| 摘要 |
PROBLEM TO BE SOLVED: To enhance NOx cleaning capacity under a lea atmosphere and to sufficiently develop the function as a ternary catalyst by adding at least one noble metal selected from the group consisting of platinum, palladium and rhodium and composite oxide represented by a specific formula. SOLUTION: An exhaust gas cleaning catalyst contains at least one noble metal selected from the group consisting of platinum, palladium and rhodium and composite oxide represented by the formula LnαZr1-αOx (wherein α is 0.4<α<0.9, x is an oxygen amt. satisfying valencies of respective atoms and Ln is at least one element selected from the group consisting of La, Pr and Nd). Composite oxide to be used contains a rare earth metal and a transition metal and avoids the compounding of a rare earth metal with alumina and facilitates the adsorption of NOx even after endurance and utilizes characteristics absorbing NOx in a lean atmosphere to enhance NOx cleaning capacity. |
