Operando Laboratory X-Ray Imaging of Silver-Based Gas Diffusion Electrodes during Oxygen Reduction Reaction in Highly Alkaline Media
| Autor: | Thomas Turek, Christina Roth, Nikolay Kardjilov, Marcus Gebhard, Melanie Paulisch, Markus Osenberg, David Franzen, André Hilger, Barbara Ellendorff, Ingo Manke |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Analytical chemistry 02 engineering and technology Electrolyte 010402 general chemistry Electrochemistry 01 natural sciences Focused ion beam lcsh:Technology Article operando Gaseous diffusion General Materials Science lcsh:Microscopy lcsh:QC120-168.85 operando -- X-ray imaging -- gas diffusion electrode -- oxygen-depolarized cathode -- oxygen reduction reaction -- chlor-alkali electrolysis oxygen reduction reaction chlor-alkali electrolysis Gas diffusion electrode lcsh:QH201-278.5 lcsh:T X-ray imaging gas diffusion electrode X-ray article X ray imaging oxygen depolarized cathode oxygen 021001 nanoscience & nanotechnology Microstructure 0104 chemical sciences lcsh:TA1-2040 Electrode ddc:540 lcsh:Descriptive and experimental mechanics lcsh:Electrical engineering. Electronics. Nuclear engineering 0210 nano-technology lcsh:Engineering (General). Civil engineering (General) lcsh:TK1-9971 oxygen-depolarized cathode |
| Zdroj: | Materials Volume 12 Issue 17 Materials, Vol 12, Iss 17, p 2686 (2019) |
| 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: | OpenAIRE |
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