'10-Dae Hwaham Mul' Opens Way for Significant Reduction in Chlorine Production Costs

Professor Choi Chang-hyuk of POSTECH and Professor Joo Sang-hoon of Seoul National University Research Team
Uncover the Secret of High-Performance Catalyst Asymmetric Structure

Domestic researchers have opened a path to produce chlorine, commonly used for sterilization and disinfection, more cheaply and efficiently.

The National Research Foundation of Korea announced on the 12th that the research team led by Professor Changhyuk Choi of Pohang University of Science and Technology and Professor Sanghoon Joo of Seoul National University revealed the secret of the asymmetric structure of high-performance catalysts that can produce chlorine at a low cost. They uncovered the design principles of catalysts that efficiently produce chlorine, bringing the commercialization of high-performance catalysts one step closer.

Chlorine is used for sterilization and disinfection and is one of the world's top 10 compounds produced annually at 75 million tons. It is produced through an electrochemical process based on saltwater, where metal oxide electrodes (DSA) are used as catalysts. However, DSA uses expensive precious metals such as iridium or ruthenium, making it costly, and when the chlorine ion concentration is low or the pH is neutral, oxygen evolution reactions occur simultaneously, reducing efficiency.

The research team developed a platinum single-atom catalyst to replace DSA for inexpensive and efficient chlorine production. Single-atom catalysts are catalysts in which metal atoms are dispersed one by one on the support surface, allowing each metal atom to be used as a reaction site, making it more efficient even when using the same weight of precious metals. The challenge was identifying the active site form where platinum single atoms show the highest performance. The team began fundamental research to elucidate the structure of high-performance catalyst active sites. It is widely known that platinum, when existing in a single-atom state, forms a symmetrical structure with four bonds in a plane, like the four legs of a chair. They predicted that symmetrical active site structures have low catalytic performance and that breaking the symmetrical structure could result in higher performance.

To support this, the team developed a platinum single-atom catalyst precisely controlled at the atomic level. Analysis of the developed single-atom catalyst structure using the latest spectroscopic techniques revealed the coexistence of symmetrical structures with four bonds and asymmetrical structures with three bonds. They experimentally demonstrated that the highly catalytically active structure is the asymmetric one and succeeded in selectively synthesizing the platinum structure with broken symmetry.

The research results were published on the 3rd of last month in the international academic journal Nature Communications.

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