Morphology-Tuneable Synthesis and Magnetic Performances of CeO₂ Hollow Nanospheres Fabricated by a Simple Template-Free Hydrothermal Method

The large-scale uniform CeO₂ hollow nanospheres with a diameter of about 200–300 nm were fabricated by a facile template-free hydrothermal method using Ce(NO₃)₃ ⋅6H₂O as cerium source, NH₄HCO₃ as precipitator, and ethanediamine as surfactant. X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS), and Raman spectrum showed that the CeO₂ hollow nanospheres with no crystalline impurity phase have a cubic fluorite structure, and many Ce³⁺ ions and oxygen vacancies exist in its surface. The magnetic measurements show that the CeO₂ hollow nanospheres have excellent room temperature ferromagnetism while its precursors exhibit paramagnetism The dominating influences on RTFM may be assigned to the morphology and size of obtained CeO₂ samples.