The dynamic of surface phenomena on a Pt(1%)/A12O3 catalyst for the reduction of NO by propene/O2 has been studied by in situ DRIFT experiments and parallel transient reactivity data using the RWF (Rectangular WaveFront) method. The results indicate that NO strongly chemisorbs over Pt oxidized surface and this inhibits Pt reactivity towards hydrocarbon oxidation, but then progressively migrates over alumina surface from which can desorb as NO2. At the temperature of maximum activity in the reduction of NO, the rate of migration is slow and thus the hydrocarbon reacts with the nitrogen oxide adsorbed species over the metal surface, whereas at higher temperature the rate of migration is faster leaving free oxidized metal surface for hydrocarbon combustion.
The surface migration of NOx adspecies as a factor determining the reactivity of supported Pt catalysts for the treatment of lean burn engine emissions
CENTI, Gabriele;
2000-01-01
Abstract
The dynamic of surface phenomena on a Pt(1%)/A12O3 catalyst for the reduction of NO by propene/O2 has been studied by in situ DRIFT experiments and parallel transient reactivity data using the RWF (Rectangular WaveFront) method. The results indicate that NO strongly chemisorbs over Pt oxidized surface and this inhibits Pt reactivity towards hydrocarbon oxidation, but then progressively migrates over alumina surface from which can desorb as NO2. At the temperature of maximum activity in the reduction of NO, the rate of migration is slow and thus the hydrocarbon reacts with the nitrogen oxide adsorbed species over the metal surface, whereas at higher temperature the rate of migration is faster leaving free oxidized metal surface for hydrocarbon combustion.Pubblicazioni consigliate
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