MoS₂-Supported Fe₂ Clusters Catalyzing Nitrogen Reduction Reaction to Produce Ammonia

Abstract

Synergistic interactions within metal clusters help to improve the catalytic activity of individual metal atoms and contribute to advance the understanding of mechanisms in multisite catalysis. Herein, the MoS2-supported Fe2 cluster was chosen as the catalyst for nitrogen reduction reaction (NRR) to produce ammonia. First-principles calculations reveal that the Fe2/MoS2 exhibits high catalytic activity for electrochemical NRR and sheds light on the enzymatic mechanism which bears a low overpotential of 0.21 V. Compared with a single Fe atom on MoS2, the presence of a vicinal Fe atom (i.e., Fe2/MoS2) enables side-on adsorption of N2, which is propitious to effective N–N bond activation. Whereas the Fe3/MoS2 catalyst, simply with one more Fe atom involved, reduces electron depletion among Fe atoms and hence represses N2 adsorption. The origin of reasonable NRR catalysis of Fe2/MoS2 is further unveiled by natural charge population and projected crystal orbital Hamilton population (pCOHP) analyses. This investigation provides an effective strategy for designing active catalysts with low cost and multisite synergy catalysis.