Continuous flow hyperpolarized¹²⁹Xe-MAS NMR studies of microporous materials

Abstract

A magic angle spinning (MAS) NMR probe has been developed to allow in situ measurements of NMR spectra. Two applications are targeted with this device: i) in situ and operando MAS NMR spectroscopy of working catalysts and ii) the hyperpolarized (HP) 129Xe spectroscopy of porous materials under MAS and continuous flow conditions. The construction of the MAS probe is described and the usefulness of this system is demonstrated by studying the adsorption of hyperpolarized xenon on AlPO-41 and ITQ-6 zeolites. The high stability of the HP xenon flow allowed us to perform two-dimensional exchange experiments under MAS conditions, in a short time and with very good resolution.