Nano-oxides of manganese synthesized from the radiolytic reduction of permanganate (MnO4-) medium at varying pH in ambient temperature showed differences in structural properties. In the present communication, we report the effect of variance in the structural morphology on the hetero-catalytic activity of manganese nano- oxides. Applications of these radiolytically generated manganese nano-oxides, as catalysts were tested by monitoring the decomposition of H2O2 and N2H4 solutions at room temperature and suitable mechanism has been proposed. The catalytic decomposition rates of H2O2 and N2H4 solutions increased in the presence of oxides formed from the radiolysis of alkaline permanganate solutions. The kinetics of the catalytic activity of the nano-oxides was correlated with their high surface area, large pore volume, adsorbed –OH groups, varying oxidation states of Mn, and their microstructures.