Preparation and Characterization of Manganese-Based Catalysts for Removing NO Under Low Temperatures

摘要

Selective catalytic reduction of NO_x with loaded urea (urea-SCR) is a promising technology to remove NO_x from the low-temperature metallurgical sintering flue gas. In present work, a series of nutshell-based activated carbon (nu-AC) supported MnO_x catalysts with loading urea were synthesized by ultrasound-assisted impregnation, and the physicochemical properties of catalysts were detected by XRD, SEM, EDS, GFAAS, BET, and XPS. Besides, NO adsorption capacity and the influences of reaction temperature, activated carbon particle size, metal oxides loading, and urea loading on catalytic activity were studied through experiment. The results of NO adsorption tests show that the adsorption capacity of nu-AC is limited, and the adsorption capacity decreases with increasing temperature. Catalytic performance test results indicate that the catalyst with 12% MnO_x and 6% urea shows the best performance, giving nearly 90% NO conversion at 50°C. Finally, the reaction mechanism of low-temperature urea-SCR for manganese-based catalyst was discussed.