Rational Design of Alkali‐Resistant NO Reduction Catalysts using a Stable Hexagonal V‐Doped MoO 3 Support for Alkali Trapping

To avoid alkali poisoning in the selective catalytic reduction (SCR) of NO x with NH 3 , it is desirable to design SCR catalysts with abundant alkali‐trapping sites spatially separated from catalytically active sites. Here we develop such a catalyst with strong resistance against alkali poisoning by using hexagonal vanadium‐doped MoO 3 (V‐HMoO) with alkali‐trapping tunnels as a catalyst support. Although pure HMoO also possesses strong alkali resistance due to size‐suitable tunnels, active Mo 5+ ions on the framework make HMoO thermally unstable, and hence pure HMoO is not able to be used as a suitable support for SCR in a normal operating temperature window of 280–420 °C. We substitute the active Mo 5+ by stable V 5+ due to its fully unoccupied electron configuration to achieve a thermally stable V‐HMoO support, as confirmed by various characterization results. After loading active V 2 O 5 onto the V‐HMoO support, the catalyst shows high SCR activity with excellent alkali resistance due to the alkali trapping function of V‐HMoO. This work may give a strategy to design stable alkali‐trapping SCR catalysts in general.