Demonstrates altered redox behavior of noble metals on cerium oxide, suggesting active roles in catalytic processes.
Noble metals such as platinum and gold are widely regarded as resistant to oxidation under ambient conditions. We show that interfacing these metals with a reducible oxide alters their redox behavior through dynamic metal–support interactions. Using in situ environmental transmission electron microscopy, we visualize reversible room‐temperature redox cycling of Pt and Au nanoparticles on CeO 2 under alternating O 2 and vacuum. Oxygen vacancies in the partially reduced support dissociate O 2 into reactive atomic oxygen, which spills over to oxidize the supported metal, driving complete conversion of Pt to crystalline Pt 3 O 4 , and the formation of ordered oxide species on Au. For Pt/CeO 2 , redox cycling also induces a reversible wetting–dewetting restructuring in which oxidation promotes dewetting into three‐dimensional oxide islands, whereas reduction drives wetting of metallic Pt into atomically thin rafts, progressively increasing metal dispersion. In contrast, Au/CeO 2 exhibits self‐limiting surface oxidation, highlighting the role of metal identity in governing restructuring pathways. Density functional theory modeling shows that this process is sustained by a Cabrera–Mott‐type field‐assisted oxidation mechanism enabled by the CeO 2 support. These results establish reducible oxides as active redox partners rather than passive supports, providing a mechanistic framework for designing low‐temperature oxidation catalysts through support‐driven dynamic chemistry.
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Ye et al. (2026) studied this question.
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