Photo- and thermo-catalytic mechanisms for elemental mercury removal by Ce doped commercial selective catalytic reduction catalyst (VO/TiO).

The elemental mercury was catalytically removed by VO/TiO and Ce doped VO/TiO 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 VO/TiO 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 Ce, Ce doping could greatly improve the mercury removal properties of the catalyst, reduce the inhibition of SO 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 Hg removal were investigated to further verify the experimental conclusion.