Abstract

Electrochemical urea synthesis through the concurrent CO₂ and NO₃⁻ reduction reaction offers a sustainable pathway for C‒N coupling under ambient environments. However, its practical operation remains restricted by competing side reactions and poor urea selectivity. Herein, we report a low-coordination Co–Ru dimer supported on a C₂N₄ ligand framework within nitrogen-doped graphene oxide (NGO), which achieves ~100% nitrogen selectivity toward urea. Pulsed laser irradiation in liquid synthesis in an NH₄OH/ethanol–water medium generates nitrogen-rich cavities on NGO substrate that stabilize atomically dispersed Co–Ru dimers through dual carbon–nitrogen coordination (CoRu–C₂N₄). The resulting dimer forms surface frustrated Lewis pairs, in which electron-deficient Lewis-acidic Ru sites and electron-rich Lewis-basic Co sites cooperatively activate CO₂ and NO₃⁻-derived intermediates, thereby promoting C‒N bond formation. Theoretical analyses reveal a substantially reduced in energy barrier for *CO‒*NO₂ coupling on CoRu–C₂N₄ compared to isolated Co–N₄ and Ru–N₄ single atom sites. Electrochemical analysis shows, CoRu–C₂N₄ achieves a urea Faradaic efficiency of 48.07% and yield rate of 149 mg h⁻¹ cm⁻² at −1.09 V vs. Ag/AgCl, outperforming Co–N₄ and Ru–N₄ analogues while suppressing NH₃ and formate formation. This study demonstrates that heteronuclear dimer engineering with asymmetric C/N coordination enables synergistic dual-site activation of C and N sources, providing an advanced design principle for selective electrocatalytic C–N coupling reactions.