Tetraethylammonium Cations Enable C2+ Product Formation in Acidic CO2 Reduction
- 1Laboratory of Inorganic Synthesis and Catalysis
- 2Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne
Abstract
Cation effect is essential to obtain selectivity towards carbon dioxide (CO 2 ) reduction reaction (CO 2 RR) over the hydrogen evolution reaction (HER) in acidic media. Selectivity towards CO 2 RR has been largely attributed to the coordination between alkali cations and CO 2 -derived intermediates. Here, we provide a different perspective by demonstrating that tetraethylammonium (Et 4 N + ), a weakly coordinating cation, can also effectively suppress the HER in acidic media, favoring CO 2 RR on both Ag and Cu electrodes. The generation of both C 1 and C 2+ products on Cu indicates that the direct participation of alkali cations as co-catalyst is not a prerequisite for CO 2 activation or C-C coupling. We find that CO 2 RR is independent of the bulk pH in the presence of 1 M Et 4 N + , as evidenced by similar selectivity across acidic, neutral, and alkaline media. In addition, rigorous impurities control reveals that millimolar-levels of triethylammonium chloride (Et 3 NHCl) substantially promote HER on Cu catalyst, hence calling for careful impurity control. Overall, this work reveals the use of Et 4 N + as an valuable platform to investigate the effects of cations or impurities for CO 2 RR.
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BibTeX
@misc{degoulange2026tetraethylammonium,
title = {{Tetraethylammonium Cations Enable C2+ Product Formation in Acidic CO2 Reduction}},
author = {Damien Degoulange and Qiucheng Xu and Miyeon Chang and Wenchao Ma and Jacobus C. Duburg and Xile Hu},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15004976/v2},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15004976/v2},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Tetraethylammonium Cations Enable C2+ Product Formation in Acidic CO2 Reduction
AU - Damien Degoulange
AU - Qiucheng Xu
AU - Miyeon Chang
AU - Wenchao Ma
AU - Jacobus C. Duburg
AU - Xile Hu
PY - 2026
DA - 2026/09/15
PB - ChemRxiv
DO - 10.26434/chemrxiv.15004976/v2
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15004976/v2
AB - Cation effect is essential to obtain selectivity towards carbon dioxide (CO 2 ) reduction reaction (CO 2 RR) over the hydrogen evolution reaction (HER) in acidic media. Selectivity towards CO 2 RR has been largely attributed to the coordination between alkali cations and CO 2 -derived intermediates. Here, we provide a different perspective by demonstrating that tetraethylammonium (Et 4 N + ), a weakly coordinating cation, can also effectively suppress the HER in acidic media, favoring CO 2 RR on both Ag and Cu electrodes. The generation of both C 1 and C 2+ products on Cu indicates that the direct participation of alkali cations as co-catalyst is not a prerequisite for CO 2 activation or C-C coupling. We find that CO 2 RR is independent of the bulk pH in the presence of 1 M Et 4 N + , as evidenced by similar selectivity across acidic, neutral, and alkaline media. In addition, rigorous impurities control reveals that millimolar-levels of triethylammonium chloride (Et 3 NHCl) substantially promote HER on Cu catalyst, hence calling for careful impurity control. Overall, this work reveals the use of Et 4 N + as an valuable platform to investigate the effects of cations or impurities for CO 2 RR.
ER -