Related Experiment Video
Updated: Aug 6, 2026
10:57
Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction
Published on: April 10, 2018
Countercation Manipulation Enables Selective Electrochemical CO2-to-Formate Conversion Over
Kimitake Kawakami1, Kentaro Yonesato1,2, Shimon Akino1
1Department of Applied Chemistry, School of Engineering, The University of Tokyo, Tokyo, Japan.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|July 22, 2026
Summary
Countercation choice significantly impacts selectivity in electrochemical CO2 reduction to formate using bismuth-polyoxometalate catalysts. Barium countercations enhance formate production, demonstrating a key strategy for efficient CO2 conversion.
Area of Science:
- Electrochemistry
- Materials Science
- Catalysis
Background:
- Electrochemical conversion of carbon dioxide (CO2) to formate (HCOO-) offers a dual solution for climate change mitigation and valuable chemical production.
- Polyoxometalates (POMs) are versatile catalysts for CO2 reduction reaction (CO2RR) due to their tunable structures and compositions.
- Developing POM-based catalysts with high selectivity for formate remains a challenge.
Purpose of the Study:
- To investigate the role of countercations in tuning the selectivity of bismuth-incorporated POMs for electrochemical CO2RR.
- To demonstrate countercation manipulation as an effective strategy for enhancing formate production.
Main Methods:
- Synthesis and characterization of bismuth-incorporated POMs ([Bi4O(γ-SiW10O36)2(OAc)]7-, Bi4) with different countercations (Ba2+ and TBA+).
- Electrochemical CO2RR experiments under gas-diffusion conditions using a 2 M KHCO3 electrolyte.
- Post-reaction analysis including characterization of catalyst structures and dispersed species.
Main Results:
- The Ba2+ salt of Bi4 immobilized on carbon (Ba-Bi4/C) achieved 84.3% Faradaic efficiency for HCOO- at -0.79 V RHE.
- The tetra-n-butylammonium (TBA+) salt (TBA-Bi4/C) showed significantly lower selectivity (26.6% at -0.79 V RHE).
- Both catalysts transformed into dispersed Bi species protected by WOx nanoaggregates, with countercations influencing performance.
Conclusions:
- Countercation selection is a critical factor in optimizing POM-based catalysts for selective electrochemical CO2 to HCOO- conversion.
- The Ba2+ countercation promotes high formate selectivity, highlighting a viable strategy for catalyst design.
- Understanding the interplay between countercations and POM-derived structures is key to advancing CO2RR technologies.
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