Transport-Based Modeling of Bubble Nucleation on Gas Evolving Electrodes
Name
Transport-based modeling of bubble nucleation ongas evolving electrodes.pdf
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Accepted version
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1008.13 KB
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Checksum (MD5)
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Author(s)
Lu, Zhengmao
Zhang, Lenan
Iwata, Ryuichi
Wang, Evelyn N
Grossman, Jeffrey C
Date Issued
2020
Journal
Langmuir
Publisher
American Chemical Society (ACS)
Citation
Lu, Zhengmao, Zhang, Lenan, Iwata, Ryuichi, Wang, Evelyn N and Grossman, Jeffrey C. 2020. "Transport-Based Modeling of Bubble Nucleation on Gas Evolving Electrodes." Langmuir, 36 (49).
Version
Author's final manuscript
Abstract
© 2020 American Chemical Society. Bubble nucleation is ubiquitous in gas evolving reactions that are instrumental for a variety of electrochemical systems. Fundamental understanding of the nucleation process, which is critical to system optimization, remains limited as prior works generally focused on the thermodynamics and have not considered the coupling between surface geometries and different forms of transport in the electrolytes. Here, we establish a comprehensive transport-based model framework to identify the underlying mechanism for bubble nucleation on gas evolving electrodes. We account for the complex effects on the electrical field, ion migration, ion diffusion, and gas diffusion arising from surface heterogeneities and gas pockets initiated from surface crevices. As a result, we show that neglecting these effects leads to significant underprediction of the energy needed for nucleation. Our model provides a non-monotonic relationship between the surface cavity size and the overpotential required for nucleation, which is physically more consistent than the monotonic relationship suggested by a traditional thermodynamics-based model. We also identify the significance of the gas diffuse layer thickness, a parameter controlled by external flow fields and overall electrode geometries, which has been largely overlooked in previous models. Our model framework offers guidelines for practical electrochemical systems whereby, without changing the surface chemistry, nucleation on electrodes can be tuned by engineering the cavity size and the gas diffuse layer thickness.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Massachusetts Institute of Technology. Department of Mechanical Engineering
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Creative Commons Attribution-Noncommercial-Share Alike
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DOI of Published Version
https://doi.org/10.1021/ACS.LANGMUIR.0C02690
