Structural study of highly porous nanocomposite aerogels

The structural properties of CoFe₂O₄–SiO₂ highly porous nanocomposite aerogels have been investigated by X-ray Absorption Spectroscopy and Transmission Electron Microscopy techniques. The aerogels are obtained by supercritical drying of composite gels obtained using a two step procedure where fast gelation is achieved using urea in the second step. The formation of CoFe₂O₄ nanocrystals in the silica matrix begins after calcination at 750 °C of the parent aerogel and is complete after calcination at 900 °C, while the high porosity of the sample is mostly retained.