Oxidative dehydrogenation of ethylbenzene over γ-Al2O3 supported ceria-lanthanum oxide catalysts: Influence of Ce/La composition

A series of CeO2/gamma-Al2O3 (CA) catalysts with CeO2 loading of 5, 10, 15 and 20 wt% were prepared by a facile incipient wetness impregnation technique. Another series of La3+ doped catalysts (LCA) were prepared, wherein, 1, 3 and 5 wt% of La2O3 was doped in 15 wt%CeO2/gamma-Al2O3, which were designated as 1LCA, 3LCA and 5LCA catalysts. Both CA and LCA catalysts were characterized by thermogravimetric analysis (TGA), BET surface area, X-ray diffraction (XRD), Infrared (FT-IR) spectroscopy, UV-vis diffuse reflectance spectra (UV-vis DRS), transmission electron microscopy (TEM), temperature programmed desorption of NH3 (TPD of NH3) temperature programmed reduction (TPR), CO2 pulse chemisorption and O-2 pulse chemisorption techniques. All CA and LCA catalysts were evaluated for ethylbenzene (EB) oxidative dehydrogenation to styrene (ST) in vapor phase under atmospheric pressure with CO2 as an oxidant. Albeit CA and LCA catalysts are active, 15CA and 3LCA catalysts are found to be the best catalysts of the respective series. Apart from compatible acid-base and redox characteristics, sufficient amount of solid solution clusters (CexLa1-xO2-delta) are responsible for superior activity of 3LCA catalyst. (C) 2017 Production and hosting by Elsevier B.V. on behalf of King Saud University.