Polyoxometalate Induced Assembly Into Surface Functionalized Multidimensional Heterostructures with Enhanced Catalytic Activity

The self-assembly of inorganic nanocrystals offers an efficient way for the fabrication of functional materials. However, it is still challenging for the construction of multidimensional nanostructures with controllable shapes, compositions and functions. Here, a series of heterostructures in different dimensions by surface modification of polyoxometalate (POM) clusters is developed. Three kinds of POM clusters (phosphomolybdic acid (PMA), phosphotungstic acid (PTA) and silicotungstic acid (STA) and five kinds of metal oxides (TiO2, VOx, La2O3, In2O3 and Gd2O3) can be used as building blocks, and a class of 1D, 2D and 3D heterostructures can be achieved by the control of surface ligand coverage. Compared with individual building blocks and other cluster-based superstructures, TiO2-PMA superstructures exhibit enhanced catalytic activity toward thioether oxidations, which is attributed to the electron transfer between TiO2 and POM clusters. This study develops a facile and general strategy for the synthesis of multidimensional superstructures by the surface modification of POM clusters, where three types of POM clusters and five kinds of metal oxides can be used as building blocks. The electron transfer between hetero-units in TiO2-PMA superstructures results in the enhanced catalytic activity toward thioether oxidation reactions.image