Synthesis and formation mechanism of manganese dioxide nanowires/nanorods

a-, beta-, gamma-, and delta-MnO2 singlecrystal nanowires/nanorods with different aspect ratios have been successfully prepared by a common hydrothermal method based on the redox reactions of MnO4- and/or Mn2+. The influences of oxidant, temperature, and inorganic cation (NH4+ and K+) template concentrations on the morphology and crystallographic forms of the final products are discussed in this paper. It is interesting to find that all the MnO2 one-dimensional nanostructures have a similar formation process: 6-MnO2, which has a layer structure, serves as an important intermediate to other forms of MnO2, and is believed to be responsible for the initial formation of MnO2 one-dimensional nanostructures. A rolling mechanism has been proposed based on the results of the series of TEM images and XRD patterns of the intermediate.