Coordination Engineering of Heteronuclear Fe−Mo Dual‐Atom Catalyst for Promoted Electrocatalytic Nitrogen Fixation: A DFT Study

Abstract

Developing efficient nanostructured electrocatalysts for N₂ reduction to NH₃ under mild conditions remains a major challenge. The Fe-Mo cofactor serves as the archetypal active site in nitrogenase. Inspired by nitrogenase, we designed a series of heteronuclear dual-atom catalysts (DACs) labeled as FeMoN_6-a X_a (a=1, 2, 3; X=B, C, O, S) anchored on the pore of g-C₃ N₄ to probe the impact of coordination on FeMo-catalyzed nitrogen fixation. The stability, reaction paths, activity, and selectivity of 12 different FeMoN_6-a X_a DACs have been systematically studied using density functional theory. Of these, four DACs (FeMoN₅ B₁ , FeMoN₅ O₁ , FeMoN₄ O₂ , and FeMoN₃ C₃ ) displayed promising nitrogen reduction reaction (NRR) performance. Notably, FeMoN₅ O₁ stands out with an ultralow limiting potential of -0.11 V and high selectivity. Analysis of the density of states and charge/spin changes shows FeMoN₅ O₁ 's high activity arises from optimal N₂ binding on Fe initially and synergy of the FeMo dimer enabling protonation in NRR. This work contributes to the advancement of rational design for efficient NRR catalysts by regulating atomic coordination environments.