Screening of Transition Metal (Sc to Zn) Decorated Mo ₃ C ₂ MXenes as a Catalyst Under Ambient Conditions for N ₂ to NH ₃ Electrocatalysis Using First Principles Method

In this study, 3d transition metal (TM) atom-decorated MXenes (TM@Mo₃C₂ where TM = ScZn) are used as potential catalysts for the nitrogen reduction reaction (NRR) using density functional theory-based screening. The favorable work function, strong N₂ activation, effective hydrogen evolution reaction (HER) suppression, and high current density collectively establish V@Mo₃C₂ as a highly promising NRR catalyst, warranting in-depth exploration. Ab initio molecular dynamics simulations confirm the thermal stability of V@Mo₃C₂ at 300 K. The side-on N₂ adsorption on V@Mo₃C₂ favors enzymatic and consecutive reaction pathways. Notably, the reaction free-energy changes in the consecutive pathway are exothermic, contributing to an exceptionally low potential-determining step. Furthermore, V@Mo₃C₂ demonstrates a Faradaic efficiency <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:mrow><mml:mo>(</mml:mo> <mml:mi>F</mml:mi> <mml:msub><mml:mi>E</mml:mi> <mml:mrow><mml:mtext>NRR</mml:mtext></mml:mrow> </mml:msub> <mml:mo>)</mml:mo></mml:mrow> <mml:annotation>$F E_{\text{NRR}} \left.\right)$</mml:annotation></mml:semantics> </mml:math> value of 99.9%. Overall, V@Mo₃C₂ exhibits remarkable selectivity for the NRR compared to the HER, exhibiting a low current density, which inhibits the HER and high Faradaic efficiency. These findings demonstrate the potential of alternate TM-based MXenes surfaces, such as V@Mo₃C₂, for efficient ammonia synthesis.