Nanobubble Formation and Coverage during High Current Density Alkaline Water Electrolysis

Hammons, Joshua A.; Kang, ShinYoung; Ferron, Thomas J.; Aydin, Fikret; Lin, Tiras Y.; Seung, Kansas; Chow, Paul; Xiao, Yuming; Davis, Jonathan T.

doi:10.1021/acs.nanolett.4c03657

DOE OSTI · 2507414

Nanobubble Formation and Coverage during High Current Density Alkaline Water Electrolysis

Hammons, Joshua A.·Kang, ShinYoung·Ferron, Thomas J.·Aydin, Fikret·Lin, Tiras Y.·Seung, Kansas·Chow, Paul·Xiao, Yuming·Davis, Jonathan T.

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Abstract

Gas bubbles are a necessary byproduct of water electrolysis whereby hydrogen and oxygen are produced from water. These attached gases reduce the electrode’s active area, which necessitates a deep understanding of the bubble life cycle starting from nanobubbles. Synchronized with the electrochemistry, the time evolution of the surface nanobubble size and coverage is resolved using grazing incidence small-angle X-ray scattering (GISAXS) and correlated with optical microscopy and theoretical calculations to show that a significant portion of the surface is covered in nanobubbles after larger micron-sized bubbles are observed. Further, these nanobubbles increase in number and decrease in size, toward 2 nm diameter, with the charge passed. The trend in size and number is consistent with an increase in supersaturation, which reduces the nascent bubble size. Altogether, this study suggests a significant portion of the surface contains nanobubbles and that strategies to reduce the dissolved hydrogen would be effective at reducing the nanobubble surface coverage.

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY Energy - Hydrogen GISAXS electrolysis gas evolution molecular dynamics nanobubbles

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Hammons, Joshua A., Kang, ShinYoung, Ferron, Thomas J., Aydin, Fikret, Lin, Tiras Y., Seung, Kansas, Chow, Paul, Xiao, Yuming, Davis, Jonathan T.. 2024-10-16. Nanobubble Formation and Coverage during High Current Density Alkaline Water Electrolysis. https://doi.org/10.1021/acs.nanolett.4c03657

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