Preparation and characterization of CeO2-MoO3/TiO2 catalysts for selective catalytic reduction of NO with NH3

Abstract

CeO2-MoO3/TiO2 catalysts were prepared by three methods: a single step sol-gel (SG), impregnation (IM) and coprecipitation (CP) method. These catalysts were investigated for selective catalytic reduction (SCR) of NO with NH3. The results indicate that the catalyst prepared by the SG method possessed the widest temperature window (about 250– 475°C), best SCR activity below 450°C and resistance against 10% H2O and 1000 ppm SO2 at a gas hourly space velocity (GHSV) of 90,000 h–1. According to the results of BET, XRD, XPS, H2-TPR and TEM, it is found that larger BET surface area, more highly dispersed active species of Ce and Mo, presence of more Ce3+ and chemisorbed oxygen, synergistic effect among ceria, molybdenum and titania, and better redox ability can contribute to the better deNOx performance of the CeO2-MoO3/TiO2 catalyst prepared by the SG method, compared with those by the IM and CP methods.