Facile hydrothermal synthesis of ultra-long manganese oxyhydroxide nanorods and their transformation into MnO2 and Mn2O3 nanorods

Abstract

Single-crystal manganese oxyhydroxide (MnOOH) nanorods with high aspect ratios have been successfully prepared employing a simple hydrothermal route based on the redox between potassium permanganate (KMnO4) and polyvinyl pyrrolidone (PVP). By adjusting the reaction temperature, reaction time and the mass ratio of PVP/KMnO4, MnOOH nanorods with lengths up to 20 μm and diameters in the range of 100-400 nm could be facilely prepared in high yield. The as-prepared MnOOH nanorods were characterised by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy and Fourier transformed infrared spectroscopy. The formation mechanism of MnOOH nanorods was preliminarily discussed based on the Ostwald's ripening process. Furthermore, MnO2 and Mn2O3 nanorods with high aspect ratios were synthesised by calcination of MnOOH nanorods. © The Institution of Engineering and Technology 2013.