부산대학교 도서관

A series of Mn/ZSM-5 catalysts for the selective catalytic reduction of NO with NH3 was prepared by precipitation method at different calcination temperature. X-ray diffraction, X-ray photoelectron spectroscopy, H2 temperature-programmed reduction and N2 adsorption/desorption technologies were conducted to explore the effects of calcination temperature on the physical and chemical properties of Mn/ZSM-5 catalysts. Results suggested that when calcined at lower temperatures (°C) MnOx existed in the form of Mn3O4 and amorphous MnO2 on the catalyst surface. However, when calcined at 600°C Mn2O3 species which is unfavorable for the SCR process were formed and became the major phase at 700°C. On the other hand, with the increase of calcination temperatures, the surface Mn concentration and the specific surface area of catalysts both decreased. The catalytic activity test indicated that the Mn/ZSM-5 catalyst calcined at 300°C demonstrated the best performance for NO removal, with almost 100% NO conversion in the range of 150–390°C. According to the characterization results, the enrichment of surface Mn, surface Mn3O4 and amorphous MnO2 species may account for its superior catalytic activity.