Relay Catalysis\nof Isolated Rhodium-Alloyed Copper\nBoosts Urea Electrosynthesis from Nitrate and CO<sub>2</sub>

Urea electrosynthesis from the coelectrolysis of NO<sub>3</sub><sup>–</sup> and CO<sub>2</sub> (UENC) presents a fascinating\napproach for simultaneously migrating NO<sub>3</sub><sup>–</sup> pollutants and producing valuable urea. In this study, isolated\nRh-alloyed copper (Rh<sub>1</sub>Cu) is explored as a highly active\nand selective catalyst toward the UENC. Combined in situ spectroscopic\nanalysis and theoretical calculations reveal the relay catalysis of\nthe Rh<sub>1</sub> site and Cu site to promote the UENC energetics,\nin which the Rh<sub>1</sub> site activates NO<sub>3</sub><sup>–</sup> to form *NH<sub>2</sub> while the Cu site activates CO<sub>2</sub> to form *CO. The formed *CO is then migrated from the Cu substrate\nto the nearby Rh<sub>1</sub> site, which promotes the C–N coupling\nof *NH<sub>2</sub> and *CO toward the urea formation. Prominently,\nRh<sub>1</sub>Cu achieves an exceptional UENC performance in the flow\ncell, exhibiting the highest urea-Faradaic efficiency of 67.10% and\nurea yield rate of 50.36 mmol h<sup>–1</sup> g<sup>–1</sup> at −0.6 V versus RHE.