An exhaust purification method and exhaust gas purification catalyst device

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PROBLEM TO BE SOLVED : To purify not only HC(hydrocarbon) and CO(carbon monoxide) but also PM(a particle-like material) in an exhaust emission control technology using a catalyst. SOLUTION : A wash coat layer 14b composed of a porous material having pores having a diameter of 0.7 to 300 nm is formed on a surface of a base body 14a of a catalyst carrier 14 interposed in an exhaust passage of an internal combustion engine, and noble metal (for example, platinum Pt) as an active ingredient and rare earth metal (for example, cerium Ce) as an adding ingredient are dispersively carried on the porous material. With such constitution, the PM having the particle size of around 100 nm included in exhaust gas is trapped in the pores of the porous material, and is restrained from being exhausted still in an unpurified state. The PM trapped in the porous material is oxidized by the noble metal and the rare earth metal carried on the porous material. Thus, trapping and oxidation of the PM are repeated so that the PM can be purified by the catalyst.