Video-STM studies of adsorbate dynamics at electrochemical interfaces

在本项目中，将使用原位高速扫描隧道显微镜（Video-STM）系统地研究电化学界面上单个吸附物的动态行为。这些测量将作为电位和温度的函数来执行，不同的阴离子（S， I， CN）和阳离子（Pb, Te，空位）吸附在Cu（100）和Ag（100）电极表面。原子尺度的吸附质运动将由时间分辨STM直接监测。基于对这些数据的广泛统计分析，将获得表面扩散和吸附物-吸附物相互作用的定量结果。特别是，将研究共吸附物质（Cl, Br，硫酸盐）和电位在吸附动力学中的作用，以(i)阐明表面传输过程中明显的电位依赖的起源，这是我们在HCl溶液中Cu（100）的Sad扩散研究中发现的，以及（ii）确定在电化学环境中无处不在的共吸附物如何影响扩散屏障和相互作用能。这个项目将由一个项目的平行应用来补充，在这个项目中，这些吸附质系统的热力学和动力学电化学数据将并行获得。总的来说，这些直接的微观和互补的电化学研究应该为电化学环境对吸附物质的扩散和相互作用的影响提供基本的见解-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.