Abstract Precise measurements and accurate analysis of reaction processes are the prerequisite for correctly understanding the key factors that control kinetics of electrode reaction. Rotating disk electrode systems are widely used to study the kinetics of reactions that may suffer from insufficient mass transfer. The commonly used Koutecky-Levich equation is only applicable for reactions affected by the mass transfer of single reactant. In this work, we propose a general method for estimating the intrinsic kinetics of reactions hampered by the mass transfer of more than one reactant. Its application is demonstrated by the kinetic study of oxygen reduction reaction (ORR) at Pt (111) in un-buffered solutions with medium pH, where the mass transfer of both O2 and H+ are slow. Our analysis reveals that the kinetic rate constant at activation overpotential around 300 mV (~0.9 V vs RHE) increases for ca. three orders of magnitude with the increase of solution pH from 1 to 3. Possible origins for such pH effect are discussed.

中文翻译：

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在旋转圆盘电极配置下量化由多种物质的传质控制的电化学反应的固有动力学

摘要 对反应过程进行精确测量和准确分析是正确认识控制电极反应动力学的关键因素的前提。旋转圆盘电极系统被广泛用于研究可能因传质不足而受到影响的反应动力学。常用的 Koutecky-Levich 方程仅适用于受单一反应物传质影响的反应。在这项工作中，我们提出了一种估计受一种以上反应物传质阻碍的反应的内在动力学的通用方法。它的应用通过在具有中等 pH 值的非缓冲溶液中 Pt (111) 的氧还原反应 (ORR) 动力学研究得到证明，其中 O2 和 H+ 的传质都很慢。我们的分析表明，大约 300 mV（~0.9 V vs RHE）的活化过电位的动力学速率常数增加了大约 随着溶液 pH 从 1 增加到 3，三个数量级。讨论了这种 pH 影响的可能来源。