Analysis of Atomic Oxygen Generation in Microcavity Plasmas Using a Multi-PMT setup and 0D Modeling

Dielectric barrier discharges (DBDs) are widely used for applications like ozone generation and VOC treatment, where performance can be enhanced through catalyst integration. A detailed understanding of reactive species formation is crucial, yet temporally resolving their production remains challenging, especially during the initial discharges. This study investigates atomic oxygen generation as a model for reactive species formation in a microcavity plasma array, a surface DBD confined to micrometer-scale cavities, which allows for catalyst integration. Optical emission spectroscopy was used to study plasma-chemical processes with 0.1–0.25% O₂ admixtures diluted in helium at atmospheric pressure. The discharge, driven by a 15 kHz, 600 V triangular voltage, achieved nearly complete oxygen dissociation, quantified via helium state-enhanced actinometry (SEA). A novel multi-photomultiplier setup enabled time-resolved tracking of atomic oxygen density and dissociation dynamics within the first discharges. Comparing the results to those of a basic 0D chemical model validated the experimental results and enabled the determination of the oxygen surface loss probability. This value was consistent with the nickel electrode's sticking coefficient reported in the literature.