Oxide Surfaces, From Bulk to Nanoparticles

非技术描述：氧化物表面是一个重要的前沿领域，在许多技术重要性领域的应用，从催化到新兴的氧化物电子学领域。我们对氧化物表面的理解是相对原始的，对于未来的商业应用，工业将需要在大尺度和纳米尺度上对氧化物进行五西格玛控制生长，这将需要定量地了解表面结构如何取决于用于制造材料的条件。这项工作的目标是确定关键的概念，使设计的氧化物表面的特定应用在催化以及控制氧化物薄膜的生长和其他应用。除了支持马克教授小组中少数民族和代表性不足的学生的活动外，该项目还支持来自世界各地2000多个团体的用户使用Wien 2k软件，这些用户来自84个不同的国家，包括美国，西班牙，和瑞典向印度等发展中国家以及南苏丹和埃及等欠发达国家出口。该项目提出的问题是什么是更复杂的氧化物表面的原子结构在介观尺度和纳米颗粒，这是如何连接到生长动力学或热力学，以及什么是氧化物表面结构的预测规则在两个尺寸尺度？如果我们不知道表面原子的位置，就不可能解释各种现象，例如不同重建上纳米颗粒的不同形状以及这如何改变它们的催化行为;不同重建上技术重要材料的不同生长模式;不同表面重建上不同的化学反应性以及氧化物生长实验的不可重复性。为了解开这一信息，该项目是一个结合实验理论的努力相结合的氧化物表面科学方法与更高分辨率的透射电子显微镜，密度泛函理论方法和基于连续介质的建模。除了氧化物表面的基础科学外，该项目还涉及对研究生和本科生进行尖端研究方法的培训，协助世界各地的科学家使用Wien 2k密度函数代码，并通过研究生开发维基百科页面进行一般科学宣传。

NON-TECHNICAL DESCRIPTION: Oxide surfaces are an important frontier, with applications in many areas of technological importance ranging from catalysis to the emerging field of oxide electronics. Our understanding of oxide surfaces is relatively primitive and for future commercial applications industry will demand five-sigma controlled growth of oxides both at the large scale and at the nanoscale, which will require quantitative understanding of how the surface structures depends upon the conditions used to make the materials. This work targets determining the key concepts to enable design of oxide surfaces for specific applications in catalysis as well as to control the growth of oxide thin films and for other applications. In addition to activities in supporting minority and underrepresented students within Prof. Mark's group, this project also supports work assisting users from more than 2000 groups around the world using the Wien2k software from 84 different countries which range from developed countries such as the USA, Spain, and Sweden to developing countries such as India and under-developed countries such as South Sudan and Egypt.TECHNICAL DETAILS: The project poses the questions of what is the atomic structure of the surface of more complex oxides at both the mesoscale and in nanoparticles, how does this connect to the kinetics of growth or thermodynamics, and what are the predictive rules for oxide surface structures at both size scales? If we do not know the positions of the atoms at the surface, it is impossible to explain phenomena such as different shapes of nanoparticles on different reconstructions and how this changes their catalytic behavior; different growth modes of technologically important materials on different reconstructions; different chemical reactivity on different surface reconstructions as well as the unspoken irreproducibility of oxide growth experiments. To unravel this information the project is a combined experimental-theoretical effort combining oxide surface science methods with higher resolution transmission electron microscopy, density functional theory methods and continuum based modelling. In addition to the underlying science of oxide surfaces, the project involves training of graduate and undergraduate students in cutting-edge research methods, assistance to scientists around the world as users of the Wien2k density functional code and general science outreach via the development of Wikepedia pages by graduate students.