Low temperature H2-SCR over platinum catalysts supported on Ti-containing MCM-41

A series of Ti-containing MCM-41 were prepared by isomorphously substitution, wet impregnation and mechanical mixing. Ti-containing MCM-41 materials, together with reference Si-MCM-41, were characterized by means of XRD, TEM and low temperature N-2 adsorption/desorption. The nature of Ti species on Ti-containing MCM-41 was analyzed by means of UV-vis and Raman spectroscopy. Pt catalysts supported on Si-MCM-41 and Ti-containing MCM-41 were studied for the selective catalytic reduction of NO by hydrogen in excess oxygen. Particular attention was paid to the promotion effect of different Ti species on the catalytic activity for H-2-SCR and the origin thereof. Pt/Ti-MCM-41 prepared by wet impregnation with the Ti/Si ratio of 0.6 exhibited the best activity and ca. 89% NOx conversion as well as ca. 79% N-2 selectivity, could be achieved at 140 degrees C with a feed stream containing 1000 ppm NO, 5000 ppm H-2, 6.7%O-2 at a high GHSV of 80,000 h(-1). Moreover, Pt-Ti-MCM-41 exhibited good duration and good tolerance to co-existing 20 ppm SO2 or 50 ppm CO, which demonstrated its potential for future applications. (C) 2009 Elsevier B.V. All rights reserved.