Exhaust gas purifying catalyst

摘要

An exhaust gas purifying catalyst which is disposed in an exhaust pipe of an internal combustion engine, includes: a substrate; and a catalyst layer, supported in the substrate and including: noble metals including platinum (Pt) and palladium (Pd); a heat-resistant inorganic oxide; and a NOx trapping material. The exhaust gas purifying catalyst adsorbs NOx in an exhaust gas when an exhaust air-fuel ratio is in a lean state and desorbs and reduces the adsorbed NOx when the exhaust air-fuel ratio is in a stoichiometric state or a rich state. (Pt/Pd) which is a ratio of amount of the platinum (Pt) to amount of the palladium (Pd) is 0.7 or more and less than 1.0.