Synthesis of porous and hollow microspheres of nanocrystalline Mn2O3

In this Letter, we report the facile synthesis of novel porous and hollow microspheres of cubic Mn2O3 nanocrystals of 50-100 nm via the heat-treatment of MnCO3 microspheres, which were prepared simply by reacting the MnCl2 · 2H2O with Na2CO3 in aqueous solution at ambient temperature and pressure. The products were characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy (TEM) and field-emission scanning electron microscopy. Through TEM observation, the growth mechanism of the MnCO3 microspheres was revealed and the possible formation mechanism of the porous and hollow structure of the nanocrystalline Mn2O3 microspheres was also proposed.