Anderson-type polyoxometalates: from structures to functions

Anderson-type polyoxometalates (POMs) are one of the most important groups of the POM family. In the past decade, the functionalization of Anderson-type POMs has achieved significant progress and these materials have already shown unique charm in catalysis, molecular devices, energy materials, and inorganic biochemical drugs. In particular, their highly flexible topological structure and diverse functionalization methods make them the most convenient and universal platforms for rational design and controllable synthesis. This review provides a deep discussion on the recent progress in the synthetic methodology, structural exploration, and promising applications of Anderson-type POMs. It also summarizes the latest research directions and provides future prospects.

From a Cerium-Doped Polynuclear Bismuth Oxido Cluster to β-Bi2O3:Ce

The simultaneous hydrolysis of Bi(NO₃)₃·5H₂O and Ce(NO₃)₃·6H₂O results in the formation of novel heterometallic bismuth oxido clusters with the general formula [Bi₃₈O₄₅(NO₃)₂₄(DMSO)_28+δ]:Ce (DMSO = dimethyl sulfoxide; cerium content <1.50%), which is demonstrated by single-crystal X-ray diffraction analysis. The incorporation of cerium into the cluster core is a result of the interplay of hydrolysis and condensation of the metal nitrates in the presence of oxygen. Diffuse-reflectance UV-vis and X-ray photoelectron spectroscopy reveal the presence of Ce^IV in the final bismuth oxido clusters as a result of oxidation of the cerium source. The cerium atoms are statistically distributed mainly on the bismuth atom positions of the central [Bi₆O₉] motif of the [Bi₃₈O₄₅] cluster core. Hydrolysis and subsequent annealing of the bismuth oxido clusters in the temperature range of 300-400 °C provides β-Bi₂O₃:Ce samples with slightly lowered band gaps of approximately 2.3 eV compared to the undoped β-Bi₂O₃ (approximately 2.4 eV). The sintering behavior of β-Bi₂O₃ is significantly affected by the cerium dopant. Finally, differences in the efficiency of the as-prepared β-Bi₂O₃:Ce and undoped β-Bi₂O₃ samples in the photocatalytic decomposition of the biocide triclosan in an aqueous solution under visible-light irradiation are demonstrated.