Zeolite supported iron catalyst for nitric oxide reduction by ammonia in the presence of oxygen

Abstract

Iron based H-ZSM-5 catalysts were used to study NO reduction with NH₃ in the presence of oxygen with and without humid conditions. The iron based H-ZSM-5 was prepared by wet impregnation method and characterized by X-ray diffraction technique, BET surface area and SEM. TPD experiments showed low and high temperature NH₃ desorption peaks. FTIR indicated only ammonia adsorbed species. Fe/ZSM-5 showed better NO_x reduction with NH₃ than H-ZSM-5 which was a poor catalyst for the NO_x reduction. The catalytic activity did not show significant difference in the NO_x conversion with and without water, but there was significant difference in NH₃ conversion. It may be said that the dispersed Fe species and acid sites were the active centers for the reduction of NO with NH₃ in the presence of oxygen.