A Study on Three Way Conversion Catalyst Thermal Deactivation and improvement

A study was made into thermal deactivation of Pt/Rh/Ce three way conversion (TWC) catalyst by the use of aging engines, as well as the changes in catalytic properties developed by thermal deactivation. As a result, crystallization of Pt and CeO₂ and the accompanied decrease in O₂ storage capacity were found as factors resulting from the thermal deactivation.

To minimize the thermal deactivation of the catalyst, CeO₂ became a focus of the study and a method to inhibit CeO₂ crystallization was pursued. The results of engine high temperature durability testing on improved catalysts employing the new technique confirmed inhibition effects of thermal deactivation.

The study successfully resulted in a new TWC catalyst minimizing thermal deactivation.