TY - THES ID - 136468031 TI - Design of Membrane Electrode Assemblies for the electrochemical reduction of carbon dioxide to formic acid AU - Hanssens, Lucas AU - Martens, Johan AU - Rongé, Jan AU - KU Leuven. Faculteit Bio-ingenieurswetenschappen. Opleiding Master in de bio-ingenieurswetenschappen. Katalytische technologie (programma voor studenten gestart vanaf 2018-2019)(Leuven) PY - 2021 PB - Leuven KU Leuven. Faculteit Bio-ingenieurswetenschappen DB - UniCat UR - https://www.unicat.be/uniCat?func=search&query=sysid:136468031 AB - One of the most important challenges of this century is the rebalancing of the carbon cycle on earth. To that purpose, Carbon Capture and Utilisation (CCU) technologies are being developed. This work focuses on the development and benchmarking of Membrane Electrode Assembly (MEA)- type reactors that electrochemically reduce CO2 to formic acid. With the emerging carbon trading schemes and taxes, a lot of attention has been going towards all kinds of CCU technologies, including electrochemical CO2 reduction. This resulted in impressive results in literature. Liquid-phase electrolysers have accomplished high selectivities and energy efficiencies. However, because of the low solubility of CO2 in liquid catholytes, rather low partial current densities (PCD) were reached. Therefore, in the most recent publications, often gas-phase (or solid-state) cathodes are used. In this master’s thesis, 2 promising reactor designs using gas-phase cathodes are evaluated and rationalised, namely, a 2-compartment concept using KOH anolyte and a 3-compartment concept. Then, based on the rationalisation of the findings in those setups, new all-solid-state reactor designs were proposed. The use of ion conducting polymers, like ionomer solutions and ion exchange beads proved to be very helpful in recreating the favourable reaction conditions, identified in the 2 reproduced designs, in an all-solid-state environment. Because the use of these ion exchange beads in electrolyser applications is rather new, data on their conductivity in gaseous environment is scarce. Thus, in this work, the conductivities of a selection of these beads were measured, as well as the dependence of the conductivity of the commonly used ion exchanger beads, Amberlyst-15, on the humidity of the gas flow. Successful synthesis of formic acid vapour in an all-solid-state reactor was demonstrated, which was only reported before by two other research groups (Lee et al. and Xia et al.) to this date [1–2]. Furthermore, it was concluded that when high product concentrations/purities are desirable, it becomes interesting to use the 2-compartment all-solid-state reactors proposed in this work, which have a substantially smaller resistance than gas-phase 3-compartment reactors. However, when the concentration/purity is not critical, the proven selectivity and stability of the 3-compartment design using liquid DI-water in the middle compartment, proposed in literature, is superior at the moment. ER -