Characterisation of Metal Nanoclusters and Catalytic Mechanisms by Microwave Spectroscopy

微波光谱表征金属纳米团簇和催化机制

• 批准号: EP/G026424/2
• 负责人: Nicholas Walker
• 金额: $ 7.18万
• 依托单位: Newcastle University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FG026424%2F2
• 关键词: Characterisation; Metal; Nanoclusters; Catalytic; Mechanisms

The speed at which an object rotates depends upon its mass and the way that mass is distributed in the object. Thus, it is harder to set a roundabout turning when somebody is riding at the edge but easier if that person stands right in the middle. It is easy to set a frisbee spinning but hard to flip a javelin end-over-end. These observations are a consequence of the relationship between mass, geometrical structure and inertia. The same relationship allows study of the structure of a molecule through measurements of its molecular rotation. Microwave spectroscopy works by causing molecules to spin and then seeing how fast they rotate. Is a given molecule shaped more like a frisbee or a javelin? The technique can also be used to determine how atoms are arranged within a molecule and to accurately measure bond distances and angles between bonds. It can tell us whether a molecule is flexible or rigid. It can say how charge is distributed, telling us about the strength and nature of chemical bonds. In a novel application, I propose to use a new tool in microwave spectroscopy to determine whether reactions are catalysed on the surface of selected metal nanoclusters. The development of more efficient, selective and greener catalysts is a key challenge of modern research in chemistry. Catalysts are often used to accelerate chemical reactions and processes of commercial significance. Industry employs the surface environment provided by solid metals to catalyse the manufacture of a wide variety of chemical products, materials and foods. For example, margarine is produced using nickel metal as a catalyst. Researchers have already described how nanoclusters of metal atoms supported on surfaces can be highly effective catalysts. It is known that the size and topology (molecular landscape of the surface) of these units can have a profound influence on their catalytic properties. This proposal seeks to contribute fundamental information on the molecular mechanisms of catalysis on metal nanoclusters on the smallest possible scale. Carbon monoxide is known to poison catalytic materials, reducing their efficiency. Metal nanoclusters with adsorbed carbon monoxide will be one target of studies. H2O and CO yield H2 and CO2 in an industrially-important catalysed reaction that is a useful source of hydrogen fuel (the water gas shift reaction). I will study whether this reaction can occur on very small metal nanoclusters, and if so, whether its efficiency is a function of cluster size. Conventional Balle-Flygare Fourier transform microwave (FTMW) spectrometers possess a narrow, 1 MHz bandwidth and are unsuitable for collecting data rapidly. The proposed research will exploit the latest 21st century digital technology for the construction of a novel chirped pulse Fourier transform microwave (CP-FTMW)spectrometer. The new CP-FTMW instrument will be broadband and allow the collection of data over an 11 GHz frequency range simultaneously. Given that it will be possible to monitor the concentration of many different components in a gas sample simultaneously, this instrument may ultimately find applications in analytical science. It will also be perfectly suited to probe the microwave spectra of many biologically-significant molecules.

物体旋转的速度取决于其质量以及质量在物体中的分布方式。因此，当有人骑在边缘时，设置环岛转弯会更困难，但如果该人站在中间，则更容易设置环岛转弯。使飞盘旋转很容易，但将标枪翻转过来却很难。这些观察结果是质量、几何结构和惯性之间关系的结果。同样的关系允许通过测量分子旋转来研究分子的结构。微波光谱的工作原理是使分子旋转，然后观察它们旋转的速度。给定分子的形状是否更像飞盘或标枪？该技术还可用于确定原子在分子内的排列方式，并准确测量键间的键距和角度。它可以告诉我们分子是柔性的还是刚性的。它可以说明电荷如何分布，告诉我们化学键的强度和性质。在一项新颖的应用中，我建议使用微波光谱学中的一种新工具来确定反应是否在选定的金属纳米团簇的表面上被催化。开发更高效、更具选择性和更环保的催化剂是现代化学研究的一个关键挑战。催化剂通常用于加速具有商业意义的化学反应和过程。工业利用固体金属提供的表面环境来催化各种化学产品、材料和食品的制造。例如，人造黄油是使用镍金属作为催化剂生产的。研究人员已经描述了表面负载的金属原子纳米团簇如何成为高效的催化剂。众所周知，这些单元的尺寸和拓扑（表面的分子景观）可以对其催化性能产生深远的影响。该提案旨在提供有关尽可能最小规模的金属纳米团簇催化分子机制的基本信息。众所周知，一氧化碳会毒害催化材料，降低其效率。吸附一氧化碳的金属纳米团簇将成为研究目标之一。 H2O 和 CO 在工业上重要的催化反应中产生 H2 和 CO2，该反应是氢燃料的有用来源（水煤气变换反应）。我将研究这种反应是否可以在非常小的金属纳米团簇上发生，如果可以，其效率是否是团簇尺寸的函数。传统的 Balle-Flygare 傅里叶变换微波 (FTMW) 光谱仪具有狭窄的 1 MHz 带宽，不适合快速收集数据。拟议的研究将利用最新的 21 世纪数字技术来构建新型线性调频脉冲傅立叶变换微波 (CP-FTMW) 光谱仪。新的 CP-FTMW 仪器将是宽带的，允许同时收集 11 GHz 频率范围内的数据。鉴于可以同时监测气体样品中许多不同成分的浓度，该仪器最终可能会在分析科学中得到应用。它还非常适合探测许多具有生物学意义的分子的微波光谱。

项目成果

Halogen bonding in the gas phase: a comparison of the iodine bond in B?ICl and B?ICF3 for simple Lewis Bases B.

气相中的卤素键合：简单路易斯碱 B 中 B?ICl 和 B?ICF3 中碘键的比较。

• DOI: 10.1007/128_2014_574
• 发表时间: 2015
• 期刊: Topics in current chemistry
• 影响因子: 8.6
• 作者: Hill JG

H3PAgI: generation by laser-ablation and characterization by rotational spectroscopy and ab initio calculations.

• DOI: 10.1039/c6cp03512d
• 发表时间: 2016-07-28
• 期刊: Physical chemistry chemical physics : PCCP
• 作者: Stephens SL;Tew DP;Walker NR;Legon AC
• 通讯作者: Legon AC

A perspective on chemistry in transient plasma from broadband rotational spectroscopy.

从宽带旋转光谱研究瞬态等离子体中的化学。

• DOI: 10.1039/c4cp04108a
• 发表时间: 2014
• 期刊: PCCP
• 作者: Zaleski DP