Ambient catalyst free nitrogen fixation with water dimer radical cation

15 May 2023, Version 2
This content is a preprint and has not undergone peer review at the time of posting.


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. Subsequent excited-state double proton transfer leads to one-step water addition to N2. The ambient 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.


nitrogen fixation
water dimer radical-cation
green chemistry
triplet state
density functional theory
infrared spectroscopy
Raman spectroscopy

Supplementary materials

Supplementary Materials for Ambient catalyst-free nitrogen fixation with water dimer radical cation
Supplementary Materials for Ambient catalyst-free nitrogen fixation with water dimer radical cation: Materials and Methods, Figs. S1 to S9, Tables S1-S2, References


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