高氧空位尖晶石型锰基催化剂用于低温NH3-SCR反应 .

Different spinel composite oxide catalysts, LiMn2O4, ZnMn2O4 and CrMn2O4 are prepared and activities of the catalysts for selective catalytic reduction of NOx by NH3 (NH3-SCR) are tested at 50~450 ℃. The effects of catalyst structure, metal elements and valence states on NH3-SCR activity are investigated. The catalysts are characterized by physical adsorption instrument (BET), X-ray diffractometer (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), NH3 temperature-programmed desorption (NH3-TPD) and H2 temperature-programmed reduction (H2-TPR), etc. The structure-activity relationship of spinel catalyst is also studied. The results show that： The LiMn2O4 spinel catalyst has the best activity with more than 90% NO conversion at the space velocity of 6×104 mL/(g∙h) at 150 ℃, and it shows more than 80% NO conversion at 100~400 ℃, demonstrating good low temperature activity and wide temperature range. However, the denitrification activity of ZnMn2O4 and CrMn2O4 is relative poor, and the two have similar activities. In the presence of water, the activity of LiMn2O4 decreased greatly, while the activities of ZnMn2O4 and CrMn2O4 decreases slightly, showing better water resistance. The conversion rate of ZnMn2O4 reach 90% at 150 ℃, which is better than that of CrMn2O4 in the presence of water. Spinel ZnMn2O4 has a good NO conversion rate in a wide temperature range and strong water resistance. [ABSTRACT FROM AUTHOR]