Abinitio molecular dynamics study of the Brnsted acid site in a gallium zeolite

Abstract

We present the results of an abinitio molecular dynamics simulation on the structure and the dynamics of a gallium sodalite, H[GaSi₁₁O₂₄]. The average geometry of the system and the simulated vibrational spectrum are compared with the results obtained for the corresponding Al-substituted zeolite (H[AlSi₁₁O₂₄]). Our results suggest that the properties of the Brønsted acid site in the gallium sodalite are quite similar to those of a silanol. This finding represents a possible explanation of the minor activity shown experimentally by Ga-substituted zeolites in many catalytic processes.