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In this study, we determined the detailed reaction mechanism of CO/NO/O2 for automotive three way catalysts. The N2O formation process obtained from measurements of the reaction properties and the formation process of adsorbed NCO species obtained from surface analysis of platinum group metals were added to a previous detailed surface reaction mechanism. The computational accuracy of the developed reaction mechanism was verified by the one-dimensional simulation software BOOST, and it was found to be sufficient for any combination of platinum group metals and gas concentrations.

It is known that the performance of three-way catalysts (TWC) considerably improves with use of ceria (CeO2) as an oxygen storage component. The effects of CeO2 on TWC activity have been reported in several studies. Observed in this investigation into the optimum CeO2 loading state was that CeO2 impregnation on the surface of washcoat alumina micro pores in the agglomerate form proves the most effective for an enhanced TWC performance. Based on this finding, an effort was made to develop a practical technique that assures CeO2 dispersed in agglomerates over the alumina washcoat. Analyses of CeO2, alumina and noble metal crystal states demonstrated that the resultant double-layered TWC offers significant improvements in catalyst activity.