EXHAUST GAS PURIFYING CATALYST AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To oxidize and decompose HC and CO in exhaust gas of a diesel engine within a low temp. region and to reduce the discharge amt. of PM by suppressing the formation of sulfate within a high temp. region. SOLUTION: This exhaust gas purifying catalyst is constituted by supporting at least one element selected from a rare earth element, alkal metal and alkaline earth metal and a noble metal on a transition metal-containing double-chain structure type clay mineral wherein at least a part of Mg and/or Al constituting double-chain structure type clay mineral at least a part of which is made amorphous is substituted with a transition metal. By supporting at least one of a rare earth element, alkali metal and alkaline earth metal along with a noble metal, the electron state of the noble metal is considered to be changed and the absorbability of HC is enhanced and that of SO2 is lowered.