Development of Zr Containing TWC Catalysts

Current major concerns m auto exhaust three-way conversion (TWC) catalyst are: 1) improved thermal stability for high temperature applications, such as low emission vehicles (LEV), and 2) high O₂ storage capacity for on-board diagnostic (OBD) systems to meet OBD-2 regulations. These are challenges to catalyst technologies posed by the regulations. Of the many possible approaches, stabilization of Rh and CeO₂ by ZrO₂ shows promise in TWC formulations.

This paper summarizes our investigations of thermally stabilized Zr containing TWC catalysts, including the chemistry of CeO₂ stabilization with ZrO₂, and their OBD-2 characteristics.