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 °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 °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.