Study on hydrogen peroxide generation by water surface discharge

Chemical activity of underwater discharge plasma and air discharge plasma generated in contact with water surface in form of streamer channels propagating along the water surface has been investigated using hydrogen peroxide as chemical probe. Point-to-plane electrode geometry and pulse high voltage of positive polarity generated with magnetic pulse compression (MPC) pulsed power modulator was used. The effects of pulse repetition rate (up to 1 000 pulses per second), air gap distance between electrode tip and water surface on the discharge characteristics and the efficiency of H₂O₂ production by plasma was determined. The comparison of both types of discharge plasmas (i.e., directly in water and in contact with water surface) was made. The production yield efficiency of H₂O₂ generation widely varied with pulse repetition rate in the case of underwater discharge plasma, while it was almost the same in the case of water surface discharge. The efficiency of underwater discharge was higher than that of water surface discharge up to 150 pps. From 500 pps the efficiency of water surface discharge was significantly higher than that of underwater discharge. No significant effect of gap distance between the needle tip and water surface on the formation of H₂O₂ by the pulsed water surface discharge has been determined.