Yaroslavl Branch of the Institute of Physics and Technology, Russian Academy of Sciencies, Universitetskaya 21, Yaroslavl, 150007, Russia.
P. G. Demidov Yaroslavl State University, Sovetskaya 14, Yaroslavl, 150000, Russia.
Sci Rep. 2016 Dec 16;6:39381. doi: 10.1038/srep39381.
Water electrolysis performed in microsystems with a fast change of voltage polarity produces optically invisible nanobubbles containing H and O gases. In this form the gases are able to the reverse reaction of water formation. Here we report extreme phenomena observed in a millimeter-sized open system. Under a frequency of driving pulses above 100 kHz the process is accompanied by clicking sounds repeated every 50 ms or so. Fast video reveals that synchronously with the click a bubble is growing between the electrodes which reaches a size of 300 μm in 50 μs. Detailed dynamics of the system is monitored by means of a vibrometer by observing a piece of silicon floating above the electrodes. The energy of a single event is estimated as 0.3 μJ and a significant part of this energy is transformed into mechanical work moving the piece. The observations are explained by the combustion of hydrogen and oxygen mixture in the initial bubble with a diameter of about 40 μm. Unusual combustion mechanism supporting spontaneous ignition at room temperature is responsible for the process. The observed effect demonstrates a principal possibility to build a microscopic internal combustion engine.
在具有快速电压极性变化的微系统中进行的水分解会产生含有 H 和 O 气体的不可见纳米气泡。以这种形式，气体能够进行水形成的逆反应。在这里，我们报告在毫米级开放系统中观察到的极端现象。在驱动脉冲频率高于 100 kHz 的情况下，该过程伴随着每 50 ms 左右重复一次的咔嗒声。快速视频显示，与咔嗒声同步，在电极之间生长出一个气泡，在 50 μs 内达到 300 μm 的大小。通过观察漂浮在电极上方的一块硅片，利用测振仪来监测系统的详细动态。单次事件的能量估计为 0.3 μJ，其中很大一部分能量转化为移动该硅片的机械功。这一观察结果可以通过直径约为 40 μm 的初始气泡中氢和氧混合物的燃烧来解释。支持室温自发点火的异常燃烧机制是该过程的原因。所观察到的效应证明了构建微观内燃机的基本可能性。
