Catalytic properties of nanocomposites based on cobalt ferrites dispersed in sol–gel silica

In this work, composites based on cobalt ferrite (CoFe2O4) dispersed in a porous silica matrix have been prepared via sol–gel method using tetraethylorthosilicate (TEOS) as a silica precursor, and iron and cobalt nitrates as precursors. In this process, Co and Fe ions dispersed in a sol–gel matrix reacted upon thermal treatment to form Co–Fe crystallites with nanometric dimensions. The structural, morphological, and textural changes of the composites treated at various temperatures were studied by X-ray diffraction, electronic microprobe, and gas adsorption. The treated composites had surface areas in the range 263–359 m2 g−1 with mesopore contribution. These materials were active as catalysts in the total oxidation of chlorobenzene in air. The most active catalyst was the composite treated at 500 °C, which was stable at a temperature as high as 600 °C for 72 h.