Abstract
The molecular building block approach
was employed effectively
to construct a series of novel isoreticular, highly porous and stable,
aluminum-based metal–organic frameworks with soc topology. From this platform, three compounds were experimentally
isolated and fully characterized: namely, the parent Al-soc-MOF-1 and its naphthalene and anthracene analogues. Al-soc-MOF-1 exhibits outstanding gravimetric methane uptake (total and
working capacity). It is shown experimentally, for the first time,
that the Al-soc-MOF platform can address the challenging
Department of Energy dual target of 0.5 g/g (gravimetric) and 264
cm3 (STP)/cm3 (volumetric) methane storage.
Furthermore, Al-soc-MOF exhibited the highest total gravimetric
and volumetric uptake for carbon dioxide and the utmost total and
deliverable uptake for oxygen at relatively high pressures among all
microporous MOFs. In order to correlate the MOF pore structure and
functionality to the gas storage properties, to better understand
the structure–property relationship, we performed a molecular
simulation study and evaluated the methane storage performance of
the Al-soc-MOF platform using diverse organic linkers.
It was found that shortening the parent Al-soc-MOF-1
linker resulted in a noticeable enhancement in the working volumetric
capacity at specific temperatures and pressures with amply conserved
gravimetric uptake/working capacity. In contrast, further expansion
of the organic linker (branches and/or core) led to isostructural
Al-soc-MOFs with enhanced gravimetric uptake but noticeably
lower volumetric capacity. The collective experimental and simulation
studies indicated that the parent Al-soc-MOF-1 exhibits
the best compromise between the volumetric and gravimetric total and
working uptakes under a wide range of pressure and temperature conditions.