Alkali-Resistant NOx Reduction over SCR Catalysts via Boosting NH3 Adsorption Rates by In Situ Constructing the Sacrificed Sites

Currently, improving the alkali resistance of vanadium-based catalysts still remains as an intractable issue for the selective catalytic reduction of NOx with NH3 (NH3–SCR). It is generally believed that the decrease in adsorbed NHx species deriving from the declined acidic sites is the chief culprit for the deactivation of alkali-poisoned catalysts. Herein, alkali-resistant NOx reduction over SCR catalysts via boosting NH3 adsorption rates was originally demonstrated by in situ constructing the sacrificed sites. It is interesting that the adsorbed NHx species largely decrease while the NH3 adsorption rate is well kept over the V2O5/CeO2 catalyst by in situ constructing the sacrificed sites. The SCR activity could be maintained after alkali poisoning because in situ constructed SO42– groups would prefer to be combined with K+ so that the specific V═O species can endow K-poisoned V2O5/CeO2 with high adsorption rate of NH3 and high reactivity of NHx species. This work provides a new viewpoint that NH3 adsorption rate plays more decisive roles in the performance of alkali-poisoned catalysts than the amount of NH3 adsorption and enlightens an alternative strategy to improve the alkali-resistance of catalysts, which is significant to both the academic and industrial fields.