Computational Study of Methane Activation on γ-Al2O3

Mitchell C. Cholewinski, Mudit Dixit, Giannis Mpourmpakis

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

The C-H activation of methane remains a longstanding challenge in the chemical industry. Metal oxides are attractive catalysts for the C-H activation of methane due to their surface Lewis acid-base properties. In this work, we applied density functional theory calculations to investigate the C-H activation mechanism of methane on various sites of low-index facets of γ-Al2O3. The feasibility of C-H activation on different metal-oxygen (acid-base) site pairs was assessed through two potential mechanisms, namely, the radical and polar. The effect of surface hydroxylation on C-H activation was also investigated to examine the activity of γ-Al2O3 under realistic catalytic surface conditions (hydration). On the basis of our calculations, it was demonstrated that the C-H activation barriers for polar pathways are significantly lower than those of the radical pathways on γ-Al2O3. We showed that the electronic structure (s- and p-band center) for unoccupied and occupied bands can be used to probe site-dependent Lewis acidity and basicity and the associated catalytic behavior. We identified the dissociated H2 binding and final state energy as C-H activation energy descriptors for the preferred polar pathway. Finally, we developed structure-activity relationships for the C-H activation of methane on γ-Al2O3 that account for surface Lewis acid-base properties and can be utilized to accelerate the discovery of catalysts for methane (and shale gas) upgrade.

Original languageEnglish
Pages (from-to)18242-18250
Number of pages9
JournalACS Omega
Volume3
Issue number12
DOIs
StatePublished - 31 Dec 2018
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2018 American Chemical Society.

Funding

Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund (ACS-PRF) for support of this research. Computational support was provided by the Center for Research Computing at the University of Pittsburgh, and the Extreme Science and Engineering Discovery Environment, which is supported by the NSF (ACI-1053575).

FundersFunder number
Extreme Science and Engineering Discovery Environment
National Science FoundationACI-1053575
Directorate for Computer and Information Science and Engineering1053575
American Chemical Society Petroleum Research Fund
University of Pittsburgh

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