Characterization and Optical Properties of Three Dimensional (3D) CeO2 Microstructures Synthesized by a Template-Free Method

Three dimensional (3D) of CeO2 nanostructures such as convex lens-like, hollow triangular prism, broccolilike, grapelike CeO2 have been successfully synthesized by cerium carbonate hydroxide (CeOHCO3) precursors, which were prepared by a hydrolysis process followed by a facile hydrothermal method without using any template or surfactant. The influence of urea amount on CeO2 nanostructures was discussed. The synthesizing mechanism and the morphological evolution of CeOHCO3 and CeO2 were proposed. The CeO2 samples were examined by XRD, SEM, TEM, UV–Vis, PL, and Raman scattering. The UV–Vis absorption spectrum of the CeO2 samples showed that the band gap energy (Eg) in rang of 2.6–2.9 eV, which is lower than that of bulk ceria.