Elucidating Relay Catalysis on Copper Clusters With Satellite Single Atoms for Enhanced Urea Electrosynthesis

Abstract Relay catalysis represents significant efficacy in alleviating competition among different reactants during coupling reactions. However, a comprehensive understanding of the reaction mechanism underlying relay catalysis for the urea electrosynthesis remains challenging. Herein, we have developed a catalyst (Cu AC ‐Cu SA @NC) comprising Cu atomic clusters (Cu AC ) with satellite Cu─N 4 single atoms (Cu SA ) sites on the nitrogen‐doped porous interconnected carbon skeleton (NC), enabling elucidation of a relay catalysis process for co‐reduction of CO 2 and NO 3 − . The designed Cu AC ‐Cu SA @NC catalyst exhibits an approximately threefold higher urea yield rate compared to that of Cu SA @NC at −1.3 V versus RHE. Ex‐situ experimental results and in‐situ attenuated total reflection surface‐enhanced infrared absorption spectroscopy analysis reveal a formation sequence between the *NH 2 and *NH 2 CO species on Cu AC ‐Cu SA @NC with increasing reduction potential. The combination of theoretical calculations further elucidates that the relay catalysis pathway involves “Cu AC ” sites facilitating the conversion of *NO 3 to *NO x , followed by a hydrogenation process to form *NH 2 with *H from water dissociation promoted by “Cu SA ” sites, which subsequently couples with *CO 2 to produce urea. This work provides novel insights into the investigation of coupling reactions, but not limit to, urea synthesis.