Investigation of redox-cycled Ce-Zr mixed oxides for automotive catalysts by electron microscopy

摘要

High-resolution transmission electron microscopy (HRTEM) has been used to study the structural changes occurring in Ce-Zr mixed oxides on redox cycling.The initial fcc fluorite-type phase is seen to be modified by this redox cycling to give rise to a new phase similar to the original but with apparent 2x2x2 superstructure.Structural models incorporating concerted displacement of anions,catin ordering or both of these phenomena occurring together were constructed.The images simulated using each of these models showed good agreement with the experimental results suggesting that all are possible structures for the new phase.