Abstract: The open circuit potential (O.C.P.) of the air electrode based on various carbon substrates was measured in alkaline solution. It was found that the O.C.P. not only depends on the catalyst activity for H₂O₂ decomposition, but also relates to the exchange current of oxygen on the carbon. The smaller the exchange current on the carbon, the greater the rate constant of the catalyst for HO₂^- decomposition and the more uniform the mixture of catalyst-carbon, the higher the O.C.P. of the oxygen electrode.

Key words: Oxygen electrode Electrochemical reaction Reaction kinetics Carbon substrate Open circuit potential