All-Inorganic Bis-Sb₃O₃‑Functionalized A‑Type Anderson−Evans Polyoxometalate for Visible-Light-Driven Hydrogen Production

An all-inorganic, novel bis-Sb₃O₃-functionalized A-type Anderson− Evans polyoxometalate, [Ni(H₂O)₆]KH[NiMo₆O₂₄(Sb₃O₃)₂]·5H₂O (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)][PF₆] photosensitizer and a triethanolamine (TEOA) sacrificial electron donor. Under minimally optimized conditions, a H₂ 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 H₂ production.