Large-scale synthesis of β-MnO2 nanorods and their rapid and efficient catalytic oxidation of methylene blue dye

Manganese dioxide (β-MnO2) nanorods have been synthesized by thermal decomposition of a template precursor of MnOOH, which was obtained by hydrothermal treatment of KMnO4 in an aqueous ethanol solution. Through X-ray diffraction and electron microscopic characterizations, the as-prepared β-MnO2 nanorods were shown to be phase-pure single crystallites with diameters of 30–400 nm and lengths of tens of micrometers. We demonstrate catalytic efficiency of the as-prepared one-dimensional β-MnO2 nanorods as catalysts in the oxidation of methylene blue dye in the presence of H2O2; the catalytic activity is much higher than that of commercial micro-sized β-MnO2 powders.