DEACTIVATION BY SULFUR-DIOXIDE OF ALUMINA-BASED CATALYSTS FOR SELECTIVE CATALYTIC REDUCTION OF NITROGEN MONOXIDE BY ETHENE

The title reaction over alumina and 5.0 wt% Me (Me: Co, Fe or Cu) adde d alumina catalysts (Me/Al2O3) was investigated in the presence of SO2 . Their NO reduction activities were decreased by SO2 poisoning, depen ding on the kinds of the catalysts. A most strongly poisoned catalyst was Fe/Al2O3, followed by Al2O3, Co/Al2O3, and Cu/Al2O3. The XPS studi es of deactivated Me/Al2O3 catalysts revealed that sulfate-ion like sp ecies were formed on all the catalysts, and moreover, on Fe or Co/Al2O 3, corresponding metal-sulfate like species were also formed. The sele ctive catalytic reduction of NO2 by ethene in the presence of SO2 was also investigated, and some mechanistic discussion was given. (C) 1997 Elsevier Science B.V.