Direct synthesis of nanocrystalline, spherical α-Mn_2O_3 particles by mechanochemical reduction

摘要

The preparation of nanocrystalline α-Mn_2O_3 by using the mechanochemical reduction of KMnO_4 with NH4Cl in stoichiometric ratio 1:1 was investigated in this work. High-energy milling with ball to powder mass ratio 20:1 and centrifugal forces 60 g lead to the completion of the reaction between the reactants after 10 min. Further 15-60 min milling transforms the amorphous and hydrated Mn_2O_3 to the nanocrystalline α-Mn_2O_3 phase. This synthesis involves a direct preparing of α-Mn_2O_3 with spherical geometry and average XRD crystallite size above 50 nm