Synthesis of macro-mesoporous niobium oxide molecular sieves by a ligand-assisted vesicle templating strategy

The synthesis of the first ordered macroporous metal oxides with ordered mesoporosity by a ligand-assisted vesicle templating strategy involving is described. These niobium oxide based materials have pore sizes in the 200-300 nm range as determined by SEM studies and roughly 20 Angstrom mesopores in the same plane as the macropores as determined by TEM and XRD. Treatment of these materials with acid results in template removal with full retention of both the mesopore and macropore structure. Attempts to alter the macropore size of these materials by generation of preformed vesicles of different sizes led to materials with the same macropore sizes of 200-300 nm. This, and other studies, suggest a cooperative macropore assembly mechanism rather than one involving performed vesicles.:(C) 1999 Elsevier Science B.V. All rights reserved.