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The Role of Gas in Determining Image Quality and Resolution During In Situ Scanning Transmission Electron Microscopy Experiments
Author(s) -
Zhu Yuanyuan,
Browning Nigel D.
Publication year - 2017
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201700474
Subject(s) - scanning transmission electron microscopy , resolution (logic) , dark field microscopy , atomic units , materials science , transmission electron microscopy , scanning electron microscope , characterization (materials science) , chemistry , microscopy , analytical chemistry (journal) , nanotechnology , optics , physics , composite material , chromatography , quantum mechanics , artificial intelligence , computer science
As gas–solid heterogeneous catalytic reactions are molecular in nature, a full mechanistic understanding of the process requires atomic‐scale characterization under realistic operating conditions. Although atomic resolution imaging has become routine in modern high‐vacuum (scanning) transmission electron microscopy ((S)TEM), both image quality and resolution nominally degrade on introduction of the reaction gases. In this work, we systematically assess the effects of different gases at various pressures on the quality and resolution of images obtained at room temperature in the annular dark field STEM imaging mode by using a differentially pumped (DP) gas cell. This imaging mode is largely free from inelastic scattering effects induced by the presence of gases and retains good imaging properties over a wide range of gas mass/pressures. We demonstrate the application of ESTEM with atomic resolution images for a complex oxide alkane oxidation catalyst MoVNbTeO x (M1) immersed in light and heavy gas environments.