ChemRxiv
These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
1/1
2 files

Decoupling Gas Evolution from Water-Splitting Electrodes

preprint
submitted on 13.08.2019 and posted on 14.08.2019 by Pablo Peñas, Peter van der Linde, Wouter Vijselaar, Devaraj van der Meer, Detlef Lohse, Jurriaan Huskens, Han Gardeniers, Miguel Modestino, David Fernandez Rivas

Bubbles are known to hinder electrochemical processes in water-splitting electrodes. In this study, we present a novel method to promote gas evolution away from the electrode surface. We consider a ring microelectrode encircling a hydrophobic microcavity from which a succession of bubbles grows. The ring microelectrode, tested under alkaline water electrolysis conditions, does not suffer from bubble coverage. Consequently, the chronopotentiometric fluctuations of the cell are weaker than those associated with conventional microelectrodes. Herein, we provide fundamental understanding of the mass transfer processes governing the transient behaviour of the cell potential. With the help of numerical transport models, we demonstrate that bubbles forming at the cavity reduce the concentration overpotential by lowering the surrounding concentration of dissolved gas, but may also aggravate the ohmic overpotential by blocking ion-conduction pathways. The theoretical and experimental insight gained have relevant implications in the design of efficient gas-evolving electrodes.

History

Email Address of Submitting Author

p.penaslopez@utwente.nl

Institution

University of Twente

Country

Netherlands

ORCID For Submitting Author

0000-0002-3503-3342

Declaration of Conflict of Interest

No conflict of interest

Version Notes

V1 (submitted)

Exports

Logo branding

Exports