Effect of Calcination Temperature on the Structure and Catalytic Performance of the Ni/Al2O3 and Ni-Ce/Al2O3 Catalysts in Oxidative Dehydrogenation of Ethane

We studied the effect of calcination temperature of Ni/Al2O3 and Ni-Ce/Al2O3 catalysts on the specific surface area, acidity, ratio of pore volume and specific surface area, reducibility reflecting the changing population of Ni(T-d) and Ni(O-h) species, and activity/selectivity in oxidative dehydrogenation of ethane It should be stressed that the role of Ce as a promoter on the catalytic activity of Ni-Ce/Al2O3 catalysts decreased with an increasing value of the calcination temperature. At a reaction temperature of 500 degrees C, the highest productivity to ethene was observed for the Ni-Ce/Al2O3 catalyst calcined at 500 degrees C. Ni-Ce/Al2O3 catalysts calcined at 500-750 degrees C showed the same selectivity to ethene. The Ni-Ce/Al2O3 catalysts calcined at 900 and 1000 degrees C showed a sharp decrease in the selectivity and the activity, which was probably associated with the formation of NiAl2O4 spinel.