Multiscale modeling of hydrogen adsorption and storage into porous frameworks for carbon-neutral energy

Abstract

Hydrogen storage and its transportation at operational temperatures remain major issues for its commercialization in onboard vehicular applications. The U.S. Department of Energy (DOE) has set hydrogen storage targets for 2025, with ultimate goals of 6.5 wt.% gravimetric capacity and 50 g/L volumetric uptake.[1] To achieve these targets, solid-state hydrogen storage by adsorbing H2 in porous materials has emerged as the most promising technology, since gas-phase hydrogen storage requires a high-pressure tank and liquid hydrogen can be stored at cryogenic temperatures, which require sophisticated tanks and raise safety concerns.[2] Porous materials such as metal-organic frameworks (MOFs) and covalent-organic frameworks (COFs) offer great promise for enhancing gas storage (especially H2-storage), CO2 capture and gas separation performance with minimal effort.[3–6] These materials have attracted significant attention in recent years from the scientific community due to their high surface area, tunable pores, and open metal sites in MOFs, which facilitate stronger binding of adsorbates.[7–9] In 2003, Yaghi et al. reported remarkable gravimetric uptake capacities of 4.5 wt.% at 77 K and pressures below 1 atm, and 1 wt.% at room temperature under 20 bar for MOF-5.[10] Omar Yaghi, Susumu Kitagawa, and Richard Robson were awarded the Nobel Prize in Chemistry in 2025 for the development of MOFs, which can be used to harvest water from desert air, capture carbon dioxide, store toxic gases or catalyze chemical reactions.