Enhanced N2 affinity of 1T-MoS2 with a unique pseudo-six-membered ring consisting of N-Li-S-Mo-S-Mo for high ambient ammonia electrosynthesis performance

The Haber-Bosch process is widely used to convert atmospheric nitrogen (N-2) into ammonia (NH3). However, the extreme reaction conditions and abundant carbon released by this process make it important to develop a greener NH3 production method. The electrochemical nitrogen reduction reaction (NRR) is an attractive alternative to the Haber-Bosch process. Herein, we demonstrated that molybdenum sulfide on nickel foil (1T-MoS2-Ni) with low crystallinity was an active NRR electrocatalyst. 1T-MoS2-Ni achieved a high faradaic efficiency of 27.66% for the NRR at -0.3 V (vs. RHE) in a LiClO4 electrolyte. In situ X-ray diffraction and ex situ X-ray photoemission analyses showed that lithium ions were intercalated into the 1T-MoS2 layers during the NRR. Moreover, theoretical calculations revealed the differences between six membered rings formed in the 1T-MoS2 and 2H-MoS2 systems with Li intercalation. The bond distances of d(Mo-N) and d(N-Li) of in Li-1T-MoS2 were found to be shorter than those in Li-2H-MoS2, resulting in a lower energy barrier of N-2 fixation and higher NRR activity. Therefore, 1T-MoS2-Ni is promising as a scalable and low-cost NRR electrocatalyst with lower power consumption and carbon emission than the Haber-Bosch process.

Automated summary

The study demonstrates that molybdenum sulfide on nickel foil (1T-MoS2-Ni) with low crystallinity is an active NRR electrocatalyst with high faradaic efficiency. In situ X-ray diffraction and ex situ X-ray photoemission analyses show that lithium ions are intercalated into the 1T-MoS2 layers during the NRR process.