Regulation of catalytic reaction performance of CO2 with ethane by metal cation substitution on CeO2 support

Abstract

The catalytic reaction of CO2 with ethane balances the resourceful conversion of CO2 and the value-added utilization of shale gas. In this paper, the effects of different metal cation substitutions on CeO2 support in Fe-Ni catalysts on the regulation of CO2 and ethane directional catalytic reaction performance were studied through experiments combined with DFT calculation simulations. It was found that the Ti-substituted Fe1.5Ni0.5/CeTi-2 catalyst had the highest ethane conversion of 11.8% and CO2 conversion of 21.2%, and presented a high-value product C2H4 selectivity higher than 80%. The Ti/La species in the substituted structure are highly dispersed into the CeO2 lattice to form a Ti/LaxCe1-xO2−δ solid solution, which induces more (-111) and (110) crystal planes with high ethylene selectivity. The Ti-substituted catalyst has the highest proportion of Ce3+, which improves the formation and transfer of active oxygen, making Fe1.5Ni0.5/CeTi-C-2 exhibit higher catalytic reactivity. The substitution of metal cations weakens the adjacent Ce-O bond strength, and the Ti substitution structure facilitates the generation of Ov as a highly active center for CO2 reduction, resulting in a decrease of the energy barrier for the CO2 dissociation process from 3.87 eV on pristine CeO2(111) to 2.17 eV, and the reaction energy endotherm is 1.03 eV. Both kinetically and thermodynamically, the reduction dissociation of CO2 on Ti-CeO2(111) is more competitive than that on Zr and La-substituted CeO2(111).