Strain-Directed Ru Redistribution to Form RuO2/Pt Mosaic Heterointerfaces for Acid-Stable Water Oxidation

초록

Doping Ru oxides with heteroatoms such as Pt can mitigate their intrinsic redox instability by redistributing charge at the interface during acidic OER conditions; however, achieving atomically intimate Pt-Ru configurations remains challenging because conventional synthesis routes cannot reliably juxtapose the two elements at structurally compatible catalytic sites. Here, we report a strain-driven atomic migration strategy that enables controlled redistribution of Ru from the exterior to the interior of PtNi multiframe during thermal oxidation. Redox-induced Ni oxidation generates lattice strain that drives inward Ru migration, leading to the formation of RuO2/Pt mosaic heterointerfaces throughout the open framework. These heterointerfaces create a Pt-biased redox environment that stabilizes Ru4+ while strongly suppressing lattice oxygen participation. Operando XAFS and 18O-labeled DEMS reveal that this Pt-Ru redox asymmetry underpins the remarkable stability, while interfacial electronic modulation steers the reaction toward an adsorbate evolution mechanism-dominated pathway with more favorable intermediate energetics. Consequently, the catalyst delivers an ultralow overpotential of 168 mV at 10 mA cm-2 and maintains stable operation for over 540 h. Overall, this work establishes strain-directed atomic migration as a versatile post-synthetic route for constructing redox-stabilized heterointerfaces, providing a broadly applicable design principle for highly active and durable water-splitting electrocatalysts.

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