MgAl2O4 was respectively synthesized by the hydrothermal method (MgAl2O4-HT) and the coprecipitation method (MgAl2O4-CP). The as-synthesized MgAl2O4 was used as support to prepare CoOx/MgAl2O4 catalyst for oxidative dehydrogenation of ethane (ODE) with CO2. The properties of these samples were characterized by X-ray diffraction (XRD), N-2 isothermal adsorption-desorption, transmission electron microscopy (TEM) and H-2 temperature-programmed reduction (H-2-TPR) techniques. In addition, the catalytic performance of these samples in ODE with CO2 was comparatively investigated. Comparing with MgAl2O4-CP, MgAl2O4-HT is high-surface-area (S-BET = 230.6 m(2) g(-1)) mesostructure (D-pore = 5 nm) nanocrystallite (ca. 10 nm) MgAl2O4 spinel. MgAl2O4-HT as support can supply a large quantity of reducible active sites on the catalyst and enhance the diffusion of reactant and product in the reaction. Therefore, CoOx/MgAl2O4-HT exhibited the stronger reducible property and the higher catalytic activity as well as the lower apparent activity energy in ODE with CO2 than CoOx/MgAl2O4-CP. (C) 2009 Elsevier B.V. All rights reserved.