Microstructured ZrO2 coating of iron oxide for enhanced CO2 conversion

Abstract This work provides a way to design oxygen carriers for chemical looping. Starting from Prussian blue microcubes, Zr-promoted Fe-based materials are developed for the conversion of CO2 into CO. Thermally induced oxidative decomposition of ZrO2-coated Prussian blue under the protection of the firstly formed ZrO2 shell leads to the formation of hollow structured materials. Detailed activity tests and in-situ characterization are used to investigate the relationship between material structure, stability and CO yield from CO2 conversion. Throughout one hundred H2-CO2 redox cycles, 10 %Fe2O3/ZrO2 exhibits a 27 times higher CO space-time yield ( 86 m m o l ∙ s - 1 ∙ k g F e 2 O 3 - 1 ) than unpromoted, yet hollow structured Fe2O3. This superior performance derives from the dual role that ZrO2 plays: protecting the structure, thereby improving the iron oxide sintering resistance, and facilitating the reduction of iron oxide during redox cycles. The hollow structure and the interaction between Fe2O3 and ZrO2 are the main reasons for the enhanced redox activity.