Two new inorganic-organic hybrids constructed by Keggin-type polyoxometalates sandwiched between lanthanide-organic layers: synthesis, structure and properties

Two new polyoxometalate-based lanthanide-organic compounds, namely [Pr4(bpdc)4(H2O)10][SiW12O40]·3H2O (1) and [Ce4(bpdc)4(H2O)10][SiMo12O40]·3H2O (2) (H2bpdc = 2,2ʹ-bipyridine-6,6ʹ-dicarboxylic acid) have been hydrothermally synthesized and characterized through single-crystal X-ray diffraction, elemental analysis, powder X-ray diffraction, IR spectroscopy and thermogravimetric analysis. In compounds 1 and 2, Keggin-type polyoxometalates are sandwiched between the adjacent lanthanide-organic layers. Their electrochemistry properties have been studied including cyclic voltammetry, electrocatalytic properties, and the amperometric sensing performances to BrO3− and pH. The behaviors for removing organic dye pollutants were also explored including the photocatalytic degradation and adsorption performances. In addition, the mechanism and the kinetic of the photocatalytic degradation and adsorption were also investigated and the adsorption process fits well with the Langmuir isotherm model.