Platinum nanoclusters topped on silica nanospheres, prepared by a seeded-growth method, have been transformed into platinum nanoshells having uniform shell thickness of 6 nm via irradiation of nanosecond laser pulses. The thickness of platinum nanoshells can be tuned readily by adjusting the concentration of H2PtCl6 for the growth of platinum nanoparticles on silica nanospheres. Compared with Pt nanoclusters-topped silica nanospheres, platinum nanoshells coated on silica nanospheres have been found to catalyze the degradation of rhodamine B very rapidly in the presence of KBH4, and they show highly active surface-enhanced Raman scattering. (C) 2010 Elsevier B.V. All rights reserved.