Active Sites in Supported Single-Site Catalysts: An NMR Perspective

Abstract

Development of heterogeneous catalysts requires detailed structural characterization of active sites, an essential step towards establishing structure-activity relationships and promoting rational designs of new catalysts. Solid-state NMR has emerged as a powerful approach to provide key molecular level information about active site structures and dynamics in heterogeneous catalysis. Here, we describe how one can apply solid-state NMR, ranging from 1D chemical shift assignments (and additional parameters, CQ and η, for quadrupolar nuclei, I > ½), 2D correlations to analysis of chemical shift anisotropy providing unprecedented structural information over a broad range of materials. We also describe how modern hyperpolarization techniques like DNP can be used to improve sensitivity of NMR, and make various challenging 1D/2D NMR experiments feasible, thus paving the way to determine the structures of surface sites.