| 摘要 |
PURPOSE: To obtain a catalytic device capable of efficiently removing HC, CO and NOx in exhaust gas while preventing the generation of NH3 due to rhodium. CONSTITUTION: Platinum and cerium are carried on the upper stream side part 2a of a catalyst carrier 2 in the flowing direction of exhaust gas and rhodium is carried on the downstream side part 2b to obtain the objective catalytic device 1. Since O2 storage effect by cerium is satisfactorily produced during passing through the upper stream side part 2a, the fuel-air ratio of exhaust gas reaching the downstream side part 2a is always made close to the theoretical fuel-air ratio. As a result, even when the fuel-air ratio of exhaust gas flowing into the catalytic device 1 shifts to the rich side, the generation of NH3 due to rhodium is inhibited. |
