EXHAUST GAS PURIFYING CATALYST AND EXHAUST GAS PURIFYING METHOD

PROBLEM TO BE SOLVED: To provide an exhaust gas purifying catalyst showing NOx occuluding capacity within a reaction temp. region of 250-650 deg.C even after a high temp. durability test and being suppressed in the lowering of NOx purifying capacity even in SOx-containing exhaust gas. SOLUTION: An exhaust purifying catalyst includes a carrier consisting of first double oxide represented by MgO-Al2O3 and second double oxide represented by TiO2-ZrO2, an NOx occluding element containing at least Na and Ba supported on the carrier and a noble metal supported on the carrier. MgO-Al2O3 double oxide is low in the reactivity with NOx occuluding element as compared with alumina and TiO2-ZrO2 double oxide is low in the reactivity with the NOx occuluding element as compared with TiO2 and Na does not generate double sulfate by the reaction with Mg liberated from double oxide and SOx and Ba is excellent in NOx occluding capacity within a low temp. region and, therefore, this catalyst can maintain high NOx purifying capacity even after a durability test.