Ceria modified FeMnO —Enhanced performance and sulphur resistance for low-temperature SCR of NOx

Abstract Low-temperature NH 3 -SCR is an environmentally important reaction for the abatement of NO x from stationary sources. In recent years FeMnO x has attracted significant attention as a potential catalyst for this process, however its catalytic activity and SO 2 resistance require further improvement. In this contribution FeMnO x has been modified to examine the effect of ceria on catalytic activity and SO 2 resistance in the low temperature region. Preparation of catalysts via the citric acid method generate modified materials that exhibit enhanced NO turnover compared to FeMnO x . A reduction in NH 3 adsorption (NH 3 -TPD) and a suitable ratio between NO sites (NO-TPD) and chemisorbed surface oxygen (XPS) are beneficial for the promotion of fast-SCR. A comparative SO 2 resistance study of FeMnO x and Ce(12.5) showed that the latter exhibited improved stability in the presence of SO 2 , as indicated by the retention of pore volume (N 2 adsorption) and surface composition (XPS). In-situ DRIFTS demonstrated that chemisorbed N-containing species on Ce(12.5) were much more stable in the presence of SO 2 compared to FeMnO x , which resulted in the formation of significantly less metal sulphates and NH 4 HSO 4 .