Approaches to Exploring Spatio-Temporal Surface Dynamics in Nanoparticles with In Situ Transmission Electron Microscopy
Approaches to Exploring Spatio-Temporal Surface Dynamics in Nanoparticles with In Situ Transmission Electron Microscopy
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DOI：
10.1017/s1431927619015228
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发表时间：
2020-02-01
影响因子：
2.8
通讯作者：
Crozier, Peter A.
中科院分区：
文献类型：
--
作者：
Lawrence, Ethan L.;Levin, Barnaby D. A.;Crozier, Peter A.
在多相催化等领域中，许多纳米粒子在化学反应过程中经历表面结构波动，这可能会控制功能。这些动态的结构变化可以理想地与时间分辨原位电子显微镜研究。我们探索了从像差校正透射电子显微镜上的直接电子探测器记录的低信噪比大型时间分辨图像数据集中提取定量信息的方法。我们专注于定量表征梁诱导的动态结构重排发生在CeO 2（二氧化铈）的表面上。采用2D高斯拟合程序来确定纳米颗粒中每个原子柱的位置和占有率，时间分辨率为2.5 ms，空间精度为0.25埃。在整个实验过程中，（100）面显示出局部快速的晶格膨胀/收缩和原子迁移，而（111）面相对稳定。将这种方法应用于其他材料将为以前无法使用其他方法的纳米颗粒表面重建行为提供新的见解，这将对理解动态结构-性质关系产生重要影响。
Many nanoparticles in fields such as heterogeneous catalysis undergo surface structural fluctuations during chemical reactions, which may control functionality. These dynamic structural changes may be ideally investigated with time-resolved in situ electron microscopy. We have explored approaches for extracting quantitative information from large time-resolved image data sets with a low signal to noise recorded with a direct electron detector on an aberration-corrected transmission electron microscope. We focus on quantitatively characterizing beam-induced dynamic structural rearrangements taking place on the surface of CeO2 (ceria). A 2D Gaussian fitting procedure is employed to determine the position and occupancy of each atomic column in the nanoparticle with a temporal resolution of 2.5 ms and a spatial precision of 0.25 angstrom. Local rapid lattice expansions/contractions and atomic migration were revealed to occur on the (100) surface, whereas (111) surfaces were relatively stable throughout the experiment. The application of this methodology to other materials will provide new insights into the behavior of nanoparticle surface reconstructions that were previously inaccessible using other methods, which will have important consequences for the understanding of dynamic structure-property relationships.