Development of Thermally Durable Three-way Catalysts for use in South America

Thermal durability of Pt/Rh and Pd/Rh three-way catalysts has been improved by developing new methods of incorporating ceria into formulations, and by identifying components which enhance stability of the oxygen storage characteristics. This increased thermal durability has allowed vehicle manufacturers to place catalysts nearer to the exhaust manifold, and obtain concomitant reductions in test cycle emissions without compromising catalyst durability. In addition, appropriate incorporation of selected promoters into these formulations has improved the sulfur tolerance of Pd/Rh catalyst technology. These effects are demonstrated by vehicle and bench engine evaluations after high temperature engine ageing.