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

Abstract

Herein, 10wt% Ce/TiO2 catalysts were prepared via wet impregnation at different calcination temperatures and used for selective catalytic oxidation (SCO) of NH3 to N2. The 10wt% Ce/TiO2 catalyst calcined at 400°C showed the highest NH3 conversion (∼96%) and N2 (∼93%) yield (at 350°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°C). Also, the morphological properties and SCO reaction mechanism of the 10wt% Ce/TiO2 catalysts were investigated using TPR, TPD, XPS, and in situ FT-IR spectroscopy. The activity for the SCO of NH3 to N2 of the 10wt% 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 N2 over Ce/TiO2 calcined at 400°C follows an internal selective catalytic reduction mechanism.