Controlled hydrothermal synthesis and optical properties of 3D hierarchical CeO2 microspheres assembled by many loosened nanocubes

The 3D hierarchical CeO2 microspheres assembled by many loosened nanocubes with a porous structure and an edge length of 300–600 nm have been successfully synthesized via controlling the morphology of CeCO3OH precursors by a simple template-free hydrothermal route. It was found that the CeO2 microspheres have a cubic fluorite structure and there are Ce3+ ions and oxygen vacancies in the surface of the samples. The photoluminescence measurement indicated that the CeO2 samples exhibit excellent optical properties at room temperature and the emission intensity increases with the increase of concentration of oxygen vacancies. There is a red-shifting in the band gap of the material compared to bulk one, which is mainly attributed to the influences of Ce3+ ions, oxygen vacancies and the morphology of samples.