Freeze Drying Significantly Increases Permanent Porosity and Hydrogen Uptake in 4,4‐Connected Metal–Organic Frameworks

Freeze the flood: After replacing high boiling-point solvents inside the channels of a metal–organic framework (MOF), benzene is frozen and then removed under vacuum by sublimation. Bypassing the liquid phase eliminates the detrimental effects of surface tension that induce mesopore collapse in MOFs, thereby enhancing their permanent porosity and hydrogen-uptake capacity (see scheme).