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 (Ti₃C₂T_x) 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.

由于大多数催化剂的选择性差，由N ₂和H ₂ O合成NH ₃的电流效率极低。在这里，我们证明了在环境条件下，附着在垂直排列的金属主体上的MXene（Ti ₃ C ₂ T _x）纳米片可以在NH ₃电合成的超低电势下实现高法拉第效率（5.78％）。根据实验和理论证据，MXene的基面是相对惰性的，其较高的活性与更多的暴露边缘位点有关。这项工作阐明了NH ₃选择性的显着提高。电合成可以通过调节活性位点和阻止氢释放活性来实现。所提出的策略为优化2D催化剂的表面性能提供了新的机会，以在环境条件下有效地固定N ₂。