Patent ID: 8323579

Claim:
An S storage catalyst equipped with: a catalytic supporter; a catalytic metal being supported on the catalytic supporter and oxidizing SO 2 to SO 3 ; and an S storage material being supported on the catalytic supporter and storing S components therein; and wherein: an exhaust-gas-inlet-side high-concentration portion in which said S storage material is supported on said catalytic supporter in a high concentration; and an exhaust-gas-outlet-side low-concentration portion in which said S storage material is supported on said catalytic supporter in a low concentration that is lower than that of the high-concentration portion; wherein a relationship “L”/15≦“L 1 ”<“L”/3 is satisfied, wherein L is an overall length of the S storage catalyst in an exhaust-gas flowing direction, and wherein L 1 is a length of said high-concentration portion in the exhaust-gas flowing direction, and a supporting amount of said S storage material at said high-concentration portion is 0.2-0.4 mol/liter.