Issue 45, 2021, Issue in Progress

Gas evolution in electrochemical flow cell reactors induces resistance gradients with consequences for the positioning of the reference electrode

Abstract

With the transfer of the electrochemical CO2-reduction from academic labs towards industrial application, one major factor is the increase in current density. This can be achieved via the usage of a gas diffusion electrode. It allows for electrochemical reactions at the three-phase boundary between gaseous CO2, liquid electrolyte and electrocatalyst. Thus, current densities in commercially relevant magnitudes of 200 mA cm−2 and beyond can be reached. However, when increasing the current density one faces a new set of challenges, unknown from low current experiments. Here, we address the issue of gas evolution causing a local increase in resistance and the impact on the operation of flow cells with gas diffusion electrodes. We set up a simple simulation model and compared the results with experiments on a real setup. As a result, the gas evolution's strong impact on current-, potential- and resistance-distributions along the flow axis can be described. Main consequence is that the positioning of the reference electrode has a significant effect on the locally measured IR-drop and thus on the measured or applied potential. Therefore, data from different setups must be compared with great care, especially with respect to the potentials, on which the cell is operated.

Graphical abstract: Gas evolution in electrochemical flow cell reactors induces resistance gradients with consequences for the positioning of the reference electrode

Supplementary files

Article information

Article type
Paper
Submitted
12 Jul 2021
Accepted
29 Jul 2021
First published
20 Aug 2021
This article is Open Access
Creative Commons BY license

RSC Adv., 2021,11, 28189-28197

Gas evolution in electrochemical flow cell reactors induces resistance gradients with consequences for the positioning of the reference electrode

Y. Jännsch, M. Hämmerle, J. J. Leung, E. Simon, M. Fleischer and R. Moos, RSC Adv., 2021, 11, 28189 DOI: 10.1039/D1RA05345K

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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