Work

Observation of Reduced Products in Oxidizing Environment During Nitrogen Fixation Using Coaxial Dielectric Barrier Discharge in Air

Year: 2026

Type: article

Abstract: Chemical processes in dielectric barrier discharge (DBD) of air are currently being explored as a “green” alternative to artificial N2-fixation for fertilizer production. Because both nitrate and ammonium are primarily taken up by plants, they are the major ingredients of nitrogen fertilizers. However, NH3synthesis by DBD in an oxidizing environment like air is challenging because NH3is itself a reduced end-product of N2-fixation. N2-fixation in a coaxial-DBD (c-DBD) reactor was carried out using dry-air (${\mathrm {NO}}_{3}^{-} + {\mathrm {NH}}_{4}^{+}$) of ~0.256 and${\sim} 0.12~\mu \mathrm {mol}\cdot \text {kJ}^{-1}$in 180 min, respectively. Introducing water directly inside the c-DBD reactor plasma–water interaction (PWI) fundamentally shifted the product distribution. The PWI configuration demonstrated a massive shift in selectivity toward ammonium, yielding${\sim}0.176~\mu \mathrm {mol}\cdot \text {kJ}^{-1}$of${\mathrm {NH}}_{4}^{+}$at a specific energy cost of${\sim}5.68~\mathrm {GJ}\cdot \text {mol}^{-1}$. The introduction of liquid water shifted the physical discharge mode, suppressing discrete filamentary microdischarges in favor of a more continuous, capacitance-driven discharge regime. The plasma-water interface also acted as an immediate solvation sink, helping gaseous${\mathrm {NH}}_{3}$dissolve in water to avoid DBD-induced dissociation. The findings of this study reveal a hybrid plasma-electrochemical pathway for nitrogen fixation without direct use of purified nitrogen and hydrogen gases.

Source: IEEE Transactions on Plasma Science

DOI: 10.1109/tps.2026.3720693