A database to compare possible MOFs for volumetric hydrogen storage, taking into account the cost of their building blocks

Abstract

Physical adsorption at cryogenic temperature can increase the density of the stored hydrogen at a lower pressure than conventional compressed gas systems. This mechanism is also reversible and involves faster kinetics than chemical storage. Materials with certain structural and porous properties are necessary for volumetrically efficient hydrogen storage, including large specific surface areas, pore volumes, and appropriated bulk densities. Metal-organic frameworks (MOF) materials are remarkable candidates as adsorbents due to their porous properties and high crystallinity. Large databases like the MOF subset from the CSD or the CoRE-MOF can be used to find the best materials for this application, providing crystallographic information, composition, and porous properties. Herein, we created a database which includes crystallographic and porous properties, metallic and organic composition, and the minimum available cost for their linkers and corresponding suppliers for those for which it was publicly available. The database is also helpful for selecting structures with potential for industrial production and starting material for computational tools like machine learning or artificial intelligence approaches that relate the composition of MOFs with their performance in different applications. A user interface allows for creating customized selections of suitable MOF structures, looking for their porous and crystalline properties, gravimetric and volumetric total uptakes, and metallic and organic composition, as well as properties for the organic linkers like name, molecular mass, price, or presence of specific functional groups. This information was used to select potential structures from up to two metals and two linkers for the volumetric cryostorage of hydrogen.

ZIF-8 Pellets as a Robust Material for Hydrogen Cryo-Adsorption Tanks

“…ZIF-8 (Zeolitic Imidazolate Framework-8) is a zeolitic-like MOF based on Zn, a cheap metal widely used in industry, and 2-methylimidazole (meIm), 29 a low-cost linker used in MOF synthesis. 30 The strong Zn–N coordination bonds within the zeolitic structure provide high thermal and mechanical stability and reduce degradation during handling and activation. 31 Compared to well-known zeolites, ZIFs show a higher BET area (up to ∼1800 m 2 g –1 ) 32 because of the larger pore size and, therefore, a higher H 2 uptake.…”