| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a catalyst for cleaning an automobile exhaust gas capable of giving high Nox purification performance even after enduring under A/F fluctuation condition. <P>SOLUTION: In the catalyst for cleaning an automobile exhaust gas including a catalyst layer (hereafter abbreviated as a catalyst layer A in some cases) including Rh, Pd or Pt as noble metals in the upstream side of the exhaust gas flow direction, and a catalyst layer (hereafter abbreviated as a catalyst layer B in some cases) including only Rh as a noble metal in the downstream side are each provided on a base material. The proportion (L<SB POS="POST">B</SB>/L<SB POS="POST">S</SB>) of a coating length (hereafter abbreviated as L<SB POS="POST">B</SB>in some cases) from a downstream end part of the catalyst layer B with respect to a total length (hereafter abbreviated as Ls in some cases) of the base material flow direction is 50 to 90%, and the proportion of an amount of Rh contained in the catalyst layer B with respect to a total amount of Rh contained in the catalyst layer A and the second catalyst layer B is 50 to 90 mass%, and the rest of Rh is contained together with Pd or Pt in the catalyst layer A. <P>COPYRIGHT: (C)2012,JPO&INPIT |
