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Low concentration CO2→CO direct conversion technology developed

Dr. Won Da-hye and Dr. Lee Woong of the Korea Institute of Science and Technology (KIST) and Professor Hwang Yoon-jung of Seoul National University have developed catalyst and process technology to produce carbon monoxide with high reaction efficiency by using carbon dioxide as reactants.

The technology to convert carbon dioxide into a useful compound is being actively studied as one of the core technologies to reduce carbon. However, this technology had an obstacle to supplying high purity carbon dioxide gas as a reaction material. This is because carbon dioxide is a chemically very stable material, making it difficult to convert to other materials, so it is necessary to increase the reaction rate and efficiency by supplying high purity carbon dioxide. In fact, exhaust gas from industrial sites contains about 10% of carbon dioxide along with nitrogen, oxygen, and nitrogen oxides, and until now, sufficient efficiency could not be ensured with such low-concentration exhaust gas.

In the process of converting carbon dioxide into carbon monoxide by an electrochemical method, a silver (Ag) catalyst with high carbon monoxide generation efficiency is mainly used. When high purity (99.99%) carbon dioxide is converted using a commercialized silver catalyst, 95% of the product is produced from carbon monoxide, and when low concentration (10%) carbon dioxide is used, 40% of carbon monoxide and 60% of hydrogen are generated.

KIST researchers have developed a nickel monoatomic catalyst to reduce hydrogen generation and increase carbon monoxide generation efficiency. Until now, ordinary metals such as iron and nickel have not been able to be made into carbon dioxide conversion catalysts due to their poor reactivity than precious metals, but the research team developed a new catalyst based on the results of a recent 1) study that making a single atom will increase efficiency. In addition, unlike the conventional method of dissolving carbon dioxide in water and reacting it, it has even developed an optimal driving technology to cause a gas-state conversion reaction.

The developed nickel monoatomic catalyst could generate 93% of the results with a low concentration (10%) of carbon dioxide at the level of exhaust gas as carbon monoxide, and it is possible to secure economic feasibility by manufacturing catalysts with low-cost materials such as nickel and carbon, not precious metals.

The developed catalyst and driving technology can be applied to various electrochemical conversion systems using low concentrations of carbon dioxide.

Journal Reference:
Electrocatalytic Reduction of Low Concentrations of CO2 Gas in a Membrane Electrode Assembly Electrolyzer
Dongjin Kim, Woong Choi, Hee Won Lee, Si Young Lee, Yongjun Choi, Dong Ki Lee, Woong Kim, Jonggeol Na, Ung Lee, Yun Jeong Hwang, and Da Hye Won
ACS Energy Letters 2021 6 (10), 3488-3495
DOI: 10.1021/acsenergylett.1c01797

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