VORw /c-Al2O3 catalyst for oxidative dehydrogenation of ethane to ethylene: Desorption kinetics and catalytic activity

Authors:  S. Al-Ghamdi, M. Volpe, M.M. Hossain, H. de Lasa

Abstract:
This study reports ethane oxidative dehydrogenation (ODH) using lattice oxygen. Ethane ODH is studied under an oxygen-free atmosphere employing a 10 wt.% VO_x supported on c-Al₂O₃. TPR and TPO show that the prepared 10 wt.% VO_x supported on c-alumina catalystis a stable catalyst over repeated reduction and oxidation cycles. XRD shows the absence of V₂O₅ bulk surface species and a high dispersion of VO_x on the support surface. Experiments are carried out in the CREC Fluidized Bed Riser Simulator at 550–600 ◦C and pressures close to atmospheric conditions. Reactivity tests show that the prepared ODH catalyst displays 6.5–27.6% ethane conversion and 57.6–84.5% ethylene selectivity in the 550–600 ◦C range. Metal–support interaction is assessed using ammonia TPD. This provides the desorption energy for both the bare c-Al₂O₃ support and for the VO_x/c-Al₂O₃ catalyst. A slightly increased desorption energy is found when using the V-loaded catalyst. This shows lowmetal–supportinteractions and as a result, a well dispersed VO_x catalyst phase with high availability of lattice oxygen for ODH. These findings are confirmed with XRD, showing no changes with respect to the XRD for the c-Al₂O₃3 alumina support. This proves that there are no other species formed due to the interaction between the VO_x surface species and the Al₂O₃ support.

Keywords:
NH3-TPD kinetics
Oxidative dehydrogenation
Ethylene
Vanadium oxide
Lattice oxygen
Riser simulator

Published in: Applied catalysis A: General  (Volume 450, Pages 1-274, 15 January 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

VORw /c-Al2O3 catalyst for oxidative dehydrogenation of ethane to ethylene: Desorption kinetics and catalytic activity

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