Reactive oxygen and nitrogen species in Ar + N2 thorn O2 atmospheric-pressure nanosecond pulsed plasmas in contact with liquid

In this paper, a nanosecond pulse gas-liquid discharge is generated in Ar and Ar with admixtures of N-2 or O-2. The discharge images and waveforms of pulse voltage and discharge current are used to characterize gas-liquid discharge characteristics; optical emission spectroscopy and Fourier-transform infrared spectroscopy are employed to diagnose the reactive species in the gas phase, and chemical probe methods are employed to investigate plasma-induced reactive species (H2O2, NO2-, and NO3-) in the liquid phase. The effects of added contents of N-2 or O-2 in Ar discharge on the formation of reactive species are investigated. It is found that the productions of gaseous O and O-3 increase obviously with the increasing O-2 ratio and the productions of gaseous N-2 (C-B), NO, NO2, and N2O increase with the increasing N-2 ratio. Additionally, for the reactive species measured in the liquid phase, the increase in the N-2 ratio in Ar discharge is beneficial for increasing the concentrations of NO3- and NO2- and decreasing the concentrations of H2O2, while the increase in the O-2 ratio in Ar discharge decreases the concentrations of H2O2 and inhibits the production of NO2-. Published under license by AIP Publishing.