Relay Catalysis of Isolated Rhodium-Alloyed Copper Boosts Urea Electrosynthesis from Nitrate and CO2

Urea electrosynthesis from the coelectrolysis of NO3– and CO2 (UENC) presents a fascinating approach for simultaneously migrating NO3– pollutants and producing valuable urea. In this study, isolated Rh-alloyed copper (Rh1Cu) is explored as a highly active and selective catalyst toward the UENC. Combined in situ spectroscopic analysis and theoretical calculations reveal the relay catalysis of the Rh1 site and Cu site to promote the UENC energetics, in which the Rh1 site activates NO3– to form *NH2 while the Cu site activates CO2 to form *CO. The formed *CO is then migrated from the Cu substrate to the nearby Rh1 site, which promotes the C–N coupling of *NH2 and *CO toward the urea formation. Prominently, Rh1Cu achieves an exceptional UENC performance in the flow cell, exhibiting the highest urea-Faradaic efficiency of 67.10% and urea yield rate of 50.36 mmol h–1 g–1 at −0.6 V versus RHE.