Durability of Palladium Only Three-way Automotive Emisson Control Catalysts

The noble metal palladium (Pd) has the capability of simultaneously converting significant quantities of HC, CO and NO/sub x/ in automotive exhaust. Primary interests in using palladium-containing TWC catalysts are overall noble metal cost reduction, reduction in rhodium usage and important performance advantages. Dynamometer aging experiments comparing palladium and platinum/rhodium catalysts were conducted under a variety of operating conditions. Vehicle evaluation of these aged catalysts under U.S. FTP-75, European ECE-15 and Japan 10-Mode conditions indicate that palladium-only TWC technology is vaiable for achieving high levels of three-way control. Vehicle aging studies (25K miles) were also conducted. The results of these studies are discussed in this work.