The hydrothermal in combination with impregnation methods are used to prepare the CeO2/CuO-X catalysts with spherical structure. The catalysts are characterized via SEM, XRD, H-2-TPR, HRTEM, XPS and N-2 adsorption desorption techniques. The study shows that the microspheres of CuO consist of the sheet-like CuO and the way of arrangement results in the formation of shell structure. There is a core in the middle of shell structure, which is composed of the nano-sized CuO particles. CeO2 particles are supported on the surface of the CuO microspheres or embedded in the pores of sheet-like CuO. It is found that there is another reason for the decrease of CO conversion above 155 degrees C except H-2 competitive oxidation. It is from the change of the CeO2/CuO catalyst during CO-PROX reaction including the reduction of CuO and the separation of metallic copper from the surface of catalyst. (c) 2014 Elsevier B.V. All rights reserved.