Unveiling the effect of W and Co on PbO resistance over FeCe catalyst for low-temperature NH₃-SCR of NO

The presence of PbO in the flue gas can poison FeCe catalyst, reducing its denitrification efficiency. In this work, the mechanism of PbO poisoning of FeCe catalyst, along with the effects of W and Co co-doping on the NO oxidation performance and PbO resistance of FeCe catalyst were investigated. The S_BET of FeCe catalyst decreased and the crystallinity increased obviously after PbO poisoning. PbO could destroy the Bronsted acid sites and redox properties of FeCe catalyst. In addition, the conversion of NO to NO₂ molecules and monodentate nitrites was also inhibited on FeCe catalyst. The NO conversion rate of the PWCo-FeCe catalyst reached 76 % at 220 °C, with larger S_BET and lower degree of crystallization compared to PbO-FeCe catalyst. Besides, the co-doping of W and Co facilitated the right shift of the Fe^{2 +} + Ce⁴⁺ ↔ Fe³⁺ + Ce³⁺ redox cycle, leading to a higher ratio of Fe³⁺ and Ce³⁺. Moreover, incorporation of W and Co boosted the number of Brønsted acid sites and enhanced the formation of NO₂ molecules and monodentate nitrite, which mitigated the suppressive effect of PbO on the NH₃-SCR reaction. The FeCe and WCo-FeCe catalysts operated via E-R and L-H mechanisms, and PbO poisoning did not affect the established reaction pathways.