Redox-Programmable Construction of RuO ₂ /Ru Interfacial Nanostructures for Enhanced Hydrogen Generation via Ammonia Borane Hydrolysis

Metal/oxide interfaces often exhibit superior catalytic properties, yet their controllable construction remains challenging. Here, we report a redox-programmable ethanol-mediated solvothermal strategy that enables stepwise transformation of RuO 2 and a RuO 2 /PdO mixture into RuO 2 /Ru and RuO 2 /Ru/Pd interfacial nanostructures, and ultimately metallic Ru and Ru/Pd nanoparticles, respectively, under mild conditions. Temperature- and time-dependent studies combined with microscopic analysis reveal a surface-initiated reduction mechanism and a three-stage evolution pathway (RuO 2 → RuO 2 /Ru → Ru 0 ). The interfacial mixed-phase catalyst delivers superior hydrogen generation performance in ammonia borane hydrolysis compared with both pure RuO 2 and fully metallic nanoparticles, demonstrating a nonmonotonic phase–activity relationship. The enhanced activity originates from synergistic bifunctional catalysis at the metal/oxide boundary, where metallic Ru promotes hydride activation and oxide domains facilitate water dissociation. These findings highlight the critical role of controllable redox evolution in tailoring interfacial structures. This work establishes a comprehensive structure–evolution–function framework for the rational design of high-performance metal/oxide catalysts via low-temperature redox control.