The effective pH at the solid-liquid interface and the local ion distribution during complex electrochemical reactions

在无缓冲或仅弱缓冲的中性介质中进行的非均相催化反应是自然环境的典型条件，通常由液/固界面处的pH值直接决定。虽然这在与表面和界面化学相关的各个领域的研究中是非常重要和众所周知的，但界面pH的影响及其与pH依赖反应的反应速率、产物和产物的质量输运以及体pH值的复杂关系只能定量地确定非常容易的系统。在这个项目中，界面pH值和靠近电极表面的整个离子分布的影响将在基本水平上进行研究，以获得对中性介质中非均相反应的更好理解和一般模型。实验研究基于特殊的离子选择、局部方法，这些方法最初应用于理想体系上的简单反应，后来应用于动力学约束反应，如电化学氧还原，甚至在不均匀的现实表面上。对影响界面pH的复杂关系的理解将最终用于改进在防腐和相关主题中的应用。

Heterogeneous catalytic reactions in un- or only weakly buffered, neutral media, which are typical conditions for natural environments, are often dominated by the pH value directly at the liquid/solid interface. Although this is highly important and well-known for several research studies in various fields related to surface and interface chemistry, the effect of the interface pH and its complex relation to reaction rates of pH dependent reactions, mass transport of educts and products, and bulk pH value can only be determined quantitatively for very facile systems. In this project the effect of the interface pH and the whole ion distribution close to the electrode surface will be investigated on a fundamental level, in order to derive an improved understanding and a general model for heterogeneous reactions in neutral media. The experimental investigations are based on special ion-selective, local methods, which are applied initially for facile reactions on ideal systems and later for kinetically constrained reactions like the electrochemical oxygen reduction even on inhomogeneous, realistic surfaces. The understanding of the complex relationships that affect the interface pH will be finally utilized for the improvement of applications in corrosion protection and related topics.