The mechanism of nitrogen reduction reaction on defective boron nitride (BN) monolayer doped with monatomic Co, Ni, and Mo–A first principles study

Abstract

In this work, transition metal atoms (TM=Co, Ni, Mo) doped with B defect (M-VB-BN) and N defect (M-VN-BN) boron nitride (BN) monolayer was constructed and used for the synthesis of ammonia with N2 and *H as raw materials (TM=Co, Ni, Mo). Based on the density functional theory (DFT), the structure of these six modified materials was optimized, and the simulation calculation of the N2 reduction reaction (N2RR) was carried out. It shows that the type of defects and TM will affect the reaction path. For Co-VB-BN and Ni-VB-BN, the most potential path is the alternate mechanism; Mo-VN-BN is most inclined to the enzymatic mechanism. In particular, for Co-VN-BN, Ni-VN-BN and Mo-VB-BN, the N2RR does not proceed from beginning to end according to any of the three basic mechanisms. It is manifested as a mixed mechanism in which the enzymatic mechanism and the associative mechanism are interleaved. In general, N defect is more suitable for N2RR than B defect. Among the six structures, Mo-VN-BN exhibits the highest catalytic activity, and its energy barrier for rate-determining step is only 0.24 eV. These findings can provide a certain reference for the selection of defect sites and transition metals in the study of two-dimensional BN material catalysts.