Space-and Time-Resolved Combined DRIFT and Raman Spectroscopy:Monitoring Dynamic Surface and Bulk Processes during NO_x Storage Reduction

摘要

Various powerful in situ spectroscopic methods and their combinations have been developed to clarify and establish relations between catalytic activity and the atomic-scale environment of catalytic active sites,particularly under actual working conditions.As demonstrated recently,the addition of the space-domain into typical time-domain spectroscopy allows a deeper understanding of structural effects on catalytic activity within crystals.Another relevant space domain in heterogeneous catalysis is that along the axial and radial directions in a catalyst bed of a continuous fixed-bed reactor,where prominent concentration and temperature gradients are known to exist.For such integral-type reactors,knowledge of concentration and temperature profiles,as well as of structural changes along the catalyst bed caused by them,is crucial for gaining insight into the governing mechanisms and for improving catalytic performance.