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Ultrafast Elemental and Oxidation-State Mapping of Hematite by 4D Electron Microscopy

Su, Zixue and Baskin, J. Spencer and Zhou, Wuzong and Thomas, John M. and Zewail, Ahmed H. (2017) Ultrafast Elemental and Oxidation-State Mapping of Hematite by 4D Electron Microscopy. Journal of the American Chemical Society, 139 (13). pp. 4916-4922. ISSN 0002-7863.

[img] PDF (Figure S1, PINEM-electron effect on the zero-loss EELS spectra and ultrafast TEM images of hematite. Figure S2, ultrafast iron oxidation-state and elemental mapping) - Supplemental Material
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We describe a new methodology that sheds light on the fundamental electronic processes that occur at the subsurface regions of inorganic solid photocatalysts. Three distinct kinds of microscopic imaging are used that yield spatial, temporal, and energy-resolved information. We also carefully consider the effect of photon-induced near-field electron microscopy (PINEM), first reported by Zewail et al. in 2009. The value of this methodology is illustrated by studying afresh a popular and viable photocatalyst, hematite, α-Fe_2O_3 that exhibits most of the properties required in a practical application. By employing high-energy electron-loss signals (of several hundred eV), coupled to femtosecond temporal resolution as well as ultrafast energy-filtered transmission electron microscopy in 4D, we have, inter alia, identified Fe^(4+) ions that have a lifetime of a few picoseconds, as well as associated photoinduced electronic transitions and charge transfer processes.

Item Type:Article
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Zhou, Wuzong0000-0001-9752-7076
Additional Information:© 2017 American Chemical Society. Received: January 28, 2017; Published: March 8, 2017. This work was supported by the Air Force Office of Scientific Research (FA9550-11-1-0055) in the Gordon and Betty Moore Center for Physical Biology at the California Institute of Technology. The studies described in this paper were conceived by Ahmed Zewail, and most of the insights that we reveal were greatly influenced by his input. We thank Prof. Nathan S. Lewis at the California Institute of Technology for helpful comments. The authors declare no competing financial interest.
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Air Force Office of Scientific Research (AFOSR)FA9550-11-1-0055
Issue or Number:13
Record Number:CaltechAUTHORS:20170327-091015176
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Official Citation:Ultrafast Elemental and Oxidation-State Mapping of Hematite by 4D Electron Microscopy Zixue Su, J. Spencer Baskin, Wuzong Zhou, John M. Thomas, and Ahmed H. Zewail Journal of the American Chemical Society 2017 139 (13), 4916-4922 DOI: 10.1021/jacs.7b00906
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:75408
Deposited By: Tony Diaz
Deposited On:27 Mar 2017 16:18
Last Modified:03 Oct 2019 16:50

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