Promotion of Fe doping on MnO -CeO2/Ti-bearing blast furnace slag low-temperature SCR catalyst with excellent Pb resistance

Mitigating Pb poisoning effect on NH3-SCR catalysts in sintering flue gas denitrification poses an intractable challenge. To address this issue, a novel MnOx-CeO2/Ti-bearing blast furnace slag catalyst (MC/ATS) was developed and its Pb poisoning mechanism was previously studied. Herein, the promotional effect of FeOx doping on Pb resistance of MC/ATS catalyst was analyzed and the anti-Pb poisoning mechanism was systematically elucidated. Fe-MC/ATS catalyst achieved nearly 100 % NO conversion at 175 °C. Compared with that before Fe doping, resistance of the modified catalyst to PbO and PbCl2 poisoning markedly increased by 41.0 % and 47.1 %, respectively. FeOx, with high electronegativity and acidity, could replenish more active acid sites, so that the NH3 adsorption capacity and SCR efficiency of Fe-MC/ATS catalyst were greatly improved. By consuming surface chemisorbed oxygen on the catalyst, FeOx could participate in Mnn+ electron transfers cycle in the forms of different Fen+ valences. This process increased the surface Mn4+ content, improved the redox capacity and reactivity of adsorbed NH3 species, which consequently boosted the catalyst Pb poisoning resistance. Hopefully, the efficient protection mechanism provides a new insight into developing novel catalysts with outstanding resistance to heavy metals.