Journal article
Role of ion-selective membranes in the carbon balance for CO2 electroreduction via gas diffusion electrode reactor designs
In this work, the effect of ion-selective membranes on the detailed carbon balance was systematically analyzed for high-rate CO2 reduction in GDE-type flow electrolyzers. By using different ion-selective membranes, we show nearly identical catalytic selectivity for CO2 reduction, which is primarily due to a similar local reaction environment created at the cathode/electrolyte interface via the introduction of a catholyte layer.
In addition, based on a systematic exploration of gases released from electrolytes and the dynamic change of electrolyte speciation, we demonstrate the explicit discrepancy in carbon balance paths for the captured CO2 at the cathode/catholyte interface via reaction with OH− when using different ion-selective membranes: (i) the captured CO2 could be transported through an anion exchange membrane in the form of CO32−, subsequently releasing CO2 along with O2 in the anolyte, and (ii) with a cation exchange membrane, the captured CO2 would be accumulated in the catholyte in the form of CO32−, while (iii) with the use of a bipolar membrane, the captured CO2 could be released at the catholyte/membrane interface in the form of gaseous CO2.
The unique carbon balance path for each type of membrane is linked to ion species transported through the membranes.
Language: | English |
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Year: | 2020 |
Pages: | 8854-8861 |
ISSN: | 20416539 and 20416520 |
Types: | Journal article |
DOI: | 10.1039/D0SC03047C |
ORCIDs: | Chorkendorff, Ib , Seger, Brian and 0000-0003-3561-5710 |