Rht-MOFs with triptycene-modified linkers for balanced gravimetric/volumetric hydrogen storage: A molecular simulation study

摘要

Computationally designed rht-MOFs with triptycene-modified linkers have been studied thoroughly by grand canonical Monte Carlo simulations for investigation of balanced hydrogen sorption from two basis - gravimetric and volumetric. Three structures have been explored: without any linkers' modifications, with triptycene and with elongated triptycene. The results obtained via simulations are compared favourably with well-known materials of similar structure and topology. The analysis performed shows that framework with elongated triptycene exhibits two times higher hydrogen uptake at 77 K and 1 bar from the gravimetric basis and more impressively four times higher from the volumetric basis: (3 wt% and 127 V/V) than unmodified (base) structure (1.5 wt% and 37 V/V). The comparison with available frameworks shows that modification by triptycene leads to significant enhancement of hydrogen uptake from both basis - volumetric and gravimetric. Mod2 framework exhibits the most balanced uptake: 12.4 wt% and 49.7 g/L at 60 bar and 77 K, reaching DOE 2017 targets for H-2 storage systems at these thermodynamic conditions. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.