Abstract
Synthetic opals composed of mesoporous SnO 2 spheres were successfully fabricated from anodization of Sn opals, double templated from polystyrene opals. The mesoporous SnO 2 spheres were 440 nm in diameter containing mesopores of 20-40 nm. The resultant mesoporous SnO 2 opals possessed a high specific surface area of 196 m 2 /g and a grain size of 12 nm as estimated from XRD patterns. Such a hierarchical structure of SnO 2 is a promising candidate for applications in gas sensors, catalysts, and electrode materials since the regularity of the sub-micron opal structure eases transfers of relevant chemical species within the structure while the mesoporosity of the constituent SnO 2 spheres offers sufficient functioning surfaces for targeted applications. © 2007 Elsevier B.V. All rights reserved.