video: Tiny water droplets from condensed water vapor contain hydrogen peroxide, as shown vividly by a paper test strip that turns blue. view more
Credit: Movie credit: Jae Kyoo Lee and Hyun Soo Han.
Micron-sized water droplets condensed from water vapor contain small amounts of hydrogen peroxide, according to a study. When water is atomized into micron-sized droplets, water molecules can become electrochemically active and catalyze a variety of reactions. Previous research has shown that water molecules can spontaneously oxidize to form hydrogen peroxide (H2O2). Expanding on the finding, Richard Zare, Fritz Prinz, and colleagues report that spontaneous H2O2 production occurs when microdroplets are formed by condensing water vapor onto low-temperature substrates, suggesting that oxidation of water into H2O2 is a general phenomenon associated with microdroplet formation, regardless of the mechanism. Through experiments on a variety of surfaces, including silicon, plastic, glass, and metal, the authors found that H2O2 yield depends on droplet nucleation and growth and on conditions at the substrate surface, such as temperature and relative humidity. The authors also suggest potential mechanisms of H2O2 formation, noting that the established presence of a strong electric field at the periphery of water microdroplets may create OH radicals that subsequently recombine. The finding that water spontaneously oxidizes into H2O2, as a general property of microdroplet formation, carries implications for a broad array of fields, from environment-friendly surface disinfection technology to research in atmospheric sciences and on the origin of life on Earth.
Article #20-20158: "Condensing water vapor to droplets generates hydrogen peroxide," by Jae Kyoo Lee, Hyun Soo Han, et al.
MEDIA CONTACTS: Richard N. Zare, Stanford University, CA; e-mail: <zare@stanford.edu; Fritz B. Prinz, Stanford University, CA; email: fprinz@stanford.ed
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Journal
Proceedings of the National Academy of Sciences