Photochemical synthesis, characterization and enhanced visible light induced photocatalysis of Ag modified TiO2 nanocatalyst.

Nanocomposite of titania (TiO2) and silver (Ag) has been synthesized by a photochemical deposition method. We investigated the simultaneous enhancement of visible light sensitivity and photocatalytic activities of as-prepared Ag-TiO2 nanocomposite photocatalyst. The resulting Ag-TiO2 nanomaterials were characterized by various analytical techniques including X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL). Photocatalytic activity was evaluated by decomposition of methylene blue (MB) dye solution under simulated visible light irradiation. Ag nanoparticles were well dispersed on the surface of TiO2 and composite nanoparticles were effectively enhanced in visible light-induced photocatalytic activity compared to that of Ag free TiO2. It was found that the enhanced activity is result from simultaneous effects of nano-Ag deposits by increasing the absorption capacity in visible region and by acting as electron trappers to promote charge separation of photoinduced electrons (e-) and holes (h+). The effect of the amount of Ag nanoparticles on its photoactivity under simulated visible light was also investigated.