Atomic-Scale View of Redox Induced Changes for Monolayer MoOx on α-TiO2(110) with Chemical-State Sensitivity

Michael J. Bedzyk*, Anusheela Das, Leighton O. Jones, Yanna Chen, Devika Choudhury, Denis T Keane, Jeffrey W. Elam, George C Schatz

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Supported molybdenum oxide (MoOx) plays an important role in catalytic transformations from alcohol dehydrogenation to transesterification. During these reactions, molybdenum and oxygen surface species undergo structural and chemical changes. A detailed, chemical-state specific, atomic-scale structural analysis of the catalyst under redox conditions is important for improving catalytic properties. In this study, a monolayer of Mo grown on α-TiO2(110) by atomic-layer deposition is analyzed by X-ray standing wave (XSW) excited X-ray photoelectron spectroscopy (XPS). The chemical shifts for Mo 2p3/2 and O 1s peaks are used to distinguish Mo6+ from Mo4+ and surface O from bulk O. Excitation of XPS by XSW allows pinpointing the location of these surface species relative to the underlying substrate lattice. Measured 3D composite atomic density maps for the oxidized and reduced interfaces compare well with our density functional theory models and collectively create a unique view of the redox-driven dynamics for this complex catalytic structure.

Original languageEnglish (US)
Pages (from-to)5304-5309
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume13
Issue number23
DOIs
StatePublished - Jun 16 2022

ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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