Enhanced performance in NOx reduction by NH3 over a mesoporous Ce-Ti- MoOx catalyst stabilized by a carbon template

Mesoporous Ce-Ti-MoOx catalysts have been prepared by stabilization with an in situ formed carbon template and used for selective catalytic reduction of NOx with NH3 (NH3-SCR). The Ce-Ti-MoOx catalysts were characterized by N-2 adsorption-desorption, XRD, HR-TEM, H-2-TPR and XPS analysis. It was found that the stabilization with a carbon template obviously improved the NOx conversion of the Ce-Ti-MoOx catalyst and the pore distribution. The Ce-Ti-MoOx catalyst stabilized with a carbon template at 850 degrees C in N2 exhibited the best NH3-SCR activity and showed a uniform mesopore distribution, and more than 90% NOx conversions were obtained at 175-425 degrees C with a GHSV of 60000 h(-1). The high stabilization temperature with a carbon template in N-2 not only led to an increase in specific surface area, pore volume and low-temperature SCR activity, but also contributed to the enhanced redox properties, highly dispersed titanium or molybdenum species and narrow mesopore distribution. The treatment of Ce-Ti-MoOx with a high calcination temperature for removal of the carbon template led to a drastic decrease in surface area, an abrupt decrease in surface oxygen and cerium, production of rutile TiO2, and a correspondingly low SCR activity.