Two-Dimensional Ordered Double-Transition Metal Carbides for the Electrochemical Nitrogen Reduction Reaction

The electrochemical nitrogen reduction reaction (NRR) provides a green and sustainable strategy as an alternative to the Haber-Bosch process. The development of electrocatalysts with low overpotential, high selectivity, and fast reaction kinetics remains a significant challenge. Here, density functional theory computations are carried out to systematically predict the prospect of 18 two-dimensional (2D) ordered double-transition metal carbides (MXenes) as NRR electrocatalysts. Our results revealed that the basal plane of Mo2Nb2C3 MXene exhibited the most outstanding catalytic activity while effectively suppressed the hydrogen evolution reaction with an overpotential of 0.48 V. The exposed Mo3 moiety moderately regulating the electron transfer between reaction intermediates is answerable for the high activity. Finally, our finding broadens the horizon of 2D materials as NRR electrocatalysts.