Article Screening and mechanistic study of bimetallic catalysts for the electrosynthesis of urea from carbon dioxide and dinitrogen

Electrocatalytic conversion of dinitrogen and carbon dioxide directly to urea by C-N coupling could be an eco-friendly alternative to the current synthetic route, which uses ammonia produced via the Haber-Bosch process. Recent experiments have shown that bimetallic catalysts with defective configurations can be synthesized. However, diverse possible element combinations and unclear mechanisms are challenges in their rational design. Here, in-depth calculations are performed to investigate the catalytic performance of a series of bimetals anchored on N-doped graphene. Through a twostep screening strategy and investigation of free energy, a TiCo@NC catalyst is found to exhibit an ultra-low onset potential of 0.23 V, catalyzing the reaction efficiently. Furthermore, molecular electrostatic potential maps and dual descriptor diagrams reveal that CO prefers to tilt-attack *N2 to promote C-N coupling effectively. The reaction process can be enhanced by controlling the transfer of electrons between two metallic sites. These results will increase the understanding of C-N coupling in urea electrosynthesis and inspire rational catalyst design.

Automated summary

Electrocatalytic conversion of dinitrogen and carbon dioxide directly to urea by C-N coupling is a promising eco-friendly alternative to the current ammonia-based synthetic route. This study investigates the catalytic performance of bimetallic catalysts anchored on N-doped graphene. A TiCo@NC catalyst is found to exhibit an ultra-low onset potential of 0.23 V, efficiently catalyzing the reaction. The results provide insights into C-N coupling in urea electrosynthesis and inspire rational catalyst design.