The enhanced Zn resistance of Mn/TiO2 catalyst for NH3-SCR reaction by the modification with Nb

Heavy metals (such as Zn and Pb) have a deactivation effect on the catalyst for selective catalytic reduction of NO with NH 3 . In this study, it was found that the modification of Mn/TiO 2 catalyst by Nb could greatly enhance its Zn resistance. From the characterization results of BET, XRD, H 2 -TPR, NH 3 -TPD, it may be concluded that the introduction of Nb into Mn/TiO 2 catalyst would lead to its lower crystallinity , more acid sites and higher concentrations of Mn 4   + and surface chemisorbed oxygen. The results of in situ DRIFT study reveal that the NH 3 -SCR reactions over Mn/TiO 2 and Mn-Nb/TiO 2 all obey both the Langmuir-Hinshelwood mechanism and the Eley–Rideal mechanism, and the doping of Nb on Mn/TiO 2 catalyst could promote the adsorption of NH 3 and NOx species on it. All these features make a contribution to the high SCR activity and good Zn resistance of Mn-Nb/TiO 2 catalyst.