Effects of Se and SeO2 on the denitrification performance of V2O5-WO3/TiO2 SCR catalyst

Abstract

Various trace elements in flue gas emitted from coal combustion can cause the deactivation of selective catalytic reduction (SCR) catalysts, yet rare studies have been reported on selenium species. Herein, the effects of Se and SeO2 on the denitrification performance of commercial V2O5-WO3/TiO2 SCR catalyst were investigated. Results indicated that the activities of Se and SeO2-doped catalysts were significantly inhibited at temperatures above 250 °C. During the NH3-SCR process, metallic Se was oxidized by V2O5 to generate Se4+ (SeO2 and binary oxides VxSeyOz), while part of Se4+ was reduced to Se by NH3. Se and SeO2 deactivated the catalyst by consuming V2O5 and NH3 during the NH3-SCR process, covering the active sites and relieved the redox performance of catalysts. With the sublimation of Se and SeO2, the deactivation effect on the catalyst was greatly relieved, while the presence of residual VxSeyOz resulted in the incomplete recovery of the catalyst activity.