Redox-driven atomic-scale changes in mixed catalysts: VOX/WOX/α-TiO2 (110)

Z. Feng, M. E. McBriarty, A. U. Mane, J. Lu, P. C. Stair, J. W. Elam, M. J. Bedzyk

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Abstract

X-ray studies of vanadium-tungsten mixed-monolayer-oxide catalysts grown on the rutile α-TiO2 (110) single crystal surface show redox behavior not observed for lone supported vanadium or tungsten oxides. Two cases are presented: sub-monolayer (sub-ML) vanadium oxide (vanadia) grown on ML tungsten oxide and ML vanadia grown on sub-ML tungsten oxide. The X-ray standing wave (XSW) and X-ray photoelectron spectroscopy (XPS) observations for both cases show coverage-dependent reversible redox-induced atomic-scale structural and chemical state changes. Atomic force microscopy shows that the mixed VOX/WOX overlayers have a conformal film-like structure in the as-deposited state. XSW analysis in light of XPS reveals that the V and W cations that are uncorrelated with the substrate lattice play an important role in catalytic redox reactions. Distinct differences in the redox-induced changes for these two mixed catalysts result from tuning the ratio of V to W, and relationships are drawn between the catalyst composition, structure, and chemistry. Comparison of these V-W mixed cases and the corresponding unmixed cases reveals a synergistic effect in which the reduction of W can be significantly enhanced by the addition of V. This journal is

Original languageEnglish
Pages (from-to)64608-64616
Number of pages9
JournalRSC Advances
Volume4
Issue number110
DOIs
Publication statusPublished - Jan 1 2014

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ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)

Cite this

Feng, Z., McBriarty, M. E., Mane, A. U., Lu, J., Stair, P. C., Elam, J. W., & Bedzyk, M. J. (2014). Redox-driven atomic-scale changes in mixed catalysts: VOX/WOX/α-TiO2 (110). RSC Advances, 4(110), 64608-64616. https://doi.org/10.1039/c4ra14140g