Tandem Catalysis for Simultaneous Removal of NO x and C 3 H 8 with Inhibition of N 2 O.

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 V 2 O 5 /TiO 2 + down-streamed Cr 2 O 3 /TiO 2 catalysts, which could achieve the efficient synergistic control of NO x and C 3 H 8 in industrial flue gas. Moreover, this arrangement successfully alleviated the unwanted N 2 O formation during the NH 3 -SCR process. Compared to the conventional impregnation method of the Cr 2 O 3 -V 2 O 5 /TiO 2 catalyst, the tandem catalysts of V 2 O 5 /TiO 2 + Cr 2 O 3 /TiO 2 could enhance the NO x and C 3 H 8 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 C 3 H 8 oxidation, and the tandem arrangement of catalysts was beneficial to even dispersion of active components on supports. Furthermore, due to the preferential NO x removal over the up-streamed V 2 O 5 /TiO 2 catalyst, the tandem catalysts obviously alleviated the N 2 O formation caused by Cr species during the NH 3 -SCR process. Herein, it significantly decreased N 2 O formation by 240.5% at 350 °C compared to the Cr 2 O 3 -V 2 O 5 /TiO 2 catalyst, achieving multipollutant emission control from industrial flue gas with the performance of "one stone three birds".