Analysis of the production mechanism of H₂O₂ in water treated by helium DC plasma jets

Abstract

In this paper, helium plasma jets are used for water activation to explore the production mechanism of H2O2 in the water. Either positive or negative DC voltage is used for the plasma excitation. It is found that the concentration of aqueous H2O2 induced by the positive plasma jet is ~4 times larger than that by the negative plasma jet with similar average discharge current. Three production pathways of aqueous H2O2 are considered important in literature, including the electrolysis, the dissolution of gaseous H2O2, and the combination of aqueous OH. However, the first two pathways are found to have similar contributions on H2O2 production for the positive and negative plasma jets. It is deduced that the OH combination in the surface layer of the plasma-activated water is most responsible for the concentration difference of aqueous H2O2 between the two plasma jets.