HONEYCOMB STRUCTURE-TYPE CATALYST FOR PURIFYING EXHAUST GAS EXHAUSTED FROM AUTOMOBILE, METHOD FOR PRODUCING THE SAME AND METHOD FOR PURIFYING EXHAUST GAS USING THE SAME CATALYST

摘要

A catalyst for purifying exhaust gas, which is a relatively cheap three-way-catalyst containing noble metal components, and is capable of suppressing sintering of the noble metals even at high temperature, and purifying a carbon monoxide (CO), a hydrocarbon (HC) and a nitrogen oxide (NOx), and is superior, in particular, in purifying the nitrogen oxide, along with a method for purifying exhaust gas. This catalyst is provided by a honeycomb structure-type catalyst having a carrier made of a honeycomb-type structure, coated with a catalyst composition in two or more layers, for purifying a carbon monoxide, a hydrocarbon and a nitrogen oxide contained in exhaust gas, characterized in that; a catalyst layer (A) at the upper layer side comprises a palladium component supported with a heat resistant inorganic oxide, an oxygen storage release material and a barium component, and a catalyst layer (B) at the lower layer side comprises a rhodium component supported with a cerium-zirconium-type composite oxide having a cerium/zirconium ratio by weight of 0.05 to 0.2, as converted to an oxide, or the like.