Study on C-N coupling reactions and catalytic mechanisms of modified boron nitride for urea synthesis: from nitrogen and carbon monoxide.

Urea is a key chemical for agriculture and industry, yet its conventional synthesis is energy-intensive and environmentally unfriendly. Electrocatalytic C-N coupling offers a sustainable alternative for urea production under mild conditions; however, significant challenges remain. Herein, density functional theory (DFT) is employed to investigate Fe- and Co-decorated defective boron nitride (BN) monolayers with mono-vacancies (VB, VN) and divacancies (VBB, VBN) as electrocatalysts. Their structural stability, activation of N2, corresponding reaction mechanism and selectivity for urea synthesis are comprehensively analyzed. Among the studied systems, Fe-VBN exhibits the lowest thermodynamic limiting potential of -0.413 V. In contrast, despite a compromised limiting potential of -0.715 V, the FeCo-VBB shows superior thermodynamic selectivity. This study provides insights into the C-N coupling mechanism on defective BN materials and may inform the rational design of electrocatalysts for urea synthesis.