Photocatalytic degradation mechanisms of self-assembled rose-flower-like CeO2 hierarchical nanostructures

Hierarchical rose-flower-like CeO2 nanostructures were formed by using solvothermal and thermal annealing processes. The CeCO3OH thin film was transformed into CeO2 roses due to thermal annealing. CeO2 nanostructured roses exhibited excellent photocatalytic activity with a degradation rate of 65% for the azo dye acid orange 7 (AO7) under ultraviolet illumination. The fitting of the absorbance maximum versus time showed that the degradation of AO7 obeyed pseudo-first-order reaction kinetics. The enhancement of the photocatalytic activity for the CeO2 roses was attributed to the high adsorptivity resulting from the surface active sites and special 4f electron configuration.