Correlation of Plasma Parameters to the Reduction Potential at the Plasma-Liquid Interface*

Atmospheric plasma in contact with aqueous solutions have been shown to act as gaseous electrodes, capable of promoting electrochemical reactions at the plasma-liquid interface. While the reduction potential in conventional electrochemical systems is controlled by applying a known voltage to a solid electrode via an external circuit, methods of controlling the reduction potential in plasma-liquid systems remain poorly understood. The hypothesis is that the plasma-liquid interface imposes a boundary condition in the solution, wherein the reduction potential is constrained by the plasma parameters. In this work, a RF-driven Ar jet impinging upon an aqueous solution was characterized using laser Thomson scattering and electrochemical measurements. The experimental findings will be discussed and an analysis establishing a link between the plasma parameters in the gas phase to the reduction potential in the liquid phase will be presented.