Synthesis and Characterization of Hematite, Magnetite and Maghemite Supported on Silica Gel

A new method for obtaining nanosized particles of iron oxides using porous silica gel is proposed. In situ magnetometry was used to study the reduction of hematite deposited on silica gel during the thermolysis of glucose. The formed magnetite and maghemite obtained by subsequent oxidation of the magnetite were studied using X-ray diffraction and Mossbauer spectroscopy. It was shown that both the size of the oxide particles and the phase composition significantly depended on the porous structure of the silica gel. In particular, the formation of superparamagnetic maghemite particles on silica gels with pore sizes of 30, 15 and 10 nm was demonstrated.