Understanding oxygen transfer on ceria with Pt single atoms for surface reaction.

Choi, Yunji; Choung, Seokhyun; Han, Jaebeom; Hwang, Jae-Eon; Jin, Hyeon; Kim, Yunkyung; Kim, Jeongjin; Park, Jeong Young et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Reducible metal oxides are widely used in surface reactions, primarily due to their ability to activate and transfer oxygen. Ceria, known for its rapid Ce<sup>3+</sup>/Ce<sup>4+</sup> redox property, is well-known to follow Mars van Krevelen mechanism. In this study, we prepare Pt/CeO<sub>2</sub>-Al<sub>2</sub>O<sub>3</sub> catalysts with different ceria domain sizes of 3.7, 5.6, and 7.3 nm to understand oxygen transfer, mainly O<sub>2</sub> activation and lattice oxygen transfer. The ceria domains are isolated on the alumina, preventing oxygen transfer between the ceria. Pt single atomic structures are meticulously prepared to exclude O<sub>2</sub> activation on Pt nanoparticles and provide uniform active sites. Interestingly, the activity trend for CO oxidation is reversed in O<sub>2</sub>-rich and O<sub>2</sub>-deficient conditions. O<sub>2</sub> activation occurs efficiently in small ceria domains of 3.7 nm. In contrast, larger ceria domains exhibit less O<sub>2</sub> activation but significant lattice oxygen transfer. This behavior is also modeled using large-scale molecular dynamics simulations with a neural network potential trained on first-principles data. Based on these understanding, the catalyst for methane oxidation is proposed by accelerating O<sub>2</sub> activation in O<sub>2</sub>-rich condition. This work provides an impactful platform for understanding metal oxide catalysts.