A Novel Palladium Catalyst for Use in Vehicle Emissions Control

A ceria stabilised zirconia supported Pd/Zn catalyst (Pd/Zn ratio=1:2) has demonstrated its ability to perform as a three-way catalyst (TWC) and to give conversions of up to 99% of a stoichiometric mixture of carbon monoxide/npropane/nitric oxide/dioxygen in dinitrogen carrier at a WHSV of 44,000 h^-1. The catalyst also exhibits excellent thermal stability inoxidising conditions. Characterisation of the catalyst has been performed using XRD, XPS, BET,and DSC. From this it has emerged that the palladium is in a highly dispersed state, closely associated with the zinc phase. In situ kinetic studies have also been conducted under continuous flow conditions.