Selective catalytic reduction of NO by hydrogen over Pt/ZSM-35

The catalytic performances of platinum catalysts supported on ZSM-5, ZSM-35 and Beta are explored for the selective catalytic reduction of NO by hydrogen (H-2-SCR). 1% Pt/ZSM-35 sample exhibits the best activity and a maximum NO conversion of 80.8% can be achieved at 120 degrees C with N-2 selectivity of 68.5% (GHSV = 80,000/h). In situ FTIR spectra are employed to get insight into the type of surface species formed during reaction, and NH4+ is found to be the key intermediate in H-2-SCR. Effects of platinum loadings on the activity of Pt/ZSM-35 are further studied between 0.1 and 2.0 wt.% Pt loading. Increase of Pt loading beyond 1.0 wt.% leads to an activity decline where a loss of strong acid sites is observed. Meanwhile, XRD and TEM results illustrate an aggregation of Pt species with increasing Pt loading on ZSM-35. (C) 2010 Elsevier B.V. All rights reserved.