Preparation of mesoscale hollow spheres of TiO2 and SnO2 by templating against crystalline arrays of polystyrene beads

Mesoscale hollow spheres of ceramic materials can be prepared by templating an appropriate sol-gel precursor against a crystalline array of monodisper se polystyrene beads, as demonstrated here. Spheres of well-controlled, uni form size and homogeneous wall thickness result, as can be seen from the Fi gure, which shows the TEM cross-sectional view of an array of TiO2 hollow s pheres.