A technology has been developed to control the pores of porous materials to 0.01 nanometers (10-⁹m), making it possible to efficiently separate deuterium, which exists in only 0.015% of all hydrogen in nature.

A research team led by Professor Oh Hyun-chul of the Department of Chemistry at UNIST and Professor Lee Eun-seong of the Department of Chemistry at Seoul National University have revealed that the pores of a porous material, a metal-organic framework (MOF), can be controlled down to 0.01 nanometers using ion exchange.

The importance of this study was acknowledged when it was published in the international scientific journal Angewandte Chemie International Edition.

The research team succeeded in controlling the size of the pore entrance from approximately 0.39 nanometers to 0.36 nanometers by exchanging the ions of the metal-organic framework JCM-1 material from nitrate (NO₃‐) ions to chloride (Cl‐) ions.

The chloride ions pulled the pore-associated external skeleton inward more strongly than the nitrate ions, thereby changing the pore entrance size.

JCM-1(Cl‐) with a reduced inlet showed nearly double the deuterium separation efficiency.

The selectivity of the existing JCM-1(NO₃‐) was 14.4, but it increased to 27.7 in JCM-1(Cl‐). This shows a selectivity that is more than 9 times better than the existing cryogenic distillation method, and achieves a selectivity increase of about 18 times or more through the chloride ion exchange method.

Researcher Hyunrim Kim, the first author, explained that JCM-1(Cl‐) shows potential for use in various industrial fields as it maintains stable performance even at a higher temperature of 50 K (-223.15°C) than the existing cryogenic distillation method performed at 24 K (-249.15°C).

Professor Oh Hyun-chul of UNIST said that this study presents a new method to precisely control the nanopore size of porous materials, and that it can be applied not only to isotope separation but also to various gas separation fields.

This study was conducted through the mid-career research and basic research project supported by the Ministry of Science and ICT.