Preparation of Metal-Incorporated SAPO-34 catalysts and their Catalytic Performance in Selective Catalytic Reduction of Nitric Oxide

Abstract

Metal-incorporated SAPO-34 catalysts were prepared by one-step hydrothermal method. Effects of various parameters including the types of metal ions, Cu2+ sources, structure directing agents (SDAs), hydrothermal temperature and time on catalyst activity of the metal-incorporated SAPO-34 catalysts were investigated. Three types of metal-incorporated SAPO-34 catalysts (Cu/SAPO-34, Fe/SAPO-34 and Mn/SAPO-34) were successfully obtained. Compared with Fe/SAPO-34 and Mn/SAPO-34 catalysts, Cu/SAPO-34 catalyst revealed complete cubic-like microstructure, wide active temperature window and high conversion rate in selective catalytic reduction (SCR) of nitric oxide. After defined Cu2+ was the favorable active site of SAPO-34 catalyst, the effects of four Cu2+ sources on SCR performance were further investigated, and found Cu2+ sources did not produce significant influence on nitric oxide conversion rates. SDAs determined the formation of Cu/SAPO-34 catalyst, and the Cu/SAPO-34 catalyst adopting tetraethylenepentamine (TEPA) as SDA could maintain higher crystal integrity and active sites, which were in favor of the SCR reaction. Moreover, hydrothermal temperature and time had great influences on the formation of Cu/SAPO-34 catalyst. When the hydrothermal temperature was higher than 150 oC and the hydrothermal time was longer than 3 days, the Cu/SAPO-34 catalyst with a cubic-like structure and high catalyst activity could be obtained.