This work investigates the effect of Ar addition on N2 gliding arc plasma to enhance ammonium ions concentration in water. The concentration of ammonium ion \(\left({\text{N}\text{H}}_{4}^{+}\right)\) increased by 50.2% when Ar gas was added upto 40% by volume to the N2 gliding arc plasma, thus indicating the significant contribution of Ar in \({\text{N}\text{H}}_{4}^{+}\) synthesis. Adding 20% Ar in N2 resulted in a maximum \({ \text{N}\text{H}}_{4}^{+}\) concentration of 16.5 ppm and a production rate of 1.31 mg hr-1. While adding 40% Ar into N2 plasma, the highest energy efficiency of 0.036 g- \({\text{N}\text{H}}_{4}^{+}\) KWh−1was obtained with a specific energy input of 742.5 J/L. The mechanisms of \({ \text{N}\text{H}}_{4}^{+}\) enrichment with Ar addition were investigated by studying the electrical properties, vibrational, rotational and electron temperature of the gliding arc plasma with respect to the addition of Ar concentration in N2 plasma. Particularly, the presence of 26.5% Ar by volume in N2 plasma results in a significant ion current, which generates high ionization of \({\text{N}}_{2}^{+}\) .
