On the performance of Fe-Cu-ZSM-5 catalyst for the selective catalytic reduction of NO with NH 3 : the influence of preparation method

The selective catalytic reduction of NO with ammonia (NH3-SCR) in the presence of H2O was studied over a series of Fe-Cu-ZSM-5 catalysts prepared by solid-state ion exchange (SSIE), aqueous ion exchange and impregnation methods. The prepared samples were characterized by various techniques (ICP-AES, N2 physisorption at 77 K, XRD, STEM-EDX, XPS, H2-TPR and DRS UV–vis) to investigate the effect of the preparation method on the activity, texture, structure and metal speciation of the studied catalysts. It was found that the aqueous ion exchange method induced a significant metal loss during the preparation procedure but without any activity deterioration of the catalyst which encloses highly dispersed metal species. The catalysts prepared by SSIE and impregnation showed the highest metal contents and a large number of oxide aggregates leading to an activity decline at high reaction temperatures due to the ammonia oxidation phenomenon.