Fe-Zeolite Catalysts Synthesized via Hydrothermal Method for Selective Catalatalytic Reduction of NOx with Ammonia

A series of Fe-ZSM-5 catalysts with varying Fe loadings were synthesized via a hydrothermal method. Their catalytic performance was evaluated for the selective catalytic reduction (SCR) of NOx with ammonia. The catalyst with a Fe:Al molar ratio of 1:1 demonstrated the highest NOx conversion (99.9%) and exhibited a broader operating temperature window (240–390°C) compared to catalysts with other Fe/Al ratios. Characterization by X-ray diffraction (XRD),scanning electron microscopy(SEM), and X-ray photoelectron spectroscopy(XPS) confirmed that the incorporation of iron ions preserved the high crystallinity and MFI structure of the ZSM-5 zeolite. NH3-temperature-programmed desorption (NH3-TPD) profiles revealed the presence of two distinct acid sites at approximately 250 °C and 400 °C.