Operando NAP-XPS unveils differences in MoO3 and Mo2C during hydrodeoxygenation
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Murugappan_maintxt.pdf
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Author(s)
Murugappan, Karthick
Anderson, Eric M
Teschner, Detre
Jones, Travis E
Skorupska, Katarzyna
Román-Leshkov, Yuriy
Date Issued
2018
Journal
Nature Catalysis
Publisher
Springer Science and Business Media LLC
Version
Author's final manuscript
Abstract
© 2018, The Author(s), under exclusive licence to Springer Nature Limited. MoO3 and Mo2C have emerged as remarkable catalysts for the selective hydrodeoxygenation (HDO) of a wide range of oxygenates at low temperatures (that is, ≤673 K) and H2 pressures (that is, ≤1 bar). Although both catalysts can selectively cleave C–O bonds, the nature of their active sites remains unclear. Here we used operando near-ambient pressure X-ray photoelectron spectroscopy to reveal important differences in the Mo 3d oxidation states between the two catalysts during the hydrodeoxygenation of anisole. This technique revealed that, although both catalysts featured a surface oxycarbidic phase, the oxygen content and the underlying phase of the material impacted the reactivity and product selectivity during the hydrodeoxygenation. MoO3 transitioned between 5+ and 6+ oxidation states during the operation, consistent with an oxygen-vacancy driven mechanism wherein the oxygenate is activated at undercoordinated Mo sites. In contrast, Mo2C showed negligible oxidation state changes during hydrodeoxygenation and maintained mostly 2+ states throughout the reaction.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
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DOI of Published Version
https://doi.org/10.1038/S41929-018-0171-9
