Influence of calcination temperature on Ce/TiO2 catalysis of selective catalytic oxidation of NH3 to N2

Herein, 10 wt% Ce/TiO2 catalysts were prepared via wet impregnation at different calcination temperatures and used for selective catalytic oxidation (SCO) of NH3 to N-2. The 10 wt% Ce/TiO2 catalyst calcined at 400 degrees C showed the highest NH3 conversion (similar to 96%) and N-2 (similar to 93%) yield (at 350 degrees C). As determined by BET and XRD studies, the ceria oxides existed in either highly dispersed or amorphous phases after preparation at low calcination temperatures (<500 degrees C). Also, the morphological properties and SCO reaction mechanism of the 10 wt% Ce/TiO2 catalysts were investigated using TPR, TPD, XPS, and in situ FT-IR spectroscopy. The activity for the SCO of NH3 to N-2 of the 10 wt% Ce/TiO2 catalysts prepared at different calcination temperatures depend on the oxidation states of the Ce species and behavior of oxygen within the catalyst. The SCO of NH3 to N-2 over Ce/TiO2 calcined at 400 degrees C follows an internal selective catalytic reduction mechanism. (C) 2013 Elsevier B.V. All rights reserved.