| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 67823 | Journal of Molecular Catalysis A: Chemical | 2007 | 7 Pages |
In this study, we carried out two-layer ONIOM calculations to determine the Gibbs free energy and the enthalpy changes for the gallium-exchanged silicoaluminophospate (Ga/SAPO-11) catalysts’ interaction with NH3, SO2, CH3NH2, CH3SH, H2, and H2O molecules, and the formation of possible intermediate species, such as oxy-hydroxy GaOm(OH)n. The results reveal that the [HGaOH]+ and [Ga]+ formation, as well as the SO2 adsorption at 773 K are thermodynamically favorable processes. This work shows for first time the potential ability of the Ga/SAPO-11 catalyst to adsorb SO2 and to oxidize H2S; that is, to be used in DeSOx reactions. NH3 and CH3NH2 adsorption were also found to be exothermic processes, but thermodynamically favourable (ΔG < 0) at temperatures below 773 K, whereas CH3SH is not adsorbed at all. This implies that the Ga/SAPO-11 catalyst behaves like a hard acid according to Pearson's rule.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide
