A comparative study of photo-assisted deposition of silver nanoparticles on TiO₂

Noble metals deposited on TiO₂ act as electron traps facilitating electron-hole separation and promoting the interfacial electron transfer process. In particular, silver nanoparticles have the ability to absorb visible light due to localized surface plasmon resonance. Here we report a photochemical and photocatalytic method for depositing Ag nanoparticles (2-20 nm) on TiO₂ by using UV light at room temperature. UV-Vis diffuse reflectance spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and time-resolved microwave conductivity were used as characterization techniques. The photocatalytic activity was investigated by measuring the decomposition of rhodamine B under UV and visible light irradiation. The fastest bleaching of RhB under visible-light irradiation has been obtained by Ag/TiO₂ plasmonic photocatalyst prepared by the photocatalytic route. These results were explained in terms of the more efficient photon absorption due to the presence of the surface plasmon resonance.