Cu-ZSM-5 zeolite highly active in reduction of NO with decane

The effect of framework aluminum content and local density on the NOx reduction with decane under lean burn conditions, i.e. in high excess of oxygen and water vapor (12%) over Cu-ZSM-5 zeolites with various Cu/Al and Si/Al ratios was investigated. The concentration of “Al pairs” located in one ring and balanced by divalent cations was estimated using divalent cobalt ions as probes. The portion of Cu ions located in vicinity of “Al pairs” or adjacent to a single framework AlO2− entity was monitored by vis–NIR spectra of Cu2+ ions. The most active and stable Cu ions in C10H22-SCR-NOx under lean burn conditions appeared to be those located in vicinity of two Al atoms in one ring coordinated the cation.