Low-temperature shift DeNOx activity of Nanoflake V2O5 loaded WO3/TiO2 as NH3-SCR catalyst

Abstract

Nanoflake V 2 O 5 loaded onto WO 3 /TiO 2 improves the low-temperature shift NH 3 -SCR catalytic activity. The low temperature shift phenomenon was obtained and dramatically shifted from 305 to 221 °C at GHSV 20000/h. • Crystalline Nanoflake (NF) V 2 O 5 loaded onto WO 3 /TiO 2 (NF V 2 O 5 -W/T) a low temperature-shift NH 3 -SCR catalyst has been prepared successfully. • NF V 2 O 5 -W/T showed 100 % NH 3 -SCR conversion efficiency at GHSV 20000/h was obtained and dramatically shifted from 305 to 221 °C according to the increase of NF V 2 O 5 loading contents (0.5 ∼ 3 wt%). • The low temperature shift phenomenon is due to the crystallinity, particle shape, size and oxidation state of (NF) V 2 O 5 loaded on W/T catalyst, compared with monodispersed and polymeric species of Im V 2 O 5 . Nanoflake V 2 O 5 supported on WO 3 /TiO 2 (NF V 2 O 5 -W/T) as a low temperature shift catalyst for selective catalytic reduction (SCR) of NO with NH 3 was prepared. The catalyst was compared with NH 4 VO 3 solution impregnated WO 3 /TiO 2 (Im V 2 O 5 -W/T) as a commercial catalyst. Dispersed 50 ∼ 200 nm NF V 2 O 5 slurry was bead-milled and exfoliated in ethanol along with the aggregated flake V 2 O 5 particles having 0.05 ∼ 1 µm crystal size. NF V 2 O 5 -W/T catalyst was designed and prepared with varying the loading amount of the dispersed NF V 2 O 5 slurry. To observe the low-temperature shift phenomenon of NF V 2 O 5 -W/T catalyst at GHSV 20000/h, a 100 % DeNOx conversion efficiency was obtained and dramatically shifted from 305 to 221 °C according to the increase of NF V 2 O 5 loading contents (0.5 ∼ 3 wt%), compare with Im V 2 O 5 -W/T. The DeNOx efficiency, along with temperature shift phenomenon of these catalysts was elucidated by the loading content, crystallinity and the V 4+ /V 5+ oxidation state ratio of V 2 O 5 loaded on W/T catalyst. It is thought that the crystalline species of NF V 2 O 5 loaded on W/T catalysts prepared in this work potentially meets their application to effectively decompose NOx at low temperature compared with monodispersed and polymeric species of Im V 2 O 5 .