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

Abstract

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.