Hydrogenation of Toluene over La0.8Sr0.2Fe1-xCoxO3-z Perovskite Catalysts

TLDR: In this article, the hydrogenation of toluene over perovskites of composition La₀.₈Sr ₈₆ was investigated.

Abstract: The hydrogenation of toluene over perovskites of composition La₀.₈Sr₀.₂Fe₁₋ₓ CoₓO₃₋z (x = 0.0, 0.2, 0.5, 0.8 and 1.0) is reported. The catalyst material has been prepared by the coprecipitation method using maleic acid as the complexing agent. The activity for the gas phase reaction of toluene and hydrogen at temperatures between 50 °C to 300 °C is reported for as-prepared and activated materials. The conversion has been found to be nearly temperature-independent over the as-prepared-per­ ovskites with a maximum of 40% conversion found for a composition La₀.₈Sr₀.₂Fe₀.₅Co₀.₅O₂.₈₆. Activation by an oxygen treatment at 500 °C was successful to enhance the activity of the Co-rich perovskites. All of these catalysts show a complete conversion of toluene at 100 °C, but activity decreases by time due to a reduction of the catalyst material. Again, La₀.₈Sr₀.₂Fe₀.₅Co₀.₅O₂.₈₆ exhibits the slowest loss of activity. A model for its special properties is mainly attributed to the p-type conduction behaviour. The conversion behaviour of the perovskite type catalysts investigated here is compared to the results obtained with noble-metal supported catalysts and it can be concluded, that the perovskites exhibit higher conversion rates, maximum temperatures and higher cracking onset temperatures than these.