| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an absorption and reduction catalyst for removing an NO<SB>x</SB>whose the sintering of the catalyst component is prevented and which is stable with time and exhibits a performance for cleaning an NO<SB>x</SB>at a wide temperature range. <P>SOLUTION: The absorption and reduction catalyst for removing NO<SB>x</SB>comprises a first catalyst having a Pt, Pd and NO<SB>x</SB>absorption material supported on an oxide support and a second catalyst having a Pt, Pd and NO<SB>x</SB>absorption material supported on an oxide support. Preferably, the molar ratio of Pd/(Pt+Pd) in the first catalyst is 0.02-0.2 and the NO<SB>x</SB>absorption material comprises at least one metal selected from Li, K and Ba. The first catalyst is preferably prepared by calcining a solution having a Pt compound and a Pd compound dissolved after impregnating into the oxide support followed by supporting the NO<SB>x</SB>absorption material. <P>COPYRIGHT: (C)2003,JPO |
