Structural insight into [Fe-S2-Mo] motif in electrochemical reduction of N2 over Fe1-supported molecular MoS2

The catalytic synthesis of NH3 from the thermodynamically challenging N-2 reduction reaction under mild conditions is currently a significant problem for scientists. Accordingly, herein, we report the development of a nitrogenase-inspired inorganic-based chalcogenide system for the efficient electrochemical conversion of N-2 to NH3, which is comprised of the basic structure of [Fe-S-2-Mo]. This material showed high activity of 8.7 mg(NH3) mg(Fe)(-1) h(-1) (24 mu g(NH3) cm(-2) h(-1)) with an excellent faradaic efficiency of 27% for the conversion of N-2 to NH3 in aqueous medium. It was demonstrated that the Fe-1 single atom on [Fe-S-2-Mo] under the optimal negative potential favors the reduction of N-2 to NH3 over the competitive proton reduction to H-2. Operando X-ray absorption and simulations combined with theoretical DFT calculations provided the first and important insights on the particular electron-mediating and catalytic roles of the [Fe-S-2-Mo] motifs and Fe-1, respectively, on this two-dimensional (2D) molecular layer slab.

Automated summary

A nitrogenase-inspired inorganic-based chalcogenide system has been developed for efficient electrochemical conversion of N-2 to NH3, showing high activity and excellent faradaic efficiency. The Fe-1 single atom on [Fe-S-2-Mo] is found to favor the reduction of N-2 to NH3 under optimal negative potential. Operando X-ray absorption and simulations, along with theoretical DFT calculations, provide insights on the electron-mediating and catalytic roles of the [Fe-S-2-Mo] motifs and Fe-1 on this 2D molecular layer slab.