Chemical Looping Dry Reforming of Methane: In-Situ Activation of Fe2O3/CeO2 Oxygen Carrier

Chemical looping dry reforming of methane holds great promise for both CO2 utilization and syngas production with high efficiency. The structure and composition of oxygen carriers are critical factors influencing CL-DRM performance. Incorporating CeO2 is known to enhance the reactivity and stability of Fe2O3 in chemical looping reforming. However, the underlying mechanism of how CeO2 synergistically interact with Fe2O3 to enhance performances remains unclear. In this work, we comparatively investigated CeO2-supported Fe2O3 OCs in interfacial and physical Fe–Ce contact modes. We found the sol–gel-synthesized Fe2O3/CeO2 OC is in-situ activated within the first cycle and transforms to pure CeFeO3 through a strong Fe2O3–CeO2 interaction. The activated CeFeO3 achieves over 80% CH4 conversion, 96% CO selectivity, and excellent stability due to the sufficient Fe–Ce interaction, proper valence state, and low-energy barrier for oxygen diffusion. Additionally, in-situ environmental transmission electron microscopy study shows that the Fe2O3–CeO2 interaction promotes the oxygen release of both oxides during reduction. Under the oxidative conditions, iron exhibits significant activity to dissolve into the CeO2 lattice and form CeFeO3. The investigation into the activation mechanism of the Fe2O3/CeO2 material provides valuable insights for designing straightforward and cost-effective OCs.