Combined Atomic Imaging and Diffraction Studies of the Electrooxidation of Supported Metal Multilayers

固体/液体界面在各种物理现象中发挥着基本作用，例如在催化、晶体生长和许多生物反应中，这些生物反应支配着人体的建造和大脑的功能。因此，解开固体/液体界面的原子结构仍然是当今表面科学面临的主要挑战之一，因为只有通过了解模型系统中的物理过程，我们才能外推到更复杂的环境。发展这一认识的关键在于制备和研究具有明确元素反应部位的模型表面。替代能源供应和储存方法的发展需要材料研究的重大进展。这些进展现在可以通过操纵分子和原子尺度的过程来实现，从而增加对新材料的物理和化学性质的理解。特别是，这些材料的设计可以从基本原理出发，即通过应用现代实验技术来理解表面性质，而不是整体材料的性质。这一建议的目的是加深对电化学界面原子和电子结构的了解，特别是对用电化学方法沉积的过渡金属多层膜的氧化和还原过程有一个基本的了解。由于电化学界面的埋藏性，大多数标准的表面科学技术都无法使用强吸附电子探针来获得表面灵敏度。对界面的研究仅限于使用穿透辐射的技术，如X射线散射，或成像技术，如扫描隧道显微镜(STM)和原子力显微镜(AFM)。利用同步辐射设施(格勒诺布尔的欧洲同步辐射设施和卢瑟福·阿普尔顿实验室的钻石光源)是该项目的一个关键组成部分。它们提供最先进的设备，用于执行高入射X射线通量、能量可调整性和高分辨率的X射线散射实验。使用这种设备，将有可能以亚单层分辨率探测表面原子结构和吸附物种的结构，并从选定的界面原子获得电子结构信息，这些界面原子形成发生电场驱动反应的固体表面和液体电解质之间的边界。通过结合X射线散射(相互作用的空间信息)和成像技术(真实的空间信息)，将有可能建立一个‘真实’工作条件下的表面结构的详细图像。

The solid/liquid interface plays a fundamental role in a diverse range of physical phenomena, for example in catalysis, crystal growth and in many biological reactions that govern the building of the human body and the functioning of the brain. Unravelling the atomic structure at the solid/liquid interface remains, therefore, one of the major challenges facing surface science today for it is only by understanding the physical processes in model systems that we can extrapolate to more complex environments. The key to developing this understanding lies in the preparation and study of model surfaces with well-defined elemental reaction sites.The development of alternative methods of energy supply and storage requires major advances in materials research. Such advances may now be achieved by the manipulation of molecular and atomic-scale processes, leading to an increased understanding of the physical and chemical properties of new materials. In particular, design of these materials may become possible from fundamental principles, i.e. understanding surface properties, as distinct from the bulk material properties, by the application of modern experimental techniques. The aims of this proposal are to further the understanding of the atomic and electronic structure at the electrochemical interface particularly to develop a fundamental understanding of the oxidation and reduction of transition metal multilayer films deposited by electrochemical methods. Due to the buried nature of the electrochemical interface, it is inaccessible to most standard surface science techniques that employ strongly adsorbed electron probes to gain surface sensitivity. Study of the interface is restricted to techniques that employ penetrating radiation, such as x-ray scattering or to imaging techniques such as scanning tunneling microscopy (STM) and atomic force microscopy (AFM). The utilization of synchrotron radiation facilities (the European Synchrotron Radiation Facility in Grenoble and the Diamond Light Source at the Rutherford Appleton Laboratory) is a key component of this project. They offer state-of-the-art equipment for performing x-ray scattering experiments with high incident x-ray flux, energy tuneability and high resolution. Using such equipment it will be possible to probe surface atomic structure and the structures of adsorbed species with sub-monolayer resolution and also to gain electronic structure information from selected interface atoms that form the boundary between the solid surface and the liquid electrolyte where electric field driven reactions occur. By combining x-ray scattering (reciprocal space information) and imaging techniques (real space information) it will be possible to build a detailed picture of a surface structure under 'real' working conditions.