The first project phase focused on the analysis and characterization of state-of-the-art electrodes and model electrodes. For this purpose, different GDEs with a range of specific properties were produced silver particles and PTFE dispersions. Comprehensive ex-situ characterizations of the pore system of the electrodes were then carried out. The used silver catalysts used and the produces GDE were also characterized with regard to their electrochemical properties using various measurements, in particular also new micro-electrochemical methods. A further important part of the investigations were the development of methods for in-situ and in operando characterization of the electrodes, which allow the measurement of the electrolyte distribution in the electrode. The full range of the experimental results was incorporated into the development of multi-physics mathematical models to describe the steady-state and dynamic behavior of the GDE.
In the second project phase, we will concentrate on the incorporation of electrowetting phenomena which are essential for proper description of the electrolyte movement and distribution inside the pore system of the GDE. Improved in-situ and in operando experiments will directly measure the electrolyte distribution in working GDE and help to formulate more realistic mathematical models. Finally, the findings obtained during the investigation of the ORR in highly alkaline electrolyte will be transferred to the more complex CO2RR taking electrochemical (hydrogen evolution) and chemical (carbon dioxide dissolution) side reactions into account.