Effect of an Al2O3-based binder on the structure of extruded Fe-ZSM-5

The effect of an alumina-based binder on the structure of a commercial Fe-ZSM-5 catalyst has been investigated. Several ex-situ characterization techniques were used to show that the binder in the catalyst formulation allows obtaining a material that possesses improved features in terms of Fe species dispersion, framework Al content and acidity. UV-Vis and X-ray absorption spectroscopy showed that the extent of Fe agglomeration in the extruded catalyst was significantly lower compared to that in the catalyst without binder. Al-27 and Si-29-MAS NMR spectroscopy demonstrated a remarkable difference in terms of framework Al migration. NH3-TPD experiments corroborated the NMR results suggesting a retention of Bronsted acidity in the extruded catalyst. We tentatively propose that by providing extra-framework Al species prior to the treatment at elevated temperature, the binder hinders the framework Al dislodgment and Fe agglomeration during calcination.

Automated summary

This study investigates the effect of an alumina-based binder on the structure of a commercial Fe-ZSM-5 catalyst. The results show that the binder improves the catalyst's dispersion of Fe species, framework Al content, and acidity, while reducing Fe agglomeration and framework Al migration.