Effects of PbO poisoning on Ce–Mn/AC catalyst for low-temperature selective catalytic reduction of NO with NH₃

As a common heavy metal in the sintering flue gas, Pb can exist in the form of oxide (PbO) and lead to the decrease in the denitration catalysts activity. Ce–Mn/AC (activated carbon) and PbO–Ce–Mn/AC catalysts were prepared by impregnation method and their selective catalytic reduction of NH₃ with NO was studied. Results showed that selective catalytic reduction activity of Ce–Mn/AC decreased remarkably after doping PbO. And the NO conversion of Ce–Mn/AC reached 94.52% at 200 °C, while the value was reduced to 65.8% after doping PbO at the same temperature. The doping of PbO decreased the total pore volume and oxygen functional groups of activated carbon, increased crystallinity of Mn oxides on the catalyst, decreased Mn⁴⁺ and chemisorbed oxygen content and then inhibited the “fast selective catalytic reduction” denitration reaction for Ce–Mn/AC catalysts. On this basis, the poisoning effects of lead oxide on Ce–Mn/AC catalysts for low-temperature selective catalytic reduction were revealed.