Tetradecacobalt(II)-Containing 36-Niobate [Co14(OH)16(H2O)8Nb36O106]20- and Its Photocatalytic H2 Evolution Activity

A gigantic Co-14-containing 36-niobate, Na12K8-[Co-14(OH)(16)(H2O)(8)Nb36O106]center dot 71H(2)O (1), has been prepared by the hydrothermal method and structurally characterized. Polyanion [Co-14(OH)(16)(H2O)(8)Nb36O106](20-) (1a) comprises a central Co-7 core, surrounded by another seven isolated Co2+ ions and six Lindqvist-type (Nb6O19) hexaniobate fragments. This is the first example of a high-nuclear cobalt-cluster-containing polyoxoniobate. The photocatalytic H-2 evolution activity of Pt-loaded 1 was observed in methanol solution under irradiation using a 300 W Xe lamp.