The relation of structure and metal-support interaction with three-way catalytic performance of Rh/(Ce,Zr,La)O2 catalysts.

Abstract

(Ce,Zr,La)O2 (CZL) mixed oxide-supported rhodium (Rh) catalysts were prepared by in situ synthesis method. Characterizations were adopted to investigate the relation of structure and metal-support interaction with catalytic behavior of catalysts. The results demonstrate that appropriate Ce/Zr ratio (2/1~1/4) could help to form more homogenous CZL ternary solid solution and promote the formation of more oxygen vacancies and defects (the lattice defects resulting from lattice distortion) in CZL supports, and thereby enhance oxygen storage/release performance. Meanwhile, it strongly affects the interaction between RhOx and CZL supports, which promotes the formation of more active Rh species (Rh0 + Rh3+) and the reduction of the oxygen species in Rh-Ce interface, leading to the enhancement of catalytic performance for HC, CO, and NOx eliminations. Rh/CZL-12 shows the best catalytic activity for HC and NOx eliminations. It could be attributed to the enhanced activation and oxygen mobility of lattice oxygen, which is verified by the results of DOSC measurement.