Immobilization of a Mo,V-polyoxometalate on cationically modified mesoporous silica: Synthesis and characterization studies

This paper presents studies on the immobilization of the polyoxometalate [PV2Mo10O40]−5 (referred to as “POM”) on modified mesoporous MCM-41. The MCM-41 host material was made cationic by functionalization of the surface with [(MeO)3Si(CH2)3N+(CH3)3]Cl. In polar solvents, POM is deprotonated and could be easily immobilized by wet impregnation of the modified silica using MeOH as the solvent. The physical properties of the samples were examined using XRD, FTIR, DR UV–Vis spectroscopy, 31P MAS-NMR, N2 physisorption, and TEM. These techniques indicated that the POM is intact on the surface after impregnation. High loadings of POM caused a decrease in the surface area and pore volume of the solid, presumably due to both pore blockage and restructuring of the silica during wet impregnation. The texture and structure of the MCM-41 was studied as a function of POM loading.