Inorganic-inorganic nanocomposite: Surface and conductive properties

Abstract

Our previous experiences with incorporation of polyoxometalates (POMs) ill different substrates have been very successful, because new nanocomposites with better conductive, catalytical and biochemical characteristics have been obtained. The results of intercalation of different mass% of ammonium decavanadate (ADV) in Al-pillared interlayered clays (Al-PILCs) are presented. The Al-PILCs were prepared using natural raw material, bentonite, containing a high percentage of montmorillonite (MM). Synthesis of ADV has been described in a previous paper. The structure of ADV hexahydrate was determined at low temperature, 100 K. A kappa refinement was performed to estimate the atomic charges. A sol-gel procedure was applied to obtain Al-PILCs composite intercalated with ADV hexahydrate (from 2 to 5 mass% of ADV). Structure and morphological properties of the new material, a nanocomposite of Al-PILCs-ADV, were investigated by X-ray powder diffraction (XRPD) and atomic force microscopy (AFM). To understand better how ADV is incorporated in the MM substrate, specific surface areas, pore structures and pore distributions were determined. Electrical and dielectric properties of the new materials were investigated by thermally stimulated depolarization currents (TSDCs) and broadband dielectric relaxation spectroscopy (DRS). The electrical conductivity of the nanocomposite was found to increase, in relation to MM, by intercalating with a small amount of ADV. (C) 2008 Published by Elsevier Ltd.