Significantly enhanced Pb resistance of a Co-modified Mn-Ce-O/TiO catalyst for low-temperature NH-SCR of NO

Lead (Pb) is one of the heavy metal elements which have an obvious deactivation effect on catalysts for selective catalytic reduction (SCR) of NO x with NH 3 . In this study, it was found that cobalt (Co) modification induced a significant enhancement of the Pb resistance of the Mn-Ce-O x /TiO 2 catalyst. The fresh and Pb-poisoned catalysts were prepared by an impregnation method and characterized by ICP-OES, XRD, N 2 adsorption, XPS, H 2 -TPR, NH 3 - and NO-TPD, NO oxidation reaction, and in situ DRIFTS. The results indicated that the introduction of Pb to the Mn-Ce-O x /TiO 2 catalyst could promote the crystallization of MnO 2 and/or CeO 2 , reduce the catalyst specific surface area, and decrease the relative concentrations of Mn 4+ and Ce 3+ on the catalyst surface. In addition, the presence of Pb in the Mn-Ce-O x /TiO 2 catalyst could result in the decrease of reducibility, adsorption capacities for NH 3 and NO, and oxidation ability for NO to NO 2 . However, modification of the Mn-Ce-O x /TiO 2 catalyst with Co could greatly alleviate these negative effects resulting from Pb doping, thus markedly improving the Pb resistance of the Mn-Ce-O x /TiO 2 catalyst. Co modification can significantly improve the performance for low-temperature NH 3 -SCR of NO x and the Pb resistance of the Mn-Ce-O x /TiO 2 catalyst.