Ultra low temperature CO and HC oxidation over Cu-based mixed oxides for future automotive applications

Abstract

Advanced combustion technologies offer significant improvement in fuel economy as well as lower NO engine out emissions due to the nature of low temperature combustion; however, the lower exhaust temperature has been a major concern in the removal of hydrocarbon and CO emissions under the future emission regulation. In the present study, we discovered that cerium zirconium mixed oxide containing copper (CZCu) was more active for CO and heavy HC (i.e. C8H10, and C12H26) oxidation at below 130 degrees C than a platinum group metal (PGM)-based alumina catalyst under simulated diesel exhausts including NO and H2O. The CZCu catalyst, however, was relatively inactive for the oxidation of light HC such as C3H6. The CZCu catalyst suffered from significant deactivation upon hydrothermal aging at 750 degrees C, and XRD and DRIFTS suggest that the deactivation could be due to the particle size growth of CuO retarding the formation of carbonyl on Cu upon the hydrothermal treatment. However, with smart integration of CZCu catalyst into the PGM-based catalyst the hybrid catalyst system provides opportunities for cost-effective as well as better performing aftertreatment systems for advanced fuel efficient engines. (C) 2014 Elsevier B.V. All rights reserved.