| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust gas purification catalyst having a high NOx purification ratio in a wide cleaning temperature region, especially a low temperature region and capable of efficiently purifying not only NOx in an oxygen excessive region discharged from an internal combustion engine but also CO and HC even if an exhaust gas is in a low temperature region. <P>SOLUTION: An inner layer containing an NOx adsorbent for adsorbing NOx in an exhaust gas and a surface layer comprising an NOx purification layer for reducing and purifying NOx discharged from the NOx adsorbent of the inner layer are provided. An isolation means, which comprises a heat-resistant porous inorganic material and temporarily holds NOx discharged from the inner layer to delay the arrival thereof to the surface layer, is interposed between the inner and outer layers. <P>COPYRIGHT: (C)2004,JPO |
