Atomically Engineered RuO x ‐Cu Interfaces Enabling Tandem Catalysis for Ampere‐Level Nitrite–Ethanol Co‐Electrolysis

ABSTRACT Designing tandem catalysts with well‐defined interfacial architectures is of great significance for promoting multi‐step electrochemical transformations, yet achieving synergistic regulation of dual active sites at the atomic level remains a formidable challenge. Herein, we develop an atomic‐level engineering strategy to construct RuO x cluster‐modified Cu‐based nanowire array electrodes with abundant interfacial structures, which act as efficient tandem catalysts for sustained nitrite–ethanol paired electrolysis at ampere‐level current densities. In situ spectroscopic analysis combined with theoretical calculations reveals that the atomically RuO x cluster serves as highly active water‐activation sites, generating abundant active hydrogen/oxygen species that subsequently react with adsorbed nitrogen and carbon‐containing intermediates, thereby enabling exceptionally favorable co‐electrolysis kinetics. Impressively, a membrane electrode assembly flow electrolyzer constructed with RuO x @R‐Cu/CF as both electrodes achieves >90% Faradaic efficiencies for NH 3 and acetate over a wide current density window of 0.2–1.0 A cm −2 , along with high yields of 5.86 mmol h −1 cm −2 (NH 3 ) and 8.65 mmol h −1 cm −2 (acetate) at 1.0 A cm −2 , and outstanding operational stability, significantly surpassing previously reported co‐electrolysis systems.