Tandem Catalysis for Simultaneous Removal of NO_<i>x</i> and C₃H₈ with Inhibition of N₂O

Tandem catalysis is widely adopted for multipollutant control in mobile sources but has rarely been reported in stationary source emission elimination. This work proposed a tandem arrangement way with up-streamed V₂O₅/TiO₂ + down-streamed Cr₂O₃/TiO₂ catalysts, which could achieve the efficient synergistic control of NO_<i>x</i> and C₃H₈ in industrial flue gas. Moreover, this arrangement successfully alleviated the unwanted N₂O formation during the NH₃ -SCR process. Compared to the conventional impregnation method of the Cr₂O₃-V₂O₅/TiO₂ catalyst, the tandem catalysts of V₂O₅/TiO₂ + Cr₂O₃/TiO₂ could enhance the NO_<i>x</i> and C₃H₈ conversion by 4.2% and 39.5%, respectively, at 350 °C. It might be attributed to the fact that Cr species was the active site for C₃H₈ oxidation, and the tandem arrangement of catalysts was beneficial to even dispersion of active components on supports. Furthermore, due to the preferential NO_<i>x</i> removal over the up-streamed V₂O₅/TiO₂ catalyst, the tandem catalysts obviously alleviated the N₂O formation caused by Cr species during the NH₃-SCR process. Herein, it significantly decreased N₂O formation by 240.5% at 350 °C compared to the Cr₂O₃-V₂O₅/TiO₂ catalyst, achieving multipollutant emission control from industrial flue gas with the performance of "one stone three birds".