All-Inorganic Bis-Sb 3 O 3 -Functionalized A-Type Anderson-Evans Polyoxometalate for Visible-Light-Driven Hydrogen Production.

An all-inorganic, novel bis-Sb 3 O 3 -functionalized A-type Anderson-Evans polyoxometalate, [Ni(H 2 O) 6 ]KH[NiMo 6 O 24 (Sb 3 O 3 ) 2 ]·5H 2 O ( 1 ), has been synthesized under hydrothermal conditions. The chemical composition, molecular structure, and elemental oxidation states of the resulting compound have been systematically characterized by various techniques, including single-crystal X-ray diffraction, thermogravimetric analysis, Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy. The title complex 1 has been investigated for the first time as a catalyst for visible-light-driven hydrogen production by coupling with a [Ir(coumarin) 2 (dtbbpy)][PF 6 ] photosensitizer and a triethanolamine (TEOA) sacrificial electron donor. Under minimally optimized conditions, a H 2 generation rate of as high as 10 358 μmol g -1 h -1 is achieved during a 6 h photocatalysis. Additional control experiments and spectroscopic analyses have demonstrated that complex 1 will undergo the in situ photoreduction during photocatalysis and its specific geometric structure is essential to efficient photocatalysis for H 2 production.