Ce-promoted Fe–Cu–ZSM-5 catalyst: SCR-NO activity and hydrothermal stability

Abstract

Fe–Cu–ZSM-5 and Ce–Fe–Cu–ZSM-5 solids prepared using solid-state ion exchange method (SSIE) were tested in the NH3–SCR of NO reaction and were characterized using N2 physisorption at 77 K, MAS 27Al magnetic resonance, X-ray diffraction, scanning electron microscopy, EPR spectroscopy and transmission electron microscopy coupled to energy-dispersive X-ray spectroscopy in order to follow the effect of Ce addition on the textural and structural properties of Fe–Cu–MFI system as well as the detection of the changes in local environment and state of iron and copper species, and the degradation of the zeolite texture and structure after a severe aging treatment at 850 °C for 5 h. Fresh Ce-promoted sample showed better NO conversion up to 450 °C than unpromoted Fe–Cu–ZSM-5 catalyst. An activity loss was observed on aged catalysts, but remaining less pronounced for the catalyst containing Ce. The changes in catalyst structure and texture did not occur during aging, while a probable migration of metal active species and change in their coordination has occurred.