Investigating the Physicochemical Properties of an Extra-large Pore Aluminosilicate ZEO-1

ZEO-1 is the first stable extra-large pore zeolite with a substantial amount of aluminum in the framework achieved directly upon synthesis, and here we present a comprehensive analysis of its physicochemical properties. Our findings show that varying the different synthesis parameters of ZEO-1 allows for controlling its crystallization kinetics, crystal size, and morphology. Investigating the acidic properties of ZEO-1 using 27 Al and 1 H solid-state nuclear magnetic resonance shows that ZEO-1 exhibits potentially three different aluminum populations. The acidic nature of the hydroxyl species within ZEO-1 is studied using pyridine and 2,6-di tert -butylpyridine and carbon monoxide via in situ infrared spectroscopy, where the extinction coefficient for the 1545 cm –1 pyridinium band is determined. Density functional theory modeling suggests that the active sites within ZEO-1 potentially occupy four different tetrahedral sites, where three of these sites are most likely located within the 12-membered ring channel, while one site is located in the 16-membered ring channel. The catalytic performance comparison of ZEO-1 with zeolites Beta and USY in the alkylation of phenol by tert -butyl alcohol, n -hexane cracking, and anisole dismutation reveals intriguing insights. ZEO-1 exhibits selectivity similar to Beta zeolite, consistent with density functional theory modeling predictions. Despite displaying weaker overall Brønsted acid sites compared to Beta, ZEO-1’s acidity remains comparable to USY zeolite. Moreover, ZEO-1 demonstrates consistent performance relative to large-pore zeolites with enhanced stability in the anisole dismutation test.