Nonheating ozone suppression in pulsed air discharges: role of pulse duration and repetition rate. (19th July 2021)

• Record Type: Journal Article
• Authors: Park, Sanghoo; Kim, Jinwoo; Lee, Hyungyu; Han, Duksun; Park, Seungil; Kim, Seong Bong; Choe, Wonho
• Is Part Of: Journal of physics. Volume 54:Number 39(2021)
• Publication Date: 2021-07-19
• Subjects: air discharge -- dielectric barrier discharge -- nanosecond pulse -- plasma chemistry -- ozone -- nitrogen oxides -- ozone-free phenomenon; Physics -- Periodicals; 530
• DOI: 10.1088/1361-6463/ac113b
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: Facilitating the separate production of ozone (O3 ) and nitrogen oxides (NO x ) in air discharges without a thermal process is of most merit in diversifying plasma technology; in particular, it is a primary requirement in certain cold, heat-sensitive plasma applications. Here, we propose a new method of nonheating ozone suppression in air discharges. The present work demonstrates that controlling the plasma chemical kinetics by adjusting the duration (width) and/or repetition frequency of the high-voltage DC pulse is effective in suppressing ozone formation in a surface dielectric barrier discharge in static ambient air. The temporal development of each oxygen- and nitrogen-related species in air discharge is complicated and shows different trends in the time range <10 µ s; relatively long-lived O3 and NO x are strongly governed by the temporal behavior of short-lived reactive species, such as excited N2 (A) and N2 ( v ). To quantify time-varying O3 and NO x, an in situ UV absorption spectroscopy is applied to our gas-tight plasma reactor, which is operated in air at 21 °C. With a fixed frequency at 10 kHz and decreasing pulse duration from 10 μ s to 0.18 μ s, ozone is quenched faster in the plasma reactor, resulting in an irreversible chemical mode transition from an O3 - to NO-rich environment. From a different set of experiment (with a 200 ns pulse duration and a frequency range of 1–10 kHz), we can conclude that the off-pulse period also plays a crucial role in the temporal evolution of O3 and NO x ; the larger the applied driving frequency is, the earlier the ozone-free phenomenon appears over the discharge time. Our findings represent a breakthrough in expanding the usage of air discharges and their application in various fields of interest.