Marangoni convection at electrogenerated hydrogen bubbles.
Marangoni convection at electrogenerated hydrogen bubbles.
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DOI：
10.1039/c8cp01050a
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发表时间：
2018-05
期刊：
影响因子：
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通讯作者：
Xuegeng Yang;D. Baczyzmalski;C. Cierpka;G. Mutschke;K. Eckert
中科院分区：
文献类型：
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作者：
Xuegeng Yang;D. Baczyzmalski;C. Cierpka;G. Mutschke;K. Eckert
电解气体析出是在大量工业应用中发生的基本现象。在这些过程中，气泡在电极处由过饱和溶液形成。由于溶解的气体可以改变表面张力，因此气体浓度梯度可以导致表面张力在气泡的界面处局部变化。表面张力梯度也可由于电解质的欧姆加热产生的温度梯度而形成。在这两种情况下，产生的剪切应力在电解质和气泡中施加对流（马兰戈尼效应）。这种现象可能影响整个电解气体析出过程，例如，通过增强的质量传递。在这项研究中，Marangoni对流附近生长的氢气泡，水电解产生的第一个证据，提供。利用高速显微成像技术研究了单个氢气泡在微电极上的演化过程。利用时间分辨粒子跟踪测速技术（PTV）测量了生长气泡界面附近的对流。结果表明，马兰戈尼对流的大小和电流之间有明显的相关性。
Electrolytic gas evolution is a fundamental phenomenon occurring in a large number of industrial applications. In these processes gas bubbles are formed at the electrode from a supersaturated solution. Since dissolved gases can change the surface tension, a gas concentration gradient may cause the surface tension to vary locally at the interface of the gas bubble. Surface tension gradients may also form due to temperature gradients generated by ohmic heating of the electrolyte. In both cases, the resulting shear stress imposes a convection in the electrolyte and the gas bubble (Marangoni effect). This phenomenon may influence the entire electrolytic gas evolution process, e.g., by an enhanced mass transfer. In this study, the first evidence of the Marangoni convection near growing hydrogen bubbles, generated by water electrolysis, is provided. Microscopic high speed imaging was applied to study the evolution of single hydrogen bubbles at a microelectrode. The convection near the interface of the growing bubble was measured by using a time-resolved Particle Tracking Velocimetry (PTV) technique. The results indicate a clear correlation between the magnitude of the Marangoni convection and the electric current.