Bimetallic Janus Nanocrystals and Their Derivatives

双金属Janus纳米晶及其衍生物

基本信息

批准号：
1804970
负责人：
Younan Xia
金额：
$ 42.27万
依托单位：
Georgia Tech Research Corporation
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：
2018-09-01 至 2022-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1804970&HistoricalAwards=false
关键词：
Bimetallic Janus Nanocrystals Their Derivatives

项目摘要

Assemblies of metal atoms with well-ordered structures in the size range of ~10 nanometers are known as nanocrystals. Controlling the spatial distributions of different metal atoms in nanocrystals offers a simple and versatile way to tailor their structures and properties. Such tailoring has the potential to vastly expand their utility as catalysts in the production of important chemicals and pharmaceuticals as well as processes used for conversion of energy and protection of the environment. In this project, Dr. Younan Xia of the Georgia Institute of Technology and Dr. Manos Mavrikakis of the University of Wisconsin-Madison are developing a bimetallic system, in which the two metals are spatially separated from each other by an interface to form nanocrystals with a Janus structure. The bimetallic Janus nanocrystals offer a broad range of unique properties and applications, including the tuning of optical response and the enhancement of catalytic activity and/or selectivity for specific chemical products. By switching to bimetallic Janus nanocrystals and their derivatives, one can substantially reduce the amount of precious metal in a nanocrystal while potentially improving the performance, enabling Society to achieve cost-effective and sustainable use of precious metals, some of the scarcest elements in the Earth's crust. However, there are only a very limited number of reports on bimetallic Janus nanocrystals, primarily due to the lack of mechanistic understanding and experimental control for their chemical synthesis. As a major requirement for the formation of bimetallic Janus nanocrystals, the atoms of one metal can only be deposited at a single site on the surface of a nanocrystal made of another metal and this particular pattern of deposition must be maintained throughout the growth process. The PIs integrate experimental studies and computational modeling in their development of predictable, deterministic, and robust synthesis of bimetallic Janus nanocrystals. They are also contributing to the preparation of a skilled workforce for science, technology, engineering and mathematics (STEM) disciplines through active engagement of graduate and undergraduate students in this collaborative, multidisciplinary research, as well as curriculum enrichment and development. The investigators are fully committed to promoting diversity in higher education by engaging underrepresented groups into this research project. With funding from the Macromolecular, Supramolecular & Nanochemistry (MSN) Program of the Chemistry Division, Drs. Xia and Mavrikakis are developing a new knowledge base for the design and deterministic synthesis of bimetallic Janus nanocrystals. They are deriving the exact range of initial reduction rate needed for achieving nucleation and growth from a single site on each individual nanocrystal and thus generating a Janus structure. They are also investigating the thermal stability of the Janus nanocrystals with respect to atomic inter-diffusion and surface diffusion. As for applications, the Janus nanocrystals are explored as building blocks for colloidal self-assembly and as sacrificial templates for the fabrication of metal nanoboxes with a single, well-defined hole on the surface, preferably located at one of the vertices. Such nanoboxes, when made of platinum, can serve as a highly active and durable catalyst towards oxygen reduction, a reaction key to the operation of hydrogen-based fuel cells. Along with the experimental studies, computational modeling is used to explain the trends and mechanisms involved in the syntheses, as well as the catalysis taking place on some of the bimetallic nanocrystals.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.

〜10纳米尺寸范围内有序结构的金属原子组件称为纳米晶体。控制纳米晶体中不同金属原子的空间分布提供了一种简单而多功能的方式来调整其结构和特性。这种剪裁有可能大大扩展其作为生产重要化学品和药品的催化剂的效用，以及用于转化能量和保护环境的过程。在该项目中，佐治亚理工学院的Younan Xia博士和威斯康星大学麦迪逊分校的Manos Mavrikakis博士正在开发一个双金属系统，在该系统中，两种金属通过界面将两种金属彼此隔开，以形成带有Janus结构的纳米晶体。双金属janus纳米晶体具有广泛的独特性能和应用，包括对光学响应的调整以及对特定化学产品的催化活性和/或选择性的增强。通过改用双金属janus纳米晶体及其衍生物，人们可以大大减少纳米晶体中的贵金属量，同时有可能改善性能，使社会能够实现成本效益和可持续的珍贵金属，这是地球甲壳中最稀有的元素。但是，关于双金属janus纳米晶体的报告数量非常有限，这主要是由于缺乏对化学合成的机械理解和实验控制。作为形成双金属janus纳米晶体的主要要求，一种金属的原子只能沉积在由另一种金属制成的纳米晶体表面的一个位置上沉积，并且在整个生长过程中必须保持这种特殊的沉积模式。 PI将实验研究和计算模型整合在其可预测，确定性和可靠的双金属janus纳米晶体的合成的发展中。他们还为科学，技术，工程和数学（STEM）学科准备熟练的劳动力，通过在这项合作，多学科研究以及课程丰富和发展中积极参与学科。调查人员致力于通过使代表性不足的群体参与该研究项目来促进高等教育的多样性。通过大分子，超分子和纳米化学（MSN）计划的资金，博士。 Xia和Mavrikakis正在为双金属Janus纳米晶体的设计和确定性综合开发一个新的知识库。他们得出了从每个纳米晶体上单个位点实现成核和生长所需的初始还原率的确切范围，从而产生了Janus结构。他们还研究了Janus纳米晶体在原子间扩散和表面扩散方面的热稳定性。至于应用，将Janus纳米晶体探索为胶体自组装的构件，以及用于制造金属纳米毒素的牺牲模板，其表面上有一个明确的孔，最好位于一个顶点。这样的纳米毒素是由铂制成的，可以作为降低氧气的高度活性且耐用的催化剂，这是基于氢的燃料电池运行的反应键。除了实验研究外，计算建模还用于解释合成中涉及的趋势和机制，以及在一些双金属纳米晶体上进行的催化。这项奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点和广泛的影响来审查CRETIRIA的法定任务。