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

The growth and sustainable development of humanity is heavily dependent upon molecular nitrogen (N) fixation. Herein we discover ambient catalyst-free disproportionation of N by water plasma which occurs via the distinctive HONH-HNOH intermediate to yield economically valuable nitroxyl (HNO) and hydroxylamine (NHOH) products. Calculations suggest that the reaction is prompted by the coordination of electronically excited N with water dimer radical cation, (HO), 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 h for NHOH and 0.37 μg cm h for HNO. Potential applications of these compounds are demonstrated to make ammonia (for NHOH), as well as to chemically react and convert cysteine, and serve as a neuroprotective agent (for HNO). The conversion of N into HNO and NHOH by water plasma could offer great profitability and reduction of polluting emissions, thus giving an entirely look and perspectives to the problem of green N fixation.