Exposing active sites in zeolites with fluoropyridines as NMR probe molecules.

ABSTRACT: Active sites in zeolites are crucial for catalysis, but their identification remains challenging due to structural complexity. Solid-state NMR, a key tool for studying zeolites, can struggle with directly detecting acidic properties due to the quadrupolar nature of ubiquitous metal dopants. Here, we use fluorinated pyridine as a probe to identify active sites in HY and HZSM-5, two important solid acid catalysts. ¹⁹F NMR effectively detects binding environments, while ¹⁹F-²⁷Al polarization transfer reveals elusive penta-coordinated Al^V Brønsted acid sites and shows that the dominant active sites are distorted framework-associated Al^IV and Al^V sites with large quadrupolar coupling constants, shedding light on catalytic propert

SUBMITTER: Hurd J 

PROVIDER: S-EPMC12227064 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature