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arXiv · 2109.03096

The air-water interface of condensed water microdroplets does not produce H$_2$O$_2$

Nayara H. Musskopf·Adair Gallo Jr.·Peng Zhang·Jeferson Petry·Himanshu Mishra
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Abstract

Recent reports on the production of hydrogen peroxide (H$_2$O$_2$) on the surface of condensed water microdroplets without the addition of catalysts or additives have sparked significant interest. The underlying mechanism is speculated to be ultrahigh electric fields at the air-water interface; smaller droplets present higher interfacial area and produce higher (detectable) H$_2$O$_2$ yields. Herein, we present an alternative explanation for these experimental observations. We compare H$_2$O$_2$ production in water microdroplets condensed from vapor produced via (i) heating water to 50-70 °C and (ii) ultrasonic humidification (as exploited in the original report). Water microdroplets condensed after heating do not show any enhancement in the H$_2$O$_2$ level in comparison to the bulk water, regardless of droplet size or the substrate wettability. In contrast, those condensed after ultrasonic humidification produce significantly higher H$_2$O$_2$ quantities. We conclude that the ultrasonication of water contributes to the H$_2$O$_2$ production, not droplet interfacial effects.

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Nayara H. Musskopf, Adair Gallo Jr., Peng Zhang, Jeferson Petry, Himanshu Mishra. 2021-09-07. The air-water interface of condensed water microdroplets does not produce H$_2$O$_2$. https://arxiv.org/abs/2109.03096

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