NOVEL OXYGEN STORAGE COMPONENTS FOR ADVANCED CATALYSTS FOR EMISSION CONTROL IN NATURAL GAS FUELED VEHICLES

摘要

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 as the OSC supported on an inert LaAlO_3 perovskite and a noble metal component supported on a separate high surface area refractory material, for example lanthana stabilized Al_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 CH4 oxidation rates. Durability tests on a physical mixture of Pd-Mn/LaAlO_3 and Pt/Al_2O_3(La) demonstrated that a temperature excursion to 950℃ for a half hour did not cause significant loss in catalyst performance 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 to enhance their performance for NO_x reduction and CO or hydrocarbon oxidation.