Analysis of Local Structure, Acidic Property and Activity of Solid Acids by Solid-State Nuclear Magnetic Resonance Spectroscopy

Abstract

Solid acid is one of the most widely applied heterogeneous catalysts for industrial hydrocarbon conversion and biomass refining. It is crucial to understand the nature of solid acid such as its local structure and acidic properties. Such knowledge renders effective design of solid acid with better activity and stability for the desired reaction. Recently, solid-state nuclear magnetic resonance (SSNMR) spectroscopy has been applied as a powerful standard method for characterizing the local structure and acidic nature of solid acid in both qualitative and quantitative manners. Additionally, the applications of advanced two-dimensional SSNMR methodologies further reveal the symmetry of surface sites, spatial relationship of different sites, and thereby unmasking the structure-activity relationship. In this review, we summarize the general methods and SSNMR techniques for the routine characterization, focusing on the progresses in the understanding of local structure and acidic properties of solid acids via the application of SSNMR with or without probe molecules.

Keywords

• brønsted acid sites
• lewis acid sites
• solid acid
• acid site structure
• solid-state nuclear magnetic resonance (ssnmr) spectroscopy