Patent ID: 6395675
Filing Date: 2002-05-28
Classification: B01D,B01J,Y02T

Abstract:
A catalyst system for purifying an exhaust gas, said catalyst system comprising a first catalyst for purifying a NOx of the exhaust gas, said first catalyst comprising:a first powder comprising a porous carrier and a noble metal loaded on said porous carrier, said noble metal being selected from the group consisting of platinum, palladium and rhodium; and a second powder comprising a first double oxide represented by the following general formula (1): (Ln1-&agr;A&agr;)1-&bgr;BO&dgr;â€ƒâ€ƒ(1) where &agr; is a number that is greater than 0 and less than 1, &bgr; is a number that is greater than 0 and less than 1, &dgr; is a number that is greater than 0, Ln is a first element selected from the group consisting of La, Ce, Nd and Sm, A is a second element selected from the group consisting of Mg, Ca, Sr, Ba, Na, K and Cs, and B is a third element selected from the group consisting of Fe, Co, Ni and Mn,wherein each of said first and second powders has an average particle diameter of not greater than 4 &mgr;m.