Musskopf Nayara H, Gallo Adair, Zhang Peng, Petry Jeferson, Mishra Himanshu
Interfacial Lab (iLab), King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering (BESE) Division, Water Desalination and Reuse Center (WDRC), Thuwal 23955-6900, Saudi Arabia.
J Phys Chem Lett. 2021 Nov 25;12(46):11422-11429. doi: 10.1021/acs.jpclett.1c02953. Epub 2021 Nov 18.
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. Specifically, we compared the HO concentration in water microdroplets condensed from the vapor realized via (i) heating water in the range of 50-70 °C and (ii) ultrasonic humidification (as exploited in the original report). Experimental results revealed that the HO level inside water microdroplets condensed via heating water was below our detection limit (≥0.25 μM), regardless of the droplet size or the substrate wettability. In contrast, water droplets condensed via ultrasonic humidification contained significantly higher (∼1 μM) HO concentrations. We conclude that the ultrasonic humidifiers contribute to HO production, not droplet interfacial effects.
最近，有关在不添加催化剂或添加剂的情况下，在冷凝水微滴表面产生过氧化氢（HO）的报道引发了广泛关注。其潜在机制被认为是气-水界面处的超高电场；较小的液滴具有更大的界面面积，并产生更高（可检测到）的HO产量。为了深入了解这一现象，我们进行了冷凝实验，并将HO的形成量量化为蒸汽源的函数。具体而言，我们比较了通过以下两种方式从蒸汽中冷凝得到的水微滴中的HO浓度：（i）将水加热至50-70°C范围；（ii）超声加湿（如原始报告中所采用的）。实验结果表明，无论液滴大小或基底润湿性如何，通过加热水冷凝得到的水微滴内部的HO水平均低于我们的检测限（≥0.25μM）。相比之下，通过超声加湿冷凝得到的水滴含有显著更高（约1μM）的HO浓度。我们得出结论，超声加湿器有助于HO的产生，而非液滴界面效应。
