Abstract
A research team, affiliated with UNIST has unveiled a novel electrochemical system that converts carbon dioxide (CO₂), a major contributor to climate change, into high-value chemical products, like formic acid. This new approach drastically reduces energy consumption by nearly 75% and triples the production rates compared to existing methods.
Led by Professor Seungho Cho in the Department of Materials Science and Engineering, alongside Professors Youngkook Kwon and Jae Sung Lee from the School of Energy Chemical Engineering, announced that they have successfully developed an ultra-low voltage electrochemical process for transforming CO₂ into formic acid.
This innovative system not only lowers the energy required for CO₂ conversion, but also effectively reduces greenhouse gases while producing a high-demand chemical. Conventional processes rely on an oxygen evolution reaction (OER), which consumes 70 to 90% of the total energy energy consumption and causes the system's operating voltage to rise up to 2 V.
To overcome this challenge, the team replaced OER with a formaldehyde oxidation reaction (FOR). This new setup can generate formic acid efficiently at an ultra-low cell voltage of 0.5 V, with Faradaic efficiencies of 96.1% at the cathode and 82.1% at the anode. Lowering the operating voltage to just a quarter of traditional systems significantly reduces power consumption.
The system achieved a formic acid production rate of 0.39 mmol/cm²·h, nearly three times higher than previous technologies. Because formaldehyde oxidation produces formic acid instead of oxygen as a paired reaction, the overall process becomes far more energy-efficient.
This breakthrough was made possible by a specially designed copper-silver composite catalyst tailored for formaldehyde oxidation. Unlike conventional catalysts that tend to lose activity rapidly, this new material maintains high efficiency, enabling sustainable and scalable CO₂ conversion.
Figure 1. (Top) Schematic of the two-electrode electrolyzer coupling FOR and CO2RR and (Bottom) Schematic of synthetic procedure. b) XRD patterns of the CuxAg10−x/CF catalysts.
Beyond CO₂ reduction, this catalyst and reaction pathway can be applied to eco-friendly, self-sustaining systems for producing ammonia, hydrogen peroxide, and hydrogen without electricity or emissions. In this study, the researchers successfully integrated formaldehyde oxidation with nitrate reduction, oxygen reduction, and hydrogen evolution reactions, demonstrating the production of ammonia, hydrogen peroxide, and hydrogen in an environmentally friendly manner.
Professor Cho explained, "This technology addresses the main inefficiency in CO₂ conversion and makes the most of limited electric energy. Its versatility opens new possibilities for sustainable chemical manufacturing and environmental protection."
The research involved Hyoseok Kim, Wonsik Jang, and Jin Ho Lee from the Department of Materials Science and Engineering, as well as Hojeong Lee from the School of Energy Chemical Engineering at UNIST, who served as first authors.
The findings of this research have been published in the online version of Angewandte Chemie International Edition on October 10, 2025. The study was also selected as a cover article and will be officially published soon. It has also been supported by UNIST InnoCORE program and the National Research Foundation of Korea (NRF).
Journal Reference
Hyoseok Kim, Dr. Wonsik Jang, Dr. Jin Ho Lee, et al., "Energy-Efficient Dual Formate Electrosynthesis via Coupled Formaldehyde Oxidation and CO2 Reduction at Ultra-Low Cell Voltage," Angew. Chem., Int. Ed., (2025).
