Theoretical insights into Mo cluster modified Fe5C2 catalysts for electrocatalytic nitrogen reduction

The pursuit of green ammonia synthesis via electrocatalytic nitrogen reduction (NRR) faces challenges in developing high-performance, selective electrocatalysts. Inspired by the nitrogenase Fe-Mo cofactor, this study explores the catalytic efficiency of Mo clusters anchored on Fe5C2 for NRR. We investigate structural stability, N2 adsorption, and Gibbs free energy, revealing that Mon clusters on Fe5C2 demonstrate robust NRR selectivity and notable catalytic activity. Each of the three cluster structures demonstrated superior adsorption capacity in the "side-on" configuration. Among the studied cluster configurations, the Mo5-Fe5C2 shows the lowest limiting potential (-0.24 V), and the Mo4-Fe5C2 exhibits heightened selectivity for NRR, minimizing interference from the hydrogen evolution reaction (HER). This enhanced performance is attributed to the unique structure and interactive dynamics of Mon-Fe5C2 and the electron orbital interactions facilitating direct nitrogen charge transfer. Our findings underscore the potential of Mo cluster-modified Fe5C2 as a pioneering catalyst for electrocatalytic nitrogen reduction. [Display omitted] •Mon-Fe5C2 provides more active centers for the NRR reaction and emerges as an ideal catalyst for NRR.•Each of the three Mo cluster structures demonstrates superior adsorption capacity in the 'side-on' configuration.•The Mo5-Fe5C2 cluster exhibits the lowest limiting potential at −0.24 V.•The Mo4-Fe5C2 cluster shows enhanced NRR selectivity with minimal interference from the hydrogen evolution reaction.•The reduction of nitrogen to ammonia via the Mon-Fe5C2 is an energy-efficient process.