Relay Catalysis of Isolated Rhodium-Alloyed Copper Boosts Urea Electrosynthesis from Nitrate and CO<sub>2</sub>
Jiaqi Xiang, Chaofan Qiang, Shiyao Shang, Yali Guo, Ke Chu
Abstract
Urea electrosynthesis from the coelectrolysis of NO 3 – and CO 2 (UENC) presents a fascinating approach for simultaneously migrating NO 3 – pollutants and producing valuable urea. In this study, isolated Rh-alloyed copper (Rh 1 Cu) 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 NO 3 – to form *NH 2 while the Cu site activates CO 2 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 *NH 2 and *CO toward the urea formation. Prominently, Rh 1 Cu 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.