Novel MnWOx catalyst with remarkable performance for low temperature NH3-SCR of NOx

Abstract

A novel W promoted MnO_x catalyst (MnWO_x) was used for the selective catalytic reduction (SCR) of NO_x with NH₃ at low temperatures, with high deNO_x efficiency from 60 to 250 °C under relatively high space velocity. The MnWO_x catalyst showed a unique core–shell structure with Mn₃O₄ covered by Mn₅O₈ while Mn⁴⁺ species at the outer surface served as a real active phase for NH₃-SCR. The W doping resulted in the smaller particle size of MnO_x active phase, increased the surface acidity and facilitated the NO/NH₃ oxidation, thus enhancing low temperature deNO_x efficiency by promoting both Langmuir–Hinshelwood and Eley–Rideal reaction pathways. This novel catalyst is promising to be used in the deNO_x process for flue gas after dust removal and desulfurization.