Alkali Cation-Mediated Modulation of CO2 Reduction Activity on Tin Electrodes in [EMIM][BF4]/H2O Electrolytes

Muchharla, Baleeswaraiah; Gautam, Manu; Nkurunziza, Francois; Ross, R. Dominic; Chatterjee, Soumya; Spurgeon, Joshua M.; Hahn, Christopher; Janik, Michael J.; Kumar, Bijandra

doi:10.1021/acselectrochem.6c00110

Title: Alkali Cation-Mediated Modulation of CO₂ Reduction Activity on Tin Electrodes in [EMIM][BF₄]/H₂O Electrolytes

Journal Article · Thu Jun 25 00:00:00 UTC 2026 · ACS Electrochemistry

DOI: https://doi.org/10.1021/acselectrochem.6c00110 · OSTI ID:3375969

Muchharla, Baleeswaraiah ^[1]; Gautam, Manu ^[2]; Nkurunziza, Francois ^[2];

^[3]; Chatterjee, Soumya ^[4];

^[2];

^[3]; Janik, Michael J. ^[4];

^[1]

Elizabeth City State University, NC (United States)
Univ. of Louisville, KY (United States)
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Pennsylvania State Univ., University Park, PA (United States)

The development of efficient CO₂ reduction technologies hinges upon a thorough understanding of the intricate interplay between solution cations and the characteristics of the electrode surface. Recently, ionic liquids (ILs) have emerged as promising electrolytes for the CO₂ reduction reaction. However, the effect of alkali cations on the electrochemical CO₂ reduction (CO₂R) reaction remains unclear in ILs. Here, in this report, we studied alkali cation effects by assessing the electrocatalytic CO₂R activity with the IL 1-ethyl-3-methylimidazolium tetrafluoroborate, [EMIM][BF₄], in water with alkali metal co-cations (i.e., Li⁺, Na⁺, and K⁺) using a polycrystalline Sn catalyst. Contrary to previous findings in purely aqueous media with inorganic cations, where alkali cations strongly enhance CO₂R via pH modulation and strengthening of interfacial electric fields, alkali cations in electrolytes containing the IL [EMIM][BF4] negatively impact CO₂R activity on Sn electrodes. These results were attributed to the larger radius and higher concentration of the IL organic cation [EMIM]⁺ that mitigates the impact of alkali cations. These findings highlight the complex interplay between IL cations and alkali metals in shaping CO₂R performance.

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Research Organization:: Energy Frontier Research Centers (EFRC) (United States). Center for Closing the Carbon Cycle; Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Univ. of California, Irvine, CA (United States)

Sponsoring Organization:: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division (CSGB)

Grant/Contract Number:: AC52-07NA27344; SC0023427

OSTI ID:: 3375969

Report Number(s):: LLNL-JRNL-2020799

Journal Information:: ACS Electrochemistry, Journal Name: ACS Electrochemistry; ISSN 2997-0571

Publisher:: American Chemical Society (ACS)Copyright Statement

Country of Publication:: United States

Language:: English

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