Bimetallic Fe-Cu/CHA zeolite catalyst for NH3-SCR of NOx

Bimetallic Fe-Cu/CHA zeolite catalysts were investigated for the selective catalytic reduction (SCR) of NOₓ with ammonia (NH₃). The study aimed to elucidate (i) how the Cu/Fe molar ratio affects catalytic performance in terms of NOₓ conversion efficiency and N₂ selectivity, and (ii) how hydrothermal aging influences the structural and chemical stability of bimetallic zeolites compared to their monometallic counterparts. Comprehensive characterization was performed using UV-vis spectroscopy, NMR, Mössbauer spectroscopy, ICP, XRD, TEM, Ar-physisorption, and temperature-programmed desorption (TPD). Catalytic activity tests were conducted in a plug flow reactor (PFR). The results demonstrate that the addition of copper significantly enhances the low-temperature activity of iron in the bimetallic catalysts. Furthermore, hydrothermal treatments led to dealumination of the CHA zeolite framework and the formation of small metal clusters, impacting the structure of the catalysts. These findings provide valuable insights into the design of more efficient and durable bimetallic zeolite catalysts for NOₓ abatement in SCR systems