One step hydrothermal synthesis of CeO2–ZrO2 nanocomposites and investigation of the morphological evolution

Abstract

Uniform cauliflower-like and rough nano-spheres of CeO₂–ZrO₂ composites were synthesized by a facile hydrothermal process using only urea as a mineralizer without any surfactant or template. The structural morphologies were found to vary with the reaction time, calcination temperature and dosage of urea and the urea was verified to play an important role in the determination of the CeO₂–ZrO₂ composite nanostructures. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and other techniques. On the basis of the characterizations, it was proven that there existed migrations or movements during the hydrothermal process especially with long hydrothermal time and a possible mechanism was proposed which would go through a series of procedures of nucleation, Ostwald ripening and Kirkendall effect to account for the structural dynamics and morphological evolutions. Subsequently, the hybrid Ce_0.9Zr_0.1O₂–GO was reduced by a hydrothermal method, which showed good adsorption for RhB.