Nuclear spin relaxation as a probe of zeolite acidity: a combined NMR and TPD investigation of pyridine in HZSM-5
Neil Robinson, Pierre Bräuer, A. York, Carmine D’Agostino
Abstract
is shown to exhibit strong sensitivity to the silica/alumina ratio (SAR) of these zeolites, which is indicative of material acidity. This trend is interpreted in terms of increased pyridine surface affinity with decreasing SAR. Temperature programmed desorption (TPD) analysis corroborates this observation, revealing a distinct increase in the heat of desorption associated with adsorbed pyridine as a function of decreasing SAR. A direct correlation between NMR and TPD data suggests NMR relaxation time analysis can be a valuable tool for the non-invasive characterisation of adsorption phenomena in microporous solids.
Topics & Concepts
ZeoliteMicroporous materialPyridineChemistryRelaxation (psychology)Physical chemistryNuclear magnetic resonance spectroscopyInorganic chemistryAnalytical Chemistry (journal)CatalysisOrganic chemistrySocial psychologyPsychologyAdvanced NMR Techniques and ApplicationsNMR spectroscopy and applicationsZeolite Catalysis and Synthesis