Optimization of V2O5–MgO/TiO2 catalyst for the oxidativedehydrogenation of propane effect of magnesia loading and preparation procedure

The effect of magnesia loading and preparation procedure of vanadia ontitania catalysts on the physicochemical characteristics and theperformance in propane oxidative dehydrogenation were investigated. Aseries of magnesia promoted vanadia catalyst (5 wt% V₂O₅) with varying amounts of MgO (1.9--10 wt%) were synthesized bysynchronous and sequential deposition on titania support. The catalystswere characterized using several techniques (BET, XRD, H₂-TPR and NH₃)-TPD). Both MgO loading and preparation procedure affect the catalyst surface properties and the behavior in the oxidativedehydrogenation of propane. Magnesia addition results in drasticincrease in propene selectivity, while the effect on activity isnegative. The activity is inversely related with the magnesia loading.Deposition of V₂O₅ on previously prepared MgO/TiO₂ presents a beneficial effect in the activity of the sample. The role of acidity and reducibility is explored. There is no correlation betweenreducibility and activity of the catalysts, whereas the acidity seems to influence the catalytic performance. Catalyst containing 5 wt% V₂O₅ and 1.9 wt% MgO prepared by sequential deposition ofV₂O₅ on already doped with MgO titania exhibits the most interesting results.