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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.

在~10纳米的尺寸范围内，结构有序的金属原子的集合被称为纳米晶体。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通用的方法来定制纳米晶体的结构和性质。这种裁剪有可能大大扩大它们作为催化剂的用途，用于生产重要的化学品和药品，以及用于转换能源和保护环境的过程。在这个项目中，乔治亚理工学院的夏尤南博士和威斯康星大学麦迪逊分校的马诺斯·马夫里卡基斯博士正在开发一种双金属系统，其中两种金属通过界面在空间上相互分离，形成具有双面神结构的纳米晶体。双金属Janus纳米晶体提供了广泛的独特性质和应用，包括调整光学响应和增强特定化学产品的催化活性和/或选择性。通过切换到双金属Janus纳米晶体及其衍生物，人们可以大大减少纳米晶体中贵金属的数量，同时潜在地提高性能，使社会能够实现经济有效和可持续地使用贵金属，这是地壳中最稀缺的元素之一。然而，关于双金属Janus纳米晶体的报道非常有限，主要是由于缺乏对其化学合成的机理理解和实验控制。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另一种金属制成的纳米晶体表面的单个位置上，并且这种特殊的沉积模式必须在整个生长过程中保持。pi将实验研究和计算建模整合到双金属Janus纳米晶体的可预测、确定性和鲁棒性合成的开发中。他们还通过研究生和本科生积极参与这种多学科合作研究以及课程丰富和发展，为科学、技术、工程和数学（STEM）学科培养熟练的劳动力。研究人员完全致力于通过让代表性不足的群体参与到这个研究项目中来促进高等教育的多样性。在化学部的大分子、超分子和纳米化学（MSN）项目的资助下，dr。Xia和Mavrikakis正在为双金属Janus纳米晶体的设计和确定性合成开发一个新的知识库。他们正在推导出从每个纳米晶体上的单个位点实现成核和生长所需的初始还原速率的精确范围，从而产生一个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，Janus纳米晶体被探索作为胶体自组装的构建块和作为金属纳米盒制造的牺牲模板，金属纳米盒表面有一个明确的孔，最好位于其中一个顶点。这种由铂制成的纳米盒可以作为一种高活性和耐用的氧还原催化剂，这是氢基燃料电池运行的关键反应。随着实验研究，计算模型被用来解释趋势和机制所涉及的合成，以及催化发生在一些双金属纳米晶体。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

期刊论文数量（33）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

How to Remove the Capping Agent from Pd Nanocubes without Destructing Their Surface Structure for the Maximization of Catalytic Activity?

DOI：
10.1002/anie.202006011
发表时间：
2020-08-26
期刊：
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
影响因子：
16.6
作者：
Shi, Yifeng;Lyu, Zhiheng;Xia, Younan
通讯作者：
Xia, Younan

Pd‐Ru Alloy Nanocages with a Face‐Centered Cubic Structure and Their Enhanced Activity toward the Oxidation of Ethylene Glycol and Glycerol

DOI：
10.1002/smtd.201900843
发表时间：
2020-05
期刊：
影响因子：
0
作者：
Ming Zhao;Zhiheng Lyu;Minghao Xie;Zachary D. Hood;Zhenming Cao;M. Chi;Younan Xia
通讯作者：
Ming Zhao;Zhiheng Lyu;Minghao Xie;Zachary D. Hood;Zhenming Cao;M. Chi;Younan Xia

General Approach to the Synthesis of Heterodimers of Metal Nanoparticles through Site-Selected Protection and Growth