Tailoring active lattice oxygen in CeO2-Based oxygen carriers for enhanced chemical looping dry reforming of methane

In this work, we highlight the significance of tailoring lattice oxygen activity through controlled morphologies of CeO₂-based oxygen carriers for achieving enhanced performance in chemical looping dry reforming of methane (CL-DRM). By combining physical-chemical characterizations (Raman and X-ray photoelectron spectroscoy) and density functional theory (DFT) calculations, we demonstrate that the bulk oxygen mobility, surface oxygen reactivity, and methane activation ability strongly depend on the morphology of CeO₂. Notably, Pd/CeO₂-Rod (Pd/CeO₂-R), which has a unique (110) crystal surface, had the highest CH₄ conversion (66 %) and exceptional syngas yields ∼1.7 and 3 times greater than those of Pd/CeO₂-Cube (Pd/CeO₂-C) and Pd/CeO₂-Octahedron (Pd/CeO₂-O), respectively, while maintaining high CO yields during the CO₂ splitting step at 550 °C. These results underscore the feasibility and importance of tailoring the active lattice oxygen in Ce-based oxygen carriers for optimizing chemical looping processes through morphology modulation.