Template-free hydrothermal synthesis and excellent optical performances of monodisperse tyre-like CeO2 hollow nanostructures with rugged surface

The monodisperse tyre-like CeO2 hollow nanostructures with a diameter of 300-800 nm have been synthesized via a simple hydrothermal technology. Numerous spherical nanoparticles with a diameter of about 50 nm randomly attach on the outline of the tyre-like nanostructures to form the rugged surface. XRD, SEM, TEM, XPS, Raman scattering and UV-vis spectrum were employed to characterize the samples. The results showed that the tyre-like CeO2 hollow nanostructures have a cubic fluorite structure of CeO2 with no crystalline impurity phase and there are Ce3+ ions and oxygen vacancies in its surface. It was also found that there is a red-shifting in the band gap of the tyre-like CeO2 hollow nanostructures compared to bulk one, which is mainly attributed to the influences of the morphology of samples, size of particles, and the amount of Ce3+ ions and oxygen vacancies.