CO₂-assisted oxidative dehydrogenation of ethane to ethylene over the ZnO-ZrO₂ catalyst

The ZnO-ZrO₂ catalyst was prepared by the deposition-precipitation method using ZrO₂ as the carrier obtained from calcining commercial zirconium hydroxide (Zr(OH)₄). And the catalytic performance was evaluated at 873 K in CO₂-assisted ethane oxidative dehydrogenation reaction (CO₂-ODHE). The physical-chemical properties and morphology were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectra, High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectra (XPS), CO₂ temperature-programmed desorption (CO₂-TPD). The results show that ZnO were doped into the surface lattice of ZrO₂ on the 5%ZnO-ZrO₂ catalyst, generating highly dispersed ZnO species and oxygen-deficient regions on catalyst surface. 5%ZnO-ZrO₂ catalyst could selectively breaking C−H bond instead of C−C bond, delivering excellent catalytic performance. 210 μmol/(g_cat·min) of C₂H₄ formation rate could compare favorably with the data reported on noble metal and transition metal carbides. Additionally, the possible mechanism is discussed.