Interfacial oxygen-transfer mediated redox reaction of Ru/CeO2

Reducible oxide supports prevail in heterogeneous catalytic processes owing to their ability to modulate both local electronic and geometric structure via variable valence and defect states for specific reactions. Nevertheless, their dynamic evolution under redox reaction conditions, often involving phase transformation via oxygen migration through a critical surface or interface, remains poorly understood at the atomic level. Herein, we utilize a RuO 2 /CeO 2 system to demonstrate the dynamic structure and phase changes during redox reaction conditions through in situ transmission electron microscopy and other spectroscopic techniques. Our investigation reveals a distinct oxygen-transfer mechanism governing interfacial dynamics at RuO 2 -CeO 2 boundaries, where reduction initiates preferentially at the metal-support interface rather than particle surfaces, propagating via an unconventional bottom-up reduction pathway characterized by sequential two-phase structural transition. The CeO 2 support demonstrates dual functionality as both oxygen reservoir and donor, enabling the re-oxidation of Ru nanoparticles via surface-mediated oxygen replenishment. This interfacial oxygen shuttle mechanism not only sheds light on the atomic-scale dynamics of reducible supports but also establishes fundamental principles for engineering metal-support architectures through precise control of interfacial charge transfer and oxygen mobility in catalytic systems.