Abstract:
Samples of electrolytic manganese dioxide (EMD) were chemically reduced using 2-propanol under reflux (82°C) for 1, 2, 3, 6
and 24 h intervals. XRD analysis showed that the γ-MnO2 structure was preserved although the lattice dimensions were observed to
increase with increasing degree of reduction to accommodate the intercalation of protons. The exception was the 24 h reduced sample
which contained two phases; γ-MnO2 and γ-MnOOH. Three regions of decomposition in the range of 50 to 1000°C were observed
using thermogravimetric analysis coupled with mass spectrometry (TG-MS) and were accounted for as water removal below
390°C, reduction of MnO2 to Mn2O3 between 400 and 600°C, and Mn2O3 to Mn3O4 between 600 and 1000°C. Again the
exception proved to be the 24 h reduced sample which was observed to decompose predominantly in one step between 400
and 600°C directly to Mn3O4.
