Hollow Ag spheres with tunable sizes in a range of 74–167nm were fabricated using a two-step synthesis including the creation of solid Ag 2 O particles and the reduction of these Ag 2 O particles in situ. Ag nanoclusters were generated by the reduction of Ag 2 O. Ag 2 O particles were as scaffolds to create Ag spheres. Namely, the reduction of Ag 2 O occurred firstly on the surface of the Ag 2 O particles. The H 2 was generated due to the hydrolysis of borohydride ions. The diffusion of H 2 and the further reduction of Ag 2 O particles resulted in the formation of a hollow part within Ag spheres. The average diameter of the hollow Ag spheres can be adjusted by varying the concentration of NaOH and NaBH 4 , the kinds of solvent, and reaction temperature.
