Volumetric Hydrogen Storage Capacity in Metal–Organic Frameworks

Abstract Molecular hydrogen storage in metal–organic frameworks (MOFs) is one possibility for on‐board storage in fuel‐cell vehicles, but so far generally only the gravimetric hydrogen storage capacity has been considered. Here we analyze the volumetric absolute hydrogen uptake of many MOFs measured at 77 K and 2.0–2.5 MPa in our laboratory in recent years and correlate these to their structure. A linear relation is found for the volumetric absolute hydrogen uptake as a function of the volumetric surface area, which yields the same hydrogen surface density as in Chahine's rule. Furthermore, the experimental data show a correlation between the specific volume and the specific surface area, which is used to develop a phenomenological model for the volumetric absolute uptake as a function of the gravimetric absolute uptake. Most of the MOFs follow this relation. However, the interpenetrated framework, CFA‐7, shows the strongest deviation and the highest volumetric absolute hydrogen storage capacity at 77 K and 2.0 MPa.