Efficient NO Abatement over Alkali-Resistant Catalysts via Constructing Durable Dimeric VO Species.

The presence of alkali metals in flue gas is still an obstacle to the practical application of catalysts for selective catalytic reduction (SCR) of NO by NH. Polymeric vanadyl species play an essential role in ensuring the effective NO abatement for NH-SCR. However, polymeric vanadyl would be conventionally deactivated by the poison of alkali metals such as potassium, and it still remains a great challenge to construct robust and stable vanadyl species. Here, it was demonstrated that a more durable dimeric VO active site could be constructed with the assistance of triethylamine, thereby achieving alkali-resistant NO abatement. Due to the rational construction of polymerization structures, the obtained TiO-supported cerium vanadate catalyst featured more stable dimeric VO species and the active sites could survive even after the poisoning of alkali metal. Moreover, the depolymerization of VO was suppressed endowing the catalysts with more Brønsted and Lewis acid sites after the poisoning of alkali metal, which ensured the efficient NO reduction. This work unraveled the effects of alkali metal on the polymerization state of active species and opens up a way to develop low-temperature alkali-resistant catalysts for NO abatement.