Countercation Manipulation Enables Selective Electrochemical CO2‐to‐Formate Conversion Over Bi‐Polyoxometalate‐Derived Catalysts
8 affiliations
- 1Department of Applied Chemistry School of Engineering The University of Tokyo Tokyo Japan
- 2Department of Advanced Materials Science Graduate School of Frontier Sciences The University of Tokyo Kashiwa‐shi Chiba Japan
- 3Department of Chemistry Graduate School of Science Tokyo Metropolitan University Tokyo Japan
- 4Japan Synchrotron Radiation Research Institute (JASRI) Hyogo Japan
- 5Department of Applied Chemistry for Environment Graduate School of Urban Environmental Sciences Tokyo Metropolitan University Tokyo Japan
- 6RIKEN SPring‐8 Center Hyogo Japan
- 7Center for Basic Research on Materials National Institute for Materials Science (NIMS) Tsukuba‐shi Ibaraki Japan
- 8Research Center for Autonomous Systems Materialogy (ASMat) Institute of Integrated Research Institute of Science Tokyo Yokohama‐shi Kanagawa Japan
Abstract
Electrochemical conversion of CO2 into formate (HCOO−) represents a promising strategy for mitigating global warming while producing an industrially important chemical. Polyoxometalates (POMs), anionic molecular metal‐oxo clusters, offer unique opportunities as catalysts and catalyst precursors for the electrochemical CO2 reduction reaction (CO2RR) owing to their structural diversity, compositional tunability, and flexibility in countercation selection. Despite these advantages, effective strategies for developing POM‐based CO2RR catalysts with high selectivity toward HCOO− remain limited. In this study, we demonstrate countercation manipulation as a powerful approach to achieving selective HCOO− production using a bismuth (Bi)‐incorporated POM, [Bi4O(γ‐SiW10O36)2(OAc)]7− (Bi4). Under gas‐diffusion CO2RR conditions with a 2 M KHCO3 aqueous electrolyte, the Ba2+ salt of Bi4 immobilized on carbon (Ba‐Bi4/C) exhibited high HCOO− selectivity with a Faradaic efficiency of 84.3% at −0.79 VRHE, whereas the corresponding tetra‐n‐butylammonium (TBA+) salt (TBA‐Bi4/C) exhibited substantially lower selectivity (26.6% at −0.79 VRHE). Post‐reaction analyses revealed that both catalysts transformed into highly dispersed Bi species protected by WO x nanoaggregates. Control experiments and detailed characterizations indicated that the countercations, in conjunction with the POM‐derived catalyst structure, play a crucial role in governing CO2RR performance.
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BibTeX
@article{kawakami2026countercation,
title = {{Countercation Manipulation Enables Selective Electrochemical CO2‐to‐Formate Conversion Over Bi‐Polyoxometalate‐Derived Catalysts}},
author = {Kimitake Kawakami and Kentaro Yonesato and Shimon Akino and Soichi Kikkawa and Seiji Yamazoe and Takuma Kaneko and Tomoya Uruga and Fumiaki Amano and Yoshiaki Honjo and Takaki Hatsui and Koji Harano and Kazuya Yamaguchi and Kosuke Suzuki},
journal = {Chemistry (Weinheim an Der Bergstrasse, Germany)},
year = {2026},
month = jul,
doi = {10.1002/chem.71437},
url = {https://doi.org/10.1002/chem.71437},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Countercation Manipulation Enables Selective Electrochemical CO2‐to‐Formate Conversion Over Bi‐Polyoxometalate‐Derived Catalysts
AU - Kimitake Kawakami
AU - Kentaro Yonesato
AU - Shimon Akino
AU - Soichi Kikkawa
AU - Seiji Yamazoe
AU - Takuma Kaneko
AU - Tomoya Uruga
AU - Fumiaki Amano
AU - Yoshiaki Honjo
AU - Takaki Hatsui
AU - Koji Harano
AU - Kazuya Yamaguchi
AU - Kosuke Suzuki
PY - 2026
DA - 2026/07/22
JO - Chemistry (Weinheim an Der Bergstrasse, Germany)
DO - 10.1002/chem.71437
UR - https://doi.org/10.1002/chem.71437
AB - Electrochemical conversion of CO2 into formate (HCOO−) represents a promising strategy for mitigating global warming while producing an industrially important chemical. Polyoxometalates (POMs), anionic molecular metal‐oxo clusters, offer unique opportunities as catalysts and catalyst precursors for the electrochemical CO2 reduction reaction (CO2RR) owing to their structural diversity, compositional tunability, and flexibility in countercation selection. Despite these advantages, effective strategies for developing POM‐based CO2RR catalysts with high selectivity toward HCOO− remain limited. In this study, we demonstrate countercation manipulation as a powerful approach to achieving selective HCOO− production using a bismuth (Bi)‐incorporated POM, [Bi4O(γ‐SiW10O36)2(OAc)]7− (Bi4). Under gas‐diffusion CO2RR conditions with a 2 M KHCO3 aqueous electrolyte, the Ba2+ salt of Bi4 immobilized on carbon (Ba‐Bi4/C) exhibited high HCOO− selectivity with a Faradaic efficiency of 84.3% at −0.79 VRHE, whereas the corresponding tetra‐n‐butylammonium (TBA+) salt (TBA‐Bi4/C) exhibited substantially lower selectivity (26.6% at −0.79 VRHE). Post‐reaction analyses revealed that both catalysts transformed into highly dispersed Bi species protected by WO x nanoaggregates. Control experiments and detailed characterizations indicated that the countercations, in conjunction with the POM‐derived catalyst structure, play a crucial role in governing CO2RR performance.
SN - 0947-6539
SN - 1521-3765
ER -