Synthesis, characterization of MCM-41 with high vanadium content in the framework and its catalytic performance on selective oxidation of cyclohexane

Abstract

V-MCM-41 with high content of vanadium in the framework was synthesized by using direct hydrothermal method under alkaline condition. Tartaric acid is the complexing reagent and cetyltrimethylammonium bromide is the structure-directing agent. The samples were characterized by X-ray fluorescence, X-ray diffraction, high-resolution transmission electron microscopy, N2 adsorption–desorption, Fourier-transform infrared spectroscopy, diffuse reflectance ultraviolet–visible spectroscopy and X-ray photoelectron spectroscopy techniques. The catalytic performance for the selective oxidation of cyclohexane was also examined. The results showed that the vanadium atoms were successfully introduced into the MCM-41 framework and the vanadium content reached up to 8.1wt.%. Moreover, the V-MCM-41 samples possessed regular and stable structure with high specific surface area (692–939m2g−1), large pore diameter (3.6–4.6nm) and large pore volume (0.86–0.95cm3g−1). The samples exhibited excellent catalytic performance of up to 22.57% cyclohexane conversion and 99.53% selectivity for cyclohexanone and cyclohexanol in the cyclohexane oxidation.