In silico screening and experimental study of anion-pillared metal-organic frameworks for hydrogen isotope separation

Abstract

Deuterium is a key energy source for fusion reaction and widely used in various application fields. Nevertheless, the separation of deuterium from its isotopic mixture with nearly same physicochemical properties is one of the greatest challenging tasks in industry. Compared with cryogenic distillation, quantum sieving effect based on nanoporous materials has been proposed as a promising strategy for isotopes separation, in which metal-organic frameworks (MOFs) are considered as an ideal platform because of their structural diversity and tailorable functionality. In this work, high-throughput molecular simulations were performed to identify optimal structural features of high-performance materials from a recently-constructed database of anion-pillared MOFs. As a proof-of-concept, the identified material SIFSIX-18-Cd was prepared using a proposed direct mixing method, which can achieve a goal of quickly preparation of such material on a large scale. The experimental pure-component adsorption isotherms of D2 and H2 confirmed the preferential adsorption of SIFSIX-18-Cd for D2 over H2 due to the quantum sieving effect. The advanced cryogenic thermal desorption spectroscopy (ACTDS) measurements further showed that the enrichment factor (EF) of an equimolar D2/H2 mixture in SIFSIX-18-Cd can reach 5.1 at 30 K and 1.0 bar, which is higher than the current cryogenic distillation method (1.5 at 24 K). Along with the proposed efficient preparation method, the high hydrophobic property of SIFSIX-18-Cd also demonstrated a broad industrial prospect of this material for hydrogen isotope separation.