SO and HO can cause severe deactivation of CeO-TiO catalysts for NH-SCR reaction. Transition metal doping is an effective method to improve the SO and HO resistance of CeO-TiO catalysts. In this study, five transition metals (W, Nb, Mo, Fe, Mn) were selected as doped elements for the CeO-TiO catalysts. Their toxicity resistance and NH-SCR reactivity were calculated by DFT. W- and Fe-doped catalysts showed better NH/NO/O adsorption but poor SO/HO resistance. CeNbTi and CeMnTi catalysts were the most resistance to HO, but their reactive gases adsorption was limited. Whereas the CeMoTi catalyst presented both excellent anti-poisoning and reaction properties. And it possessed larger NH/NO adsorption energies after HO poisoning than the CeO-TiO. Mo doping caused the sulfated catalyst to adsorbed more NH and less NO which reduced the generation of surface inert nitrate. Doping Mo effectively reduced the HO dissociation energy barrier, which favored the competitive adsorption of NH. Compared to the CeO-TiO, the adsorption energy and oxidization ability of SO was lower that on the CeMoTi. This allowed SO to be not easily generated and desorbed into the gas phase to form (NH)SO and NHHSO with HO and NH. Mo doping reduced sulfate deposition and enhanced NH-SCR reaction.
