Three-Way Catalytic Converter

WARNING: This page is about a different car, the 2007 Mazda B3000. However, it is still accessible from the selected car via links, so may be relevant.

The three-way catalytic (TWC) converter contains either platinum (Pt) and rhodium (Rh) or palladium (Pd) and rhodium (Rh). The TWC converter catalyzes the oxidation reactions of unburned HCs and CO and the reduction reaction of NOx. The three-way conversion only occurs with the air fuel/ratio near stoichiometry.