Understanding the Catalytic Deactivation upon Hydrothermal Aging at 850 degrees C of WO3/Fe-Cu-ZSM-5 Catalyst for Selective Catalytic Reduction of NO by NH3

A WO3/Fe-Cu-ZSM-5 catalyst was prepared using the solid state ion exchange method (SSIE) and its performance for the Selective Catalytic Reduction of NO with NH3 (NH3-SCR of NO) was investigated. The study shows that the tungsten addition can slightly improve the high temperature catalytic activity of Fe-Cu-ZSM-5. The influence of hydrothermal aging at 850 degrees C for 5 h on the structural and textural properties of WO3/Fe-Cu-ZSM-5 was also studied in this paper. The XRD and FE-SEM measurements did not indicate a breakdown of the zeolite structure upon steam treatment for both aged catalysts. The aged W-base catalyst demonstrates a lower deactivation and better catalytic activity for NO reduction than the bimetallic catalyst after hydrothermal aging despite the lower acidic properties as shown by FTIR-Pyr spectroscopy owing to the presence of tungsten oxide crystallites. The severe stage of aging occurring in the absence of W led to the formation of copper oxide agglomerates detected using STEM and H-2-TPR techniques being responsible for the deterioration of SCR activity of the aged Fe-Cu-ZSM-5.

Automated summary

The addition of tungsten can slightly improve the high temperature catalytic activity of Fe-Cu-ZSM-5, and the W-based catalyst shows lower deactivation and better catalytic activity for NO reduction after hydrothermal aging compared to the bimetallic catalyst. Severe aging without tungsten leads to the formation of copper oxide agglomerates responsible for the deterioration of SCR activity of aged Fe-Cu-ZSM-5.