Synthesis, structure, and photocatalytic hydrogen evolution of a trimeric Nb/W addendum cluster

摘要

We present the second example of mixed Nb/W addendum based trimer, Cs₁₂[(SiW₉Nb₃O₃₈)₃WO₃(OH)₃]·33H₂O by utilizing in situ formed Keggin-type {SiW₉(NbO₂)₃} unit as the secondary building block. The polyanion [(SiW₉Nb₃O₃₈)₃WO₃(OH)₃]12? incorporates three saturated niobium-substituted tungstosilicate {SiW₉Nb₃} clusters that are linked together by three Nb–O–Nb bridges and a tungsten joint. The compound has been thoroughly characterized by single crystal X-ray diffraction, UV-Vis spectroscopy, TG analysis, PXRD and FTIR spectra. In addition, the photocatalytic activities of the title compound and the two precursors A-α-Na₁₀[SiW₉O₃₄]·23H₂O and K₇HNb₆O₁₉·13H₂O for H₂ evolution were also evaluated.