| abstract |
An exhaust emission control catalyst which is capable ofnexhibiting an excellent NO x converting ability in an excessive-oxygennatmosphere even after being exposed to a high-temperaturenenvironment including oxygen and water vapor. The catalystncontains a crystalline aluminosilicate with a catalytic metalncarried thereon and CeO 2 as the basic forming components. Thencrystalline aluminosilicate has at least one of Mg, Ca, Sr, Ba, Ti,nV, Fe, Zn, Ga, Y, Zr, Mo, In, La, Ce, Nd, Ir, Pb and Sn carriednthereon. The catalytic metal exhibits an oxidizing ability and anreducing ability to an exhaust gas. The crystallinenaluminosilicate has a function of adsorbing HC to concentrate itnand to supply such HC to the catalytic metal. Each of Mg, Ca, Sr,nand Ba has a function of maintaining the function of thencrystalline aluminosilicate, and each of the other metal elementsnhas a function of maintaining the function of the catalytic metal. |