New Synthesis of Ferrite–Silica Nanocomposites by a Sol–Gel Auto-Combustion |
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Authors: | Cannas C Musinu A Peddis D Piccaluga G |
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Institution: | (1) Dipartimento di Scienze Chimiche, Cittadella Universitaria di Monserrato, Bivio per Sestu, 09042 Cagliari, Italy; Tel.: |
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Abstract: | A sol–gel autocombustion method was used to synthesize nanometric metal-oxide powders, and was extended for the first time to prepare ferrite–silica nanocomposites. The gels obtained by mixing suitable amounts of citric acid, metal nitrates, ammonia (pure phases) and tetraethylortosilicate (nanocomposites) were converted directly to ferrite (either γ-Fe2O3 or CoFe2O4) or ferrite–silica composites through a rapid autocombustion reaction. The combustion involves a thermally induced autocatalytic oxidation–reduction reaction between the nitrate and the citrate ions. The sample characterization by X-ray diffraction, transmission electron microscopy and N2 physisorption measurements revealed nanosized pure phase powders and nanocomposites in which small spherical nanoparticles (mean size 3.5 and 5.0nm, respectively for the γ-Fe2O3and CoFe2O4) are homogeneously dispersed over a mesoporous silica matrix. |
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Keywords: | autocombustion sol– gel ferrite nanocomposite nanoparticle synthesis |
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