Transport-Based Modeling of Bubble Nucleation on Gas Evolving Electrodes
Zhengmao Lu1, Lenan Zhang2, Ryuichi Iwata2
1Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
Langmuir : the ACS Journal of Surfaces and Colloids
|December 1, 2020
Summary
Understanding bubble nucleation in electrochemical systems is key. This study introduces a transport-based model revealing how surface geometry and electrolyte transport influence nucleation energy, offering new optimization strategies.
Area of Science:
- Electrochemistry
- Surface Science
- Computational Modeling
Background:
- Bubble nucleation is crucial for gas-evolving electrochemical systems, yet fundamental understanding is limited.
- Previous research primarily focused on thermodynamics, neglecting transport phenomena and surface geometry interactions.
- Optimizing electrochemical systems requires a deeper insight into the bubble nucleation mechanism.
Purpose of the Study:
- To develop a comprehensive transport-based model for bubble nucleation on gas-evolving electrodes.
- To investigate the influence of surface heterogeneities and electrolyte transport on nucleation.
- To provide a more physically consistent model for nucleation overpotential.
Main Methods:
- Established a comprehensive transport-based model framework.
- Accounted for electrical field, ion migration, ion diffusion, and gas diffusion effects.
- Incorporated surface heterogeneities and gas pocket formation from surface crevices.
Main Results:
- Neglecting transport effects leads to significant underprediction of nucleation energy.
- Identified a non-monotonic relationship between surface cavity size and nucleation overpotential.
- Highlighted the importance of gas diffuse layer thickness, influenced by external flow and electrode geometry.
Conclusions:
- The developed model provides a more accurate understanding of bubble nucleation mechanisms.
- Surface geometry and transport phenomena are critical factors in bubble nucleation.
- Model offers guidelines for tuning nucleation on electrodes by engineering cavity size and gas diffuse layer thickness.
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