Synthesis, reactivity, and cations inversion studies of nanocrystalline MnFe2O4 particles

Abstract Nanocrystalline MnFe 2 O 4 particles were synthesized by using citrate precursor technique. Thermal decomposition of the precursor was studied by using TGA, DTG, DTA techniques. The decomposition products were characterized by gas and chemical analyses, IR, NMR, and XRD techniques. There are three major steps that involve in the decomposition process. The dehydration step, formation of intermediate acetonedicarboxylate complex and subsequent decomposition of acetonedicarboxylate to the stoichiometric, single phase MnFe 2 O 4 at 350 °C with the evolution of H 2 O, acetone, CO and CO 2 gases. The XRD crystallite size was found to be 7.0 nm and the surface area for this sample was measured to be 98.0 m 2  g −1 . Electron micrographs confirmed the nanostructured nature, spherical morphology and showed 11 nm aggregates of particles. Thermal analysis studies of nanocrystalline MnFe 2 O 4 particles indicate the higher degree of inversion and at 380 °C confirmed the irreversible rearrangement of Mn 2+ cations from the octahedral site to tetrahedral site, that is associated with small a heat change.

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