Application of 29Si and 27Al solid-state NMR for zeolite-geopolymer composites

Abstract

29Si and 27Al solid-state nuclear magnetic resonance (NMR) spectroscopy has been established as a powerful technique for investigating the network connectivity and coordination environments for diverse crystalline and amorphous silicate materials. Recently, zeolite-geopolymer composites, emerging as sustainable and functional construction materials, have garnered significant interest for their mechanical properties and adsorption capabilities. However, the coexistence of crystalline and amorphous phases, as well as complex Si-Al coordination environments, makes detailed structural characterization challenging. In this mini-review, recent applications of 29Si and 27Al solid-state NMR to zeolite-geopolymer compo- sites are summarized, highlighting the isotopic chemical shift ranges of geopolymer gels in comparison with coexisting crystalline phases. Perspectives on future studies are also discussed.