Enhancing selective production of atomic oxygen through nanosecond pulse-burst driven mode in a He/O₂ dielectric barrier discharge

Abstract

In this study, the temporal evolution of O atoms in a nanosecond burst-pulsed dielectric barrier discharge (DBD) is measured by two-photon absorption laser-induced fluorescence (TALIF) spectroscopy. The experiment is conducted at burst conditions of 50, 100, and 200 kHz pulse frequency, 10 Hz burst frequency, and 20 to 400 pulses in 0.1%~2% O2 + He mixtures. The accumulation effect of O atoms in the burst mode is observed and the density gradually saturates at around 100 pulses. Increasing the pulse frequency effectively enhances the O saturation density. The 0-dimensional kinetic model reveals that the saturation effect is primarily balanced by the formation and loss characteristics of O atoms. Similar saturation effect is also observed in the typical continuous periodic pulse mode (one pulse each cycle), but with a saturation density about one order of magnitude lower than that in the burst case, highlighting the burst excitation mode as an effective method for enhancing the instantaneous peak production of O atoms. Further investigations into the influence of O2 proportion on the selective production of O atoms are also performed. The results suggest that a low O2 proportion (<2%) and pulse-burst driven mode for the He/O2 DBD facilitates the selective production of O atoms while competing with O3 formation.