(Invited) Electrochemical Characterization of the Interface between Atmospheric Noble Gas Plasma Jet and Aqueous Solution

Abstract

Elucidation of general features of the interface between atmospheric pressure plasma jets and aqueous solutions would be beneficial to environmental, agricultural and biomedical applications. Such fundamental descriptions are critically important to design process chemistries and scale-up production. In this presentation, our recent efforts towards that end will be discussed. The focus of the talk will be on free jets of low temperature radiofrequency (RF) plasma generated using noble gas in contact with water, in contrast to the often used two-electrode configuration with e.g. micro-plasmas. Experiments will be presented in support of a perspective that views the plasma-liquid interface as a boundary condition that locally constrains the reduction potential, which can be controlled using parameters such as the plasma gas composition, applied RF power, and jet stand-off distance. A unique spatial distribution of the reduction potential that develops to maintain charge neutrality in the aqueous solution will be presented. The consequences for process design and scale-up will be expanded upon.