The hydrogen adsorption capacity and heat of adsorption at 77 K have been evaluated for several porous metal terephthalate MOFs (MIL-53(Fe), MIL-125(Ti) and UiO-66(Zr)), as well as in their –NH₂ and –(CF₃)₂ functionalized isoreticular structures. The capacity of hydrogen is basically related to the textural properties of the solids and not to their composition. The heats of adsorption at low coverage are on the whole close to those usually reported for MOFs (6–7 kJ mol⁻¹), except for the UiO-66(Zr) and MIL-53(Fe)-(CF₃)₂ analogues, whereas the presence of Lewis acid sites and/or a confinement effect enhances significantly the strength of interaction with hydrogen.

TiFe-based alloys are key materials for large-scale applications based on solid-state hydrogen storage. A comprehensive overview is here provided on chemical substitutions in TiFe for tuning at will their reversible hydrogen storage properties.