Moderate temperature production of manganese oxides via thermal treatment – Structural and thermal properties

In this work, few precursors (MnCl₂.4H₂O, MnCO₃, MnO₂, and KMnO₄) were simply heated at 650 ​°C for 10 ​h and examined their phase formation and thermal features of Mn-based oxides. Cubic Mn₂O₃ phase materials with space group, Ia-3 (206) formed for the heat treated products of MnCl₂.4H₂O and MnO₂ precursors. However, the purity is differed for the heat treated product of MnCl₂.4H₂O, for this three weak impurities are noted along with the major Mn₂O₃ phase. Mixed phases of Mn₂O₃ and Mn₅O₈ were observed for the heating of MnCO₃ precursor. The resemblance of δ-MnO₂ phase was observed for the heat treated product of KMnO₄ precursors. While the heat treated products of MnCl₂.4H₂O, MnCO₃, and MnO₂ precursors show the low weight loss of 1.5–3.3 %, the heat treated KMnO₄ precursor shows relatively high weight loss of 22.6 % with weak exothermic and endothermic peaks at 100 and 797 ​°C, respectively. The Mn₂O₃ nanomaterials exhibit a morphology resembling nanorods.