Synthesis Of Hollow Porous Silica Nanospheres Encapsulating Metal Oxides And Their Applications In Methylene Blue Degradation

In this study,we used charge-driven micelle as templates to synthesize porous hollow silica nanospheres encapsulating functional metal oxide nanoparticles in cavities by a one-pot method,and H2O2 degradation of dyes over the hollow silica nanospheres were studied.The detailed studies are as follows:(1)Syntheses of hollow silica nanospheres encapsulating metal oxide.Charge-driven self-assembly micelles were used as templates to deposit silica by hydrolysis of TMOS in acidic conditions or by hydrolysis of TMOS in basic conditions,and following crystallization and subsequent calcination in air gave porous hollow silica nanospheres encapsulating pure rare earth metal oxide or mixed Ce/Cu oxide nanoparticles in cavities.Various characterization techniques,such as transmission electron microscopy,N2 physical adsorption and energy disperse spectroscopy,are employed to investigate the influence of synthetic parameters on the structure of as-synthesized materials.The results reveal the following:the average diameters of the whole silica nanospheres are from 22.8 nm to 33.3 nm,and the average sizes of the cavities are 11.1 nm to 14.8 nm;the nanospheres synthesized in the acidic conditions have abundant pores with high specific surface areas while those synthesized in basic conditions have relatively small specific surface areas.(2)The degradations of methylene blue over porous hollow silica nanospheres with function metal oxides inside cavities.The degradations of methylene blue over porous hollow silica nanospheres encapsulating rare earth metal oxide nanoparticles were investigated,and the comparison between the materials containing CexOy synthesized in various pH values and the traditional supported catalysts were carried out.The results show that nanoreactors synthesized in the acidic conditions show the better performance than the counterparts prepared in the basic conditions and supported ones;the additional substrates such as organic compounds will decrease the degradation efficiency of methylene blue.In addition,degradations of methylene blue over porous hollow silica nanospheres encapsulating mixed Ce/Cu oxide nanoparticles were investigated and their reaction conditions were optimized.