Microstructural characteristics of chemically processed manganese oxide nanofibres

Nanostructured fibrous manganese oxide cryptomelane-type hollandite powders were prepared via a chemical route. Powders were obtained by the chemical reaction of the aqueous solutions of potassium permanganate and manganese sulfate in the presence of a strong acid, followed by crystalline growth at elevated temperatures. These powders were characterized by powder X-ray diffraction (XRD), Rietveld refinement, analytical scanning electron microscopy (SEM), transmission electron microscopy (TEM) combined with micro-micro diffraction (μμd), and high resolution transmission electron microscopy (HRTEM). The crystalline structure, morphology, crystallite size, fibre growth direction, and structural defects are discussed.