Controlled hydrothermal synthesis and optical properties of 3D flower-like CeO2 building with 3D hierarchical porous structure

The beautiful 3D flower-like CeO2 building with 3D hierarchical porous structure has been successfully synthesized via a facile hydrothermal method. The XRD results indicate that all the samples have a cubic fluorite structure of CeO2 with no crystalline impurity phase. The SEM images display that the building blocks of 3D flower-like CeO2 change from 3D shuttle-like hierarchical porous structure to 3D bundle-like hierarchical structure, then to spindle-shape nanorods with the increase of the amount of NH4HCO3. XPS and Raman analyses indicate that there are Ce3+ ions and oxygen vacancies in the surface of samples. Ce3+ ions and oxygen vacancies may account for the similar room temperature photoluminescence emission peaks of all samples. Their PL intensity is different from each other, which can be attributed to the influence of different morphology and size of the samples.