-doped TiO2 thin films as visible-light-activated photocatalyst

Novel visible-light-activated photocatalytic Ag/InVO4-TiO2 thin films were developed in this paper through a sol-gel method from the TiO2 sol containing Ag and InVO4. The photocatalytic activities of Ag/InVO4-TiO2 thin films were investigated based on the oxidation decomposition of methyl orange in aqueous solution. The Ag/InVO4-TiO2 thin films were characterized by X-Ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and UV-vis absorption spectroscopy (UV-vis). The results revealed that the Ag/InVO4-TiO2 thin films extended the light absorption spectrum toward the visible region; the Ag and InVO4 co-doped thin films significantly enhanced the methyl orange photodegradation under visible light irradiation. It has been confirmed that the Ag/InVO4-TiO2 thin films could be excited by visible light (E < 3.2 eV). The significant enhancement in the Ag/InVO4-TiO2 photo activity under visible light irradiation can be ascribed to the simultaneous effects of doped noble metal Ag by acting as electron traps and InVO4 as narrow band gap sensitizer.