Characterization of diffusion in hierarchical zeolites by infrared spectroscopy
Characterization of diffusion in hierarchical zeolites by infrared spectroscopy
Abstract: This work aimed at developing and benchmarking a new method of investigation of molecular diffusion in zeolite-based materials. It consists in the hyphenation of gravimetric analysis and infrared spectroscopy. The former allows assessing the diffusion from the gas phase to all the porosity, while IR spectroscopy allows for selective assessment of the diffusion to the zeolite active sites located in the micropores by monitoring the evolution of their coverage by the molecular probe. An original method of data processing, based on the inversion of the integral equations describing the uptake curves or infrared spectra has also been developed. These methods were applied to the characterization of (i) model mechanical mixtures of H-MFI and H-FAU zeolites, (ii) hierarchical H-MFI zeolites obtained by treatment in a fluoride medium, and (iii) model composite catalyst made of Al-MCM-41 and hierarchical H-MFI. Our results show that the relative values of diffusion rates as measured by gravimetric and IR spectroscopy are indicative of the quality of connectivity between meso- and microporous networks, and could thus be used to qualify zeolite-based hierarchical materials.
Keywords: Zeolite-based materials, Hierarchical zeolite, Diffusion, Catalytic cracking, Gravimetric analysis, Infrared spectroscopy.
La soutenance de thèse aura lieu le lundi 14 décembre à 10h00 par visioconférence, avec le jury suivant:
Jean-Pierre BELLAT, Professeur, Université de Bourgogne
Benoît LOUIS, Directeur de recherche CNRS, Université de Strasbourg, Rapporteur
Sandrine BOURRELLY, Maître de Conférences, Université de Marseille, Examinatrice
Thomas BELIN, Maître de Conférences, Université de Poitiers, Examinateur
Gerhard PIRNGRUBER, Ingénieur de recherche, Chef de projet, IFPEN, Lyon, Examinateur
Alexandre VIMONT, Co-directeur de thèse, LCS
Arnaud TRAVERT, Directeur de thèse, LCS