Modeling the electrochemical CO2 reduction using gas diffusion electrodes
The electrochemical reduction of CO2 is a promising process for the use of carbon dioxide as raw material in the chemical industry while simultaneously reducing the CO2 emissions. Depending on the catalyst material a very broad product spectrum is possible. This project is focussed on the production of synthesis gas (CO+H2), which is needed for a variety of chemical processes, e.g. for the production of synthetic fuels by Fischer-Tropsch synthesis using silver gas-diffusion electrodes (GDE). These electrodes are already commercially used on a large scale as oxygen depolarized cathodes in chlor-alkali electrolysis.
In the CO2 reduction, not only electrochemical reactions but also several protolytic reactions take place in the electrolyte, which strongly influence the local concentrations within the electrode. To gain a better understanding of this complex system, a mathematical model is developed. On the basis of validation measurements, the model should describe the real system as accurately as possible. The model can then be used to make predictions about the influence of various factors, such as reaction conditions or the GDE structure on the electrochemical CO2 reduction process. In the long term, the model will be used for the development and optimization of operating concepts for a technical CO2 electrolyser by means of various extensions.