Ag Nanoparticles Decorated TiO2 Thin Films with Enhanced Photocatalytic Activity

A highly photocatalytic Ag/TiO2 thin film is prepared by the photocatalytic deposition of Ag nanoparticles (NPs) on reactive sputtered columnar TiO2 structures. By altering the ultra-violet (UV) exposure time, the authors control the morphology and surface coverage of deposited Ag NPs. While a surface coverage of 1-4% (by Ag NPs) leads to a significant increase in the photocatalytic activity, depositing more Ag NPs yield a decrease in the photocatalytic performance (lower than that of bare TiO2). This may arise due to the blocking of UV light incoming to the TiO2 by the formation continuous network of Ag clusters on the surface. Such highly interconnected Ag clusters might also trigger the recombination of electron-hole pairs. After five consecutive photocatalysis tests, the Ag (1 min)/TiO2 thin film remains intact.