Operando Laboratory X-Ray Imaging of Silver-Based Gas Diffusion Electrodes during Oxygen Reduction Reaction in Highly Alkaline Media
Autor: | Melanie Cornelia Paulisch, Marcus Gebhard, David Franzen, André Hilger, Markus Osenberg, Nikolay Kardjilov, Barbara Ellendorff, Thomas Turek, Christina Roth, Ingo Manke |
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Jazyk: | angličtina |
Rok vydání: | 2019 |
Předmět: |
operando
X-ray imaging gas diffusion electrode oxygen-depolarized cathode oxygen reduction reaction chlor-alkali electrolysis Technology Electrical engineering. Electronics. Nuclear engineering TK1-9971 Engineering (General). Civil engineering (General) TA1-2040 Microscopy QH201-278.5 Descriptive and experimental mechanics QC120-168.85 |
Zdroj: | Materials, Vol 12, Iss 17, p 2686 (2019) |
Druh dokumentu: | article |
ISSN: | 1996-1944 |
DOI: | 10.3390/ma12172686 |
Popis: | Operando laboratory X-ray radiographies were carried out for imaging of two different silver-based gas diffusion electrodes containing an electroconductive Ni mesh structure, one gas diffusion electrode composed of 95 wt.% Ag and 5 wt.% polytetrafluoroethylene and one composed of 97 wt.% Ag and 3 wt.% polytetrafluoroethylene, under different operating parameters. Thereby, correlations of their electrochemical behavior and the transport of the 30 wt.% NaOH electrolyte through the gas diffusion electrodes were revealed. The work was divided into two parts. In the first step, the microstructure of the gas diffusion electrodes was analyzed ex situ by a combination of focused ion beam technology and synchrotron as well as laboratory X-ray tomography and radiography. In the second step, operando laboratory X-ray radiographies were performed during chronoamperometric measurements at different potentials. The combination of the ex situ microstructural analyses and the operando measurements reveals the impact of the microstructure on the electrolyte transport through the gas diffusion electrodes. Hence, an impact of the Ni mesh structure within the gas diffusion electrode on the droplet formation could be shown. Moreover, it could be observed that increasing overpotentials cause increasing electrolyte transport velocities and faster droplet formation due to electrowetting. In general, higher electrolyte transport velocities were found for the gas diffusion electrode with 97 wt.% Ag in contrast to that with 95 wt.% Ag. |
Databáze: | Directory of Open Access Journals |
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