Metal nanoparticle coating of oxide nanospheres for core-shell structures

Abstract

A low-temperature route for coating oxide nanospheres with metal nanoparticles to achieve core-shell structures is introduced. First results indicating a dense coverage of silica nanospheres of about 300 nm size with regularly arranged Ag and Au nanoparticles deposited by a modified incipient wetness impregnation procedure are presented. This synthesis works completely without external reducing agents or media, adhesive aids or functionalizing agents. Metal particles of only a few nanometers in size may serve as seeds for continuous metal coating of the oxide spheres by complementary processes. Structural characterization of the materials by transmission electron microscopy reveals a nearly spherical shape of the metal particles, the structure of which ranges from single crystalline to single twinned and multiply twinned configurations.