Catalytic oxidative dehydrogenation of ethane using carbon dioxide as a soft oxidant over Co‐HMS catalysts to ethylene

Abstract In this work, a series of cobalt doped hexagonal mesoporous silica (Co‐HMS) with the different Co content were prepared by direct hydrothermal method and applied to oxidative dehydrogenation (ODH) reaction of ethane with carbon dioxide. Structural and chemical properties of the catalysts were characterized by nitrogen adsorption, X‐ray powder diffraction (XRD), transmission electron microscopy (TEM), electron dispersive spectroscopy (EDS), X‐ray photoelectron spectroscopy (XPS), and Raman and ultraviolet–visible (UV‐vis) spectroscopy. These characterizations showed that cobalt not only entered the framework of Co‐HMS catalysts but also was evenly dispersed in the bulk. The valence state and coordination mode of cobalt played an important role in the whole ODH reaction system of ethane with carbon dioxide. 2% Co‐HMS with dominant Co 2+ had the highest conversion of ethane (26.0%). With the different cobalt content in the catalyst, the proportion of Co 2+ (Td) and Co 2+ (Oh) is also different. 1% Co‐HMS with more Co 2+ (Td) performed the highest ethylene selectivity of 86.7%, which was stable during the 10 h reaction time.