Advancing the Understanding of Oxygen Vacancies in Ceria: Insights into Their Formation, Behavior, and Catalytic Roles

Oxygen vacancies (OV's) in ceria (CeO2) are critical structural and electronic features that underpin ceria's remarkable oxygen storage capacity, redox catalytic performance, and wide-ranging applications in catalysis, solid oxide fuel cells, and gas sensors. These vacancies, which result from the removal of oxygen atoms, enable dynamic oxygen exchange between the solid and its environment, profoundly influencing ceria's catalytic properties. The intricate surface structures of ceria play a key role in determining its properties and its interactions with supported metal catalysts. Over the past decade, advancements in state-of-the-art in situ characterizations, first-principles calculations, and emerging machine learning frameworks have significantly enhanced our understanding of the formation mechanisms, behaviors, and catalytic roles of OV's. This perspective highlights recent experimental and theoretical progress in ceria surface research, emphasizing the dynamic interplay between surface structures and reactive environments. Additionally, the perspective addresses key challenges in elucidating ceria's defect chemistry and explores opportunities to tailor its properties using multiscale modeling and AI-driven methodologies.

Effects of Subsurface Oxide on Cu1/CeO2 Single-Atom Catalysts for CO Oxidation: A Theoretical Investigation

Supported atomic dispersion metals are of great interest, and the interfacial effect between isolated metal atoms and supports is crucial in heterogeneous catalysis. Herein, the behavior of single-atom Cu catalysts dispersed on CeO₂ (100), (110), and (111) surfaces has been studied by DFT + U calculations. The interactions between ceria crystal planes and isolated Cu atoms together with their corresponding catalytic activities for CO oxidation are investigated. The CeO₂ (100) and (111) surfaces can stabilize active Cu⁺ species, while Cu exists as Cu²⁺ on the (110) surface. Cu⁺ is certified as the most active site for CO adsorption, which can promote the formation of the reaction intermediates and reduce reaction energy barriers. For the CeO₂ (100) surface, the interaction between CO and Cu is weak and the CO adsorbate is more likely to activate the subsurface oxygen. The catalytic performance is closely related to the binding strength of CO to the active Cu single atoms on the different subsurfaces. These results bring a significant insight into the rational design of single metal atoms on ceria and other reducible oxides.