1T-MoS Nanosheets Coupled with CoS Nanoparticles: Electronic Modulation for Efficient Electrochemical Nitrogen Fixation.

Electrocatalytic nitrogen reduction reaction (eNRR), a substitute process for the conventional Haber-Bosch for NH production, has drawn tremendous attention due to its merits in mild conditions, abundant reactant sources, low energy consumption, and environmental protection. However, electrocatalysts for eNRR are still subjected to low catalytic activity and selectivity. Herein, we constructed a CoS/1T-MoS heterostructure with CoS nanoparticles uniformly loaded on 1T-MoS nanosheets and applied it as an eNRR electrocatalyst for the first time. Theoretical calculation suggests that electron transfer from CoS to 1T-MoS across their contact interface optimizes the local electronic structure of 1T-MoS, where the electron-depletion region near CoS is in favor of accepting lone-pair electrons from N to enable N absorption, and the electron-accumulation region near 1T-MoS is conductive to break inert N≡N triple bonds. Unlike pure 1T-MoS, the potential-determining step (PDS) demonstrates a significantly lower energy barrier. In addition, the weak interaction between CoS/1T-MoS and hydrogen discourages competitive hydrogen evolution reaction. As a result, CoS/1T-MoS exhibited noticeably improved eNRR activity and selectivity, with an NH yield of 59.3 μg h mg and a high Faradaic efficiency of 26.6%.