Atomic modeling was employed in conjunction with experimental characterization to interrogate the influence of varying Al substitution characteristics on the properties of the H-ZSM-5 lattice and Br�nsted acid sites. The long-range lattice characteristics of the VASP density functional theory fully-minimized models with varying Si/Al ratio were predicted to be in good agreement with experimental measurements. However, the predicted character of the Br�nsted acid sites was also found to be sensitive to the local reaction site environment. Most of the Br�nsted acid sites were predicted to increase in acidity with decreasing Si/Al ratio. This corresponded to the increased isopropyl amine decomposition activity observed by temperature programmed desoprtion-mass spectrometry with decreasing Si/Al ratio. Atomic modeling showed clear correlations of the predicted favorability of hydrocarbon cracking reactions with varying Br�nsted site acidity. These results show the importance of both long- and short-range effects for describing zeolite lattice and reaction site characteristics.

Influence of the Si/Al ratio on H-ZSM-5 lattice and reaction site characteristics

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.