Low temperature SCR de-NO_x performance and mechanism of heteropolyacid VPO-Cr-PEG/TiO₂ catalyst

Highlights

• The heteropolyacid catalyst VPO-Cr-PEG/TiO₂ for NH₃-SCR was developed.

• The addition of PEG increased the crystallinity of VPO.

• VP(1/5)O-Cr-PEG/TiO₂ showed good resistance to SO₂ & H₂O.

Abstract

In this paper, a heteropolyacid catalyst VPO-Cr-PEG/TiO₂ was developed and the low temperature de-NO_x performance of catalyst was studied. The experimental results showed that the de-NO_x efficiency reached over 98% at the low temperature of 150–350 °C. The catalyst exhibited excellent sulfur and water resistance in the presence of 1000 ppm SO₂ and 8 vol% H₂O. In the presence of polyethylene glycol (PEG), the crystal surface energy of the catalyst decreased, and (VO)₂P₂O₇ was the main active crystal phase of the catalyst. The selective catalytic reduction of NO_x by NH₃ over VP(1/5)O-Cr-PEG/TiO₂ catalyst simultaneously followed the Langmuir-Hinshelwood and Eley-Rideal mechanisms.