Comparative study on photocatalytic and bactericidal activity between Ag@TiO2 core-shell nanoparticles and Ag@TiO2 surface doped nanostructures

Silver@titanium dioxide (Ag@TiO2) core-shell nanostructures and Ag surface doped TiO2 particles (TiO2@Ag) have been designed and synthesized by sol-gel and hydrothermal methods under mild conditions. These two types of Ag-TiO2 nanocomposites were characterized in terms of their properties. Specifically, the photocatalytic performance and antibacterial behavior of such nanocomposites have been investigated and compared. It was found that the Ag@TiO2 core-shell nanostructures exhibit superior photocatalytic property to the Ag surface doped TiO2 particles under the reported conditions, while the same situation happened in the bactericidal test. This is probably because the Ag cores tend to facilitate charge separation for TiO2, producing greater hydroxyl radicals on the surface of the TiO2 particles. These findings would be useful for the design and synthesis of Ag-TiO2 nanocomposites with desirable photocatalytic and antimicrobial activity for environmental applications.