Surface, structural and morphological characterization of nanocrystalline ceria-zirconia mixed oxides upon thermal aging

摘要

The effect of thermal aging on the physico-chemical properties of Ce-Zr oxides, as a function of Ce/Zr molar ratio, has been studied from the point of view of their application as catalytic nanomaterial. Homogeneous in size dimension and morphology, nanosized, single phase Ce-Zr solid solutions with various compositions were synthesized by the sol-gel like method. Upon thermal aging, important modifications of the textural and structural properties, which apparently create a strong effect on their catalytic performance, were observed. Their specific activity was found to be dependent on Ce/Zr molar ratio with the maximum observed over Ce_(0.75)Zr_(0.25)O2. Higher surface area, smaller particles, lower amount of particles agglomerates as well as higher amount of crystal faces, edges, and corners generate better catalytic activity, especially as long as cubic symmetry of mixed oxides was maintained.