Effect of carbonization temperature on the textural properties of Ce0.8Zr0.2O2 solid solution by an improved citrate sol-gel method

Ce0.8Zr0.2O2 solid solutions were prepared via an improved citrate sol-gel method, in which a carbonization pretreatment in N2 atmosphere at a high temperature was employed prior to the calcination of the citrate precursor in air atmosphere. The effect of carbonization temperature on the textural properties of Ce0.8Zr0.2O2 solid solutions has been investigated, using TG-DSC, Raman, XRD, TEM, SEM and BET techniques. With low carbonization temperature, the Ce0.8Zr0.2O2 oxides in intermediate carbonized mixtures remained in amorphous state, which could eventually agglomerate to large particles with low surface area after subsequent calcination in air atmosphere. In comparison, with high carbonization temperature, thermodynamic force drove Ce0.8Zr0.2O2 oxides to be crystallized into large particles, which would not agglomerate further in oxidation step (carbon removal), thus leading to a material with high surface area and porous structure.