Abstract
Chemical C-N coupling from CO(2) and NO(3)(-), driven by renewable electricity, toward urea synthesis is an appealing alternative for Bosch-Meiser urea production. However, the unmatched kinetics in CO(2) and NO(3)(-) reduction reactions and the complexity of C- and N-species involved in the co-reduction render the challenge of C-N coupling, leading to the low urea yield rate and Faradaic efficiency. Here, we report a single-atom copper-alloyed Pd catalyst (Pd(4)Cu(1)) that can achieve highly efficient C-N coupling toward urea electrosynthesis. The reduction kinetics of CO(2) and NO(3)(-) is regulated and matched by steering Cu doping level and Pd(4)Cu(1)/FeNi(OH)(2) interface. Charge-polarized Pd(δ-)-Cu(δ+) dual-sites stabilize the key *CO and *NH(2) intermediates to promote C-N coupling. The synthesized Pd(4)Cu(1)-FeNi(OH)(2) composite catalyst achieves a urea yield rate of 436.9 mmol g(cat.)(-1) h(-1) and Faradaic efficiency of 66.4%, as well as a long cycling stability of 1000 h. In-situ spectroscopic results and theoretical calculation reveal that atomically dispersed Cu in Pd lattice promotes the deep reduction of NO(3)(-) to *NH(2), and the Pd-Cu dual-sites lower the energy barrier of the pivotal C-N coupling between *NH(2) and *CO.