Non-pitch coal-based activated coke introduced CeOx and/or MnOx for low temperature selective catalytic reduction of NOx by NH3

摘要

Modified activated coke was prepared by introducing CeOx and MnOx on non-pitch coal-based activated coke (NPAC) using a novel non-pitch binder. Employing a fixed bed reactor and N-2 adsorption-desorption, X-ray diffraction, and X-ray photoelectron spectroscopy techniques, we investigated the changes of surface functional groups, pore structure characteristics, denitrification activity and adsorption behavior. It was also found that the presence of Ce3+ and Ce4+ species, promoting NO oxidation adsorption, significantly increased the starting denitrification activity and the catalysis of Mn species, helping NH3 adsorption, showed a gradual increase in activity after a time delay. For co-impregnation modification of MnOx and CeOx, the manganese species and cerium species incorporated activated coke to formed cerium manganese carbide. With the increase in impregnation amount, the graphite crystalline structure was destroyed, causing the degree of graphitization to be reduced and the peak of Mn 2p(3/2) to be shifted to a lower binding energy. The addition of CeOx played an important role in changing the existing state of the manganese oxide and adding MnOx contributed to the oxidation of Ce3+ to Ce4+. On MnOx-CeOx-7.40 adsorbed NH3 can react with adsorbed NOx species (adsorbed NO3 and NO2) following a Langmuir-Hinshelwood mechanism. The denitrification rate of MnOx-CeOx-7.40 at 140 degrees C was as high as 75.36%.