Novel oxygen storage components for advanced catalysts for emission control in natural gas fueled vehicles

Abstract

Advanced catalysts based on a novel oxygen storage component (OSC) were developed for emission control in natural gas fueled vehicles. The catalysts contain a manganese oxide (MnO x ) as the OSC supported on an inert LaA1O 3 perovskite and a noble metal component (Pd) supported on a separate high surface area refractory material, for example lanthana stabilized A1 2O 3. The MnO x has higher oxygen storage capacity, and faster oxygen absorption and oxide reduction rates than the present commercial ceria-stabilized alumina support materials. Temperature programmed techniques and dynamic cycled experiments were used to measure oxygen storage capacity, activity for NO reduction and CO and CH 4 oxidation rates. Durability tests on a physical mixture of Pd-Mn/LaAlO 3 and Pt/A1 2O 3(La) demonstrated that a temperature excursion to 950°C for 30 min did not cause significant loss in catalyst activity for either NO reduction or CO or CH 4 oxidation. We have also shown that the MnO X can be added to conventional three-way catalysts (TWC) to enhance their performance for NO x reduction and CO or hydrocarbon oxidation.