Promoting N₂ electroreduction to ammonia by fluorine-terminating Ti₃C₂T_x MXene

Two-dimensional MXene-based materials are potential of presenting unique catalytic performances of electrocatalytic reactions. The surface functionalization of MXene-based catalysts is attractive for developing efficient electrocatalysts toward nitrogen reduction reaction. Herein, we reported a Ti₃C₂T_x MXene with a medium density of surface functionalized fluorine terminal groups, as an excellent N₂ reduction reaction electrocatalyst with enhanced adsorption and activation of N₂. The Ti₃C₂T_x MXene catalyst showed a production rate of ammonia as 2.81 × 10^-5 μmol·s^-1·cm^-2, corresponding to a partial current density of 18.3 μA·cm^-2 and a Faradic efficiency of 7.4% at - 0.7 V versus reversible hydrogen electrode in aqueous solutions at ambient conditions, substantially exceeding similar Ti₃C₂T_x MXene catalysts but with higher or lower densities of surface fluorine terminal groups. Our work suggests the capability of developing surface functionalization toolkit for enhancing electrochemical catalytic activities of two-dimensional MXene-based materials.