Synthesis and characterisation of microstructural α-Mn₂O₃materials

Abstract

Low-dimensional α-Mn2O3 materials with novel surface morphologies have been prepared by thermal decomposition of hydrothermal-derived MnCO3. The powder X-ray diffraction pattern reveals that the Mn2O3 microstructures are of cubic phase structure. From Fourier transform infrared spectroscopy results, the peaks around 600–450 cm−1 correspond to Mn–O bending vibrations. From the TGA results, the observed major weight loss ∼31% between 350 and 540°C is due to the decomposition of MnCO3 into Mn2O3. The X-ray photoelectron spectroscopy results showed that Mn is in +3 oxidation state. The peaks at 641.2 and 652.73 eV are assigned to the Mn2p3/2 and Mn2p1/2 of Mn+3 states, respectively. The scanning electron microscope images showed that the α-Mn2O3 products exhibit spheres, dumbbell- and peanut-shaped microstructure. These microstructures are mainly composed of wires/rods and particles. The scanning electron microscope results also revealed that the obtained α-Mn2O3 maintains the frame structure of the precursor MnCO3.