Stable Cu^δ+ sites derived from analogous rectifying interface in AgCu biphasic aerogels for efficient urea...

Urea electrosynthesis through CO₂ and NO₃^- coupling presents a promising alternative to energy-intensive industrial processes. However, intricate catalytic mechanisms and competitive reactions impede achieving high-efficiency C-N coupling. Herein, we constructed analogous rectifying interfaces in AgCu biphasic aerogels, by leveraging electronegativity difference to derive stable Cu^δ+ active sites, which simultaneously promoted *NOH adsorption and *CO coverage, thereby improving C-N coupling dynamics, confirmed by both operando technique and theoretical calculations. Specifically, notable urea yield (54.8 mmol h^-1 g_cat.^-1) with Faradaic efficiency (FE, 36.6%) at a low potential (-0.52 V vs. RHE) was achieved using Ag₆₇Cu₃₃ in a flow-cell. As a proof-of-concept demonstration for practicability, Ag₆₇Cu₃₃ exhibited bifunctional electrosynthesis for urea (FE: 56.07%, yield: 104.6 mmol h^-1 g_cat.^-1) and HCOOH (FE: over 90%) at 40 mA cm^-2 in two-electrode system, with durability over 60 h. This work provides an indicative rationale to construct active sites for C-N coupling, facilitating the development of urea electrosynthesis.