Controlled deposition of ultra-small Ag particles on TiO₂ nanorods: Oxide/metal hetero-nanostructures with improved catalytic activity

TiO₂-Ag hetero-nanocrystals (HNCs) with controllable Ag particle numbers and domain size were synthesized by in situ reduction of silver acetate and further growth of Ag on TiO₂ nanorods. The nucleation of Ag on TiO₂ as well as the tuning of Ag number and size can be explained by the electrostatic attraction between Ag precursor and TiO₂ nanorods as well as further deposition of Ag onto initially formed Ag domains. The formation of hetero-nanostructures was verified by XRD patterns and UV-Vis absorbance. The reported synthesis provides an effective method to produce ultra-small (1-2 nm) nanocatalysts, as the hetero-nanostructures are intrinsic advantageous in forming nanocrystals due to the confinement of nano-size supporting materials, which present improved catalytic activities than most isolated Ag nanocrystals in nanoscale.