Ambient catalyst-free nitrogen fixation with water dimer

The growth and sustainable development of humanity is heavily dependent upon the process of fixing nitrogen (N2) to ammonia (NH3). However, the currently adopted methods are associated with severe environmental hazards and tremendous energy costs, which limit their sustainability and profitability. Herein we discovered a catalyst-free disproportionation reaction of N2 by water dimer radical cation, (H2O)2+, which occurs under mild ambient conditions via distinctive HONH-HNOH+ intermediate to yield economically valuable nitroxyl (HNO) and hydroxylamine (NH2OH) products, in alternative to NH3. Calculations suggest that the reaction is prompted by the coordination of electronically excited N2 with (H2O)2+ in its two-center-three-electron (2c-3e) configuration. The ambient one-step fixation of N2 into HNO and NH2OH with high selectivity offers great profitability and total avoidance of polluting emissions, such as CO2 or NOy, thus giving an entirely new look and perspectives to the problem of green N2 fixation.