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[Display omitted] Due to the accumulation of heavy metal compounds produced by the sintering process in steel industry, the catalysts used for low-temperature selective catalytic reduction of NO with NH 3 (NH 3 -SCR) might be seriously deactivated. In this work, the deactivation effect of PbCl 2 , Pb(NO 3) 2 , and PbSO 4 on Mn-Ce activated carbon supported catalyst for low-temperature NH 3 -SCR of NO was investigated and compared. Poisoned catalysts were provided by impregnating fresh catalysts with Pb(NO 3) 2 , PbSO 4 and PbCl 2 aqueous solutions, respectively. Deactivation could be observed on the poisoned samples, and the deactivation degree was following PbCl 2 > PbSO 4 > Pb(NO 3) 2. The catalytic activities of all samples were tested, and the physicochemical properties of fresh and poisoned catalysts were assessed. PbCl 2 caused the most severe deactivation of the catalyst, owing to its poor redox property and surface acidity. Cl- could also react with Mn active sites to form -O-Mn-Cl bonds, resulting in additional acid sites, although these newly generated sites were not reactive in NH 3 -SCR reaction process. PbSO 4 exhibited moderate poisoning effect due to the addition of SO 4 2-, which created new Brønsted acid sites, facilitating the NH 3 adsorption and NO reduction. Pb(NO 3) 2 had the least poisoning impact on the catalyst due to the NO 3 –, promoting the NH 3 activation. The in situ DRIFTS results revealed that NH 3 -SCR reaction over all samples was governed by Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) mechanism, and did not change due to the lead poisoning. Finally, a possible mechanistic model for different lead salts poisoning over Mn-Ce/AC catalyst was proposed. [ABSTRACT FROM AUTHOR]

• Synergistic interaction of Sm and Fe enhanced Pb-resistance of Mn-Ce/AC catalyst. • Sm and Fe co-doping alleviated the damage of Pb species to catalyst structure. • Surface acidity and redox ability of Mn-Ce/AC catalyst were protected by Sm and Fe from lead. • NH 3 -SCR reaction on catalysts after Pb poisoning followed L-H and E-R mechanism. A novel anti-Pb poisoning Sm and Fe co-doped Mn-Ce/AC catalyst was prepared by impregnation method for low-temperature NH 3 -SCR of NO reaction. Maintaining the excellent low-temperature activity of Mn-Ce/AC catalyst, Sm and Fe co-doping remarkably enhanced the catalyst's Pb-resistance with NO conversion up to 77%. Sm and Fe co-doped poisoning-catalysts exhibited large specific surface area and pore volume, and the crystallinity of the MnO x and CeO x reduced. The redox properties and surface acidity of the lead poisoned SmFeMnCe/AC catalyst were effectively retained, which could promote NO oxidation and NH 3 activation, further benefiting the SCR reaction. In situ DRTFTS results indicated that the low-temperature NH 3 -SCR mechanism of all poisoned catalysts followed both L-H mechanism and E-R mechanism, and the L-H mechanism was dominated. On the one hand, the extraordinary lead resistance of Sm weakened the damage of lead species on the physicochemical properties of the catalyst; on the other hand, the high oxidation properties and surface acidity of Fe enhanced the catalytic activity of the poisoned catalyst. Finally, a possible synergistic mechanism model of Sm and Fe co-doping on Mn-Ce/AC catalyst against Pb-poisoning was proposed. [ABSTRACT FROM AUTHOR]