The status quo and prospect of ESR imaging applications to study on catalysts

Abstract

ESR imaging technique supplies us with the possibility of spatial imaging of spin species, and has been widely accepted as a useful tool in many fields. ESR imaging can be applied to observing the spatial distribution of spin species and determining the diffusion processes. These applications will certainly interest chemists in catalyst field. In this paper, the characteristics and limitations of ESR imaging technique, and the status quo and prospect, of ESR imaging applications to catalyst study are discussed. With a current ESR apparatus, the sensitivity and spatial resolution are good enough for the most applications in catalyst studies. Although few works in this field have been reported, its prospect will be interesting. We suggestin situ observation of spatial distribution of paramagnetic species (such as reactants, products and intermediates) in a catalyst system, determination of diffusion in a catalyst pellet and characterization of poisoning in micro fixed-bed reactors with ESR imaging method. Not only paramagnetic species could be studied directly, but also antimagnetic species, which quench spin signals, could be studied indirectly with this method.