Theoretical study of transition metal doped ?-borophene nanosheet as promising electrocatalyst for electrochemical reduction of N2

Ammonia synthesis is an essential industrial production process. Through first principle calculations, this work investigated 3d/4d transition metal (TM) embedded alpha-borophene monolayer (BM-alpha) as efficient electrocatalyst for N2 reduction reaction (NRR). The computational results show that V, Cr, and Mo@BM-alpha exhibit excellent catalytic activity for ammonia synthesis via the enzymatic pathway. Analyses reveal that the unoccupied d orbitals of TM (V, C, and Mo) accept lone pair electrons from N2 while the anti-bonding orbitals of N2 accept a large amount of negative charge from TM, which lead to the elongation of the N---N triple bond, thus effectively activating the nitrogen. In addition, V@BM-alpha and Mo@BM-alpha show a strong suppressive effect on hydrogen evolution reaction (HER) and overcome the possible oxidation on the catalyst surface. Our results demonstrate the alpha-borophene is a superior substrate for single atom catalysts which can be designed as high performance NRR electrocatalysts.