Reactive Species Transport To Water Micro-Droplets In Atmospheric Pressure Rf Glow Discharges

Chemical reactivity transfer from gas-phase plasmas to liquid can be significantly enhanced when a plasma interacts with small liquid micro-droplets as opposed to bulk liquid. In this contribution, the role of • OH as well as non- • OH driven chemistry on the degradation of an organic compound (formate) by activation of water micro-droplets by atmospheric pressure diffuse RF glow plasmas in He and different gas admixtures (Ar, H 2 , O 2 , H 2 O) is explored. Using detailed gas-phase plasma diagnostics, droplet characterization and ex situ chemical analysis of the plasma- treated droplets, the effect of short-lived species such as O • , H • and • OH, O 2 ( a ), electrons/ions, and metastable atoms of He and Ar is quantified. With increasing droplet residence time, the formate decomposition increases in electronegative plasmas (He/H 2 O He/Ar/H 2 O, He/O 2 ), with a maximum of ~70% within ~15 ms, while an inverse trend is observed in electropositive plasmas (He, He/H 2 , He/Ar), with >75% degradation within ~5 ms.