Electrochemical Behavior of Manganese Oxide Nanoparticles for Oxygen Reduction Reaction Environment in PEM Fuel Cells

In this study, manganese oxide nanoparticles in the form of Mn2O3 and Mn3O4 with different particle sizes are used as a catalyst for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells. The microstructure of manganese oxide nanoparticles catalysts are characterized using XRD, FE-SEM and SEM equipped with EDS. Then, the ORR activity of the catalysts along with their durability are studied by cyclic voltammograms and accelerated stability test in N-2 and O-2 saturated 0.1 M HClO4 electrolyte using rotating disk electrode method. The results show that the ORR activity of manganese oxide nanoparticles catalysts strongly depends on their metal oxidation states and particle size. The catalytic activity of manganese oxide nanoparticles increases with increase in the particle size. Moreover, the Mn2O3 nanoparticles catalyst with +3 oxidation state exhibits higher ORR activity compared to the Mn3O4 nanoparticles catalyst with mixed (+2, +3) oxidation state.