Preparing an active cerium oxide catalyst for the catalytic incineration of aromatic hydrocarbons

Abstract

We tested the efficacy of seven metal oxide catalysts in the catalytic incineration of aromatic hydrocarbons and found CeO 2 to be the most active of the seven. With the use of CeO 2, complete oxidation of toluene was achieved at 240 °C. There was a similar outcome in the incineration of p-xylene, whereas benzene was more refractory. In preparation of the CeO 2 catalyst, four different methods were evaluated; a redox reaction in hydrogen peroxide was found to produce the most active catalyst. This is because CeO 2 prepared using this method (designated as CeO 2-A) had the smallest crystallite size and the largest BET surface area, both characteristics that confer higher activity. O 2-TPD and toluene-TPD also demonstrated the superior activity of the CeO 2-A catalyst, as it was best able to adsorb both toluene and O 2. The effect of calcination temperature was also assessed to find the optimal preparation conditions. CeO 2 calcined at 500 °C was the most active catalyst; its higher activity can be attributed to its smallest crystallite size and hence largest surface area. In the reaction, a higher reaction temperature was necessary for 100% conversion of toluene at higher values of weight hourly space velocity (WHSV) and higher toluene concentrations.