Study of the Marangoni effect on the gas evolution during electrolysis


Study of the Marangoni effect on the gas evolution during electrolysis

Hossain, S.; Mutschke, G.; Eckert, K.; Massing, J.; Yang, X.; Baczyzmalski, D.; Cierpka, C.

Electrolytic gas evolution is a fundamental phenomenon occurring in a large number of industrial applications where gas bubbles grow at electrodes from a supersaturated solution. Since dissolved gases or ionic species can change the surface tension, a gradient may exist along the interface between the gas bubble and the electrolyte. Surface tension gradients may also arise from temperature gradients generated from Ohmic heating by the Faradaic current. The resulting shear stress can drive convection at the interface (Marangoni effect) which may influence the mass transfer across the interface during growth and finally the departure of the gas bubble.
In this study, numerical simulations are performed on Marangoni convection around a hydrogen gas bubble grown electrochemically at a microelectrode in an acidic electrolyte. The results are compared with recent experimental results on the near-bubble convection obtained by a Particle Tracking Velocimetry (PTV) technique and on corresponding temperature measurements. A clear evidence for the Marangoni effect is found [1], and the ratio of thermal and solutal Marangoni effects is discussed.

[1] X. Yang et al., Phys. Chem. Chem. Phys., accepted (2018).

Keywords: electrolysis; gas evolution; Marangoni effect; convection; numerical simulation

  • Lecture (Conference)
    12. European Fluid Mechanics Conference, 09.-13.09.2018, Wien, Österreich

Permalink: https://www.hzdr.de/publications/Publ-27935
Publ.-Id: 27935