The poisoning effect of heavy metals doping on Mn/TiO2 catalyst for selective catalytic reduction of NO with NH3

Heavy metals have been proven to be of deactivation effect on SCR catalyst. In this paper, the poisoning effect of heavy metals (Zn and Pb) on Mn/TiO2 catalyst was investigated based on experimental and theoretical study. It was found that both of Zn and Pb had a poisoning effect on Mn/TiO2 catalyst and the poisoning effect of Zn was more obvious. The characterization results indicated that the doping of heavy metals on Mn/TiO2 surface would lead to a great decrease of reducibility, surface acidity and NO adsorption ability. The results of XPS characterization revealed the decrease of Mn4+ atomic concentration and chemisorbed oxygen species caused by the doping of heavy metals. Based on the above mentioned unfavorable properties, the doping of heavy metals would cause a serious deactivation of Mn/TiO2 catalyst. From the results of OFT calculations, it could be concluded that the doping of heavy metals on Mn/TiO2 catalyst resulting in a great decrease of NH3 adsorption capacity and NO adsorption ability, which agrees well with the experimental results. (C) 2015 Elsevier B.V. All rights reserved.