Homogeneous and Heterogeneous Catalytic Reactions in Cobalt Oxide/Graphite Air Electrodes: II . Homogeneous Role of Co(II) Ions during Oxygen Reduction on Electrodes

Abstract

The mechanism and kinetics of reduction on Teflon‐bonded electrodes in alkaline solutions have been studied by steady‐state polarization and ac impedance methods. The homogeneous role of dissolved cobaltous ions during reduction is to reduce the mass transport hindrance and to increase the pseudo‐exchange current density. More significantly, the kinetics as well as mechanism of reduction on systems are also influenced by the homogeneous and heterogeneous decomposition process of the formed as intermediate. The efficiency of such homogeneous and heterogeneous reactions in reduction are largely affected by the interfacial distribution of the cobalt oxide/graphite catalysts. The factors which influence the electrode stability in the earlier stage of polarization were also investigated.