Boichuk T. The influence of composition of Fe-, Co-containing zeolite and zirconia catalysts on decomposition and reduction of nitrogen(I) oxide

Fe-containing catalysts based on pentasil and mordenite, as well as containing the cation-decationized forms with the zirconyl ion, which are characterized by strongly acidic surface sites in accordance with NH3-TPD data, are the most active in direct decomposition of nitrous oxide. Activity of cobalt-zirconium oxide catalysts depends on the amount of cobalt oxide deposited (0,5-10%). The conditions of positive effect of NO and SO2 on conversion of nitrous oxide over iron-containing zeolite-based catalysts were found in contrast to cobalt-containing catalysts. The results have been interpreted from the standpoint of N2O decomposition mechanism. In the presence of excess oxygen (in conditions of the SCR process) over Fe-containing zeolite-based catalysts, the best results (high 90-94 % conversion of N2O at lower temperatures) were obtained by using hydrocarbons as reducing agents, in contrast to CO, which are activated at the strongly Bronsted acidic centers of the catalysts. The comparison of activityof iron- and cobalt-containing catalysts in the reaction of simultaneous reduction of nitrogen(I, II) oxides by C3-C4 alkanes (including SCR process) demonstrates that in the range of 400-450oC higher conversions of N2O (90-95 %) are achieved on iron-containing, and NO (60-78 %) - on cobalt-containing zeolite (H-ZSM-5) catalysts, which is connected with different routes of reagent activation.