Catalytic Oxidation of Toluene on Hydrothermally Prepared Ceria Nanocrystals

Ceria nanocrystals were prepared hydrothermally and tested as potential catalysts for oxidation of volatile organic compounds using toluene as a model compound. Pure ceria with a crystallite size of 4 nm, determined by the Scherrer method from XRD pattern has been obtained. The specific surface area of the prepared nanoparticles determined by BET analysis yielded 201 m(2) g(-1), while the band gap of 3.2 eV was estimated from DRS spectrum via Tauc's plot. Catalytic tests were performed on calcined ceria (500 degrees C) with increased crystallite size (9 nm) caused by thermal treatment. The tests showed good activities for the toluene oxidation with T-50 temperatures, corresponding to 50 % toluene conversion, observed at 250 degrees C and even lower temperatures depending on the total flow rate of the gas mixture. The one-dimensional pseudo-homogeneous model of the fixed bed reactor was proposed to describe the reactor performance and the appropriate kinetic parameters were estimated. Good agreement between experimental data and the proposed model was observed.