Efficient catalyst-free N₂ fixation by water radical cations under ambient conditions

The growth and sustainable development of humanity is heavily dependent upon molecular nitrogen (N₂) fixation. Herein we discover ambient catalyst-free disproportionation of N₂ by water plasma which occurs via the distinctive HONH-HNOH^+• intermediate to yield economically valuable nitroxyl (HNO) and hydroxylamine (NH₂OH) products. Calculations suggest that the reaction is prompted by the coordination of electronically excited N₂ with water dimer radical cation, (H₂O)₂^+•, in its two-center-three-electron configuration. The reaction products are collected in a 76-needle array discharge reactor with product yields of 1.14 μg cm^-2 h^-1 for NH₂OH and 0.37 μg cm^-2 h^-1 for HNO. Potential applications of these compounds are demonstrated to make ammonia (for NH₂OH), as well as to chemically react and convert cysteine, and serve as a neuroprotective agent (for HNO). The conversion of N₂ into HNO and NH₂OH by water plasma could offer great profitability and reduction of polluting emissions, thus giving an entirely look and perspectives to the problem of green N₂ fixation.