Controllable synthesis and characterization of alpha -MnO sub(2) nanowires

Size controllable alpha -MnO sub(2) nanowires were synthesized from KMnO sub(4) and ethanol via a low-temperature hydrothermal route assisted with subsequently heat treatment. No acid or alkali was added. XRD and SEM results clarified alpha -MnO sub(2) nanoparticles (5-30 nm) began to form at room temperature, and then grew up to nanowires (~12 nm in diameter) when temperature increasing up to 120-160 degree C for an appropriate reaction time. Otherwise, octahedron-like Mn sub(3)O sub(4) began to form at 120 degree C more than 4 h or at 160 degree C more than 2 h. Hydrothermal-synthesized alpha -MnO sub(2) show well thermal-stability even it was heated at 900 degree C. And various size alpha -MnO sub(2) nanowires were controllable prepared by adjusting heat treatment temperature of hydrothermal-synthesized alpha -MnO sub(2) at range from 150 degree C to 750 degree C for 3 h, which show the strongest diffraction peak (211) plane. The capacity of hydrothermal-synthesized alpha -MnO sub(2) at 120 degree C for 2 h was about 125 F/g, which exhibited a promising electrochemical property.