Abstract: A series of Sn/Al2O3 catalysts were prepared by co-precipitation of SnCl4 and an aluminum salt using different precipitants. The catalyst activity for the selective catalytic reduction of NO by propylene in excess oxygen was investigated. The relationship between the catalytic property and the structure of the Sn/Al2O3 catalysts was explored usingX-raypowder diffraction, scanning electron microscopy, N2 adsorption-desorption, infrared spectroscopy of adsorbed pyridine, and temperature-programmed reduction. The results indicated that over the Sn/Al2O3 catalyst prepared using NH3•H2O and NH4HCO3 as the precipitants and NH4Al(SO4)2 as the aluminum source, NO conversion was the highest (90.9%) at 350 ℃, and the optimal catalytic temperature was lowered to 350 ℃. The specific surface area and the pore volume of this catalyst were 254 m2/g and 0.878 cm3/g, respectively. Distribution of pore size lied in the range of 3-8 nm, and dual-peak nano-structure was observed. Most of Sn species existed as crystalline SnO2. The introduction of NH4Al(SO4)2 increased the amount of Lewis acidity of the catalyst.

Key words: tin, alumina, propylene, selective catalytic reduction, nitric oxide, co-precipitation, aluminum ammonium sulfate