| abstract |
Catalytic traps effective for the conversion of NO x in the exhaust gas stream are inert to high temperature reactions of basic oxygenated compounds of lithium, sodium or potassium. The catalyst trap may be substantially free of the silica component, the catalyst trap material comprising a refractory metal oxide support such as alumina, and a catalyst component such as a platinum group metal catalyst component dispersed thereon, and at least one NO x adsorbents consisting of basic oxygenated compounds. The catalyst trap material is coated on a suitable carrier component such as made from stainless steel, titanium, alumina, titania, zirconia, or silica-leached cordierite. Treatment of the gas stream method containing NO x is NO x that during the step, and the gas stream that maintains the shift period for the said gas stream (1) a lean condition, and (2) rich or stoichiometric conditions, lean operation period Contacting the catalyst trap under conditions that are adsorbed and released during the enrichment run and reduced to nitrogen. |