Preparation and characterization of Ag-magadiite nanocomposites

摘要

Well-defined Ag-magadiite nanocomposites were successfully prepared by an ion-exchange method using a silver ammine complex, [Ag(NH_3)_2]NO_3, 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 (H_(0.2)Na_(1.8)Si_(14)_O_(29) centre dot 7.8H_2O) and H-magadiite (H_(1.4)Na_(0.6)Si_(14)O_(29) centre dot 3.9H_2O). Such Ag-nanoparticles appear to be caused by heating [Ag(NH_3)_2]~+ ions incorporated into the interlayer spaces of the magadiite materials by ion exchange with Na~+ ions. Furthermore, in nanocomposites heated at 120 deg 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 approx 180 deg C.