Mixed-Valence Intermetallic Compounds for Urea Electrosynthesis

Efficient urea electrosynthesis relies on precisely controlling the kinetics of two parallel reduction reactions, i.e., carbon dioxide (CO₂) reduction and nitrate (NO₃^-) reduction. However, a major challenge lies in constructing stable and different active sites at the atomic scale, which are essential for synchronizing the reaction kinetics of these two reactions and facilitating C-N coupling. Herein, we introduce a mixed-valence intermetallic compound (Mv-IMC) Cu₂Sb, featuring Cu⁺-Cu²⁺ dual-sites as modular building blocks to regulate and synchronize CO₂ and NO₃^- reduction kinetics. Mechanistic studies reveal that the constructed dual-sites stabilize *CO and *NO intermediates, lower the energy barrier of C-N coupling, and significantly enhance the urea synthesis efficiency. The Cu₂Sb catalyst achieves a urea yield of 22.9 mmol h^-1 g_cat^-1 with a Faradaic efficiency of 64.9% at -0.4 V, maintaining stability over 200 h, surpassing most previously reported catalysts. This work pioneers the precise construction of multivalent active sites in Mv-IMCs, establishing a paradigm for designing high-performance electrocatalysts tailored to value-added organic synthesis.