Nano-Ce O2 hollow spheres were synthesized via a two-step process. The precursor was synthesized by template-free solvothermal method at 160 ℃ using ethylene glycol and deionized water as solvent. Then it was calcinated at 500 ℃ for 1 h in the air to produce nano-Ce O_2 hollow spheres. The physical and chemical properties of the precursor and the sample were researched by X-ray diffraction( XRD),scanning electron microscope( SEM) and transmission electron microscope( TEM). The sample after calcination conta...