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 -NH(2) and -(CF(3))(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)-(CF(3))(2) analogues, whereas the presence of Lewis acid sites and/or a confinement effect enhances significantly the strength of interaction with hydrogen.

Wet hydrogen peroxide catalytic oxidation (WHPCO) is one of the most important industrially applicable advanced oxidation processes (AOPs) for the decomposition of organic pollutants in water. It is demonstrated that manganese functionalized silicate nanoparticles with interparticle porosity act as a superior Fenton‐type nanocatalyst in WHPCO as they can decompose 80% of a test organic compound in 30 minutes at neutral pH and room temperature. By using X‐ray absorption spectroscopic techniques it is also shown that the superior activity of the nanocatalyst can be attributed uniquely to framework manganese, which decomposes H2O2 to reactive hydroxyls and, unlike manganese in Mn3O4 or Mn2O3 nanoparticles, does not promote the simultaneous decomposition of hydrogen peroxide. The presented material thus introduces a new family of Fenton nanocatalysts, which are environmentally friendly, cost‐effective, and possess superior efficiency for the decomposition of H2O2 to reactive hydroxyls (AOP), which in turn readily decompose organic pollutants dissolved in water.

Structural dynamics of Ca(BDC)(DMF)(H 2 O) with rhombic-shaped channels and 4 4 net topology upon heating and hydration were elucidated by using complementary methods of diffraction (XRD) and spectroscopy (FT-IR, MAS NMR, EXAFS, XANES). During heating the Ca(BDC)-(DMF)(H 2 O) framework underwent structural changes in two steps. The first change at 150 °C includes breaking of Ca−O bonds with H 2 O and DMF molecules. In this step, DMF is removed from the surface or near the surface of the crystals. The affected parts of the crystals are transformed to a new nonporous Ca-BDC(400) phase that prevents the diffusion of DMF from the cores of the crystals. Second transition at 400 °C led to the complete transformation to Ca-BDC(400). This phase is reversibly transformed to a pseudo-3-D framework Ca(BDC)(H 2 O) 3 upon exposure to humid environment. We proposed mechanisms of Ca-BDC(RT) → Ca-BDC(400) and Ca-BDC(400) → Ca(BDC)(H 2 O) 3 transformations, which include breaking of the bonds between Ca 2+ and carboxylate groups, rotating of BDC ligand, and recoordination of COO − groups to Ca 2+ centers. The crystal-to-crystal transformations are driven by the tendencies to change the bonding modes between COO − and Ca 2+ with the change of Ca 2+ coordination number. Thus the decrease in Ca 2+ coordination number, which is usually a consequence of activation, does not lead to the expansion or contraction of the pores, but it leads to pronounced structural rearrangement. Such behavior can explain the lack of porosity in Ca-MOF systems.