A DFT Study of the Reaction Products/Mechanism in Plasma-Assisted Ammonia Synthesis from Water and Nitrogen and Their...

This paper presents a thorough investigation of potential reaction products when water and nitrogen react in the gas phase and a reaction mechanism is proposed. We present thermochemistry and simulated infrared (IR) spectroscopy of reactions involved in the synthesis of ammonia (NH₃), hydrazine (N₂H₄), and some new ammonia-based molecules (NH₂OOH, ONH₂OH) from water (H₂O) and nitrogen gas (N₂). The production of ammonia and hydrazine is of significant interest because of their essential roles as chemical feedstocks, propellants, and potential clean energy carriers. However, the underlying chemical processes and their energy requirements have not been fully explored, especially considering the environmental effects of their use as fuels in internal combustion engines (ICE). We find that there are 6 different reaction products that may be formed during the ammonia synthesis from N₂ and H₂O, which include ammonia, hydrazine, hydroxylamine (NH₂OH), ammonia oxide (NH₃ ⁺-O^-), and two forms of hydroxylamine oxide (NH₂OOH, ONH₂OH), and the latter chemical species have not been previously reported or synthesized. The partially oxidized products of ammonia have similar formation energies to those of ammonia, which suggests that they could be produced during the plasma-assisted synthesis. Our simulated infrared spectra can help in the identification and characterization of ammonia synthesis products.