New insights into complex molecule-surface interactions through local structure determination

通过局部结构测定对复杂分子-表面相互作用的新见解

• 批准号: EP/D034329/1
• 负责人: David Woodruff
• 金额: $ 37.12万
• 依托单位: University of Warwick
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FD034329%2F1
• 关键词: New; insights; into; complex; molecule

Solids interact with their surroundings through their surfaces, so it is the surface properties which dominate the reactivity of solids as catalysts, their response to corrosive environments, and in the way they can bond to other solids to make electronic devices. Knowledge of the structure of these surfaces (the relative positions of the atoms and molecules) is the key to most attempts to understand the chemical and electronic properties. This project seeks to use one particular specialised method, scanned-energy mode photoelectron diffraction (PhD), to investigate a series of specific structural problems selected to give insight into distinct classes of surface processes. The special features of this method are that it can provide the local geometry of specific atoms within a molecule bonded to a surface, distinguishing atoms of different elements and atoms of the same element in different local bonding environments. This means that one can tackle problems of increasing complexity and thus of increasing relevance to 'real world' surface processes. For example, the interaction with surfaces of large biological molecules, such as proteins and DNA, is potentially important in medical screening for disease, and in ensuring the body does not reject medical implants (e.g. artificial hip joints).These molecules are far too large for their surface interaction to be probed at an atomic scale with any available methods. However, these molecules interact with surfaces through key molecular components, and while even these 'small' molecules present a major challenge for surface structure determination, use of the PhD method should allow the local bonding structure to be determined; one objective of this work is thus to understand the interaction of surfaces with the simplest of these component molecules. Other problems to be addressed mostly involve simpler molecular and atomic adsorbates, but more complex surfaces. In particular, while most surface science experiments have been performed on metal and semiconductor surfaces, a very important class of materials with surface chemical properties of practical importance are oxides, but these are mostly insulators and prove difficult to study by standard methods. In particular, there is a dearth of structural information on oxide surfaces. Recent work using the PhD technique to probe the surfaces of ultra-thin oxide films has proved very successful in obtaining adsorption structures on model surfaces, some of the results highlighting failures in current theoretical understanding of these materials. A significant extension of this work to make inroads into our understanding of molecule-oxide surface interactions is envisaged as a key ingredient of this research programme.The project also aims to explore an important novel extension of the technique to allow structure determination under 'real' chemical reaction conditions. The way atoms and molecules interact with surfaces underpins the hugely important area of heterogeneous catalysis, but the practical application of this technology, such as the clean-up of car exhaust gases in the car's catalytic converter, operate around one atmosphere of pressure. Most methods to probe surface properties, however, have been developed to work only in very good ('ultra-high') vacuum conditions; lowering the pressure of the gas (air) surrounding a surface lowers the rate at which molecules arrive from the air and contaminate the surface, and to ensure this process is slow enough to keep a sample clean for an hour or so, one needs to work in a pressure of about one million-billionth of an atmosphere (comparable to, but somewhat higher than, the pressure in outer space). Finding a way to obtain local structural information at pressures closer to those of 'real' reactions is thus an important goal, and this proposal seeks to explore one possible method to achieve this in by a method capable of unravelling the complexity of such a surface.

固体通过其表面与周围环境相互作用，因此表面特性决定了固体作为催化剂的反应性、它们对腐蚀性环境的响应以及它们与其他固体结合以制造电子设备的方式。了解这些表面的结构（原子和分子的相对位置）是大多数理解化学和电子特性的尝试的关键。该项目旨在使用一种特殊的专业方法，即扫描能量模式光电子衍射（PhD），来研究一系列特定的结构问题，以深入了解不同类别的表面过程。该方法的特点是它可以提供键合到表面的分子内特定原子的局部几何形状，区分不同元素的原子和同一元素的原子在不同的局部键合环境中。这意味着人们可以解决日益复杂的问题，从而与“现实世界”的表面过程越来越相关。例如，与蛋白质和 DNA 等大型生物分子表面的相互作用对于疾病的医学筛查以及确保身体不会排斥医疗植入物（例如人工髋关节）具有潜在的重要作用。这些分子太大了使用任何可用的方法在原子尺度上探测它们的表面相互作用。然而，这些分子通过关键分子成分与表面相互作用，虽然这些“小”分子对表面结构的确定提出了重大挑战，但使用博士方法应该可以确定局部键合结构；因此，这项工作的一个目标是了解表面与这些最简单的组成分子的相互作用。其他需要解决的问题主要涉及更简单的分子和原子吸附物，但涉及更复杂的表面。特别是，虽然大多数表面科学实验都是在金属和半导体表面上进行的，但具有实际重要性的表面化学性质的一类非常重要的材料是氧化物，但这些材料大多是绝缘体，并且很难通过标准方法进行研究。特别是，缺乏氧化物表面的结构信息。最近使用博士技术探测超薄氧化膜表面的工作已证明在模型表面获得吸附结构方面非常成功，其中一些结果凸显了当前对这些材料的理论理解的失败。这项工作的重大扩展旨在加深我们对分子-氧化物表面相互作用的理解，被设想为该研究计划的关键组成部分。该项目还旨在探索该技术的重要新颖扩展，以允许在“真实”情况下确定结构化学反应条件。原子和分子与表面相互作用的方式支撑着非均相催化这一极其重要的领域，但这项技术的实际应用，例如汽车催化转化器中汽车尾气的净化，是在一个大气压下进行的。然而，大多数探测表面特性的方法都只能在非常好的（“超高”）真空条件下工作。降低表面周围气体（空气）的压力会降低分子从空气到达并污染表面的速率，并且为了确保这一过程足够慢以保持样品清洁一小时左右，需要工作在大约百万分之一大气压的压力下（与外层空间的压力相当，但略高于外层空间的压力）。因此，寻找一种在更接近“真实”反应的压力下获取局部结构信息的方法是一个重要的目标，并且该提案旨在探索一种可能的方法来通过能够揭示这种表面的复杂性的方法来实现这一目标。

项目成果

The local structure of OH species on the V2O3(0001) surface: A scanned-energy mode photoelectron diffraction study

V2O3(0001) 表面 OH 物种的局部结构：扫描能量模式光电子衍射研究

• DOI: http://dx.10.1016/j.susc.2008.01.033
• 发表时间: 2008
• 期刊: Surface Science
• 影响因子: 1.9
• 作者: Kröger E

Photoelectron diffraction investigation of the structure of the clean Ti O 2 ( 110 ) ( 1 × 1 ) surface

清洁Ti O 2 ( 110 ) ( 1 × 1 ) 表面结构的光电子衍射研究

• DOI: http://dx.10.1103/physrevb.75.195413
• 发表时间: 2007
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Kröger E

The local structure of SO2 and SO3 on Ni(111): A scanned-energy mode photoelectron diffraction study

Ni(111) 上 SO2 和 SO3 的局部结构：扫描能量模式光电子衍射研究

• DOI: http://dx.10.1016/j.susc.2009.04.001
• 发表时间: 2009
• 期刊: Surface Science
• 影响因子: 1.9
• 作者: Knight M

Quantitative determination of the local structure of thymine on Cu(110) using scanned-energy mode photoelectron diffraction

使用扫描能量模式光电子衍射定量测定 Cu(110) 上胸腺嘧啶的局部结构

• DOI: http://dx.10.1016/j.susc.2007.07.006
• 发表时间: 2007
• 期刊: Surface Science
• 影响因子: 1.9
• 作者: Allegretti F

Adsorption structure of glycine on TiO2(1 1 0): A photoelectron diffraction determination

甘氨酸在TiO2(1 1 0)上的吸附结构：光​​电子衍射测定

• DOI: http://dx.10.1016/j.susc.2009.05.009
• 发表时间: 2009
• 期刊: Surface Science
• 影响因子: 1.9
• 作者: Lerotholi T