Photoinduced dissolution and redeposition of Au nanoparticles supported on TiO2

Au particles (mean size ca. 3 nm) supported on TiO2 particles were irradiated by UV light (>300 nm) in aqueous solutions at 278 K. Photo-induced dissolution of Au nanoparticles followed by redeposition occurred in aqueous solutions containing halogen ions. The dissolution of Au nanoparticles yielded a Au(III) complex with a halogen ion; subsequent reduction of the Au(III) complex caused precipitation of larger Au particles on TiO2.