Polyoxometalates (POMs) are molecular metal oxides composed of transition metals in their highes oxidation states (Mo,W,V,Nb,Ta). The high solubility and low specific surface area of pure inorganic POMs limi its practical applications in polar solvents. Due to the widespread applications of organic?inorganic hybrid POMs and immobilized POMs in the field of catalysis, energy conversion, storage and magnetism have attracted considerable attention.The design and synthesis of transition metal/Lanthanide modified organic?inorganic polyoxometalates and immobilized polyoxometalates composites are reviewed,and the practical applications of POMs with novel structures are summarized and outlooked.

In this work, the HTO (H_4x/3Ti_2-x/3□ _x/3O₄·nH₂O) was used as the precursor raw material, and the nanoscale titanium oxide particles (ST01) were loaded on the surface of the HTO by water bath impregnation, and the TiO₂ homogeneous structure composite was topologically synthesized by calcination method. Using X?ray diffraction （XRD）, Raman spectroscopy (Raman) and other testing methods, the effect of calcination temperature on the phase transition process with titanium dioxide was studied in detail. The results indicate that the HTO can transfer to TiO₂（B）, anatase TiO₂ and rutile TiO₂ with increased temperatures, and the TiO₂ homophase composites are obtained with various structure and content of TiO₂. The degradation experiment was carried out with Rhodamine B （RhB） as the pollutant model. The photocatalytic activity of the sample at 600 ℃ is significantly higher than that of other samples, mainly because the separation efficiency of electrons and holes of the sample is the highest at this time, indicating that the structure and composition of homogeneous composite TiO₂ affect its photocatalytic activity. In addition, dye?sensitized solar cell （DSSCs） experiments show that the reason for the higher optoelectronic performance of the samples at 600 ℃ is that the two?dimensional sheet?like morphology facilitates the rapid migration of photogenerated carriers.