Tuning metal oxide-support interaction and crystal structure of prussian blue derived iron-based oxygen carriers for enhanced chemical looping CO2 conversion.

• Microstructured Fe-based oxides are developed for chemical looping CO 2 conversion. • Metal oxide-support interaction leads to an effect on surface morphology and particle size. • Zr supported oxygen carriers obtain maximum CO space–time yield with limited deactivation. • m-ZrO 2 acted as an active promoter in enhancing CO 2 conversion. • High HCl concentration and PVP addition are beneficial for enhancing redox reactivity. Iron-based oxygen carrier is a promising material for chemical looping CO 2 conversion into value-added chemicals but suffers easy reactivity deactivation. Using self-templated metal–organic framework (MOF) to develop efficient iron-based oxygen carriers is an effective way. However, the effect of metal oxide-support interaction and crystal structure on the reactivity of MOF-derived iron-based materials is still unclear. Toward that end, a series of iron-based oxygen carriers are synthesized via selecting Prussian blue (PB) with different coating types (Al 2 O 3 , MgO, MgAl 2 O 4 , ZrO 2) and synthesis environments (HCl concentration and PVP addition). Isothermal H 2 -CO 2 redox cycles and characterization techniques are applied to interpret the structure-performance relationship. PB-derived Fe-Zr oxygen carrier shows the best activity (0.9 and 24.1 mmo l [ O ] · s - 1 · kg F e 2 O 3 - 1 for reduction and oxidation rates) with limited deactivation. The superior performance originates from: (i) no inactive intermedia formation from interaction between Fe 2 O 3 and ZrO 2 ; (ii) the presence of m-ZrO 2 acted as an active promoter, comparing to other promoters and coprecipitated material, respectively. High HCl concentration and PVP addition are beneficial for enhancing redox reactivity. This study provides a useful way to optimize the interface and structure of MOF-derived oxygen carriers for improving redox activity and stability. [ABSTRACT FROM AUTHOR]