Recent advances towards aqueous hydrogen peroxide formation in a direct current plasma-liquid system

The aqueous phase hydrogen peroxide(H_(2)O_(2aq))produced from the plasma-liquid interactions can directly or synergistically(with other substances)affect the liquid chemistry,and therefore it is important to unfold the H_(2)O_(2aq)formation mechanism.However,up to now,a consensus on the H_(2)O_(2aq)formation mechanism is not reached.This review aims to survey the recent advances on the understanding of the H_(2)O_(2aq)formation mechanism in the system of a direct current discharge plasma operated over a liquid electrode.Theoretical and experimental analyses indicate that the recombination of dissolved OH radicals(OHaq)is the dominant process for the H_(2)O_(2aq)formation,while the purported plasma-induced photolysis of water and the dissolution of gaseous H_(2)O_(2)are ruled out.