Lead oxide (PbO) as one of the typical heavy metals in flue gas from power plants has strong accumulation as well as poisoning effects on SCR catalysts. In this paper, a series of PbO-doped Mn-Ce/TiO2 catalysts were synthesized by impregnation method. The poisoning effects of PbO over Mn-Ce/TiO2 samples for selective catalytic reduction of NO by NH3 were investigated based on catalytic activity test and characterizations. The NO conversion of Mn-Ce/TiO2 was greatly decreased after the addition of PbO. It was obvious that the NO conversion efficiency of Mn-Ce/TiO2 catalyst declined from 96.75% to about 40% at 200 degrees C when Pb:Mn molar ratio reached 0.5. Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Hydrogen temperature programmed reduction (H-2-TPR), Ammonia temperature programmed desorption (NH3-TPD) and Fourier transform infrared spectroscopy (FT-IR) were carried out to study the deactivation reasons of PbO poisoned catalysts. Manganese oxides' crystallization, less reducible of manganese and cerium oxides, the decreasing of surface area, Mn4+ as well as Ce3+ concentration and chemisorbed oxygen (O-b) after the introduction of PbO, all of these resulted in a poor SCR performance. Furthermore, the alteration of acid sites (especially Bronsted acid sites), low ammonia adsorbance, an obvious reducing of ad-NOx species (only a spot of bidentate nitrates remained) and the vanishing of amide species contributed to the deactivation of Mn-Ce/TiO2 catalyst by PbO doping as well. (C) 2016 Elsevier B.V. All rights reserved.