3D extended polyoxoniobates/tantalates solid structure: Preparation, characterization and photocatalytic properties

Two novel 3D extended polyoxotantalates/niobates solid complexes: [Na-6(H2O)(13))][Li(H2O)(H3O)] [(Ta6O19)] (1) and [Na-6(H2O)(13)][Li(H2O)(2)][H(Nb6O19)] (2) have been assembled successfully based on double alkali metal ions (Li+ and Na+) and Lindqvist clusters ([Ta6O19](8-)/[Nb6O19](8-)) under aqueous solution. Both compounds have been characterized by IR, TG analysis and single-crystal X-ray diffraction. It is worth noting that Li and Na ions, different kinds of alkali ions, are first observed coexisting in two resultant solid crystal structures of polyoxotantalates/niobates. Further photocatalytic investigations show that methylene blue (MB) dye solution can be degraded by UV irradiation effectively in the presence of [Nb6O19](8-)/[Ta6O19](8-). The experiments indicate that the degradation efficiency depends on pH value, irradiation time, initial MB concentration and different types of POM anions etc. (c) 2009 Elsevier B.V. All rights reserved.