CATALYST FOR PURIFYING EXHAUST GAS AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To enhance NOx purifying performance of a NOx trapping catalyst 5. SOLUTION: This NOx trapping catalyst 5 is obtained by depositing noble metals (Pt and Rh) and NOx trapping materials (Ba, K, Mg and Sr) on a supporting material obtained by mixing alumina particles with Pr6 O11 particles. The catalyst 5 is arranged on an exhausting passage 3 of an engine 1 so that the exhaust gas from the engine 1 is brought into contact with the catalyst 5 when the driving lean in air/fuel ratio and the driving rich in air/fuel ratio are repeated alternately.