Electro-catalytic effect of manganese oxide on oxygen reduction at teflonbonded carbon electrode

Oxygen reduction(OR)on Teflon-bonded carbon electrodes with manganese oxide as catalyst in 6 mol/L KOH solution was investigated using AC impedance spectroscopy combined with other techniques. For OR at this electrode, the Tafel slope is −0.084 V/dec and the apparent exchange current density is (1.02-3.0) × 10−7 A/cm2. In the presence of manganese oxide on carbon electrode, the couple Mn3+/Mn4+ reacts with the O2 adsorbed on carbon sites forming O2− radicals and acceletes the dismutation of O2−, which contributes to the catalytic effect of manganese oxide for OR reaction.