Solid-State NMR Characterization of Framework Structure of Zeolites and Zeotype Materials

Abstract

This chapter introduces the application of solid-state NMR to characterize the framework structure of zeolite and zeotype materials. Zeolites are inorganic crystallites containing pores and cavities of molecular dimensions with well-defined structures. The framework of zeolite is composed of tetrahedra (TO4, T = Si, Al, B, P, etc.), which can be comprehensively characterized by the well-established and robust solid-state NMR techniques. Chemical environment of the metal or non-metal elements in zeolites and zeotype materials could be studied by the multi-nuclear MAS NMR spectroscopy including 29Si, 27Al, 31P, 17O NMR. Additionally, the detailed information about coordination, connectivity, and framework ordering can be obtained from multi-nuclear and two-dimensional NMR spectroscopy as well as distance constraints’ measurement. Moreover, the structure features and communication of cages and channels in porous materials can be extracted by 129Xe NMR spectroscopy.