By using carbon supported Sn/SnOx gas diffusion electrodes (GDE), an efficient electrochemical conversion of CO2 to formic acid can be realized. The porous structure of the GDEs strongly affects the electrochemical performance of these GDEs. In detail, the intrusion of the electrolyte and CO2 into the electrode has a considerable influence onto the cathodes physicochemical characteristics. The intrusion behaviour of the electrolyte was investigated to determine the inner hydrophobicity, by using a combination of the Lucas-Washburn and Owens-Wendt method. To further investigate the penetration behaviour a custom-made cell was used to measure the capillary pressure.
Additionally iridium oxide based electrodes are used as anodes for the oxygen evolution reaction (OER) and optimized regarding their electrochemical performance. With these anodes and the above mentioned GDEs a continuous working full-cell set-up can be realized. The full-cell set-up was investigated by polarisation- and electrochemical impedance spectroscopy-measurements.