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

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 FeMoN6-aXa (a=1, 2, 3; X=B, C, O, S) anchored on the pore of g-C3N4 to probe the impact of coordination on FeMo-catalyzed nitrogen fixation. The stability, reaction paths, activity, and selectivity of 12 different FeMoN6-aXa DACs have been systematically studied using density functional theory. Of these, four DACs (FeMoN5B1, FeMoN5O1, FeMoN4O2, and FeMoN3C3) displayed promising nitrogen reduction reaction (NRR) performance. Notably, FeMoN5O1 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 FeMoN5O1 ' 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. A set of heteronuclear dual-atom catalysts (DACs) denoted as FeMoN6-aXa (a=1, 2, 3; X=B, C, O, S) immobilized within the pores of g-C3N4 was designed by density functional theory computations, aiming to explore the nitrogen fixation activity of the Fe-Mo center and the influence of the coordination environment.image