Subproject 1

Stationary modeling of the overvoltage on silver-based gas diffusion electrodes during reductions in aqueous electrolyte

In subproject 1 the different silver-based gas diffusion electrodes for oxygen and CO₂ reduction are manufactured and physically and electrochemically characterized. In addition to electrodes, suitable half cells for electrochemical characterization will be supplied to all project partners. By variations in the manufacturing process of the GDE, the reaction zones within can be adjusted in a defined way, which allows a localization of the penetration depth of the electrolyte. The correlation between electrode properties and overvoltage during oxygen and CO₂ reduction will be quantified in systematic series of measurements. The data obtained are used to validate a stationary GDE model.

The already existing model for oxygen reduction will be extended and improved based on the new findings. The localization of the reaction zone (SP1 Turek), the measured real electrolyte distribution (SP4 Manke), effects of electro-wetting (SP5 Nieken), a quantitative reaction kinetics (SP6 Vidakovic-Koch) and experimentally determined local activities (SP7 Schuhmann) are incorporated into the transfer to a 2D-pore network model. The existing knowledge will then be used to adapt the model to CO₂ reduction. A comparison and a merging with the dynamic model (SP2 Krewer) will be aimed for.