Investigation of the promotion effect of WO3 on the decomposition and reactivity of NH4HSO4 with NO on V2O5–WO3/TiO2 SCR catalysts

Abstract

In this study, we systematically investigated the interaction between NH₄HSO₄ and WO₃-promoted V₂O₅/TiO₂ catalysts in the selective catalytic reduction of NO with NH₃, along with the promotion effect of WO₃ on the decomposition and reactivity of NH₄HSO₄ with NO. In the NH₄HSO₄-deposited samples, WO₃ addition increased the electron cloud density around the S atoms in SO₄²⁻, which was beneficial for the reduction of S atoms with +6 formal oxidation number, as in NH₄HSO₄, to those in the +4 oxidation state, as in SO₂. Consequently, WO₃-doping led to an increase in the amount of SO₂ released at low-temperature regions during the heating process as well as an obvious enhancement in the decomposition behavior of NH₄HSO₄, as illustrated by decreases in temperatures attributed to the weight loss peaks. Meanwhile, the introduced WO₃ had a slight promotion effect on the reactivity of NH₄HSO₄ with NO, together with an inhibitory effect on the production of N₂O during the reaction process. Finally, WO₃-promoted catalysts exhibited enhanced SO₂-resistance.