How to Enhance Gas Removal from Porous Electrodes?

This article presents a structure-based modeling approach to optimize gas evolution at an electrolyte-flooded porous electrode. By providing hydrophobic islands as preferential nucleation sites on the surface of the electrode, it is possible to nucleate and grow bubbles outside of the pore space, fa...

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Bibliographic Details
Published in:Scientific reports 2016-12, Vol.6 (1), p.38780-38780, Article 38780
Main Authors: Kadyk, Thomas, Bruce, David, Eikerling, Michael
Format: Article
Language:English
Subjects:
639/301/299/1013
639/638/161
639/638/77/886
639/766/189
Bubbles
Deactivation
Diffusion
Electrodes
Electrolytes
Humanities and Social Sciences
Hydrophobicity
Kinetics
multidisciplinary
Nucleation
Pores
Science
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Summary:This article presents a structure-based modeling approach to optimize gas evolution at an electrolyte-flooded porous electrode. By providing hydrophobic islands as preferential nucleation sites on the surface of the electrode, it is possible to nucleate and grow bubbles outside of the pore space, facilitating their release into the electrolyte. Bubbles that grow at preferential nucleation sites act as a sink for dissolved gas produced in electrode reactions, effectively suctioning it from the electrolyte-filled pores. According to the model, high oversaturation is necessary to nucleate bubbles inside of the pores. The high oversaturation allows establishing large concentration gradients in the pores that drive a diffusion flux towards the preferential nucleation sites. This diffusion flux keeps the pores bubble-free, avoiding deactivation of the electrochemically active surface area of the electrode as well as mechanical stress that would otherwise lead to catalyst degradation. The transport regime of the dissolved gas, viz. diffusion control vs. transfer control at the liquid-gas interface, determines the bubble growth law.
ISSN:2045-2322
2045-2322
DOI:10.1038/srep38780