Nonisothermal decomposition kinetics of pure and Mn-doped Fe3O4 nanoparticles

Pure Fe3O4 and Mn-doped Fe3O4 nanoparticles were synthesized by simple wet chemical reduction technique using nontoxic precursors. Manganese doping of two concentrations, 10 and 15%, were employed. All the three synthesized nanoparticles were characterized by stoichiometry, crystal structure, and surface morphology. Thermal studies on as-synthesized nanoparticles of pure ferrite (Fe3O4) and manganese (Mn) doped ferrites were carried out. The thermal analysis of the three as-synthesized nanoparticles was done by thermogravimetric (TG), differential thermogravimetric, and differential thermal analysis techniques. All the thermal analyses were done in nitrogen atmosphere in the temperature range of 308-1233 K. All the thermocurves were recorded for three heating rates of 10, 15, and 20 K min(-1). The TG curves showed three steps thermal decomposition for Fe3O4 and two steps thermal decompositions for Mn-doped Fe3O4 nanoparticles. The kinetic parameters of the three as-synthesized nanoparticles were evaluated from the thermocurves employing Kissinger-Akahira-Sunose (KAS) method. The thermocurves and evaluated kinetic parameters are discussed in this paper.