Facile synthesis of MnCO3 hollow dumbbells and their conversion to manganese oxide

Manganese carbonate (MnCO3) hollow dumbbells were synthesized via a polyol process. Based on the structural analysis of the samples obtained at different reaction times, a mechanism of nucleation-growth-aggregation-ripening was proposed to account for the formation of the hollow dumbbells. Moreover, the manganese oxide has also been obtained from the MnCO3 crystals after thermal transformation in laboratory air, and the phase of final product could easily be controlled to be either MnO2 or Mn2O3, simply by altering the calcination conditions. The manganese oxide powder products possessed mesoporosity and essentially preserved the pristine morphology of the MnCO3 precursor.