Synthesis, characterization and catalytic activity of nano-spherical MCM-41 modified with vanadium.

Abstract

Vanadium modified MCM-41 nanospheres were synthesized by the impregnation and sol-gel super-molecular method respectively. Structure and morphology of the obtained materials were characterized using X-ray diffraction (XRD), inductively coupling plasma (ICP), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM) and N2-adsorption-desorption techniques. The influence of particle sizes on their catalytic activities in styrene oxidation and benzene hydroxylation was investigated. Results revealed that all the samples had regular sphere shape and adjustable particle size within 40-160 nm, and exhibited high catalytic activities in the oxidation of styrene and hydroxylation of benzene. The smaller the particle size is, the higher the activity becomes. Meanwhile, the catalysts synthesized by the sol-gel method are more effective than that synthesized via impregnation method, indicating the vanadium species in the mesoporous framework are probably the catalytic active sites.