In-situ generation of the spinel structural 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 are 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 the FeCr2O4 during the CO2-ODHE reaction can enhance the thermostability of the Cr-Fe catalyst. Furthermore, the unique weak basicity of FeCr2O4 effectively adsorbs and activates CO2 molecules to reduce the generation of deposited carbon on the surface of the Cr-Fe catalyst.