Imaging of Element-Specific 3D Distribution Dynamics in Working Bimetallic Catalysts by in-situ Anomalous Small-Angle X-Ray Scattering

通过原位反常小角 X 射线散射对工作双金属催化剂中元素特异性 3D 分布动力学进行成像

基本信息

批准号：
2002960
负责人：
Yugang Sun
金额：
$ 37.64万
依托单位：
Temple University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-15 至 2024-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2002960&HistoricalAwards=false
关键词：
Imaging Element Specific 3D Distribution

项目摘要

With this award, the Chemical Measurement and Imaging (CMI) Program in the Division of Chemistry is supporting Dr. Yugang Sun at Temple University to combine computation and X-ray methods to develop a rapid chemical imaging tool that maps out the location of individual metals. Utilizing this tool, he and his team seek to glean a real-time, three-dimensional "picture" of metals in nanoscale metal catalyst particles on an atom-by-atom basis. Many alternative fuel sources are derived from catalytic processes based on such metal nanoparticles. New measurement methods that reveal information about the arrangement and location of metal atoms in the catalyst and how atom location and arrangement change during the chemical conversion process have great potential to enhance our fundamental understanding of catalysis in these systems. This novel solution to a long-standing challenge may well provide new insights into the how atomic-level structure affects behavior of nanometer-sized catalysts, while also holding potential to understand how the chemical behavior of other nanoparticles is influenced by their environment over time. These new measurement methods are anticipated to lead to significant impacts on chemical reactions used in industry, ranging from those that produce chemical or pharmaceutical building blocks to those that produce alternative fuels. The use of the state-of-the-art large-scale synchrotron X-ray facilities at national laboratories trains the students to become specialists in a significant area that is underrepresented in the typical chemist's skill set. More broadly, the research educates a highly diverse group of students about the use of cutting-edge chemical measurement tools to address important scientific problems, with an emphasis on workforce development in the field of alternative fuels. Dr. Sun and his team also integrate research outcomes into the Philadelphia community and beyond through a range of education and outreach programs to students and teachers at local urban/high-need schools and Community Colleges, as well as students participating in a National Science Foundation undergraduate research program and the Temple University TUteach initiative.In this project, Dr. Sun and his research team integrate small-angle X-ray scattering (SAXS) measurements with ab initio modeling and calculation results to construct models of the three-dimensional (3D) geometry of uniform nanoparticles of well-defined chemical composition. This project is developing this imaging protocol to enable the study of the element-specific evolution of 3D atom distributions in bimetallic nanoparticle catalysts under working conditions. Such endeavors require two consecutive steps. First, the element-specific SAXS patterns are deconvoluted from the highly convoluted anomalous small-angle X-ray scattering (ASAXS) of bimetallic nanoparticles based on penalized regression methods. Second, an imaging protocol is being developed to determine element-specific 3D images of the composition distribution in bimetallic nanoparticles through ab initio modeling of the deconvoluted element-specific SAXS patterns. The ASAXS imaging protocol may then be applicable to in-situ ASAXS imaging through its use with working reactors, allowing for the study of the time-resolved evolution of element-specific 3D distributions of metals in bimetallic catalysts in operando.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.

有了这个奖项，化学划分的化学测量和成像（CMI）计划支持Temple University的Yugang Sun博士结合计算和X射线方法，以开发快速化学成像工具，以绘制单个金属的位置。利用此工具，他和他的团队试图在纳米级金属催化剂粒子中以原子原子为基础，在纳米级金属催化剂颗粒中进行实时的三维“图片”。许多替代燃料来源都是从基于此类金属纳米颗粒的催化过程中得出的。新的测量方法揭示了有关金属原子在催化剂中的布置和位置的信息，以及化学转化过程中原子位置和布置如何变化具有巨大的潜力，可以增强我们对这些系统中催化的基本了解。这项长期挑战的新颖解决方案可以很好地提供有关原子级结构如何影响纳米大小催化剂的行为的新见解，同时还具有了解其他纳米颗粒的化学行为如何随着时间的推移而受到环境的影响。预计这些新的测量方法将对工业中使用的化学反应产生重大影响，从生产化学或药物构建块的化学反应到产生替代燃料的构建块的化学反应。国家实验室的最先进的大规模同步X射线设施的使用训练学生在典型化学家技能中的重要领域中成为专业领域的专家。从更广泛的角度来看，该研究对一群高度多样化的学生进行了教育，以使用尖端的化学测量工具来解决重要的科学问题，重点是替代燃料领域的劳动力发展。 Sun博士和他的团队还通过一系列教育和外展计划，通过一系列教育和外展计划将研究成果整合到费城社区，并向当地的城市/高需求学校和社区学院的学生和老师组成，以及参加国家科学基金会本科生研究计划的学生以及Temple University tuteach的一项tuteach Initiative。构建均匀纳米颗粒的三维（3D）几何形状的模型。该项目正在开发此成像方案，以研究在工作条件下的双金属纳米粒子催化剂中3D原子分布的特定元素特异性演化。此类努力需要两个连续的步骤。首先，特定于元素特异性的萨克斯模式是根据基于惩罚回归方法的双金属纳米粒子的高度复杂的异常小角X射线散射（ASAXS）反价文vlo。其次，正在开发一个成像协议，以确定双金属纳米颗粒中组成分布的特定元素特异性3D图像，通过从头开始建模，对反价vol的元素特异性SAXS模式。然后，通过与工作反应堆的使用，可以将ASAXS成像协议适用于原位ASAXS成像，从而可以研究Operando中双金属催化剂中金属特异性3D分布的时间分解演变，这是NSF的法定任务，反映了通过评估的构成师的构成师的构成师的构成师的影响力，并具有范围的范围。