Moderate Intermediate Adsorption Boosts Electrocatalytic C─N Coupling via Coordination Engineering

The electrocatalytic synthesis of urea from carbon dioxide and nitrate represents a sustainable route, with the C─N coupling between *CO and *NO intermediates being critical. However, achieving high efficiency remains challenging due to insufficient control over intermediate adsorption and reaction pathways. In this work, we reveal that the coordination number (CN) of Cu inversely regulates the adsorption strength of *CO and *NO, while C─N coupling activity follows a volcano-type relationship with CN. Alloying Cu with intrinsically inert Ga atoms lowers the CN of Cu, upshifts d-band center, and finely tunes intermediate adsorption, thereby facilitating the formation of the key *ONCO. The optimized Cu_0.875Ga_0.115 catalyst, with a moderate CN of 9.3 situated between its counterparts (6.0 and 12.0), balances adsorption and coupling activity, delivering a desirable urea yield rate of 575.6 mmol h^-1 g^-1 and a Faradaic efficiency of 30.4% at -1.4 V versus RHE. This work underscores coordination engineering as an effective strategy for guiding efficient C─N coupling toward urea synthesis.