Controllable Assembly of Planar Defect-Rich Bimetallic Oxide Interfaces for Efficient Ammonia Production

The electrocatalytic nitrate reduction reaction (NitRR) is a promising dual-functional strategy for carbon-free ammonia synthesis and sustainable wastewater treatment. The complexity of the eight-electron/nine-proton transfer process in the NitRR highlights the need for improved catalysts to optimize reaction pathways and suppress competitive side reactions. Herein, the successful growth of CuCo₂O_x nanowires with tailored defect structures is reported with the assistance of graphdiyne (GDY) through an atomic-level heterointerface engineering strategy. The synergistic interactions between GDY electron-rich sp-C atoms and electron-deficient bimetallic atoms induce self-optimized planar defects along nanowires and accelerate interfacial charge transfer via metal‒carbon covalent hybridization. These properties significantly facilitate dynamic NO₃ ^- adsorption-activation and completely suppress byproduct formation via intermediate stabilization. As a result, CuCo₂O_x/GDY exhibites a remarkable NitRR performance of 100% Faradaic efficiency (FE), a record-high NH₃ yield rate (Y_NH3, 3332 µg cm^-2 h^-1) at an ultralow operational potential (-0.132 V vs RHE), no side reactions, and long-term durability. This work pioneers atomic-level interface engineering in GDY-based systems, establishing a general method for synthesizing high-performance electrocatalysts in sustainable nitrogen cycles.