Direct atomic-scale observation of redox-induced cation dynamics in an oxide-supported monolayer catalyst: WOx/α-Fe2O 3(0001)

Zhenxing Feng, Chang Yong Kim, Jeffrey W. Elam, Qing Ma, Zhan Zhang, Michael J. Bedzyk

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

(Figure Presented) For the case of one-third of a monolayer of tungsten grown by atomic layer deposition on a hematite α-Fe2O 3(0001) surface, we report direct atomic-scale observations of the structural and chemical changes that occur as this model interfacial system evolves from the as-deposited state to the oxidized state, then to the reduced state, and finally back to the oxidized state. In situ X-ray standing-wave atomic images relative to the hematite lattice show dramatic (but redoxreversible) changes to the W cation locations with respect to the occupied and unoccupied Fe surface sites. These structural changes are concurrent with X-ray photoelectron spectroscopy chemical shift changes, where W is observed to go from the 6+ to 5+ oxidation state. These novel observations of redox-induced cation dynamics in an oxide-supported catalyst are explained by models that account for W incorporation at the interface in Fe sites with various coordination schemes. Our proposed structure models are supported by our X-ray absorption fine structure measurements.

Original languageEnglish (US)
Pages (from-to)18200-18201
Number of pages2
JournalJournal of the American Chemical Society
Volume131
Issue number51
DOIs
StatePublished - Dec 30 2009

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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