Activity of the Ni–Al Mixed Oxides Prepared from Hydrotalcite-Like Precursors in the Oxidative Dehydrogenation of Ethane and Propane

摘要

The activity of Ni–Al mixed oxides obtained by the thermal pre-treatment of Ni–Al hydrotalcite-like precursors was studied in the ODH of ethane and propane. The activity of the Ni–Al mixed oxide catalysts was studied with respect to (i) the role of Ni content and (ii) the role of temperature during Ni–Al HTs thermal pre-treatment. The structure analysis and the activity of Ni–Al mixed oxides were discussed in three groups; (A) the catalysts pre-treated at 500 °C, (B) the catalysts pre-treated at 600 °C and (C) the Ni2–Al catalyst with constant Ni content pre-treated at 500–900 °C. Ni–Al mixed oxides were active and selective catalysts in the ODH of ethane even at 450 °C. On the other hand, the catalysts posses low selectivity to propene. It is supposed that the interaction of NiO with alumina phase plays the critical role in the active and selective catalysts. The Ni–Al mixed oxides were characterized by XRD, H₂-TPR and diffuse reflectance spectroscopy.