Ag-TiO₂ nanocomposites with improved photocatalytic properties prepared by a low temperature process in polyethylene glycol

TiO₂ nanotube-nanoparticle mixture was prepared by a rapid anodization process in a perchlorate containing electrolyte followed by an ultrasonic process. Ag-TiO₂ nanocomposites were prepared at low temperature in polyethylene glycol (PEG600) solution, in which PEG600 was employed as the stabilizing agent as well as the reducer which can reduce Ag⁺ on the surface of prepared TiO₂ nanocrystals. The synthesized samples were characterized by X-ray diffraction, transmission electron microscopy, energy dispersive X-ray detector, X-ray photoelectron spectroscopy and UV-vis absorption spectroscopy. Results showed that well dispersed Ag nanoparticles with a typical size of 5-10nm can be synthesized on the surface of TiO₂ nanocrystals assisted by the PEG600. To investigate the photocatalytic activity of the samples, TiO₂ powders with different Ag contents were prepared and employed to decompound methyl orange under UV-light irradiation. Compared with pure TiO₂ nanocrystals and commercial P25, a great improvement of photocatalytic performance was found for the Ag-TiO₂ nanocomposites. It is believed that the excellent photocatalytic properties of the samples prepared in our experiment mainly result from promoted separation of photogenerated electron-hole pairs and higher reductive power due to the formed heterostructure between TiO₂ and Ag as well as the advanced absorption of light due to surface plasmon effect of Ag nanoparticles.