Weakly ordered nanostructured silver disilicate and its colloidal solutions: preparation and properties

It was shown that the interaction of silver cations in alkaline aqueous solutions with various kinds of silicates, regardless of their chemical and aggregation state, leads to the formation of an exclusively disilicate form of silver salt. We develop procedures for synthesis of nanostructured weakly ordered nonstoichiometric silver disilicate Ag$_{6-x}$H$_{x}$Si$_{2}$O$_{7}$ capable of forming aqueous colloids. We study the micellular structure of colloidal particles in these solutions and demonstrate that permeability of silicic acid layers enveloping nanosized salt cores of these micelles depends on pH. Colloidal silver disilicate is found to exhibit a high catalytic activity in photoinduced oxidation of a broad spectrum of different compounds, which is demonstrated for compounds stable in aqueous solutions such as some organic dies and ferrocyanide complex (Fe(CN)$_6^{-4}$).