Substantially enhanced anti-lead poisoning performance on the CeO2-WO3 pairs supported by red mud: Sacrificial effect of Fe2O3

• A carrier-sacrificing approach was proposed to prepare anti-lead catalysts. • Red mud was used as a sacrifice carrier replacing the traditional TiO 2 . • PbWO 4 adsorbed NH 3 more easily than TiO 2 and inhibited the activation of NH 3 . • Fe 2 O 3 bond with Pb prior to WO 3 , which reduced the formation of inert PbWO 4 . • Besides CeO 2 , Fe 2 O 3 also participated in the redox cycle, while TiO 2 did not. Lead (Pb) species are inevitable poisonous constituents of the flue gas in the non-electric industry, which hinders the NH 3 -SCR reactions. Herein, we proposed a facile and low-cost carrier-sacrificing approach for the preparation of anti-lead catalysts which exhibited promising benefits. Innovatively, Fe 2 O 3 from solid waste of red mud (RM) was used as a sacrifice carrier replacing the traditional TiO 2 . On the one hand, Fe 2 O 3 was involved in the redox cycle of the reaction, so that the RM-based catalysts could still ensure the redox cycle after Pb poisoning. On the other hand, Fe 2 O 3 was more preferentially bonded with Pb compare to WO 3 species, thus protecting the WO 3 species from being poisoned. The NO x conversion of the poisoned (with 5 wt % of Pb) RM-based catalyst (Pb-Ce-W/RM) was above 90% at 225 – 470 °C and kept the same NO x conversion as fresh catalyst (Ce-W/RM) at 275 – 400 °C. In comparison, the NO x conversion of poisoned TiO 2 -based catalyst (Pb-Ce-W/Ti) dropped 17 – 50% at 200 – 475 °C. Pb transformed the structure of the WO 3 phase and formed Pb 2+ -O-W 6+ sites over the Ce-W/Ti catalyst. When most NH 3 adsorbed on PbWO 4 sites, its bonding strength increased thus suppressing the further activation and dehydrogenation of adsorbed NH 3 species. However, Fe 2 O 3 , as the sacrificial agent would bond with Pb species prior to WO 3 , reducing the formation of inert PbWO 4 on the catalyst surface, thus leading to higher Pb resistance.