Ultrahighly Alkali-Tolerant NO Reduction over Self-Adaptive CePO/FePO Catalysts.

Catalyst deactivation caused by alkali metal poisoning has long been a key bottleneck in the application of selective catalytic reduction of NO with NH (NH-SCR), limiting the service life of the catalyst and increasing the cost of environmental protection. Despite great efforts, continuous accumulation of alkali metal deposition makes the resistance capacity of 2 wt % KO difficult to enhance via merely loading acid sites on the surface, resulting in rapid deactivation and frequent replacement of the NH-SCR catalyst. To further improve the resistance of alkali metals, encapsulating alkali metals into the bulk phase could be a promising strategy. The bottleneck of 2 wt % KO tolerance has been solved by virtue of ultrahigh potassium storage capacity in the amorphous FePO bulk phase. Amorphous FePO as a support of the NH-SCR catalyst exhibited a self-adaptive alkali-tolerance mechanism, where potassium ions spontaneously migrated into the bulk phase of amorphous FePO and were anchored by PO with the generation of FeO at the NH-SCR reaction temperature. This ingenious potassium storage mechanism could boost the KO resistance capacity to 6 wt % while maintaining approximately 81% NO conversion. Besides, amorphous FePO also exhibited excellent resistance to individual and coexistence of alkali (KO and NaO), alkali earth (CaO), and heavy metals (PbO and CdO), providing long durability for CePO/FePO catalysts in flue gas with multipollutants. The cheap and accessible amorphous FePO paves the way for the development and implementation of poisoning-resistant NO abatement.