Effect of ozone and humidity addition on hydrogen peroxide generation characteristics of plasmas in oxygen bubbles

The effects of addition of ozone (O3) and humidity on oxygen (O2) bubbles during hydrogen peroxide (H2O2) generation by AC plasmas in the bubbles were investigated. The best H2O2 generation characteristics, with a generation rate and an efficiency of 161 mg/h and 1.74 g/kWh, respectively, were achieved when humidified O3 was used with ballast capacitors of 100 pF at 3 kHz. Zero-dimensional simulations of gas-phase reactions with different water vapor concentrations were performed to investigate the H2O2 generation reactions. It was confirmed that the use of humidified O3 contributed to hydrogen peroxide formation by enhancing OH radical generation via reactions involving O, H, and HO2 radicals.