Molybdenum modified CeAlOx catalyst for the selective catalytic reduction of NO with NH3

A series of MoO3 doped CeAlOx mixed oxide catalysts with different Mo/Al molar ratios were prepared by the simple coprecipitation method and used for selective catalytic reduction of NO with NH3. The Ce-Mo-AlOx catalyst with the Mo/Al molar ratio of 0.5 exhibited excellent activity and high H2O or/and SO2 poisoning resistance at 250 degrees C. XRD revealed that the molybdenum oxide existed in either highly dispersed or amorphous phases on the catalyst surface. BET analysis results showed that the total pore volume and the average pore diameter of the CeAlOx catalyst was improved by the addition of MoO3. As determined by the H-2-TPR and NH3-TPD, the redox capacity and total acidity of the CeAlOx catalyst were also enhanced by the introduction of MoO3, which are critical for the NH3-SCR reaction. The SCR reaction mechanism was also studied by the in situ DRIFTS, the coordinated NH3 and ionic NH4+ species together with the monodentate and bidentate nitrate were active intermediates on the CeMo0.5AlOx catalyst surface during the NH3-SCR reaction. (C) 2014 Elsevier B.V. All rights reserved.