Hydrothermal synthesis and catalytic performance of high-surface-area mesoporous nanocrystallite MgAl2O4 as catalyst support

MgAl2O4 was respectively synthesized by the hydrothermal method (MgAl2O4-HT) and the co-precipitation 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), N2 isothermal adsorption–desorption, transmission electron microscopy (TEM) and H2 temperature-programmed reduction (H2-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 (SBET = 230.6 m2 g−1) mesostructure (Dpore = 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.