The relation between deactivation of CuZSM-5 in the selective reduction of NO and dealumination of the zeolite

Direct catalytic decomposition of nitric oxide. Final report

“…These results suggest that the presence of Ce and Cu cations in ZSM-5 zeolite stabilizes the crystal structure. Using 27Al-NMR, Grinsted, et a1 [22] observed aluminum stabilization in H-ZSM-5 by Cu cations after the sample had been exposed to a 10% H20-containing gas at 410°C for 113 hours. Effects of cocations on the hydrothermal stability of the zeolite structure are discussed below.…”

Direct synthesis of zeolite coatings on cordierite supports by in situ hydrothermal method

“…As for pure zeolite catalysts, the dealumination process results in changes in acidity and decline in surface area [34,35]. As for ion-exchanged zeolites, the dealumination process can disturb the exchanged cations and then result in a deactivation of active centres [36,37]. By in situ synthesis, the dealumination process of zeolite could be suppressed efficiently and the potential of zeolites might be further developed.…”

Structure Characteristics and NO Selective Catalytic Reduction Property of SnxZr1-xO2 Solid Solution Catalysts

“…Although metal-exchanged zeolitic catalysts have attracted considerable attention since the first report of Cu/ZSM-5 by Iwamoto et al [5] and Held et al [6], their deactivation under hydrothermal conditions due to dealumination from the framework is a problem from a practical viewpoint [7]. Moreover, metal oxide catalysts such as alumina, zirconia and titania also catalyze NO reduction by hydrocarbon quite selectively in the presence of high concentration of oxygen and water vapor [8][9][10].…”