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Discovering the Facet-Selective Chemistry that Drives Anisotropic Growth of Metal Nanostructures

发现驱动金属纳米结构各向异性生长的面选择性化学

基本信息

批准号：
1808108
负责人：
Benjamin Wiley
金额：
$ 38.76万
依托单位：
Duke University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-08-15 至 2022-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1808108&HistoricalAwards=false
关键词：
Discovering Facet Selective Chemistry Drives

项目摘要

Nanostructures are materials whose shape is controlled on the nanoscale, length scales 1000 times smaller than the diameter of a human hair. By controlling the shape of nanostructures, scientists can optimize their properties for a very wide range of applications. This can enable the production of cheaper solar cells, higher capacity batteries, and better catalysts that lower the energy required to produce fuels and chemicals. Many nanostructures can be grown from atoms, resulting in nanoscale crystals suspended in liquid solutions. However, nanostructure chemists do not completely understand the surface chemistry that results in growing nanostructures with a certain shape. In this project, Prof. Wiley of Duke University is developing new analytical tools and methods to test ideas for how and why nanostructures grow to form different shapes. Such understanding is necessary to produce large quantities of nanostructures with precisely controlled sizes and shapes in a way that minimizes the environmental impact of nanostructure manufacturing. Prof. Wiley works with Dr. Moffat at the National Institute of Standards and Technology to develop these analytical methods. They also organize symposia that bring together researchers focused on nanostructure synthesis and surface chemistry to cross-fertilize these disciplines with new perspectives. Prof. Wiley disseminates his work through hands-on activities at public events. He also hosts promising high school students in his lab for summer internships to encourage their pursuit of a career in scientific research. Production of nanostructures relies on some form of anisotropic growth, but how and why anisotropic growth occurs in many solution-phase metal nanostructure syntheses remains a matter of debate. With funding from the Macromolecular, Supramolecular and Nanochemistry (MSN) Program of the Chemistry Division, Professor Wiley at Duke University is providing new insights into the facet-selective surface chemistry that is driving anisotropic atomic addition through the use of electrochemical measurements on single crystal surfaces, as well as by using nanostructures themselves as substrates for in situ electrochemical quartz crystal microbalance, surface-enhanced Raman spectroscopy, and surface-enhanced infrared absorption spectroscopy measurements. These measurement techniques are being used to test the hypothesis that, in syntheses of Cu, Ag, and Au nanowires, preferential adsorption of halides onto (100) facets promotes adsorption of organic capping agents onto (100) facets. This in turn leads to preferential atomic addition to (111) facets. In addition, Prof. Wiley is determining the role of capping agents and halides in modulating the rate of nanowire growth through a combination of in situ visualization of nanowire growth rates, and single-crystal electrochemical measurements in the reaction solution. This work is forging a stronger link between the fields of metal nanostructure synthesis and electrochemistry, in part through a new electrochemical society symposium that brings together researchers from both of these fields. The analytical methods and deeper mechanistic understanding developed during this project could enable the rapid development of syntheses with higher productivities and less waste based on fast electrochemical measurements of the conditions that promote anisotropic atomic addition. Prof. Wiley is engaged in educational outreach through the Duke Chemistry Outreach Program, the Durham Museum of Life and Science, and hosting high school students in his lab for summer internships.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

纳米结构是其形状控制在纳米尺度上的材料，长度尺度比人类头发的直径小1000倍。通过控制纳米结构的形状，科学家们可以优化它们的性能，以适应非常广泛的应用。这可以生产更便宜的太阳能电池，更高容量的电池和更好的催化剂，从而降低生产燃料和化学品所需的能量。许多纳米结构可以从原子中生长出来，导致纳米晶体悬浮在液体溶液中。然而，纳米结构化学家并不完全理解导致生长具有特定形状的纳米结构的表面化学。在这个项目中，杜克大学的Wiley教授正在开发新的分析工具和方法，以测试纳米结构如何以及为什么生长形成不同形状的想法。这种理解对于以最小化纳米结构制造对环境影响的方式生产大量具有精确控制的尺寸和形状的纳米结构是必要的。Wiley教授与美国国家标准与技术研究所的Moffat博士合作开发这些分析方法。他们还组织专题讨论会，将专注于纳米结构合成和表面化学的研究人员聚集在一起，以新的观点交叉这些学科。Wiley通过在公共活动中的实践活动传播他的工作。他还在他的实验室举办有前途的高中生暑期实习，以鼓励他们追求科学研究的职业生涯。纳米结构的产生依赖于某种形式的各向异性生长，但是在许多溶液相金属纳米结构合成中如何以及为什么发生各向异性生长仍然是一个争论的问题。在化学系大分子，超分子和纳米化学（MSN）计划的资助下，杜克大学的Wiley教授正在提供对小面选择性表面化学的新见解，该表面化学通过在单晶表面上使用电化学测量来驱动各向异性原子加成，以及通过使用纳米结构本身作为原位电化学石英晶体微天平的基底，表面增强拉曼光谱和表面增强红外吸收光谱测量。这些测量技术被用来测试的假设，在合成的Cu，Ag，和Au纳米线，优先吸附的卤化物到（100）面促进吸附的有机封端剂到（100）面。这又导致原子优先添加到（111）面。此外，Wiley教授正在确定封端剂和卤化物在调节纳米线生长速率中的作用，通过结合纳米线生长速率的原位可视化和反应溶液中的单晶电化学测量。这项工作正在金属纳米结构合成和电化学领域之间建立更紧密的联系，部分原因是通过一个新的电化学学会研讨会，将这两个领域的研究人员聚集在一起。在该项目期间开发的分析方法和更深入的机理理解可以基于促进各向异性原子加成的条件的快速电化学测量来快速开发具有更高生产率和更少浪费的合成。Wiley教授通过杜克化学外展计划、达勒姆生命和科学博物馆从事教育外展工作，并在他的实验室接待高中生进行暑期实习。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。