▎ 摘　　要

Currently, industrial-scale NH3 production almost relies on energy-intensive Haber-Bosch process from atmospheric N-2 with large amount of CO2 emission, while low-cost and high-efficient catalysts are demanded for the N-2 reduction reaction (NRR). In this study, Mn3O4 nanoparticles@reduced graphene oxide (Mn3O4@rGO) composite is reported as an efficient NRR electrocatalyst with excellent selectivity for NH3 formation. In 0.1 M Na2SO4 solution, such catalyst obtains a NH3 yield of 17.4 gh(-1)mg(cat)(-1). and a Faradaic efficiency of 3.52% at -0.85 V vs. reversible hydrogen electrode. Notably, it also shows high electrochemical stability during electrolysis process. Density functional theory (DFT) calculations also demonstrate that the (112) planes of Mn3O4 possess superior NRR activity.