Magnetic field improves ozone production in an atmospheric pressure surface dielectric barrier discharge: understanding the physico-chemical mechanism behind low energy consumption.

Herein, we studied the combined effects of the magnetic field and the alternating current driven air surface dielectric barrier discharge on ozone production, and found that a 0.13 T perpendicular magnetic field introduced into the discharge area significantly enhanced the ozone generation performance with a 36-108% increase in ozone number density and 24-80% increase in ozone yield depending on discharge voltage and frequency differences. To reveal the micro physico-chemical mechanism of the influence of a magnetic field and discharge parameters of discharge voltage and frequency on ozone generation, a plasma chemical reaction network involving electron collision-chain reactions was considered. The results show that these parameters jointly influence ozone generation by affecting electron collision reactions and chain chemical reactions by changing the mean electron energy and plasma gas temperature. In this study, both the experimental results and mechanism analysis suggested that an optimal discharge parameter for ozone generation is the magnetic field assisted, low frequency, high voltage (6.5 kHz, 6.5 kV) surface dielectric barrier discharge. These insights provide guidance for optimizing the discharge parameters of the magnetic field assisted discharge to increase ozone production and reduce energy consumption.

Reduced electric field and gas temperature effects on chemical product dynamics in air surface dielectric barrier discharges: from macro-physical parameters to micro-chemical mechanisms.

To gain insights into the mechanisms of plasma chemical product interactions, the dynamic changes of the surface dielectric barrier discharge (SDBD) products are experimentally related to the reduced electric field and gas temperature. The higher applied voltage and frequency cause faster product changes from the O3-containing to the O3-free state, while raising the electron energy and gas temperature. The electron energy affects the electron collision reactions and the production of various reactive species, steering the chemical reactions towards the predominant production of NO over O3. The gas temperature affects the generation and quenching rates of the key products. Collectively, this work bridges macro-physical parameters and micro-chemical mechanisms through the electron energy and gas temperature effects, and contributes to better understanding of the physico-chemical processes in low-temperature plasmas.