Simultaneous removal of elemental mercury and NO from simulated flue gas using a CeO2 modified V2O5–WO3/TiO2 catalyst

Abstract

To provide insight into optimizing flue gas treatment, simultaneous removal of elemental mercury (Hg⁰) and NO using a CeO₂ modified V₂O₅–WO₃/TiO₂ catalyst was investigated. The results show that a novel V₂O₅–WO₃/TiO₂–CeO₂ catalyst exhibits excellent Hg⁰ oxidation efficiency (88%) and NO conversion efficiency (89%) at 250 °C. Furthermore, CeO₂ modified V₂O₅–WO₃/TiO₂ not only exhibits enhanced catalytic activity but also good resistance in SO₂ and H₂O. These catalysts were also characterized using BET, SEM, XRD, XPS, and H₂-TPR. We found lower crystallinity, more reduced species and better texture properties to be presented, which were all ascribed to CeO₂ doping. Also, the redox cycle (V⁴⁺ + Ce⁴⁺ ↔ V⁵⁺ + Ce³⁺) plays a key role in promoting Hg⁰ oxidation and NO conversion. In tune with the experimental results, a mechanism for the simultaneous removal of Hg⁰ and NO was proposed for the V₂O₅–WO₃/TiO₂–CeO₂ catalysts.