Nitrogen Bicoupled Carbon Bonding for Electrocatalysis of CO2 and Nitrobenzene via Engineering Hydroxyl Assisted Cobalt Single Atom

Abstract

AbstractThe coupling of CO2 and nitrogen‐containing species nitrobenzene has become an appealing and sustainable strategy for synthesizing high‐valuable organic nitrides. However, how to realize the nitrogen bicoupled carbon bonding (C─N─C) between two CO2 and nitrobenzene has been an insurmountable challenge. Hydroxyl‐assisted cobalt single atom (CoN2O2‐(OH)2) is engineered to achieve C─N─C bonding for N, N‐dimethylaniline synthesis. The CO2 is adsorbed through hydroxyl groups, that can be reduced and C─N coupling with nitrobenzene reduction intermediate on nearby Co site, and the vacant hydroxyl group continues to adsorb next CO2, which is sequentially coupled with an intermediate of C─N coupling, achieving C─N─C bonding for synthesis N, N‐dimethylaniline. Herein, first, C─N─C bonding is achieved for green synthesis of N, N‐dimethylaniline via electrocatalytic reduction of nitrobenzene and CO2 in an aqueous phase, with a yield of 505.2 µmol L−1 h−1 on CoN2O2‐(OH)2. In situ characterizations and DFT calculations together demonstrated that the key of C─N─C bonding is that *PhNCH3 intermediate of C─N bonding continues to couple with *CO achieving C─N─C bonding to generate *PhNCOCH3 for N, N‐dimethylaniline synthesis with a much lower free energy is far easier to take place on CoN2O2‐(OH)2. This work provides inspiring new insight into the green synthesis of long‐chain organic nitrides.