(511f) Deactivation Kinetics and Deactivation Mechanism During the Selective Reduction of NOx Catalyzed by Metal-Zeolites

Metal-containing zeolites are used during the selective reduction of NOx under lean conditions, but their operation in the presence of H2O leads to deactivation. There are strong differences in the deactivation pattern that depend on the type of zeolite and the charge-balance cation, and the process is far from understood. In this work we model successfully the kinetics of deactivation for catalysts based on Mordenite and on ZSM5, with Cobalt or Cu as the exchange cations, and show how deactivation relates to changes in the siting of those cations within the zeolites. Spectroscopic measurements and DFT calculations are used to validate the proposed mechanism.