CATALYST FOR PURIFYING EXHAUST GAS AND PURIFYING METHOD OF EXHAUST GAS

摘要

PROBLEM TO BE SOLVED: To moreover improve the durability of NOx purifying capacity by depositing platinum and rhodium separately and also improving the durability of the powder carrying the rhodium. SOLUTION: The catalyst has the constitution in which the first powder carrying rhodium on the compound oxide expressed by MOx.nAl2O3 and the second powder carrying the NOx occluding material selected among alkali metals, alkaline earth metals and rare earth elements and the platinum on porous carrier particles are allowed to coexist. High NOx purifying capacity is manifested even after use at high temp. since the growth of particles of the platinum is suppressed by the rhodium and also the first powder carrying the rhodium on the MOx.nAl2O3 is high in hydrogen production amount after using over a long period of time.