Clustered Au on TiO2 Snowman-Like Nanoassemblies for Photocatalytic Applications

摘要

Snowman-like Au-TiO2 nanoassemblies comprising of clusters of Au nanostructures (nanospheres and nanorods) on TiO2 nanoparticles have been synthesized using a controlled hydrolysis method and their photocatalytic activity under both ultraviolet radiation and visible light was investigated. The photocatalytic activity was evaluated by monitoring the degradation of a model dye, methylene blue (MB) and a colorless hazardous fungicide, carbendazim (CZ). The Au nanoclusters play the role of co-catalyst when ultraviolet radiation was used, while it plays the role of light harvester when visible light was used for photocatalysis. In both the cases, these clustered Au on TiO2 snowman- like nanoassemblies possess enhanced photocatalytic activity compared to bare TiO2 and their superior performance can be ascribed to the efficient charge separation of the photo generated electrons and holes at the Au-TiO2 interface, facilitated by the close proximity of the Au nanostructures in the cluster. In essence, this study illustrates that the concept of having a cluster of noble metal nanoparticles on to a semiconductor oxide provides distinctive advantages in enhancing the photocatalytic performance of hybrid nanoassemblies under both ultraviolet and visible light irradiations.