Oxidative and non-oxidative dehydrogenation of ethanol to acetaldehyde over different VOx/SBA-15 catalysts

In this present study, characteristics and catalytic properties of different VOx/SBA-15 catalysts for oxidative and non-oxidative dehydrogenation of ethanol to acetaldehyde were determined and well related. First, the SBA-15 supports were synthesized using the sol-gel (SG) and hydrothermal (HT) methods with Zr and La modification. Then, VOx species (2 wt% of V) were deposited on different SBA-15 supports. Among all catalysts, the V-Zr-La/SBA-15-HT showed the highest catalytic activity having 80% conversion of ethanol and acetaldehyde yield of ca. 38% at 400 degrees C in non-oxidative dehydrogenation, while 98% conversion of ethanol and acetaldehyde yield of ca. 40% were obtained for this catalyst at lower temperature (300 degrees C) in oxidative dehydrogenation. In fact, two of the most powerful techniques used to elucidate the nature of VOx species dispersed on Zr-La/SBA-15 supports were X-ray photoelectron spectroscopy (XPS), and CO2 temperature-programmed desorption. It is worth noting that isolated monomeric VOx species, particularly the V4+ species, as well as the amounts of weak basic sites essentially played important role in non-oxidative dehydrogenation and oxidative dehydrogenation of ethanol to acetaldehyde.