Three modes of high-efficient photocatalysis using composites of TiO2-nanocrystallite-containing mesoporous SiO2 and Au nanoparticles

摘要

A mesoporous SiO2 template containing TiO2 nanocrystals is synthesized via a sol-gel route, and Au nanoparticles (NPs) are deposited in the tubular mesochannels of the template by a photodeposition method (Au/SiO2-TiO2). Both of the photocatalytic activities under ultraviolet (UV) and visible (Vis) light irradiation are improved by the deposition of Au NPs. A commercially available photocatalyst, Degussa P25 is employed as a reference, and a comparative study shows that Au/SiO2-TiO2 possesses higher photocatalytic activity than that of P25. An action spectrum of methylene blue (MB) photobleaching using Au/SiO2-TiO2 reveals that the photocatalysis of Au/SiO2-TiO2 is carried out by three triggers: UV absorption by TiO2, and Vis light absorptions by Au NPs and MB.