| 摘要 |
PROBLEM TO BE SOLVED: To speed up the recovery treatment of the performance of a catalyst by forming an inside layer to be formed on a high performance catalyst on a first carrier material through adding platinum stacked on a first oxygen occlusion component and forming an outside layer through adding the platinum and rhodium stacked on a second carrier material. SOLUTION: A three-dimensional catalyst to be used for cleaning contaminants such as CO, HC and NOx contained in an exhaust gas from an internal combustion engine, has an inside and an outside layer containing a precious metal of the platinum family stacked on a carrier material, formed on an inactive carrier. In this catalyst, the inside layer is formed on a first carrier material through adding platinum stacked on a first oxygen occlusion component. The outside layer is formed through adding the platinum and rhodium stacked on a second carrier material and at the same time, adding a second oxygen occlusion component. Thus it is possible to speed up the recovery treatment of the catalyst after its aging at a high temperature under lean exhaust gas conditions by forming the double-layer catalyst as described. |
