A 2D Ba₂N Electride for Transition Metal-Free N₂ Dissociation under Mild Conditions

N₂ activation is a key step in the industrial synthesis of ammonia and other high-value-added N-containing chemicals, and typically is heavily reliant on transition metal (TM) sites as active centers to reduce the large activation energy barrier for N₂ dissociation. In the present work, we report that a 2D electride of Ba₂N with anionic electrons in the interlayer spacings works efficiently for TM-free N₂ dissociation under mild conditions. The interlayer electrons significantly boost N₂ dissociation with a very small activation energy of 35 kJ mol^-1, as confirmed by the N₂ isotopic exchange reaction. The reaction of anionic electrons with N₂ molecules stabilizes (N₂)^2- anions, the so-called diazenide, in the large interlayer space (∼4.5 Å) sandwiched by 2 cationic slabs of Ba₂N as the main intermediate.