ABSTRACT

Zeolite and related microporous materials are currently used in a wide range of technological processes, including gas separation, molecular sieving and heterogeneous  catalysis. They are also under active investigation as host materials for encapsulating and organizing adsorbed molecules, crystalline nano-phases and supramolecular entities. Space confinement   (inside zeolite pores and cages ) of guest chemical species, and host-guest electrostatic interaction, results in nano-composite materials having novel optical electronic and magnetic properties. Potential applications of these materials are expected in a number of fields, such as chemical and biological sensing, selective membranes, semiconductor devices and photonics. Developments in all of these fields, including selective catalysis for pollution control and the synthesis of fine chemicals, heavily depends upon improved methods for zeolite characterization and for studying intrazeolite chemistry. For both of these purposes several instrumental techniques are currently being used, often in conjunction with quantum chemical calculations and computer modelling.  Among instrumental techniques, infrared spectroscopy deserves special attention, on account of its wide potential and versatility. Recent trends in IR spectroscopy of zeolites include the use of new probe molecules, variable temperature procedures, synchrotron infrared radiation and ultrafast time–resolved IR spectrometry. These advances are highlighted, and examples are given of how infrared spectroscopy is strongly contributing to an improved understanding of zeolites and intrazeolite chemical processes.