Cation synergies affect ammonia adsorption over VOX and (V,W)OX dispersed on α-Al2O3 (0001) and α-Fe2O3 (0001)
| Autor: | Martin E. McBriarty, Donald E Ellis |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Inorganic chemistry
Oxide Selective catalytic reduction Protonation 02 engineering and technology Surfaces and Interfaces 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Vanadium oxide 0104 chemical sciences Catalysis Surfaces Coatings and Films Metal chemistry.chemical_compound Crystallography Monomer Adsorption chemistry visual_art visual_art.visual_art_medium Materials Chemistry 0210 nano-technology |
| Zdroj: | Surface Science. 651:41-50 |
| ISSN: | 0039-6028 |
| DOI: | 10.1016/j.susc.2016.03.015 |
| Popis: | The catalytic behavior of oxide-supported metal oxide species depends on the nature of the support and the presence of co-catalysts. We use density functional theory (DFT) to explore the relationship between the structure and chemical behavior of vanadium oxide in light of its industrial use for the selective catalytic reduction of nitric oxide with ammonia (NO-SCR). The relative stabilities of dispersed VO X monomers, dimers, and long-chain oligomers on two model oxide support surfaces with similar structure but drastically different chemical behavior, α-Al 2 O 3 (0001) and α-Fe 2 O 3 (0001), are determined. The effect of added tungsten, known to promote NO-SCR, is also investigated on the relatively inert α-Al 2 O 3 (0001) support. We find that the adsorption behavior of NH 3 , representing the first step of the NO-SCR reaction, depends strongly on the VO X local structure. Protonation of NH 3 to NH 4 + over surface hydroxyls is energetically favorable over VO X -WO X dimers and VO X oligomers, which are stabilized by the reducible α-Fe 2 O 3 (0001) support. |
| Databáze: | OpenAIRE |
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