Synthesis and Characterization of Structured Metal/Silica Clusters

Abstract

ABSTRACTThe synthesis of two component clusters of Au/SiO2, Ag/SiO2 and Cu2O/SiO2 is described. These heteronuclear clusters are synthesized as metal/silicon clusters of controlled composition and controlled size using a novel gas aggregation source and by means of gas phase annealing are transformed into ‘structured’ particles. The final metal/oxide and oxide/oxide clusters are formed by air exposure. The structure of these nanostructured particles is determined by electron diffraction and transmission electron microscopy (TEM). The clusters exhibit two distinct structural forms: (1) clusters consisting of a metal rich core surrounded by a silicon rich skin and (2) clusters having a metal rich domain and a silicon rich domain separated by a sharp interface.