Unique Electrochemistry and Optical Properties of Metal Nanoparticle Assemblies

在这个由化学系的大分子，超分子和纳米化学项目资助的项目中，路易斯维尔大学的弗朗西斯P. Zamborini教授和他的团队使用化学表征技术的组合研究了小金纳米颗粒的氧化。纳米粒子是包含数千个原子的微小粒子。虽然它们比只包含几个原子的化学分子大得多，但它们仍然比包含数万亿个原子的固体材料小得多。纳米尺度材料是独特的，因为它们的尺寸介于分子和固体之间，但有时具有不容易通过平均两个极端尺寸来预测的特性。该研究的目的是了解小于2 nm的金属纳米颗粒和合金纳米结构组成，排列和反应性的不寻常的电化学反应性。其目的是为金属纳米结构开发新的分析工具，并揭示其独特的性质，反应性和应用。该项目通过研究培训和将纳米技术更广泛地纳入本科课程，对各级学生的教育产生影响。每年一次的为期一天的研讨会突出了从中学到学术和工业专业人士的所有年龄段的妇女的研究。这次研讨会的目的是激励更多的年轻女学生追求长期的科学事业。这些活动通过广泛的传播影响了肯塔基州及其他地区的教育和经济。该项目旨在将特定尺寸与低于2 nm的纳米球的氧化电位相关联，该纳米球显示出不寻常的电化学反应性，其作为尺寸的函数发生显着变化。该项目还通过确定电化学氧化行为来解决双组分合金纳米球中金属的原子排列。这种方法允许在加热或催化反应期间发生的转变的灵敏检测。该项目的另一个重点是在电极上选择性电化学沉积带负电荷的金纳米球。这一过程具有潜在的高活性负载型电催化剂的设计。研究小组还使用金纳米片-纳米球二聚体结构作为通过表面增强拉曼光谱（Sers）进行灵敏分子检测的平台。结构的图像直接与Sers信号相关。一种独特的三聚体结构被用来研究非SERS活性金属上的催化反应。良好控制的纳米片-纳米球二聚体和三聚体组装有助于更好地理解和控制Sers检测，以在单分子水平上研究反应。

In this project funded by the Macromolecular, Supramolecular, and Nanochemistry program of the Division of Chemistry, Professor Francis P. Zamborini of the University of Louisville and his team study the oxidation of small gold nanoparticles using a combination of chemical characterization techniques. Nanoparticles are tiny particles that contain thousands of atoms. While they are much larger than chemical molecules, which contain only a few atoms, they are still much smaller than solid materials that are large enough to see with the naked eye, containing trillions of atoms. Nanoscale materials are unique because they have sizes intermediate between molecules and solids, but sometimes have properties not easily predicted by averaging the two size extremes. The aim of the research is to understand the unusual electrochemical reactivity of metal nanoparticles smaller than 2 nm and of alloy nanostructure composition, arrangement, and reactivity. The aim is to develop new analytical tools for metal nanostructures, and also uncover unique properties, reactivity, and applications. The project impacts the education of students at all levels through research training and wider incorporation of nanotechnology into the undergraduate curriculum. A yearly one-day symposium highlights research by women of all ages from middle school up to academic and industrial professionals. The goal of this symposium is to inspire more young female students to pursue a long term career in science. These activities impact the education and economy in Kentucky and beyond through broad dissemination. This project aims to correlate the specific size with the oxidation potential for nanospheres below 2 nm, which show unusual electrochemical reactivity that change dramatically as a function of size. The project also addresses the atomic arrangement of metals in two-component alloy nanospheres by determining electrochemical oxidation behavior. This method allows the sensitive detection of transformations that occur during heating or catalytic reactions. Another focus of the project is the size-selective electrochemical deposition of negatively-charged gold nanospheres onto electrodes. This process has potential for the design of highly active supported electrocatalysts. The research team also uses gold nanoplate-nanosphere dimer structures as a platform for sensitive molecular detection by surface enhanced Raman spectroscopy (SERS). Images of the structures are directly correlated to the SERS signal. A unique trimer structure is used to study catalytic reactions on non-SERS active metals. The well-controlled nanoplate-nanosphere dimer and trimer assemblies aid in better understanding and controlling SERS detection for the study of reactions at the single molecule level.