N2O5 in air discharge plasma: energy-efficient production, maintenance factors and sterilization effects

N2O5, a reactive species produced by air discharge plasma, has recently attracted much attention. Due to its high reactivity and solubility, N2O5 is a key molecule in nitrogen fixation processes and exhibits promising prospects in plasma biomedicine. However, thus far, it is not well known how to produce N2O5 efficiently and then maintain its concentration under the action of fast removal reactions. In view of this, N2O5 production by dielectric barrier discharge (DBD) alone and by the combination of DBD and gliding arc discharge is compared in this paper. It is found that the combination method can yield over three times the concentration of N2O5 compared to the single DBD method with the optimum discharge power. Moreover, the concentration of N2O5 in the effluent gas can be maintained once O-3 also exists because O-3 can continually produce N2O5 to compensate for its reduction. Finally, the sterilization effects of both the plasma effluent gas and plasma-activated water have trends similar to the trend of the gaseous N2O5 concentration, implying that N2O5 plays an important role in sterilization. This paper enhances the understanding of N2O5 chemistry in air discharge plasma and provides an effective way to produce and maintain N2O5 for subsequent applications.