Atomic-resolution environmental TEM for quantitative in-situ microscopy in materials science.
Atomic-resolution environmental TEM for quantitative in-situ microscopy in materials science.
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DOI：
10.1093/jmicro/dfs096
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发表时间：
2013-02
期刊：
影响因子：
1.8
通讯作者：
S. Takeda;H. Yoshida
中科院分区：
文献类型：
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作者：
S. Takeda;H. Yoshida
我们已经编制了我们最近的原位定量环境透射电子显微镜（ETEM）研究典型的金纳米颗粒催化剂的低温氧化CO描述的问题，周围的应用ETEM，特别是关于催化剂化学。由于最近发展的高分辨率环境透射电子显微镜，可以稳健地工作，在受控环境中积累观测数据，我们可以处理电子辐照效应和真实的催化剂的异质性。我们建立了一个结构演化图，总结了电子辐照下催化剂的结构作为电子电流密度和电子剂量D的函数。通过外推到λ = 0，D = 0，我们可以推断出在各种环境中（包括反应环境）的本征催化结构（无电子辐照）。通过数值和统计分析大量的金纳米粒子的ETEM图像，我们建立了一个形态相图，总结了大多数金纳米粒子如何系统地改变其形态作为CO和O（2）分压的函数。类似的图表将有助于阐明与ETEM观测确定的催化活性直接相关的现象。使用这些定量分析，我们可以分析催化剂的Cs校正的ETEM图像。在反应条件下，通过与CO分子的相互作用，金纳米颗粒的表面结构重建。利用高分辨率ETEM技术，在反应条件下观察到CO分子在催化剂表面上的存在。最后，我们讨论了潜在的环境透射电子显微镜定量原位显微镜在原子尺度。
We have compiled our recent in-situ quantitative environmental transmission electron microscopy (ETEM) studies on typical gold nanoparticulate catalysts for the low-temperature oxidation of CO to describe the issues surrounding the application of ETEM, with a special regard to catalyst chemistry. Thanks to the recent development of high-resolution environmental transmission electron microscopes that can work robustly to accumulate observation data in controlled environments, we can deal with the electron irradiation effects and heterogeneity of real catalysts. We established a structural evolution diagram that summarizes the structure of catalysts under electron irradiation as a function of the electron current density ϕ and the electron dose, D. By extrapolating to ϕ = 0, D = 0, we could deduce the intrinsic catalysis structure (without electron irradiation) in various environments, including reaction environments. By numerically and statistically analyzing a substantial number of ETEM images of gold nanoparticles, we established a morphology phase diagram that summarizes how the majority of gold nanoparticles change their morphology systematically as a function of the partial pressures of CO and O(2). Similar diagrams will be helpful in elucidating the phenomena that directly correlate with the catalytic activity determined from ETEM observations. Using these quantitative analyses, we could analyze Cs-corrected ETEM images of the catalysts. The surfaces of gold nanoparticles were structurally reconstructed under reaction conditions, via interactions with CO molecules. CO molecules were observed on the surfaces of catalysts under reaction conditions using high-resolution ETEM. Finally, we discuss the potential of environmental transmission electron microscopy for quantitative in-situ microscopy at the atomic scale.