Morphology-controlled synthesis and growth mechanisms of branched α-MnO2 nanorods via facile microwave-assisted hydrothermal method

Multiple branched manganese oxide nanorods were obtained through the rapid one-step microwave-assisted hydrothermal synthesis by the reduction of potassium permanganate in hydrochloric acid solution without using any catalysts or surfactants. The formation mechanism of the branched alpha-MnO2 was studied by systematically varying the reaction time, which were "oriented attachment" and rolling-cum-phase process. The electrochemical performance of the samples was examined by cyclic voltammetry. The specific surface area of the branched alpha-MnO2 and the electrolyte in the solution were found to remarkably affect the specific capacitance. This microwave-assisted technique enables the quick and simple preparation of branched MnO2 nanorods under mild conditions and maybe readily extended to the preparation of many other branched nanoparticles.