CATALYST FOR PURIFICATION OF EXHAUST GAS

摘要

PURPOSE: To efficiently remove NOX in exhaust gas contg. excess oxygen from a diesel engine, etc., over a wide temp. range by using a catalyst consisting of a mordenite type zeolite carrier and Y, etc., and a noble metal carried on the carrier in combination with a reducing agent made of hydrocarbon. CONSTITUTION: A catalyst consisting of a mordenite type zeolite carrier and at least one of Y and La and a noble metal such as Pt carried on the carrier is used in combination with a reducing agent made of hydrocarbon such as light oil. The hydrocarbon such as light oil is adsorbed on the carrier and activated. Since the dispersibility of the noble metal is improved by a porous structure peculiar to the carrier and a moderate acidity, light oil is activated even at a low temp. and an NOX removal reaction is allowed to proceed. At least one of Y and La suppresses the sintering of Pt at the time when thermal load is applied to the catalyst.