KClO3, a strong oxidant, was employed in the template-free hydrothermal synthesis of flower-like CeO2. The structure and physicochemical properties of the samples were characterized via the XRD, N-2 adsorption, FE-SEM, TEM, HRTEM, H-2-TPR techniques. Through a series of experiments, the formation of flower-like CeO2 is strongly dependent on reaction time. Meanwhile, the transformation of two phases (Ce(HCOO)(3) and CeO2) and a possible mechanism for the formation of flower-like CeO2 were preliminarily proposed. The result shows that the H-2 consumption for surface reduction of the flower-like CeO2 sample is significantly higher than the commercial CeO2 sample and the BET surface area of the flower-like ceria nanoparticles is 38.8 m(2)/g, which are benificial to the catalytic reaction. Compared with the commercial CeO2, the as-prepared flower-like CeO2 possesses the better catalytic performance for CO conversion. (C) 2014 Elsevier Ltd. All rights reserved.