On the Dynamics of Hydrogen Bubbles at Pt Microelectrodes

ORAL

Abstract

The growth of single hydrogen bubbles at Pt microelectrodes is studied during water electrolysis performed in an acidic electrolyte over a wide range of concentrations and cathodic potentials. New bubble growth regimes have been identified and summarized in the regime map. The regimes differ in terms of whether the bubble evolution proceeds with a monotonic or oscillatory variation of the electric current and if and how a carpet of microbubbles underneath the bubble evolves. Key features such as the growth law of the bubble radius, the dynamics of the microbubble carpet, the onset time of the oscillations, and the oscillation frequencies have been characterized as a function of the concentration and electric potential. Based on the analysis of the forces involved including electric and hydrodynamic (induced by Marangoni convection) forces, a sound hypothesis is formulated regarding the mechanism of the bubble oscillations and the evolution of a micro-bubble carpet.

*This project is supported by the German Space Agency (DLR) with funds provided by the Federal Ministry of Economics and Technology (BMWi) due to an enactment of the German Bundestag under Grant No. DLR 50WM1758 (project MADAGAS) and Grant No. DLR 50WM2058 (project MADAGAS II), the Federal State of Saxony in terms of the "European Regional Development Fund" (H2-EPF-HZDR), the Helmholtz Association Innovation pool project "Solar Hydrogen" and the Hydrogen Lab of the School of Engineering of TU Dresden.

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Publication: [1] Bashkatov, A., Hossain, S. S., Yang, X., Mutschke, G., & Eckert, K. (2019). Oscillating hydrogen bubbles at Pt microelectrodes. Physical Review Letters, 123(21), 214503.
[2] Hossain, S. S., Mutschke, G., Bashkatov, A., & Eckert, K. (2020). The thermocapillary effect on gas bubbles growing on electrodes of different sizes. Electrochimica Acta, 353, 136461.
[3] Bashkatov, A., Yang, X., Mutschke, G., Fritzsche, B., Hossain, S. S., & Eckert, K. (2021). Dynamics of single hydrogen bubbles at Pt microelectrodes in microgravity. Physical Chemistry Chemical Physics, 23(20), 11818-11830.
[4] Bashkatov, A., Hossain, S. S., Mutschke, G., Yang, X., Rox, H., Weidinger, I., and Eckert, K. (2022). On the Growth Regimes of Hydrogen Bubbles at Microelectrodes. Submitted to Physical Chemistry Chemical Physics.
[5] Hossain, S. S., Bashkatov, A., Yang, X., Mutschke, G., and Eckert, K. (2022). Detailed investigation of electrolytic bubble dynamics. Submitted to Physical Review E.

Presenters

  • Aleksandr Bashkatov

    • Helmholtz-Zentrum Dresden-Rossendorf
    • Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, Dresden, 01328 Germany

Authors

  • Aleksandr Bashkatov

    • Helmholtz-Zentrum Dresden-Rossendorf
    • Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, Dresden, 01328 Germany

  • Syed Sahil Hossain

    • Helmholtz-Zentrum Dresden-Rossendorf
    • Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, Dresden, 01328 Germany

  • Alexander Babich

    • Helmholtz-Zentrum Dresden-Rossendorf
    • Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, Dresden, 01328 Germany

  • Hannes Rox

    • Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, Dresden, 01328 Germany

  • Xuegeng Yang

    • Helmholtz-Zentrum Dresden-Rossendorf
    • Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, Dresden, 01328 Germany

  • Gerd Mutschke

    • Helmholtz-Zentrum Dresden-Rossendorf
    • Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, Dresden, 01328 Germany

  • Kerstin Eckert

    • Helmholtz-Zentrum Dresden-Rossendorf
    • Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, Dresden, 01328 Germany