Study On Preparation And Performance Of Automotive Three-way Catalyst For Gasoline Engine

In this paper, the catalytic conversions processes of CO, HC and NOx over the automotive three-way catalyst (TWC) for gasoline engine were investigated in a synthetic exhaust mixture, and the results show that NO in exhaust is reduced by both CO in exhaust and CO generated by HC oxidation.The effect of alumina coating materials with different thermal stabilities on the catalytic performance of THC aged was studied. We have found that the TWC prepared with alumina (A-B) with high thermal stability exhibits the excellent performance and thermal stability, after being aged on engine bench for 75 hours, aged for 80,000 km. Comparing with the TWC sample made from foreign country after being aged for 100,000 km, our TWC sample shows better catalytic properties, and its catalytic properties reaches the emission requirement of the Euro-Ⅳ.When alkaline earth Ba is added to the washcoating of TWC, the catalytic performance of TWC catalyst and its NOx storge ability at transient lean-burn condition can be improved obviously,and the catalytic performance will be decreased when Sr is added in the washcoat of TWC. Comparing with the sample prepared with average coating, using zone coating art can decrease the usage amount of Pd when meeting the same emission requirement. It is also found that the ratio of Pd/Rh can affect the conversions of CO, HC and NOx over the TWC.The canning structure of TWC has a great influence on the airflow distribution of the end of the TWC device, thereby affects the catalytic performance of the TWC device for the vehicle emission.