INFRARED STUDY OF CATALYTIC REDUCTION OF LEAN NOX WITH ALCOHOLS OVER ALUMINA-SUPPORTED SILVER CATALYST

Two intense IR absorption bands due to surface isocyanate (-NCO) speci es have been observed at 2262 and 2232 cm(-1) when an alumina-supporte d silver catalyst is exposed to a mixture of NO, O-2 and ethanol at 15 0 degrees C and subsequently heated to > 300 degrees C in vacuum. The intensity of the isocyanate band is hardly affected by the water exist ing in the mixture. Methanol is less reactive than ethanol for the for mation of isocyanate species. The reaction mechanism of catalytic redu ction of lean NOx with alcohols is discussed based on these IR spectro scopic findings.