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Hartwig, Carl Eric ; Tschernoster, Jan ; Hawe, Philipp ; Moos, Ralf ; Roth, Christina:
Challenges of CO₂ Crossover in CO₂RR Flow Cells Achieving High Current Density.
2025
Veranstaltung: 76th Annual Meeting of the International Society of Electrochemistry
, 7.9.-12.9.2025
, Mainz, Germany.
(Veranstaltungsbeitrag: Kongress/Konferenz/Symposium/Tagung
,
Poster
)
Abstract
The scale-up of promising CO₂ electroreduction reaction (CO₂RR) concepts from H-cell setups is a crucial step toward the development of sustainable chemical production and utilization of excess CO2. Among various reactor designs, flow cells provide an essential platform for transferring insights from those small-scale H-cell experiments while maintaining control over key parameters such as electrolyte and gas flow to mitigate mass transport limitations.
In CO2RR on Cu-based electrodes, where multiple hydrocarbon products can occur, the concept of a single Tafel slope to determine the activity of the electrode is inadequate to capture the complexity of the reaction mechanism. For this reason, the possibility of making statements on activity and selectivity is limited to the continuous analysis of the products.
Gas chromatography is the most widely used method to determine the gaseous products. An important factor in this analysis is the precise determination of the output gas flow. However, as cell size and current density increase, new challenges emerge that have been neglected at smaller scales.
One of these challenges is the significant reduction of the CO₂ feed due to CO₂ crossover, a phenomenon often overlooked in the literature. This effect is not solely driven by CO₂ diffusion through the membrane but primarily by the physical dissolution of CO₂ in the electrolyte and the dynamic equilibrium of carbonic acid species. Initial investigations have empirically demonstrated a dependence of CO₂ crossover on the applied reduction current and product selectivity.
CO₂ crossover presents a critical issue, leading not only to a reduced gas flow at the output—impacting GC measurements—but also to decreased CO₂ availability at the reaction interface. Both factors must be carefully considered in experimental setups.
Our insights provide practical recommendations for a better understanding of CO₂ crossover and an empirical approach to compensate for volume flow losses. Additionally, best practices for accurately determining the output gas flow are outlined to improve accuracy in high-current CO₂RR flow cell experiments.
Weitere Angaben
| Publikationsform: | Veranstaltungsbeitrag (Poster) |
|---|---|
| Begutachteter Beitrag: | Ja |
| Institutionen der Universität: | Fakultäten > Fakultät für Ingenieurwissenschaften Fakultäten > Fakultät für Ingenieurwissenschaften > Lehrstuhl Werkstoffverfahrenstechnik > Lehrstuhl Werkstoffverfahrenstechnik - Univ.-Prof. Dr.-Ing. Christina Roth Fakultäten > Fakultät für Ingenieurwissenschaften > Lehrstuhl Funktionsmaterialien > Lehrstuhl Funktionsmaterialien - Univ.-Prof. Dr.-Ing. Ralf Moos Profilfelder > Advanced Fields > Neue Materialien Forschungseinrichtungen > Zentrale wissenschaftliche Einrichtungen > Bayreuther Materialzentrum - BayMAT |
| Titel an der UBT entstanden: | Ja |
| Themengebiete aus DDC: | 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften |
| Eingestellt am: | 13 Nov 2025 08:54 |
| Letzte Änderung: | 13 Nov 2025 08:54 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/95207 |