N-doped graphene and TiO2 supported manganese and cerium oxides on low-temperature selective catalytic reduction of NOx with NH3

摘要

A series of N-doped graphene （NG） and TiO2 supported MnOx--CeO2 catalysts were preparedby a hydrothermal method. The catalysts with different molar ratios of Mn/Ce （6 ： 1, 10 ： 1, 15 ： 1）were investigated for the low-temperature selective catalytic reduction （SCR） of NOx with NH3. Thesynthesized catalysts were characterized by HRTEM, SEM, XRD, BET, XPS, and NH3-TPDtechnologies. The characterization results indicated that manganese and cerium oxide particlesdispersed on the surface of the TiO2-NG support uniformly, and that manganese and cerium oxidesexisted in different valences on the surface of the TiO2-NG support. At Mn element loading of 8 wt%,MnOx-CeO2（10：1）/TiO2--1%NG displayed superior activity and improved SO2 resistance. On thebasis of the catalyst characterization, excellent catalytic performance and SO2 tolerance at lowtemperature were attributed to the high content of manganese with high oxidation valence, extensiveoxidation of NO into NO2 by CeO2 and strong NO adsorption capacity, and electron transfer ofN-doped graphene.