A novel approach for synthesis of visible-light-active nano-crystalline TiO2 photocatalyst

Silver doped TiO2 nanoparticles were prepared by combination of sol-gel and arc discharge methods in liquid. The Ag/TiO2 nanoparticles were characterized by X-Ray diffraction (XRD), transmission electron microscopy (TEM) and ultra violet-visible absorption spectroscopy (UV-Vis). The visible light photocatalytic activities were successfully demonstrated for the degradation of Rhodamine B (Rh. B) as a standard organic compound under the irradiation of 90 W halogen light for 2 h. The results revealed that the Ag/TiO2 nanoparticles extended the light absorption spectrum toward the visible region and significantly enhanced the Rh. B photodegradation under visible light irradi-ation. 0.05 gr Ag/TiO2 nanoparticles exhibited highest photocatalytic efficiency. It has been confirmed that the Ag/TiO2 nanoparticles could be excited by visible light (E < 3.2 eV). The significant enhancement in the Ag/TiO2 nanoparticles photocatalytic activity under visible light irradiation can be ascribed to the effect of doped noble metal Ag by acting as electron traps in TiO2 band gap.