Confinement of metal-organic polyhedra in silica nanopores.

Metal-organic polyhedra (MOPs) have been incorporated into silica nanopores for the first time. Three MOPs with identical geometries but different ligand functionality (namely tert-butyl, hydroxyl, and sulfonic groups) were employed. A typical mesoporous silica, SBA-15, with a two-dimensional hexagonal pore regularity was used as the host. In comparison with bulk MOPs, which prefer to aggregate, MOPs confined in silica nanopores can be well dispersed, making the active sites and pores in the MOPs accessible. These dispersed MOPs showed apparently superior H(2) adsorption capacity in comparison with aggregated bulk MOPs. Moreover, the thermal stability of the MOPs was enhanced upon their confinement in silica nanopores.