In situ generation of the spinel structured FeCr2O4 catalyst for CO2-assisted ethane oxidative dehydrogenation

Abstract

Ethylene (C₂H₄) is a crucial raw material for the chemical industry. Recently, the oxidative dehydrogenation of ethane (C₂H₆) using CO₂ as a milder oxidant (CO₂-ODHE) has been proposed as a potential method for C₂H₄ production through the efficient utilization of shale gas and the mitigation of CO₂ emissions. In this work, a series of Fe, Cr–Fe, and Cr oxides were prepared by a two-step urea precipitation method with Fe₃O₄, FeCr₂O₄, and Cr₂O₃ components, in which the Cr–Fe catalyst exhibits better activity with the conversion of ethane (35%) and CO₂ (27%) and stable C₂H₄ yield (18%) at 650 °C. Through TEM, SEM, Raman, XAFS and in situ XRD results, it was found that the in situ formation of FeCr₂O₄ during the CO₂-ODHE reaction can enhance the thermostability of the Cr–Fe catalyst. Furthermore, the generated FeCr₂O₄ effectively adsorbs and activates CO₂ molecules to reduce the generation of deposited carbon on the surface of the Cr–Fe catalyst.