Low temperature CO2 conversion facilitated by the preserved morphology of metal oxide-perovskite composite

Abstract

This work addresses the effect of incorporating a small portion of LaFeO3 into Fe2O3 on CO2 splitting in reverse water-gas shift chemical looping. Bare Fe2O3 suffers deactivation due to the structural change from sintering and agglomeration as the reaction progresses. The applied LaFeO3 perovskite acts as a sintering barrier between metal oxides, blocking the transport of metallic cations between adjacent particles and alleviating the Kirkendall effect by changing the direction of oxide growth. As a result, the structural deformation can be prevented, allowing sustainable CO2 conversion. In addition, the electrical conductivity of the particles is increased with the addition of the perovskite, and the conduction of the oxygen anions is improved accordingly. Therefore, Fe2O3-LaFeO3 demonstrates both enhanced CO yield and stability at the same time. It presents the highest CO yield (12.1 mmol/gcat) and CO production rate (605 μmol/gcat/min) for 50 redox cycles reported to date at 750 K.