'Exhaust Gas Levels' Low-Concentration Carbon Dioxide Also Captured and Recycled as Resources

KIST Researchers Develop Catalyst and Process Technologies

Performance comparison between nickel single-atom catalysts and commercial silver catalysts according to carbon dioxide concentration. Image courtesy of KIST.

[Asia Economy Reporter Kim Bong-su] A domestic research team has developed a technology that captures low-concentration carbon dioxide (CO2) from factory exhaust gases and converts it into carbon monoxide (CO), a key raw material used in industrial sites.

The Korea Institute of Science and Technology (KIST) announced on the 29th that a research team led by Dr. Won Da-hye and Dr. Lee Woong from the Clean Energy Research Center, in collaboration with Professor Hwang Yoon-jung's team at Seoul National University, developed catalyst and process technologies that enable the production of carbon monoxide with high reaction efficiency using low-concentration carbon dioxide at factory exhaust gas levels as a reactant.

Technology that converts carbon dioxide into useful compounds is actively being researched as a core technology for reducing carbon emissions. However, this technology has faced the obstacle of requiring high-purity carbon dioxide gas as a reactant. Because carbon dioxide is chemically very stable and difficult to convert into other substances, supplying high-purity carbon dioxide is necessary to increase reaction speed and efficiency. In actual industrial exhaust gases, carbon dioxide is included at about 10% along with nitrogen, oxygen, and nitrogen oxides, but until now, sufficient efficiency could not be secured using such low-concentration exhaust gases.

In the electrochemical process of converting carbon dioxide into carbon monoxide, silver (Ag) catalysts, which have high carbon monoxide generation efficiency, are mainly used. When converting high-purity (99.99%) carbon dioxide using commercial silver catalysts, 95% of the product is carbon monoxide; however, when using low-concentration (10%) carbon dioxide, 40% carbon monoxide and 60% hydrogen are produced.

The research team developed a nickel single-atom catalyst to reduce hydrogen generation and increase carbon monoxide generation efficiency. Until now, common metals such as iron and nickel have not been used as carbon dioxide conversion catalysts because their reactivity is lower than that of precious metals. Inspired by recent research showing that efficiency improves when made in a single-atom form, they developed a new catalyst. Additionally, unlike the conventional method of dissolving carbon dioxide in water before reaction, they developed an optimal driving technology that allows the conversion reaction to occur with carbon dioxide in the gas phase.

The developed nickel single-atom catalyst was able to produce 93% carbon monoxide from low-concentration (10%) carbon dioxide at exhaust gas levels, and by fabricating the catalyst from low-cost materials such as nickel and carbon instead of precious metals, economic feasibility was also secured.

Dr. Won said, “The catalyst and driving technology developed this time can be applied to various electrochemical conversion systems utilizing low-concentration carbon dioxide,” and added, “Various technologies are also being developed to directly utilize exhaust gases without separate purification processes to secure the economic feasibility of electrochemical carbon dioxide conversion technology.”

The research results were published in the latest issue of the international energy journal ‘ACS Energy Letters’ (IF: 23.101, JCR top 3.302%).

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