Electrochemical Properties of MnCo₂O₄Spinel Bifunctional Catalyst for Oxygen Reduction and Evolution Reaction

MnCo 2 O 4 (MCO) spinel powders have been synthesized by a sol–gel process with glucose as pore-former. The samples are characterized by XRD, SEM, BET. SEM and BET results show that MCO-700 has a porous structure and a high specific surface area of 11.1 m 2 g −1 . Catalytic activities of these oxides for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in 0.1 M KOH solution have been studied by using a rotating ring-disk electrode (RRDE) technique. RRDE results show that MCO-700 exhibits better catalytic activity for the ORR. The ORR mainly favors a direct four electron pathway, and a maximum cathodic current density of 6.69 mA cm −2 at 2500 rpm has been obtained, which is close to that of commercial Pt/C electrocatalyst under the same testing conditions. Anodic linear scanning voltammograms results show that MCO-700 is more active for the OER. Although MCO-700 shows a stable catalytic activity for the ORR, a serious attenuation exists for the OER due to the oxidization of carbon under high potential.