▎ 摘　　要

The development of affordable and green ammonia synthesis techniques is highly desirable. By employing first-principles calculations, we propose a nonnoble metal-doped graphene layer for N-2-to-NH3 conversion. Our results show that the cooperation of Co and B in the form of CoB4 exhibits outstanding catalytic activity for N-2 reduction reaction (NRR), and the reaction pathway preferably followed a distal or alternating mechanism with a small activation barrier of 0.36 eV, which is less than that of reported single-atom Ru (0.42) and Cr (0.59 eV) catalysts. The catalytic ability of the CoB4 catalyst arises from both the electronic effect of B dopants, which serve as charge contributors, and the complementary role of Co, which serves as a desorption site for NH3* formation or further NH3 release. This work provides a potential nonprecious-metal catalyst for N-2 activation and conversion. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.