期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2020
卷号：117
期号：49
页码：30934-30941
DOI：10.1073/pnas.2020158117
出版社：The National Academy of Sciences of the United States of America
摘要：It was previously shown [J. K. Lee et al. , Proc. Natl. Acad. Sci. U.S.A ., 116, 19294–19298 (2019)] that hydrogen peroxide (H 2 O 2 ) is spontaneously produced in micrometer-sized water droplets (microdroplets), which are generated by atomizing bulk water using nebulization without the application of an external electric field. Here we report that H 2 O 2 is spontaneously produced in water microdroplets formed by dropwise condensation of water vapor on low-temperature substrates. Because peroxide formation is induced by a strong electric field formed at the water–air interface of microdroplets, no catalysts or external electrical bias, as well as precursor chemicals, are necessary. Time-course observations of the H 2 O 2 production in condensate microdroplets showed that H 2 O 2 was generated from microdroplets with sizes typically less than ∼10 µm. The spontaneous production of H 2 O 2 was commonly observed on various different substrates, including silicon, plastic, glass, and metal. Studies with substrates with different surface conditions showed that the nucleation and the growth processes of condensate water microdroplets govern H 2 O 2 generation. We also found that the H 2 O 2 production yield strongly depends on environmental conditions, including relative humidity and substrate temperature. These results show that the production of H 2 O 2 occurs in water microdroplets formed by not only atomizing bulk water but also condensing water vapor, suggesting that spontaneous water oxidation to form H 2 O 2 from water microdroplets is a general phenomenon. These findings provide innovative opportunities for green chemistry at heterogeneous interfaces, self-cleaning of surfaces, and safe and effective disinfection. They also may have important implications for prebiotic chemistry.
