Multiple branched α-MnO2 nanofibers: A two-step epitaxial growth

Pure α-MnO2 nanofibers with multiple branches were prepared through a simple refluxing method in the absence of catalysts or surfactants as templates. The synthetic procedure was based on the use of MnO4- to oxidize Mn2+Mn2+ under a weak acidic condition. A two-step epitaxial coalescence for the formation of this complex architecture was revealed by transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). First of all, the small nanofibers coalesced together through the (1 1 0) plane to form larger monocrystalline nanofibers, which then attached one by one through two of (1 1 0) and {2 1 1} planes, resulting in the final multiple branched architectures.