| 摘要 |
PROBLEM TO BE SOLVED: To suppress generation of SO3 and sulfate while oxidizing and decomposing performances of SOF, HC, etc., within a low temperature range are kept at least equivalent to conventional ones. SOLUTION: A catalytic noble metal is supported containing fine particles 3 of at most 5nm mean particle size on an upper stream side of an exhaust gas flow. On a down stream side the catalytic noble metal is supported as a coarse particle 4 of at least 10nm mean particle size, and SO2 is further difficult to be oxidized than HC. Therefore, HC is selectively oxidized on the upper stream side, and oxidation of SO2 is delayed on the down stream side, and so, generation of SO3 and sulfate are suppressed. |
