Effect of pre-oxidation process on V2O5/AC catalyst for the selective catalytic reduction of NOx with NH3

Abstract

Activated coke-based catalysts have attracted extensive attention in denitration by selective catalytic reduction by NH 3 (NH 3 -SCR), due to their excellent catalytic performance at low temperature. In the paper, the V 2 O 5 /AC catalyst was prepared by the impregnation method to investigate the effect of pre-oxidation process on its NH 3 -SCR activity. Activity test results show that the V 2 O 5 /AC catalyst with 4-h pre-oxidation exhibits the best NO x removal efficiency, which reaches the NO x conversion is over 75% in the range of 200-240 °C and exhibits an excellent resistance to SO 2 and H 2 O. Characterization results demonstrate that the V 4+ was oxidized by oxygen molecule during pre-oxidation process, which contributes to the formation of V 5+ ions and surface-active oxygen species. The surface-active oxygen species are conducive to promoting the "fast SCR" reaction; thus, the pre-oxidized process can contribute to the superior NH 3 -SCR performance for V 2 O 5 /AC catalyst at low temperature.