Triadic σ–π Coordination Programs Cu^δ+ Sites to Drive Sequential Dual‑N Species C–N Coupling for Efficient Urea Electrosynthesis

These effects improve proton-coupled electron transfer (PCET) compatibility and increase the synchronized local coverages of *CO and *NH_<i>x</i> near the active site. More importantly, Cu–N–CMPs establishes a sequential dual-N-species C–N coupling pathway initiated by *NH and completed by *NH₂, with *CONH identified as the key intermediate in the first coupling step. As a result, Cu–N–CMPs delivers a Cu-site-normalized TOF of 1321.2 h^–1 at −0.6 V_RHE.

In the membrane electrode assembly (MEA) electrolyzer, it further delivers a urea formation rate of 92.8 mmol g_cat.^–1 h^–1 with 77.6% FE_urea and stable operation for 85 h. This work demonstrates that Cu site electronic programming can coordinate sequential dual-N species C–N coupling, providing a transferable atomic-site engineering strategy for complex multi-intermediate electrocatalysis.