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 Rh-1 site and Cu site to promote the UENC energetics, in which the Rh-1 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 Rh-1 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.