Effects of montmorillonite and anatase TiO2 support on CeO2 catalysts during NH3-SCR reaction

Cerium supported on titanium oxides are regarded as the most potential alternative catalysts for removing NOx by selective catalytic reduction. However, their poor catalytic activity in low and high temperature range seriously limit their practical applications. Herein, a series of hybrid catalysts (xCe-Ti/Mt) combining certain amount of CeO2 supported on montmorillonite (Mt) and anatase TiO2 were prepared by sol-gel method for NH3-SCR reaction. xCe-Ti/Mt showed excellent catalytic activity in the temperature range of 275 °C–450 °C. The catalysts were studied by XRD, SEM, BET, XPS, H2-TPR and NH3-TPD techniques. The characterization results verified that the integration of montmorillonite and anatase TiO2 can obviously increase the surface acidity, H2 consumption, the ratio of chemisorbed oxygen Oα/(Oα+Oβ) and Ce3+/(Ce3++ Ce4+). These were believed to be the causes that promote the NH3-SCR performance of the samples. The effect of Ce concentration on the NH3-SCR reaction was also explored, the catalyst of 6Ce-Ti/Mt exhibited the best catalytic activity over the samples.