Probing the Vibrational States of Surface Sites on Catalytic Nanoparticles with Atomic Resolution Electron Energy-Loss Spectroscopy

用原子分辨率电子能量损失谱探测催化纳米粒子表面位点的振动状态

• 批准号: 2109202
• 负责人: Peter Crozier
• 金额: $ 48万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-15 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2109202&HistoricalAwards=false
• 关键词: Probing; Vibrational; States; Surface; Sites

With the support of the Chemical Measurement and Imaging (CMI) Program in the Division of Chemistry, and partial co-funding from the Catalysis Program in the Division of Chemistry and the Atomic, Molecular, and Optical Physics Program in the Division of Physics, Professor Peter Crozier of Arizona State University is studying development of a new imaging tool to measure the vibrations of atoms on the surface of small particles, with the latter being targeted as catalysts for important chemical conversion processes. The atoms on the surface of a material are constantly vibrating in a variety of different ways, with those different types of vibrations corresponding to different vibrational pathways, referred to as modes. These vibrational modes of the atoms on the surface of a material can help transfer energy to molecules bound to the surface of the material, which may drive catalytic chemical changes in the molecular structure of the surface-bound molecules. However, there are limited methods for gaining information about vibrational modes across the surface of small particles. Professor Crozier will develop and apply novel microscopy techniques that use electrons for the imaging process so as to detect and study the characteristics of surface vibrational modes on very small particles. The fundamental principles anticipated from this study have the potential for long-term impact not only in catalysis but also in other areas of materials and life science. To engage students, teachers, and the public in this research, an educational module entitled “Good Vibrations” will be developed, which will link the area of atomic-level vibrations to vibrational sound waves found in music. A web-based application will be developed that allows students and the public to decompose music passages into fundamental vibrational (harmonic) modes. By incorporating music from contemporary artists, the team hopes to engage high school students in the excitement of vibrational science and generate enthusiasm for careers in science, technology, engineering, and mathematics. The goal of this project is to probe and develop a fundamental understanding of vibrational states at distinct surface sites on catalytic nanoparticles with atomic resolution. To improve our understanding of the vibrational energy exchange process, it is necessary to have information on the local vibrational modes that exist at surface sites. Vibrational dynamics on nanoparticle surfaces are not well understood, in part because there have been no methods to perform atomic resolution probing of surface vibrational modes. The Krozier team will address this deficiency by developing novel approaches to vibrational electron energy-loss spectroscopy (EELS) in the scanning transmission electron microscope (STEM) using the impact component of inelastic electron scattering. Electron scattering in STEM carries information about vibrational states in a manner similar to inelastic neutron scattering, but it can provide atomic resolution. Moreover, the signal may be associated with short wavelength modes that are most sensitive to atomic defects. Overall, this research has the potential to provide a useful new vibrational description of the surfaces of catalysts.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.

在化学系化学测量和成像（CMI）计划的支持下，以及化学系催化计划和物理系原子，分子和光学物理计划的部分共同资助下，亚利桑那州立大学的Peter Crozier教授正在研究开发一种新的成像工具来测量小颗粒表面原子的振动，后者被用作重要化学转化过程的催化剂。 材料表面上的原子以各种不同的方式不断振动，这些不同类型的振动对应于不同的振动路径，称为模式。 材料表面上的原子的这些振动模式可以帮助将能量转移到与材料表面结合的分子，这可以驱动表面结合分子的分子结构中的催化化学变化。 然而，有有限的方法来获得有关小颗粒表面振动模式的信息。 Crozier教授将开发和应用新的显微镜技术，使用电子进行成像过程，以检测和研究非常小的颗粒表面振动模式的特征。 从这项研究中预期的基本原则不仅在催化领域，而且在材料和生命科学的其他领域都有可能产生长期影响。 为了让学生、教师和公众参与这项研究，将开发一个名为“良好振动”的教育模块，将原子级振动与音乐中的振动声波联系起来。 一个基于网络的应用程序将被开发，允许学生和公众分解成基本振动（谐波）模式的音乐段落。 通过融入当代艺术家的音乐，该团队希望让高中生参与振动科学的兴奋，并激发他们对科学、技术、工程和数学职业的热情。 这个项目的目标是探索和发展的振动状态的基本理解，在不同的表面位点的催化纳米粒子与原子分辨率。 为了提高我们对振动能量交换过程的理解，有必要了解存在于表面位置的局部振动模式。 纳米粒子表面的振动动力学还没有很好的理解，部分原因是没有方法来执行表面振动模式的原子分辨率探测。 Krozier团队将通过使用非弹性电子散射的冲击分量在扫描透射电子显微镜（STEM）中开发振动电子能量损失谱（EELS）的新方法来解决这一缺陷。 STEM中的电子散射以类似于非弹性中子散射的方式携带关于振动状态的信息，但它可以提供原子分辨率。 此外，信号可以与对原子缺陷最敏感的短波长模式相关联。 总的来说，这项研究有可能提供一个有用的新的振动描述的催化剂的表面。这个奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。