Surface dielectric barrier discharge - From O3 mode to NOx mode as a function of dielectric temperature

Surface dielectric barrier discharges (SDBDs) operating in atmospheric air are efficient sources of reactive oxygen and nitrogen species (RONS), making them promising candidates for food decontamination applications. However, their chemical output strongly depends on operating conditions and environmental humidity that can affect treatment efficacy and reproducibility. In this work, we characterize the transition between ozone-dominant (O3 mode) and nitrogen-oxidesdominant (NOX mode) operating regimes by combining ICCD imaging, optical emission spectroscopy, and time-resolved absorption measurements of O3 and NO2 . We demonstrate that an increase of the applied voltage and the dielectric temperature accelerates the shift from net ozone production to rapid O₃ destruction driven by NOx catalytic cycles, while water vapor further suppresses ozone formation through enhanced OH-and H-driven reactions. Spatiotemporal ICCD measurements reveal that humidity simultaneously modifies streamer morphology and enhances overall plasma intensity. These findings establish quantitative operating windows to control RONS production for applications requiring either oxidative (O3 -rich) or nitrosative (NOx -rich) biocidal environments, providing essential knowledge for optimizing plasma-based food safety technologies.