Propane Oxidative Dehydrogenation Over Ln-Mg-Al-O Catalysts (Ln = Ce, Sm, Dy, Yb)

Ln-Mg-Al mixed oxide catalysts (Ln = Ce, Sm, Dy, Yb) were prepared from layered double hydroxide precursors, characterized using XRD, N-2 adsorption, TG-DTG, EDX, H-2-TPR and CO2-TPD techniques and tested in the oxidative dehydrogenation of propane in the temperature range 450-600 A degrees C. For all the catalysts the conversion increases with increasing the reaction temperature while the propene selectivity decreases to the benefit of carbon oxides for Ce-based system and of cracking products for the others. The best yields in propene were obtained with Dy- and Sm-Mg-Al-O catalysts. No correlation between the reducibility of the rare-earth cation and the catalytic performances was observed. A linear correlation between the catalyst basicity and the propene selectivity was evidenced.