Atomic Ru‐Mediated Spontaneous Heterointerface Phase Transition Enables Ampere‐Level Catalytic Performance in Paired Electrolysis

Phase transition regulation is a promising strategy to optimize the catalytic properties of catalysts, playing a crucial role in enhancing electrocatalytic efficiency. However, the intrinsic relationship between atomic-scale interface phase transitions and catalytic performance remains unclear. Herein, we report a heteroatomic interfacial phase transition of Co₃S₄/Co heterostructured nanosheets to Co₉S₈/Co by anchoring single-atom Ru under thermal treatment (Ru_SA-Co₉S₈/Co-T), resulting in ampere-level catalytic performance for the sustained paired electrosynthesis. Theoretical calculations and in situ spectroscopy confirm the spontaneous transition to a more stable structure triggered by atomic Ru, which synergistically optimizes the formation kinetics of key intermediates and reduces the energy barrier of the rate-determining steps on Ru_SA-Co₉S₈/Co-T. Impressively, this catalyst can be directly applied in membrane electrode assembly electrolyzers for nitrite-glycerol co-electrolysis. Within a wide potential window of 1.2-2.0 V, the average Faradaic efficiencies of NH₃ and formate exceed 90%, with the highest yields reaching 95.83 mg h^-1 cm^-2 and 567.38 mg h^-1 cm^-2 at 2.0 V, respectively, alongside stable operation for 100 h at an industrial current density of 500 mA cm^-2. Our work provides new insights into the development of high-performance catalysts.