Synthesis of lacunary polyoxometalate encapsulated into hexagonal mesoporous silica and their catalytic performance in esterification

• Lacunary polyoxometalate encapsulated into the molecular sieves HMS.
• Lacunary polyoxometalate are dispersed uniformly in the samples.
• Samples possess an ordered structure with ribbing to cobweb shape cavity framework.
• The samples show excellent catalytic performance for esterification.

The lacunary polyoxometalate (LPOM) encapsulated into the hexagonal mesoporous silica matrix materials were successfully prepared via a directly synthesis method by adjusting pH of the preparation system from 2.0 to 6.0. The materials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, N2 adsorption–desorption measurements, scanning electron microscopy, X-ray fluorescence analysis, and high-resolution transmission electron microscopy. The results show that the samples possess an ordered pore structure with which changed from uniform ribbing-type to cobweb shape cavity along with the LPOM content increasing from 0% to 30%. The materials possess a high specific surface area of 878–626 m2 g−1 and a mesopore diameter of about 3.8 nm. They also show an excellent catalytic performance and a good reusability for the esterification of n-butanol with acetic acid.

Lacunary polyoxometalate was encapsulated into the molecular sieves HMS to prepare hybrid catalysts which possess an ordered structure with a ribbing-type to a cobweb shape cavity framework and exhibit an excellent catalytic performance in esterification.Figure optionsDownload as PowerPoint slide