Shell-by-shell synthesis of tin oxide hollow colloids with nanoarchitectured walls: Cavity size tuning and functionalization

A new hydrothermal shell-by-shell templating strategy suitable for the preparation of nearly monodisperse tin oxide hollow colloids with nanoarchitectured wall structures is discussed. The prepared tin oxide hollow colloids are polycrystalline with robust walls due to the formation of multishell structures. The cavity of these hollow colloids can be functionalized with other functional nanoparticles. The crystallographic structure of as-deposited SnO₂ was determined by X-Ray Powder Diffraction (XRD). The hollow particles functionalized with magnetic nanoparticles is useful in targeted drug delivery and separation. Result shows that the cagelike particles appear largely hollow with well defined double-shelled structure, and the gap between two shell was found to be relatively large due to the small template size. EDX analysis indicated that the only a small amount of silica remains with the atomic Sn:Si ratio of approximately six.