研究了MnO2 催化氧还原的电催化性质 ,通过比较MnO2 的自还原和催化氧还原的相关性 ,结合极化曲线分析和中间产物检测 ,提出了氧在MnO2 上电催化机理 .根据这一机理 ,MnO2 首先还原为MnOOH ,随之氧的还原通过化学氧化MnOOH ,两者协同进行 .依此导出的极化曲线形式能够较好地解决实验中观测到的动力学特征
The oxygen electroreduction on the MnO 2 electrode was investigated by analysis of the polarzation properties of oxygen reduciton and its dependence on MnO 2 discharge state,in combination with the characterization of discharge intermediate and the kinetic parameters of the oxygen reduction.Based on the experimental observation and mechanistic analysis,it was suggested that the reduction of oxygen was closely related to the discharge behaviors of MnO 2 .When MnO 2 was electrochimically reduced to MnOOH,it was immediately oxidized by oxygen molecules. Thus the oxygen reduction proceeds through continuous oxidation of the discharge product of MnO 2 and the MnO 2 catalyst behaves like an eletron mediator to provide rapidly the reduction reagent via its discharge.The I_E relationship derived from this mechanism can very well explain the observed polarization properties of oxygen reduction on MnO 2 electrode.
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