Application of multinuclear MRI and solid state MRI in heterogeneous catalysis

This paper presents some of the existing applications of the NMR imaging (MRI) technique relevant to catalytic research. Through the examples presented, it is demonstrated that MRI is a powerful addition to other modern techniques employed to characterize properties of catalysts and catalytic reactors and their performance. It is shown that the existing MRI approaches can be applied to get insight into a broad range of characteristics of catalysts and reactors. The examples presented include preparation and characterization of porous catalyst supports, dynamic studies of supported catalysts preparation by solution impregnation, packing and structure of catalyst beds and reactors, and various types of mass transport in the catalyst particles as well as in the entire reactor. Last but not least, it is shown that rapid MRI strategies are useful to study dynamic processes in operating catalytic reactors, with the multiphase catalytic hydrogenation reaction at elevated temperatures used as a representative example. These in situ studies demonstrate a number of essential phenomena including ignition of individual catalyst particles and their mutual influence, while combination of the spectroscopic and imaging modalities of the NMR technique can be useful for the characterization of the chemical conversion under reactive conditions.