Growth of nano-α-Fe2O3 in a titania matrix by the sol–gel route

Abstract

Nano-α-Fe2O3 in a titania matrix was prepared by the sol–gel route. The nanocomposites containing various sizes of α-Fe2O3 were precipitated by the heat treatment of the dried gel in a temperature range 100–1200 °C. Differential thermal analysis of the TiO2–Fe2O3 system showed peaks at 325, 390 and 730 °C. The formation of anatase as well as the rutile phase of TiO2 and the growth of α-Fe2O3 were predicted from the above peak analysis. These results were in agreement with the X-ray diffraction studies. The sizes of the nanoparticles were analysed by transmission electron microscopic studies. The Mossbauer spectra of TiO2–Fe2O3 nanocomposites showed paramagnetic and superparamagnetic doublets for all the specimens containing nanoparticles of α-Fe2O3. The electron paramagnetic resonance study indicated the presence of a paramagnetic phase in the nanocomposite samples. © 1998 Chapman & Hall