Deciphering the Nitrogen Activation Mechanisms on Group VIII Single Atoms at MoS<sub>2</sub>
Hengyue Xu, Fupeng Zhang, LiuRu Fang, Yiqi Xu, Zhi‐Wu Yu, Lan Ma, Daqin Guan, Zongping Shao
Abstract
The activation of nitrogen (N 2 ) is vital for sustainable ammonia production and nitrogen fixation technologies. This study employs density functional theory (DFT) to investigate the nitrogen activation and reduction capabilities of Group VIII single-atom catalysts anchored on MoS 2 . Among these, osmium anchored on MoS 2 (Os@MoS 2 ) emerged as the most promising catalyst, exhibiting the highest N 2 activation and the lowest nitrogen reduction reaction (NRR) overpotential (0.624 V). A pronounced “electron drift” effect was observed for Os@MoS 2, leading to significant charge redistribution that weakens the N ≡ N triple bond, facilitating its activation. The N–N dissociation energy barrier at the *N–NH 2 intermediate was calculated to be only 0.82 eV, confirming Os@MoS 2 ’s superior catalytic efficiency. Detailed analyses, including electrostatic potential maps, electron localization functions, spin density, and charge transfer, revealed the pivotal role of orbital interactions in driving N 2 activation. Interestingly, the trends in adsorbed N 2 bond energies and NRR overpotentials showed a consistent diagonal pattern across the Group VIII catalysts, emphasizing the importance of electronic and geometric factors. This work offers valuable insights into nitrogen activation mechanisms and provides a framework for designing efficient catalysts, highlighting Os@MoS 2 ’s potential in sustainable ammonia synthesis.