Core-shell type ceria zirconia support for platinum and rhodium three way catalysts

摘要

Ceria zirconia support with core-shell structure was investigated as a novel item for platinum and rhodium three way catalysts (TWC). Core-shell type CeO2/ZrO2 nanocomposite support was obtained by precipitation of CeO2 nanoparticle followed by heat treatment at 800 degrees C on pure zirconia surface. A novel support was characterized by X-ray diffraction, Raman spectra, transmission electron microscopy and energy dispersive spectroscopy. The interesting morphology and dispersion were observed for pure CeO2 nanoparticles on pure ZrO2; thus, it can provide a number of active sites, resulting in the total oxygen storage capacity (OSC) value of 2.7 ml/g when Ce/Zr = 1/9. As to supported catalysts, the repeated TPR induced high dispersion and reducibility of Pt and Rh supported on present CeO2/ZrO2 support. The TWC activities of Pt catalyst are enhanced by a designed core-shell type ZrO2/CeO2 support. In addition to enhanced CO oxidation, C3H6 oxidation was promoted immediately to produce intermediate reductant species for NO reduction, resulting in the enhancement of TWC performance. It was confirmed that a new support does not have a negative effect on the TWC of Rh/ZrO2. (C) 2016 Elsevier B.V. All rights reserved.