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

Abstract

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.

Keywords

• Heat treatment
• Manganese oxides
• Structural
• Thermal analysis
• Optical properties