Selective catalytic reduction of N2O in industrial emissions containing O-2, H2O and SO2: behavior of Fe/ZSM-5 catalysts

The catalytic behavior in N2O reduction by propane in the presence of O-2, H2O and SO2 of Fe/ZSM-5 catalysts prepared by ion exchange and chemical vap our deposition (CVD) is reported. The catalyst prepared by CVD shows a lowe r dependence of the rate of selective N2O reduction on the decrease in C3H8 to N2O ratio in the feed and a higher resistance to deactivation by SO2 in accelerated durability tests with high SO2 concentration (500 ppm). This c atalyst shows stable catalytic behavior in the presence of SO2 for more tha n 600 h of time-on-stream. Characterization of the catalysts by UV-VIS-NIR diffuse reflectance indicates that the poor performances of the sample prep ared by ion exchange could be related to the presence of highly clustered F e3+ species, in this catalyst. On the other hand, Fe2O3 particles are not p resent in the sample prepared by CVD while mainly isolated Fe3+ ions and ir on-oxide nanoclusters are present. (C) 1999 Elsevier Science B.V. All right s reserved.