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Title: Detecting structural variances of Co 3O 4 catalysts by controlling beam-induced sample alterations in the vacuum of a transmission electron microscope

This article summarizes core aspects of beam-sample interactions in research that aims at exploiting the ability to detect single atoms at atomic resolution by mid-voltage transmission electron microscopy. Investigating the atomic structure of catalytic Co 3O 4 nanocrystals underscores how indispensable it is to rigorously control electron dose rates and total doses to understand native material properties on this scale. We apply in-line holography with variable dose rates to achieve this goal. Genuine object structures can be maintained if dose rates below ~100 e/Å 2s are used and the contrast required for detection of single atoms is generated by capturing large image series. Threshold doses for the detection of single atoms are estimated. An increase of electron dose rates and total doses to common values for high resolution imaging of solids stimulates object excitations that restructure surfaces, interfaces, and defects and cause grain reorientation or growth. We observe a variety of previously unknown atom configurations in surface proximity of the Co 3O 4 spinel structure. These are hidden behind broadened diffraction patterns in reciprocal space but become visible in real space by solving the phase problem. Finallly, an exposure of the Co 3O 4 spinel structure to water vapor or othermore » gases induces drastic structure alterations that can be captured in this manner.« less
Authors:
ORCiD logo [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Molecular Foundry
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Biosciences Division
  3. Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Engineering
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Sciences Division and Joint Center for Artificial Photosynthesis
  5. California Inst. of Technology (CalTech), Pasadena, CA (United States). Joint Center for Artificial Photosynthesis
  6. Haldor Topsoe A/S, Kongens Lyngby (Denmark)
Publication Date:
OSTI Identifier:
1330729
Grant/Contract Number:
AC02-05CH11231
Type:
Published Article
Journal Name:
Advanced Structural and Chemical Imaging
Additional Journal Information:
Journal Volume: 2; Journal Issue: 1; Journal ID: ISSN 2198-0926
Publisher:
Springer
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY