| AVS 66th International Symposium & Exhibition | |
| Plasma Science and Technology Division | Monday Sessions |
| Session PS1-MoA |
| Session: | Plasma-Liquid Interactions, Medicine, and Agriculture |
| Presenter: | Hernan E. Delgado, University of Notre Dame |
| Authors: | H.E. Delgado, University of Notre Dame D.M. Bartels, University of Notre Dame P. Rumbach, University of Notre Dame D.B. Go, University of Notre Dame |
| Correspondent: | Click to Email |
A common configuration used in plasma-liquid interactions is that in which a direct current (DC) gas discharge is generated between a liquid and a metal. Under this configuration, known as plasma electrolysis or glow-discharge electrolysis, the liquid itself functions as a plasma cathode or anode, for a positive or negative DC bias, respectively. However, it is not clear exactly how the liquid participates in the formation and sustaining of the plasma, including charge transfer at the plasma-liquid interface. This is especially true when the liquid is acting as a cathode, and secondary emission from the liquid is ostensibly required to sustain the plasma. In this work, we use measurements of the breakdown and discharge voltages to understand this process. Voltage measurements for an argon plasma in contact with an aqueous solution are conducted in an electrochemical H-cell reactor to test for conditions that would facilitate secondary emission from the liquid. Voltage measurements across the plasma show a strong dependence on ionic strength, and no dependence on pH (from pH = 0 to 14) while controlling for ionic strength. The voltage was also found to be strongly dependent on the temperature of the liquid. Free radical scavengers nitrite and nitrate had no significant effect on the plasma voltage even at 1.0 M concentration, suggesting that the solvated electron, the pre-solvated electron, and the hydrogen atom do not play a crucial role in secondary emission as previously proposed.