R. Sinclair1, S. C. Lee2, and A. L. Koh3
1Dept. of Materials Science & Engineering, Stanford University, Stanford, U.S.A. This email address is being protected from spambots. You need JavaScript enabled to view it.
2Dept. of Materials Science & Engineering, Stanford University, Stanford, U.S.A.
3Stanford Nano Shared Facilities, Stanford University, Stanford, U.S.A.
The environmental transmission electron microscope (ETEM) allows the study of material reactions in situ, in a mild gaseous environment, at atomic resolution. Higher pressures and liquids are possible with a closed-cell specimen holder, albeit at lower resolutions [1]. Such studies represent the fastest growing field within in situ TEM. In this paper, we will assess the results obtained in situ compared with equivalent ex situ or low electron beam dose rate observations. It will be seen that on occasion the imaging electron beam can mimic important real experimental conditions while many times it induces completely different results. Specific systems to be considered include the hydrogenation of amorphous molybdenum sulphide [2], the reduction of epitaxial ceria thin films [3] and the oxidation of carbon nanotubes [4]. The care necessary to ensure reliable observations will then be emphasized.
References
[1] A. L. Koh, S. C. Lee and R. Sinclair, "A Brief History of Controlled Atmosphere Transmission Electron Microscopy", in: "Controlled Atmosphere Transmission Electron Microscopy - Principles and Practice", ed. T. W. Hansen and J. B. Wagner, (Springer Publishing Company, New York) (2016) pp. 3-43, https://doi.org/10.1007/978-3-319-22988-1_1
[2] S.C. Lee, J.D. Benck, C. Tsai, J. Park, A.L. Koh, F. Abild-Pedersen, T.F. Jaramillo and R. Sinclair, "Chemical and Phase Evolution of Amorphous Molybdenum Sulfide Catalysts for Electrochemical Hydrogen Production", ACS Nano, 10 (2016) pp. 624-632, https://doi.org/10.1021/acsnano.5b05652
[3] R. Sinclair, S.C. Lee, Y. Shi and W.C. Chueh, "Structure and Chemistry of Epitaxial Ceria Thin Films on Yttria-Stabilized Zirconia Substrates, Studied by High Resolution Electron Microscopy", Ultramicroscopy, 176 (2017) pp. 200-211, https://doi.org/10.1016/j.ultramic.2017.03.015
[4] A.L. Koh and R. Sinclair, "Assessing and Ameliorating the Influence of the Electron Beam on Carbon Nanotube Oxidation in Environmental Transmission Electron Microscopy", Ultramicroscopy, 176 (2017) pp. 132-138, https://doi.org/10.1016/j.ultramic.2016.12.009
