Quantitative characterization of the temporal-spatial evolution of RONS in air surface micro-discharge using UV–VIS optical absorption spectroscopic diagnosis and modeling approach

Abstract

The research of the chemically active species of cold atmospheric pressure plasmas is a essential step for a more in-depth comprehension of the effects of its interaction with the target. In this paper, the temporal and spatial evolution of key species O3, NO2 and NO3 produced by surface micro-discharge in air were investigated. UV–VIS optical absorption spectroscopy at 254 nm, 400 nm and 662 nm were used to measure the concentrations of O3, NO2 and NO3, respectively. The results show that the temporal evolution of O3, NO2 and NO3 are revealed a significant correlation with the surface power density (SPD). The phenomenon of O3 and NO3 quenching occur once the SPD overcomes a critical value of 0.15 W cm−2. An O3-enriched atmosphere (peak concentration around 3000 ppm) is formed when the SPD is below the critical value, and a NO2-enriched atmosphere (maximum NO2 density around 600 ppm) is formed at higher SPD. In addition, the concentration distribution of O3, NO2 and NO3 in the chamber ranging from 10–100 mm of the downstream of the mesh electrode tends to be uniform. Finally, a zero-dimensional model of the afterglow chemistry, validated using the experimental measurements, is developed to determined important reactions affecting O3, NO2 and NO3 respectively, and obtain insight into the evolutionary behavior of the considered reactive species.