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 NH3. In this study, it was found that the modification of Mn/TiO2 catalyst by Nb could greatly enhance its Zn resistance. From the characterization results of BET, XRD, H-2-TPR, NH3-TPD, it may be concluded that the introduction of Nb into Mn/TiO2 catalyst would lead to its lower crystallinity, more acid sites and higher concentrations of Mn4+ and surface chemisorbed oxygen. The results of in situ DRIFT study reveal that the NH3-SCR reactions over Mn/TiO2 and Mn-Nb/TiO2 all obey both the Langmuir-Hinshelwood mechanism and the Eley-Rideal mechanism, and the doping of Nb on Mn/TiO2 catalyst could promote the adsorption of NH3 and NOx species on it. All these features make a contribution to the high SCR activity and good Zn resistance of Mn-Nb/TiO2 catalyst. (C) 2016 Elsevier B.V. All rights reserved.