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，在许多重要的技术领域都有应用，从催化到新兴的氧化物电子领域。我们对氧化物表面的理解相对原始，对于未来的商业应用，工业将需要在大尺度和纳米尺度上控制氧化物的五西格玛生长，这将需要对表面结构如何依赖于制造材料的条件进行定量理解。这项工作的目标是确定关键概念，以便为催化中的特定应用设计氧化物表面，以及控制氧化物薄膜的生长和其他应用。除了支持Mark教授小组内的少数民族和代表性不足的学生之外，该项目还支持帮助来自84个不同国家的2000多个小组的用户使用Wien2k软件，这些国家包括美国、西班牙和瑞典等发达国家、印度等发展中国家和南苏丹和埃及等欠发达国家。技术细节：该项目提出的问题是，在中尺度和纳米颗粒中，更复杂的氧化物表面的原子结构是什么，这与生长动力学或热力学有何联系，以及在两种尺寸尺度上氧化物表面结构的预测规则是什么？如果我们不知道原子在表面的位置，就不可能解释诸如不同形状的纳米颗粒在不同的重构上以及这如何改变它们的催化行为等现象；技术重要材料在不同重构上的不同生长方式；不同表面重构的不同化学反应性以及氧化物生长实验的不可再现性。为了揭示这些信息，该项目将实验和理论结合起来，将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体的建模相结合。除了氧化物表面的基础科学外，该项目还包括对研究生和本科生进行尖端研究方法的培训，帮助世界各地的科学家使用Wien2k密度功能代码，并通过研究生开发维基百科页面进行一般科学推广。

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.