Mn-Ce mixed oxide was loaded onto activated semi-coke (ASC) via impregnation method and the low temperature selective catalytic reduction (SCR) of NO with NH3 was investigated. The NO conversion and NO oxidation rates were both influenced by the ratios of Ce/(Mn + Ce), and Mn-Ce(0.3)/ASC with loading 5% (mass ratio) Mn-Ce oxides performed the highest catalytic conversion rate of 96.6% and NO oxidation rate of 18.4% at 250 degrees C and GHSV = 6000 h(-1). The changes of physical properties, microstructure, functional groups, crystal structure, surface atomic state, redox property and acid strength for the catalysts were characterized by BET, SEM, FT-IR, XRD, XPS, H-2-TPR and NH3-TPD. The results showed that surface functional groups were increased after nitric acid treatment and abundant oxygen groups were observed on semi-coke surface, which were considered to be beneficial for the gas adsorption. Ce doping could raise the Mn4+/Mnx+ rate which played a vital role in catalytic reaction, enhancing the amount of weak and strong acid sites, increasing oxygen vacancies and accelerating the molecular oxygen turning into reactive oxygen species, which could enhance the NO oxidation activity thus contributed to the denitration efficiency. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.