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

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 N-2 physisorption at 77 K, MAS Al-27 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 degrees C for 5 h. Fresh Ce-promoted sample showed better NO conversion up to 450 degrees 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.

Automated summary

The addition of Ce affects the textural and structural properties of the Fe-Cu-MFI system, with Ce-promoted samples showing better NO conversion activity up to 450 degrees Celsius. The presence of Ce in aged catalysts also reduces the loss of activity.