Effects of platinum and palladium impregnation on the performance and durability of automobile exhaust oxidizing catalysts

Abstract

The performance and durability properties of noble metal-alumina oxidation catalysts are strongly influenced by the relative location of the metals along the radius of the porous catalyst pellets. Five Pt- and Pd-containing catalysts were prepared by systematically varying the noble-metal distribution along the radius of the catalyst pellets. The catalysts were poisoned on a dynamometer or sintered in a high-temperature furnace. The results showed sizable improvements in both steady-state and light-off performance when the catalyst had an outer shell of Pt and an inner shell of Pd.