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.

Automated summary

Moderate temperature chemical looping processes can effectively mitigate the sintering and deterioration of oxygen carriers. In this study, co-doping Fe2O3 with La and Sm in CeO2 improved oxygen-ion conduction and increased oxygen capacity, resulting in enhanced CO2-splitting performance at 650 degrees C.