Lattice distortion-induced Cu–Fe spin engineering rectifies N-intermediate adsorption to reinforce C–N coupling for urea electrosynthesis

Iron-based catalysts with strong oxophilicity typically induce inert O-end adsorption of nitrogen-containing intermediates, severely constraining C‒N coupling efficiency in urea electrosynthesis. To break this thermodynamic limit and actively invert the adsorption configuration, we deliver a “geometry-spin” synergistic strategy to construct a surface-segregated Cu‒Fe@NC bimetallic electrocatalyst. Cu‒Fe interfacial tensile strain and orbital hybridization induce Fe-site spin depolarization, forming an atomic “spin-valve” for enhanced NO₃⁻/CO₂ co-reduction. It achieves 61.8% urea Faradaic efficiency, with remarkable yields of 2,273.7 and 21,176.7 μg h⁻¹ mg⁻¹ in H-type and flow cells, respectively. Mechanistic investigations elucidate that surface segregation optimizes spatial distance for Cu-activated ∗CO and Fe-immobilized ∗NO₂; meanwhile, Cu incorporation realigns Fe d-band center toward the Fermi level, promoting ∗NO₂ inversion to active N-end adsorption, thereby reducing the C‒N coupling kinetic barrier for urea electrosynthesis. This work offers a universal paradigm for oriented electrosynthesis by leveraging the geometry-spin coupling effect to reverse the adsorption configuration of key intermediates.