Electrochemical performance of dual catalysts system based on nickel phthalocyanine and nano-manganese dioxide for O₂ reduction

The electrochemical performance of the dual-catalyst system composed of nickel phthalocyanine (NiPc) and nano-manganese dioxide (nano-MnO₂) for O₂ reduction in alkaline media was studied. The electrocatalytic activities for oxygen reduction were evaluated by cyclic voltammeter method and linear sweep voltammeter method. The optimum ratio of NiPc and nano-MnO ₂ was established by Job's method. The methanol tolerance property of dual catalysts with the optimum ratio was tested. The results implied that the dual catalysts showed excellent ORR activity involving a four-electron mechanism, with a Tafel slope of about 130 mV, indicating a one-electron process in the rate-determining step.