Efficient Electrocatalytic N2 Fixation with MXene under Ambient Conditions

The current efficiency of NH3 electrosynthesis from N2 and H2O is ultralow as a result of poor selectivity in most catalysts. Here, we demonstrate that under ambient conditions, MXene (Ti3C2Tx) nanosheets attached to a vertically aligned metal host can achieve a high faradic efficiency (5.78%) at an ultralow potential for NH3 electrosynthesis. On the basis of experimental and theoretical evidence, the basal plane of MXene is relatively inert, and its higher activity is related to a greater number of exposed edge sites. This work elucidates that significantly improved selectivity of NH3 electrosynthesis can be achieved by tuning active sites and retarding hydrogen evolution activity. The proposed strategy provides a new opportunity to optimize the surface properties of 2D catalysts for efficient N2 fixation under ambient conditions.