VO x/SiO2 Catalyst Prepared by Grafting VOCl3 on Silica for Oxidative Dehydrogenation of Propane.

The VO _x/SiO₂ catalysts for oxidative dehydrogenation of propane were synthesized by a simple grafting method. The VOCl₃ was first grafted at the surface of SiO₂, which was dehydrated at different temperature (from 200 to 1000 °C). The formed grafted complexes were then calcined in air, leading to the formation of VO _x/SiO₂ catalysts. The synthesized catalysts were characterized by nitrogen adsorption, SEM, Raman spectroscopy, temperature-programmed reduction, and extended X-ray absorption fine structure analysis. The SiO₂ pretreatment temperature has an evident effect on the loading and dispersion of VO _x on SiO₂, which finally affects their catalytic performance. High SiO₂ treatment temperature is beneficial to dispersing the vanadium oxide species at the SiO₂ surface. These materials are efficient catalysts for the catalytic oxidative dehydrogenation of propane to propylene. The best selectivity to propylene is achieved on the VO _x/SiO_2-(1000) catalyst. The high selectivity and activity are well maintained for three days catalytic reaction. [ABSTRACT FROM AUTHOR]