Atomic-Scale View of VOX–WOX Coreduction on the α-Al2O3 (0001) Surface
| Autor: | Michael J. Bedzyk, Tasha Drake, Gavin P. Campbell, Peter C. Stair, Jeffrey W. Elam, Donald E Ellis, Martin E. McBriarty |
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| Rok vydání: | 2015 |
| Předmět: |
Chemistry
Inorganic chemistry Oxide Selective catalytic reduction Vanadium oxide Surfaces Coatings and Films Electronic Optical and Magnetic Materials Overlayer Catalysis Atomic layer deposition chemistry.chemical_compound General Energy X-ray photoelectron spectroscopy Physical and Theoretical Chemistry Single crystal |
| Zdroj: | The Journal of Physical Chemistry C. 119:16179-16187 |
| ISSN: | 1932-7455 1932-7447 |
| Popis: | The catalytic activity of oxide-supported vanadium oxide is improved by the presence of tungsten oxide for the selective catalytic reduction of nitric oxides. We propose a mechanism for V–W synergy through studies of the reduction–oxidation behavior of near-monolayer VOX and WOX species grown by atomic layer deposition on the α-Al2O3 (0001) single crystal surface. In situ X-ray standing wave measurements reveal an overlayer of W6+ species that is correlated with the substrate lattice as well as a redox-reversible shift from uncorrelated V5+ to correlated V4+. X-ray photoelectron spectroscopy and electronic structure calculations show a partial reduction of W6+ in the presence of V4+, improving the Bronsted acidity in mixed V–W catalyst systems. This mechanism of V–W synergy suggests that control of W d-states might be used as a design parameter for Bronsted acid sites in multicomponent oxide catalysts. |
| Databáze: | OpenAIRE |
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