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

Abstract

A novel WO3-doped Fe2O3 catalyst was investigated for the selective catalytic reduction of NOx by NH3 (NH3-SCR). It was found that the WO3/Fe2O3 catalyst exhibited high NH3-SCR activity in a wide range of operating temperatures and high resistance against H2O and SO2. The highly dispersed WO3 acted as both "chemical" and "structural" promoters, which inhibited the crystallization of the Fe2O3 phase, leading to the high surface area. The synergetic effect between WO3 and Fe2O3 makes WO3/Fe2O3 catalyst remain a proper redox property, effectively weaken the unselective catalytic oxidation of NH3, thus resulting in the enhanced NH3-SCR performance. In particular, introducing WO3 to Fe2O3 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 NH3. All of these factors, collectively, accounted for the superior deNO performance of WO3/Fe2O3 catalyst. (C) 2016 Elsevier B.V. All rights reserved.