Stabilizing Black Phosphorus Via Covalent Functionalization Of Solvent Formamide

Black phosphorus (BP) has been attracting increasing scientific and technological interest for its excellent materials properties, but suffers from the intrinsic easy oxidization due to the high reactivity of lone-pair electrons in each phosphorus atom. Herein, solvent formamide (FM) is proposed for the covalent modification of BP by a one-step ultrasonication without any additive. FM is demonstrated to functionalize BP by the formation of single covalent bond P-N, thus occupying the active lone-pair electrons of P atoms and leading to the significant enhancement of the antioxidative capacity of BP. Density functional theory calculations also rationalize the formation of stable P-N bond and its contribution to the high solvent-exfoliated efficiency during the exfoliation of BP. The plausible reaction mechanism of FM with BP and the final 5-membered ring structure of products are also proposed to explain the formation process of the stable P-N bonds.