Experimental and model-based investigation of overpotentials during oxygen reduction reaction in silver-based gas-diffusion electrodes - Couverture souple

Franzen, David

 
9783736975149: Experimental and model-based investigation of overpotentials during oxygen reduction reaction in silver-based gas-diffusion electrodes
Couverture souple
ISBN 10 : 3736975147 ISBN 13 : 9783736975149
Editeur : Cuvillier, 2021

Synopsis

Chlorine is one of the most important basic chemicals, which is used directly or indirectly in the production of around 60 % of all chemical products. The production is almost exclusively based on energy intensive electrolysis processes, with an average of 2.5 - 3.5 MWh of electrical energy required per ton of chlorine generated. This means that chlorine production alone accounts for around 3 % of the electrical energy used worldwide in industry. By using oxygen depolarized cathodes (ODC), it is possible to reduce the demand for electrical energy on an industrial scale by about 25 %. Instead of hydrogen evolution, oxygen reduction takes place. Due to the low solubility of oxygen, the electrode is designed as a gas-diffusion electrodes (GDE). These are porous silver-based electrodes with hydrophobic regions due to the use of polytetrafluoroethylene (PTFE). During operation, the liquid electrolyte penetrates the pore structure, but the PTFE prevents complete flooding of the electrode. Oxygen is supplied via a gas compartment and enters the internal structure of the electrode. A three-phase interface is formed, consisting of liquid electrolyte, gas and catalytically active solid, at which the electrochemical reaction takes place. Although the technology is already successfully used industrially, many processes, especially the electrolyte distribution, inside the GDE remain unknown. In this dissertation, the influence of PTFE is first systematically investigated. Subsequently the process is described in a pseudo-2D model supported by operando experiments. Finally, the exact penetration depth of the electrolyte is analyzed using specially designed electrodes.

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Éditeur
Cuvillier
Date d'édition
2021
Langue
anglais
ISBN 10 
3736975147
ISBN 13 
9783736975149
Reliure
Broché
Nombre de pages
136
Coordonnées du fabricant
info@cuvillier.de
info@cuvillier.de

Nonnenstieg 8
Göttingen
37075
Allemagne