2H Magic-angle spinning nuclear magnetic resonance (MAS NMR), echo 27Al NMR, two-dimensional (2D) echo 1H MAS NMR and 1H, 27Al and 29Si MAS NMR have been applied to study the acid sites of dehydrated zeolites. The quadrupole coupling constants CQCC determined from 2H MAS NMR spectra of Si-OH-Al sites increase with the framework aluminium content of the zeolites from 208 Hz (H-ZSM-5) to 236 kHz ...

MFI-type zeolite membranes (ZSM-5) were prepared on α-alumina tubular supports and tested for separation of H2/CO mixtures. The effect of pressure and temperature on H2 and CO flows and selectivity was investigated. The best results in this work were obtained with a ZSM-5 membrane prepared over a porous α-alumina tube seeded with zeolite nanocrystals synthesized with m...

Optimizing the number, distribution, and accessibility of Brønsted acid sites in zeolite-based catalysts is of a paramount importance to further improve their catalytic performance. However, it remains challenging to measure real-time changes in reactivity of single zeolite catalyst particles by ensemble-averaging characterization methods. In this work, a detailed 3D single molecule, single tur...

Visualizing proton-transfer processes at the nanoscale is essential for understanding the reactivity of zeolite-based catalyst materials. In this work, the Brønsted-acid-catalyzed oligomerization of styrene derivatives was used for the first time as a single molecule probe reaction to study the reactivity of individual zeolite H-ZSM-5 crystals in different zeolite framework, reactant and solven...

Fe/ZSM-5 nanosheet zeolites of varying thickness were synthesized with di- and tetraquaternary ammonium structure directing agents and extensively characterized for their textural, structural, and catalytic properties. Introduction of Fe3+ ions in the framework of nanosheet zeolites was slightly less effective than in bulk ZSM-5 zeolite. Steaming was necessary to activate all catalysts for N2O ...

Two infrared OH stretching bands are produced after interaction of CO with H-ZSM-5 bridging hydroxyls. These two bands are not due to heterogeneity of the acid sites but arise from Fermi-resonance.

One-dimensional medium-pore zeolites are promising catalysts for propylene production from naphtha cracking due to their high selectivity. However, fast deactivation pore mouth blockage is preventing these being widely used in commercial applications. In this study, we molecular dynamics simulations investigate the diffusion of three one-dimensional aluminosilicate frameworks (ZSM-23, ZSM-22, Z...