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

This study reports ethane oxidative dehydrogenation (ODH) using lattice oxygen. Ethane ODH is studied under an oxygen-free atmosphere employing a 10 wt.% VOx supported on c-Al2O3. TPR and TPO show that the prepared 10 wt.% VOx supported on c-alumina catalyst is a stable catalyst over repeated reduction and oxidation cycles. XRD shows the absence of V2O5 bulk surface species and a high dispersion of VOx 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 VOx/c-Al2O3 catalyst. A slightly increased desorption energy is found when using the V-loaded catalyst. This shows low metal–support interactions and as a result, a well dispersed VOx 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-Al2O3 alumina support. This proves that there are no other species formed due to the interaction between the VOx surface species and the Al2O3 support.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (153 K)Download as PowerPoint slideHighlights► We developed a 10 wt.% VOx supported on c-Al2O3 fluidizable catalyst. ► We studied ODH in a fluidized bed in an O2-free atmosphere at 500–600 °C. ► Reactivity tests gave 6.5–27.6% ethane conversion and 57.6–84.5% ethylene selectivity. ► We used TPR and TPO to show catalyst stability over repeated reduction–oxidation cycles. ► We employed ammonia TPD to assess VOx–support interaction.