On the formation of hydrogen peroxide in water microdroplets.

Recent reports on the formation of hydrogen peroxide (HO) in water microdroplets produced pneumatic spraying or capillary condensation have garnered significant attention. How covalent bonds in water could break under such mild conditions challenges our textbook understanding of physical chemistry and water. While there is no definitive answer, it has been speculated that ultrahigh electric fields at the air-water interface are responsible for this chemical transformation.

The Air-Water Interface of Water Microdroplets Formed by Ultrasonication or Condensation Does Not Produce HO.

Recent reports on the production of hydrogen peroxide (HO) on the surface of condensed water microdroplets without the addition of catalysts or additives have sparked significant interest. The underlying mechanism is thought to be ultrahigh electric fields at the air-water interface; smaller droplets present larger interfacial areas and produce higher (detectable) HO yields. To gain insights into this phenomenon, we performed condensation experiments and quantified HO formation as a function of the vapor source.