Preparation and characterization of Ag-magadiite nanocomposites

Well-defined Ag-magadiite nanocomposites were successfully prepared by an ion-exchange method using a silver ammine complex, [Ag(NH3)2]NO3, as the starting material. These nanocomposites were found to have a structure in which Ag-nanoparticles consisting of a single-crystalline particle were well dispersed in the interlayer spaces of two types of magadiite materials: Na-magadiite (H0.2Na1.8Si14O29·7.8H2O) and H-magadiite (H1.4Na0.6Si14O29·3.9H2O). Such Ag-nanoparticles appear to be caused by heating [Ag(NH3)2]+ ions incorporated into the interlayer spaces of the magadiite materials by ion exchange with Na+ ions. Furthermore, in nanocomposites heated at 120 °C in air, Ag-nanoparticles show a relatively uniform particle size of 3–5 nm, whereas a heterogeneous enlargement of Ag-nanoparticles occurs when the temperature exceeds ∼180 °C.