Self-assembly and photocatalytic hydrogen evolution of a niobium-containing polyoxometalate

A tetra-Keggin polyoxometalate (POM), Cs19K2[Nb4O6(SiW9Nb3O40)4]Cl·27H2O (1) with a photocatalytic property has been synthesized by utilizing the self-assembly of W/Nb mixed-addendum POM [SiW9(NbO2)3O37]7 − under hydrothermal conditions. Its structure was determined by single-crystal X-ray diffraction, and further characterized by IR spectroscopy, thermogravimetric analysis, and cyclic voltammetry. Moreover, the photocatalytic activity of 1 for H2 evolution from water was observed under UV irradiation, suggesting that 1 might be a promising photocatalytic catalyst.