CeO2-doped low-V2O5-based catalysts (V0.5WCe/Ti) were investigated and showed outstanding stability for the simultaneous removal of NO (92.5%) and Hg-0 (75%) from oxy-fuel combustion flue gas in 50 h compared to a normal VLOW/Ti catalyst. The good NH3-SCR performance of the V0.5WCe/Ti catalyst was due to the enhancement in acidity that arose from the introduced vanadium oxide, the better redox capability and greater amount of surface adsorbed oxygen species (O-2(-), O- and O-2(-)) by Ce-modification, which generated a large amount of NO2, conducting the "fast SCR reaction". Hg-0 oxidation was strongly affected by surface adsorbed oxygen and C=0 functional groups in the absence of HCl in CO2-enriched flow conditions, while the reaction was mostly between Hg-(ad)(0)/HgO(ad) and gaseous Cl* or Cl-2 in the presence of both HCl and O-2. In addition, a high concentration of CO2 inhibited NO conversion, because of the rate of diffusion, but promoted Hg-0 removal. Furthermore, while a high concentration of HCl prohibited NO conversion due to the formation of V-Cl and Ce-Cl on the catalyst surface, Hg-0 adsorption and catalytic oxidation were inhibited when SO2 and H2O coexisted in the flue gas.