Analyses of chemical reactions in plasma generated within humid oxygen bubbles with highly concentrated ozone*

We have used plasma generated within oxygen bubbles for generation of liquid-phase hydrogen peroxide. In this study, effects of additions of ozone and water vapor to the bubbles on the hydrogen peroxide generation were investigated. Ozone addition slightly increased rate and energy efficiency of hydrogen peroxide generation when the bubbles were not humidified. With humidification, on the other hand, different tendencies were observed depending on the plasma input power. The rate and efficiency increased with increasing ozone concentration when the input power was high. At ozone concentration of 100 g/m^_3, twice the rate and efficiency were achieved as without ozone addition. However, the hydrogen peroxide generation was suppressed with such highly concentrated ozone with low input power. The reactions in the plasma were analyzed by numerical simulations with a global model which included electron-impact reactions and chemical reactions.