Three-way Catalyst Concepts with Optimized Low Precious Metal Loadings

The general introduction of three-way catalysts in W-Europe starting in 1992 focusses again the attention of car manufacturers on the costs of the precious metals formulation.

Three strategies to reduce those costs are discussed: 1. the decrease of the platinum/rhodium loading; 2. the replacement of platinum by palladium and 3. the combination of platinum/rhodium with palladium/rhodium catalysts. The results show that under appropriate conditions of use catalysts with about 20 US$/1 precious metal cost could be a valuable automotive emission control tool.