| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 58630 | Catalysis Today | 2006 | 5 Pages |
Ammonia adsorption on Brønsted acid sites of WO3 cluster supported on metal oxide supports: SnO2, ZrO2, and TiO2, is analyzed by PIO analysis. We employed (HO)(WO3)4(H) and (HO)(WO3)9(H) on (SnO2)12, (ZrO2)12, and (TiO2)12, respectively, as supported Brønsted acid models and examined two types of Brønsted acid sites, an edge type and a face type. We estimated ammonia adsorption strength by total overlap population (∑OP) of all PIOs between the Brønsted acid site and NH3. The order of acidity (∑OP) of each model is as follows: edge type: SnO2, 0.0096 > ZrO2, 0.0048 > TiO2, −0.0001 ≫ face type: ZrO2, −0.0759 > TiO2, −0.0761 > SnO2, −0.0867. The edge type adsorption is far stronger than the face type one. This order in the edge type coincides with the experimental results. The reason of these results is explained by the difference of the influence of oxygen atoms sitting near the N atom of NH3.
Graphical abstractAmmonia adsorption on Brønsted acid sites of WO3 cluster supported on metal oxide supports: SnO2, ZrO2, and TiO2, is analyzed by PIO analysis. The edge type adsorption is far stronger than the face type one. The strength of acidity of supported WO3 cluster is following order: SnO2 > ZrO2 > TiO2. Figure optionsDownload full-size imageDownload as PowerPoint slide
