Korea University Unveils the Secret of How CO₂ Becomes a Hydrogen Storage Material [Reading Science]

Formic Acid Formation Mechanism Identified... Overturns Academic Consensus

"Carbon-Bound Intermediate, Not Oxygen-Bound, Drives the Reaction"

The core mechanism involved in converting carbon dioxide (CO₂) into formic acid—a next-generation hydrogen storage material—has been identified by a Korean research team. This finding overturns the prevailing academic consensus and is expected to offer a new direction for the development of carbon neutrality and hydrogen energy technologies in the future.

On June 12, the research team led by Professor Seoin Baek at Korea University KU-KIST Graduate School of Convergence Science announced that they had uncovered the atomistic reaction mechanism by which formic acid is generated during the electrochemical carbon dioxide reduction reaction (CO₂RR).

A schematic diagram illustrating the carbon dioxide to formic acid conversion mechanism proposed in the study. Provided by the research team

The electrochemical carbon dioxide reduction reaction is a technology that converts atmospheric carbon dioxide into useful chemicals. Formic acid in particular is drawing attention as a next-generation hydrogen storage material because of its high energy density and its ability to release hydrogen on demand.

Formic Acid Formation Principle Overturns Academic Consensus

Until now, the academic community believed that on bismuth (Bi)-based catalysts, carbon dioxide is converted into formic acid via an “oxygen-bound intermediate (*OCHO).” However, the research team, through molecular dynamics simulations that precisely replicate actual reaction environments, confirmed that this pathway is in fact suppressed.

Instead, they revealed that the “carbon-bound intermediate (*COOH),” previously known as the route for carbon monoxide (CO) formation, serves as the key pathway for formic acid generation. This result overturns the existing academic understanding of the formic acid formation mechanism.

The team conducted molecular dynamics simulations that comprehensively considered various factors acting at the actual electrode–electrolyte interface, including water molecules, electrolyte cations, and reaction intermediates. Moreover, the presence of the carbon-bound intermediate predicted by the simulations was directly detected through spectroscopic analysis, enhancing the credibility of the research findings.

Research team photo. (From left) Jeong Hyundong, Integrated MS-PhD Program, KU-KIST Graduate School of Convergent Science and Technology, Korea University (first author); Paik Sein, Professor, KU-KIST Graduate School of Convergent Science and Technology, Korea University (corresponding author); Kun Jiang, Professor, Fudan University (corresponding author). Courtesy of Korea University

This study is also significant in that it applied dynamic modeling that goes beyond conventional static thermodynamic calculations, reflecting both real reaction environments and voltage conditions. The research team expects that the research platform established in this study can be utilized in the future to elucidate the principles of various electrochemical catalytic reactions and to design high-performance catalysts.

Professor Seoin Baek stated, “By combining dynamic simulations that accurately model the real reaction environment with experimental verification, we have identified complex catalytic reaction mechanisms at the atomic level. This approach can be widely used in future studies to understand and predict various catalytic reactions.”

The results of this study were published on May 29 in the international academic journal ‘Angewandte Chemie International Edition,’ which is issued by the German Chemical Society.

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