Activity enhancement of WO3 modified Fe2O3 catalyst for the selective catalytic reduction of NOx by NH3

Abstract A novel WO 3 -doped Fe 2 O 3 catalyst was investigated for the selective catalytic reduction of NO x by NH 3 (NH 3 -SCR). It was found that the WO 3 /Fe 2 O 3 catalyst exhibited high NH 3 -SCR activity in a wide range of operating temperatures and high resistance against H 2 O and SO 2 . The highly dispersed WO 3 acted as both “chemical” and “structural” promoters, which inhibited the crystallization of the Fe 2 O 3 phase, leading to the high surface area. The synergetic effect between WO 3 and Fe 2 O 3 makes WO 3 /Fe 2 O 3 catalyst remain a proper redox property, effectively weaken the unselective catalytic oxidation of NH 3 , thus resulting in the enhanced NH 3 -SCR performance. In particular, introducing WO 3 to Fe 2 O 3 resulted in the increased number of Lewis acid sites, thus preventing the formation of nitrate and leaving more active sites available for the adsorption and activation of NH 3 . All of these factors, collectively, accounted for the superior deNO x performance of WO 3 /Fe 2 O 3 catalyst.