Cobaltous oxide supported on MFI zeolite as an efficient ethane dehydrogenation catalyst

Cobalt catalysts supported on submicron ZSM-5 with different Si/Al ratio have been prepared and characterized by XRD, N2 adsorption, SEM, MAS NMR, XPS, UV–vis, Py-IR and H2-TPR. They are effective for direct dehydrogenation of ethane to ethylene. HZSM-5 supported catalyst is far more active than NaZSM-5 and SBA-15 supported ones with same Co content. The optimal catalyst exhibited an ethane conversion of 54.5% with 87.8% selectivity to ethylene. The dispersed cobaltous species play a vital role in dehydrogenation, which were formed by in situ reduction of Co3O4 and CoOx species during the initial reaction period. Higher amount of cobaltous species can be obtained on the support having stronger interaction with the loaded Co species, resulting in an enhancement in catalytic activity. The strong interaction can also stabilize the cobaltous species, preventing the over-reduction of cobaltous species to metallic Co during the reaction which leads to deactivation. [Display omitted] •Submicron HZSM-5 supported CoOx exhibited excellent dehydrogenation activity.•Excellent activity comes from strong interaction between support and Co species.•Highly dispersed Co (II) are the active species for dehydrogenation.•Reduction of Co (II) to metallic Co is the prominent cause for deactivation.