Video-STM studies of adsorbate dynamics at electrochemical interfaces

本项目将利用现场高速扫描隧道显微镜(Video-STM)系统地研究单个吸附体在电化学界面上的动态行为。这些测量将作为不同阴离子(S，I，CN)和阳离子(铅，Te，空位)吸附在铜(100)和银(100)电极表面的电位和温度的函数进行。原子尺度的吸附运动将由时间分辨扫描隧道显微镜直接监测。在对这些数据进行广泛的统计分析的基础上，将获得关于表面扩散和吸附-吸附相互作用的定量结果。特别是，将研究共吸附物种(氯、溴、硫酸盐)和电势对吸附动力学的作用，以(I)阐明表面输运过程明显的势依赖的起源，这一点在我们对SAD在盐酸溶液中在铜(100)上的扩散的开创性研究中发现，以及(Ii)确定在电化学环境中普遍存在的共吸附如何影响扩散势垒和相互作用能。对该项目的补充将是对一个项目的并行应用，在该项目中，将并行获得关于这些吸附体系的热力学和动力学电化学数据。总而言之，这些直接的、微观的和互补的电化学研究应该提供对电化学环境对吸附物种扩散和相互作用的影响的基本见解--这是许多电极反应的中心基本步骤。

In this project the dynamic behavior of individual adsorbates at electrochemical interfaces will be studied systematically by in situ high-speed scanning tunneling microscopy (Video-STM). These measurements will be performed as a function of potential and temperature for different anionic (S, I, CN) and cationic (Pb, Te, vacancies) adsorbates on Cu(100) and Ag(100) electrode surfaces. The atomic-scale adsorbate motion will be directly monitored by time-resolved STM. Based on an extensive statistical analysis of these data quantitative results on surface diffusion and adsorbate-adsorbate interactions will be obtained. In particular, the role of coadsorbed species (Cl, Br, sulfate) and potential on the adsorbate dynamics will be investigated, to (i) elucidate the origin of the pronounced potential dependence of the surface transport processes, found in our pioneering studies on Sad diffusion on Cu(100) in HCl solution, and to (ii) determine how coadsorbates, which are ubiquitously present in electrochemical environment, influence the diffusion barriers and interaction energies. This project will be complemented by a parallel application for a project, in which thermodynamic and kinetic electrochemical data on these adsorbate systems will be obtained in parallel. In total, these direct microscopic and complementary electrochemical studies should provide fundamental insights into the effect of the electrochemical environment on the diffusion and interaction of adsorbed species – a central elementary step in many electrode reactions.