Electrocatalytic Studies of Oxygen Reduction by Lanthanum Barium Manganate

Abstract

The electrocatalysis of the oxygen reduction reaction by Lanthanum Barium Manganate, (La0.5Ba0.5MnO3) (LBM) has been studied by cyclic voltammetry using the rotating ring-disc electrode technique (RRDE) in alkaline medium. From the ring-disc data and other kinetic parameters it has been assumed that the oxygen reduction occurs by dissociative chemisorption at low overpotentials. At higher overpotentials, the formation of hydrogen peroxide (HO2 - in this case) has been observed on this electrocatalyst. The apparent exchange current density value for oxygen reduction on LBM has been found to be 4 x 10-8 Acm-2, while the corresponding Tafel slope is 0.115 V per decade. The possible reaction mechanism for electroreduction of oxygen on this oxide catalyst has been discussed.