Barely porous organic cages for hydrogen isotope separation

• Published in: Science (American Association for the Advancement of Science) Vol. 366; no. 6465; pp. 613 - 620
• Main Authors: Liu, Ming, Zhang, Linda, Little, Marc A., Kapil, Venkat, Ceriotti, Michele, Yang, Siyuan, Ding, Lifeng, Holden, Daniel L., Balderas-Xicohténcatl, Rafael, He, Donglin, Clowes, Rob, Chong, Samantha Y., Schütz, Gisela, Chen, Linjiang, Hirscher, Michael, Cooper, Andrew I.
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 01.11.2019; The American Association for the Advancement of Science
• Subjects: Adsorption; Apertures; Cage molecules; Cages; Cavities; Deuterium; Hydrogen; Hydrogen isotopes; Isotope separation; Isotopes; Kinetics; Nuclear fusion; Pore size; Porosity; Selectivity; Sieves; Ultrafines
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.aax7427

The separation of hydrogen isotopes for applications such as nuclear fusion is a major challenge. Current technologies are energy intensive and inefficient. Nanoporous materials have the potential to separate hydrogen isotopes by kinetic quantum sieving, but high separation selectivity tends to correlate with low adsorption capacity, which can prohibit process scale-up. In this study, we use organic synthesis to modify the internal cavities of cage molecules to produce hybrid materials that are excellent quantum sieves. By combining small-pore and large-pore cages together in a single solid, we produce a material with optimal separation performance that combines an excellent deuterium/hydrogen selectivity (8.0) with a high deuterium uptake (4.7 millimoles per gram).