The elemental mercury was catalytically removed by V2O5/TiO2 and Ce doped V2O5/TiO2 catalysts under the UV irradiation at 30–160 °C to determine whether the catalysts could simultaneously have both thermo- and photo-catalytic activities. The physicochemical properties of catalysts were characterized by XRD, SEM, EDX, BET, XPS, UV–visible, PER and EIS. The experimental results demonstrated that V2O5/TiO2 and Ce-doped catalysts possessed both thermo- and photo-catalytic reactivities. A suitable reaction temperature (120 °C) and UV light had promoting effects on mercury removal efficiency. In addition, owing to the high oxidation capability as well good oxygen storage performance of Ce4+, Ce doping could greatly improve the mercury removal properties of the catalyst, reduce the inhibition of SO2 and make NO the component with enhanced effect. Ce doping also had the capability of enhancing the light absorption intensity in the UV region as well as the separation rate of photoinduced carriers. Finally, DFT calculations of V-Ti and Ce-V-Ti for Hg0 removal were investigated to further verify the experimental conclusion.