Redox properties and catalytic performance of ceria-zirconia nanorods

The redox properties and catalytic performance of Ce1-xZrxO2 (0 <= x <= 0.2) nanorods, mainly exposing {110} and {100} planes, were comparatively examined with spherical Ce1-xZrxO2 nanoparticles that predominantly exposed {111} planes. The CeO2 nanorods had a superior redox property and much higher activity towards CO oxidation than the CeO2 nanoparticles, primarily because of the preferential exposure of the reactive {110} planes. However, this shape effect was weakened considerably in Ce1-xZrxO2 (x = 0.05-0.20) nanomaterials. ZrO2-doping promoted the reducibility of the nanoparticles more signifciantly than that of the nanorods, involving different rate-determining steps in the reduction process. The activity for CO oxidation enhanced with increasing ZrO2 content on the nanoparticles but decreased over the nanorods. These results demonstrate that the shape effect of Ce1-xZrxO2 nanomaterials is associated with the amount of zirconia that is incorporated into the ceria lattice.