Tuning Local CO Concentration to Maximize Ethylene Selectivity in CO2 and CO Electrolysis
Rottmann D, Kollmuss R, Haufe S, Grund R, Mayrhofer K (2025)
Publication Type: Journal article
Publication year: 2025
Journal
Book Volume: 172
Article Number: 124524
Journal Issue: 12
DOI: 10.1149/1945-7111/ae2bae
Abstract
The selective electrochemical reduction of CO2 to ethylene remains challenging due to the multiple competing pathways within the complex reaction mechanism. One promising strategy is to increase the local CO* concentration at the catalyst surface to promote CO* dimerization and consequently ethylene formation. In this study, we investigate how the applied current density influences the optimal CO2 volume flow for selective ethylene formation within a flowcell system. Our results reveal a strong interdependence between current density and CO2 flow rate, effectively captured by the λC2H4 value. An optimized balance of current density and CO2 flow leads to high CO* concentration and enhanced ethylene formation. When switching to CO electrolysis to further raise CO* concentration, ethylene production increases only slightly while oxygenate formation raises strongly, lowering the ethylene:oxygenate ratio. This suggests an optimal CO* concentration for maximizing ethylene. Reducing the CO partial pressure within the CO volume flow enables to constrain the CO* concentration and achieve a FEC2H4 of 47%. These findings highlight the importance of tuning feed composition, current density and flow rates for achieving the optimal CO* concentration for ethylene formation.
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APA:
Rottmann, D., Kollmuss, R., Haufe, S., Grund, R., & Mayrhofer, K. (2025). Tuning Local CO Concentration to Maximize Ethylene Selectivity in CO2 and CO Electrolysis. Journal of The Electrochemical Society, 172(12). https://doi.org/10.1149/1945-7111/ae2bae
MLA:
Rottmann, Daniel, et al. "Tuning Local CO Concentration to Maximize Ethylene Selectivity in CO2 and CO Electrolysis." Journal of The Electrochemical Society 172.12 (2025).
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