Novel Branched γ-MnOOH and β-MnO₂ Multipod Nanostructures

Abstract

A convenient hydrothermal processing followed by a postheat treatment route is proposed to synthesize well-dispersed, branched β-MnO2 multipods from a branched γ-MnOOH precursor. The key steps in our approach are as follows: (1) by controlling the reactant concentration and reaction time, the monoclinic phase of MnOOH with novel branched multipod nanostructures is synthesized via the hydrothermal reaction of MnSO4·H2O and NaClO3 at 160 °C for 200 min; (2) the prepared branched γ-MnOOH multipods are heated under an air atmosphere at 400 °C for 2 h, and the branched β-MnO2 nanostructures can be successfully obtained without changing the precursor morphologies. The new structures presented here enrich the nanoscale community with new basic materials and offer a new approach for increasing structural complexity and enabling greater potential applications. Furthermore, brief discussions about their formation mechanisms provide insight into the formation processing of other transition-metal oxide multipods.