Three-Way Catalyst Performance Using Minimized Rhodium Loadings

The reduction of precious metal usage especially the rhodium content for three-way catalysts application due to limited resources and high precious metal prices seems to be favoured worldwide.

Various platinum-rhodium and palladium-rhodium catalysts with different precious metal loadings and increasing ratios as well as catalysts containing no rhodium, i.e. only platinum-palladium were evaluated. Engine dynamometer sweep data and vehicle tests (US FTP 75) indicated that several catalyst formulations exhibit three-way catalyst performance even after high temperature engine aging and severe laboratory oven air treatment.

Thus, the application of three-way catalysts with improved alumina washcoat technology and reduced loadings of rhodium and platinum seems to be possible.