A 29Si MAS and 1H NMR investigation of Fe2O3-SiO2 nanocomposites

Fe2O3-SiO2 nanocomposites and silica matrices, prepared by a sol-gel method and submitted to the same heat treatments in the range 150-700 degrees C, were investigated using the Si-29 magic angle spinning (MAS), nuclear magnetic resonance (NMR) technique. For the Fe2O3-SiO2 samples, an analysis of the integrated NMR peak areas revealed that only Si-29 nuclei far from the iron ions were detected. As far as the host matrix is concerned, no structural modifications have been induced by the nanoparticles. The H-1 NMR spectrum for the prepared silica matrix showed a signal due to solvation water, while the spectrum of the as prepared nanocomposite showed a much broader signal shifted to low field. The overall findings are discussed in terms of possible interactions between the nanoparticles, the host matrix and water molecules in the cavities at the nanoparticle-silica interface. (C) 1998 Elsevier Science B.V. All rights reserved.