Nanostructured MnO2 synthesized via methane gas reduction of manganese ore and hydrothermal precipitation methods

A three-stage methane gas (CH4) reduction of manganese ore, dissolution, and precipitation from solution procedure was conducted to synthesize MnO2 nanorods. Methane gas reduction was carried out at 850, 875, 900, 925, and 950 °C for 120 min. Precipitation of the α-MnO2 nanorods was performed in the temperature range of 25-90 °C with a constant reaction time of 90 min. The morphology and particle size of the products were determined from scanning electron microscope (SEM) images and X-ray diffraction (XRD) patterns. The BET and BJH of the products were found out by the surface area analyzer. Reduction results indicated that MnO-rich phase is significantly formed at 950 °C as MnO2 phase disappears. Precipitation results also showed an average diameter size of ∼ 50 nm for the embedding α-MnO2 nanorods with BET surface area of 174 m2/g.