Development of High Performance Three-Way-Catalyst

-Technology to Lower NOx Emission-

Abstract

A subject of reducing the PGM applied on a catalytic converter is a decline in its NOx conversion efficiency. This paper investigates the primary factor of this decline to be HC poisoning. To maintain higher NOx conversion efficiency as the PGM reduces, the Rh activation improvement becomes significant, overcoming the HC poisoning. As analysis conducted on Rh deterioration mechanism, it is effective to separately arrange Rh and CeO2 on the converter, improving the Rh activation. By this improvement, we confirmed a reduction effect more than 25% of Rh loading.