| NUKLEONIKA 2013, 58(1):87-92
SYNTHESIS AND CHARACTERIZATION OF IRON-COBALT NANOPARTICLES EMBEDDED IN MESOPOROUS SILICA MCM-41Zbigniew Surowiec1, Marek Wiertel1, Mieczysław Budzyński1, Wojciech Gac2 1 Maria Curie-Skłodowska University, Institute of Physics, 1 M. Curie-Skłodowskiej Sq., 20-031 Lublin, Poland 2 Maria Curie-Skłodowska University, Faculty of Chemistry, Department of Chemical Technology, 3 M. Curie-Skłodowskiej Sq., 20-031 Lublin, Poland Fe1–xCox/MCM-41 nanocomposite materials were prepared by wet impregnation of the silica mesoporous support with aqueous solution of iron and cobalt salt mixtures. Samples, after calcination, were reduced at 573 K in order to obtain homogeneous distribution of (Fe-Co)3O4 oxide species over the MCM-41 support. Bimetallic systems were achieved through high temperature reduction, carried out at 1073 K. The temperature-programmed reduction studies indicated complex nature of the oxide species. The phase analysis of the obtained samples after low temperature reduction process carried out by means of X-ray diffraction method and using 57Fe Mössbauer spectroscopy revealed the presence of nanostructured magnetite- and maghemite-like phases. The samples with higher cobalt contents (x >= 0.2) contained additionally bimetallic phases. The complete transformation of oxide phases to bimetallic Fe-Co systems occurred during reduction process in hydrogen at 1073 K. It was observed that high temperature processing caused partial transformation of highly dispersed iron oxide nanocrystallites into fayalite species embedded in the silica walls. Close X |