Promising prospects for 2D d²-d⁴ M₃C₂ transition metal carbides (MXenes) in N₂ capture and conversion into ammonia

Density functional theory investigations of M₃C₂ transition metal carbides from the d², d³, and d⁴ series suggest promising N₂ capture behaviour, displaying spontaneous chemisorption energies that are larger than those for the capture of CO₂ and H₂O in d³ and d⁴ MXenes. The chemisorbed N₂ becomes activated, promoting its catalytic conversion into NH₃. The first proton-electron transfer is found to be the rate-determining step for the whole process, with an activation barrier of only 0.64 eV vs. SHE for V₃C₂.