Controllable synthesis of Ce1 − xZrxO2 hollow nanospheres via supercritical anti-solvent precipitation

Nanocrystalline Ce1-xZrxO2 hollow nanospheres were successfully synthesized via supercritical anti-solvent precipitation using supercritical CO2 as the anti-solvent. It was found that the as-produced samples exhibited hollow spherical structures with uniform diameters ranging from 30 to 50 nm and the sphere walls were composed of various oriented nanocrystallites, with sizes of 3-7 nm. The results of high-resolution transmission electron microscopy showed that the formation of the hollow structures could be controlled by adjusting the solution concentration. The results of temperature-programmed reduction and oxygen storage capacity measurements showed that the hollow nanospheres had enhanced redox properties. A possible mechanism for the formation of Ce1-xZrxO2 hollow nanospheres has also been proposed and experimental investigated.