An FT-IR study of NO adsorption over Cu-exchanged MFI catalysts: Effect of Si/Al ratio, copper loading and catalyst pre-treatment

NO adsorption, at room temperature, has been studied by infrared spectroscopy on copper MFI catalysts with different Si/Al ratios and copper loadings. The relative amount of the overall Cu2+-NO and Cu+-NO complexes has been evaluated for each catalyst, as well as that of the different Cu2+-NO components. ESR spectra have also been recorded in order to check the different Cu2+ coordinations. It clearly appears that square planar copper sites predominate for high Cu/Al catalysts, A comparison with reactivity data, relative to SCR of NO by propene, under an excess of oxygen, strongly suggests that these sites are involved in the considered reaction. (C) 1998 Elsevier Science B.V.