Synthesis of hierarchical TiO₂ nanoflower with anatase-rutile heterojunction as Ag support for efficient visible-light photocatalytic activity.

Hierarchical flower-like TiO₂ with an anatase-rutile heterojunction was prepared by a hydrothermal process in the presence of titanium trichloride and poly(sodium-p-styrenesulfonate) (PSS). The morphology evolution process and formation mechanism of the as-obtained products were investigated in detail. It was found that morphology and crystalline phase can be easily adjusted by changing the reaction time or solution system. On the basis of this hierarchical nanoflower structure, a visible light sensitive Ag/hierarchical flower-like TiO₂ plasmonic photocatalyst was fabricated. The obtained composite exhibited significantly visible-light photocatalytic activity, which could be attributed to the existence of a large number of uniformly distributed Ag-TiO₂ effective nanojunctions, enhanced visible light-harvesting and improved charge separation due to the migration across the anatase-rutile interface.