PLATINUM-CATALYZED REDUCTION OF NITRIC-OXIDE BY N-BUTANE IN THE PRESENCE OF OXYGEN - ROLE OF THE HYDROCARBON

The mechanism of the catalytic reduction of nitric oxide by n-butane i n an oxidizing atmosphere has been investigated at temperatures from 3 73 to 723 K. The reaction was carried out with a TAP (temporal analysi s of products) reactor on a platinum sponge catalyst. When admitting p ulses of NO alone on a reduced surface until reaching a steady surface coverage, the processes of NO reduction into N-2 and N2O occur on tim e scales noticeable under TAP conditions according to the well accepte d decomposition mechanism. When admitting oxygen and n-butane, the nit ric oxide reduction is promoted: the N-2 yield reached 74% at 633 K co mpared to 6% only when admitting NO alone. The role of the hydrocarbon is not limited to the creation of free sites where NO can adsorb and dissociate. Carbon containing surface species formed during the hydroc arbon combustion increase the NO reduction by direct reaction between NO and these carbon containing species.