Tailoring active lattice oxygen in CeO2-Based oxygen carriers for enhanced chemical looping dry reforming of methane
Yanhui Long, Linggen Gao, Na Yang, Ang Cao, Yilin Zhang, Wee‐Liat Ong, Xiaodong Li, Xin Tu, Hao Zhang, Jianhua Yan
Abstract
In this work, we highlight the significance of tailoring lattice oxygen activity through controlled morphologies of CeO 2 -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 CeO 2 . Notably, Pd/CeO 2 -Rod (Pd/CeO 2 -R), which has a unique (110) crystal surface, had the highest CH 4 conversion (66 %) and exceptional syngas yields ∼1.7 and 3 times greater than those of Pd/CeO 2 -Cube (Pd/CeO 2 -C) and Pd/CeO 2 -Octahedron (Pd/CeO 2 -O), respectively, while maintaining high CO yields during the CO 2 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. • The morphological-performance relationship of ceria on CL-DRM was systemically investigated. • Pd/CeO 2 -Rod with unique (110) crystal surface achieves the highest CH 4 conversion and syngas yield among different morphologies. • Pd/CeO 2 -Rod possesses the strongest bulk oxygen mobility and surface oxygen reactivity. • Pd 4 /CeO 2 -(110) is demonstrated to favor CH 4 decomposition.