| 摘要 |
PROBLEM TO BE SOLVED: To reduce the exhaust amount of particulates all through a low temperature zone to a high temperature zone by constituting a catalyst formed of specified first carrier powder, specified second carrier powder, a first catalyst metal composed of noble metal and carried on the first carrier powder and a second catalyst metal carried on the first or second carrier powder. SOLUTION: First carrier powder 20 is selected out of TiO2 -SiO2 , ZrO2 -SiO2 and SiO2 . Second carrier powder 21 can be used, provided the adsorptivity of SOF is higher than that of the first carrier powder. As for the carrier, it is desirable to use a carrier selected out of Al2 O3 of particularly high SOF adsorptivity, Al2 O3 , Al2 O3 -TiO2 , Y type zeolite and ZSM-5 type zeolite. As the first catalyst metal 22, noble metal such as Pt, Pd, Rh or Ag can be used, and among other things, Pt of particularly superior oxidation power is used desirably and carried on the first carrier powder. The second catalyst metal 23 is selected from Fe and Ce and carried on the first carrier powder or the second carrier powder. |
