Spectroscopic identification of acid-base pairs in solid catalysts

Abstract

A systematic characterization of acid-base pairs in solid catalysts was conducted using advanced two-dimensional homonuclear or heteronuclear correlation solid-state nuclear magnetic resonance spectroscopy. Pyridine-d5 or trimethylphosphine was employed as the probe for acid sites, while pyrrole was used to identify base sites. These probe molecules were co-adsorbed onto the catalyst surface. Their spatial proximity was carefully established, thereby revealing the spatial correlations in acid-base pairs and further guiding the rational design and optimization of high-performance bifunctional acid-base catalysts.