Catalytic oxidative dehydrogenation of n-butane over V2O5/MO-Al2O3 (M = Mg, Ca, Sr, Ba) catalysts

Abstract

V2O5/MO-Al2O3 (M = Mg, Ca, Sr, Ba) catalysts with different V2O5 loading were prepared by impregnation with ammonium metavanadate as the V precursor and characterized and tested for the selectively oxidative dehydrogenation of n-butane to butenes. Characterization by BET, XRD, FTIR, H2-TPR and Raman spectra showed that the catalysts doped with different alkaline earth metals had different structure and catalytic activity. The catalysts doped with Ca, Sr or Ba had the orthovanadate phase that was difficult to reduce, so their redox cycles could not be established and they exhibited low activity. The catalysts doped with Mg showed high catalytic activity and selectivity. The catalyst with 5% V2O5 loading exhibited the highest n-butane conversion (30.3%) and total butene selectivity (64.3%) at 600 °C. This was due to the well dispersed VOx species and the existence of the MgO crystalline phase, which were both present at a V2O5 loading of 5%.