Isocyanate Intermediates in Ammonia Formation over Noble Metal Catalysts for Automobile Exhaust Reactions

Isocyanate species have been detected on the surface of noble metal catalysts during the reactions of carbon monoxide with nitric oxide. The intensity of the surface isocyanate infrared band correlates with the known ammonia-forming tendencies among the noble metals. The discovery of this isocyanate species suggests a new mechanistic pathway to the ammonia formed during catalytic reduction of nitrogen oxides in automobile exhaust.