A La, Sm co-doped CeO₂ support for Fe₂O₃ to promote chemical looping splitting of CO₂ at moderate temperature

Moderate temperature chemical looping processes can effectively mitigate the sintering and deterioration of oxygen carriers at elevated temperatures (>800 degrees C). However, lower temperatures have a degrading effect on reaction activation and oxygen release and uptake, resulting in slow redox kinetics. In this work, we proposed La, Sm co-doped CeO2 as an active support for Fe2O3 to promote CO2-splitting performance in reverse water-gas shift with chemical looping at 650 degrees C. Characterization demonstrates that La, Sm co-doping improves the oxygen vacancy content of the support materials. Pulse tests demonstrated much-enhanced oxygen-ion conduction, which determines the overall reaction efficiency, in both reduction and reoxidation reactions. In addition, the solid-state reaction between Fe2O3 and CeO2 to form CeFeO3 was suppressed by La, Sm co-doping, thus providing more oxygen capacity for CO2 splitting. As a result, Fe2O3/La0.1Sm0.1Ce0.8O2-delta presents superior CO2 splitting performance with a CO yield of 8.93 mmol g(-1) and an average CO2 splitting rate of 595.6 mu mol g(-1) min(-1). The performance remains stable over 40 cycles. We hope that the results in this work will have an impact on the rational design of oxygen carriers for mid-temperature applications.