Synthesis of Spinel MnCo2O4 by Thermal Decomposition of Carbonates and Kinetics of Thermal Decomposition of Precursor

The cubic MnCo₂O₄ was prepared by calcining MnCO₃-2CoCO₃?1.5H₂O above 600 ^°C in air. The precursor and its calcined products were characterized by thermogravimetry and differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray powder diffraction, scanning electron microscopy, and vibrating sample magnetometer. The result showed that high-crystallized MnCo₂O₄ with cubic structure space group Fd-3m(227)] was obtained when the precursor was calcined above 600 ^°C in air for 6 h. Magnetic characterization indicated that cubic MnCo₂O₄ behaved weak magnetic behavior at room temperature. The thermal process of the precursor in air experienced three steps, which are: first, the dehydration of 1.5 water molecules, then the decomposition of MnCO₃-2CoCO₃ into cubic MnO₂ and cubic Co₃O₄, and at last the reaction of MnO₂ with Co₃O₄ into cubic MnCo₂O₄. Based on the KAS equation, the values of the activation energies associated with the thermal process of MnCO₃-2CoCO₃?1.5H₂O were determined.