Solvothermal synthesis of monodisperse self-assembly CeO2 nanospheres and their enhanced blue-shifting in ultraviolet absorption

Monodisperse CeO2 nanospheres with the average size of 40 nm, self-assembled by well-crystalline CeO2 ultrafine nanoparticles were synthesized through a facile solvothermal route using n-butanol as solvent in the absence of any surfactant or template. The formation process of the monodisperse self-assembly CeO2 nanospheres is briefly discussed. The key function of n-butanol is investigated by comparative experiments. It is found that n-butanol not only serves as solvent, but also acts as surfactant in the formation of monodisperse self-assembly CeO2 nanospheres. Raman and XRD spectra show that the sample is pure cubic fluorite type of structure. Compared to the bulky CeO2 materials, the prepared CeO2 nanospheres exhibited an obvious blue-shifting in UV absorbance. The direct band gap energy of the obtained sample increases by exceeding 10%. Our study provides an effective approach to control CeO2 morphology which has potential application in synthesis of other nanomaterials.