Influence of cerium and cesium promoters on vanadium catalyst for sulfur dioxide oxidation

We studied the catalytic performance of vanadium catalyst promoted with cerium and cesium for sulfur dioxide oxidation. The catalyst samples were characterized by FT-IR, Raman, XRD, SEM, BET and XPS. The results showed that the properties of the catalyst promoted with 4 wt% CeO₂ and 7 wt% Cs₂SO₄ were superior to the commercial V₂O₅-K₂SO₄/SiO₂ and V₂O₅-K₂SO₄-Cs₂SO4/SiO₂ catalysts, in terms of low temperature activity, thermal stability, SO₂ oxidation efficiency and ignition temperature. The FT-IR, Raman, XRD and XPS results evidenced the formation of V₂O₅-Cs₂S₂O₇ pyrosulfate, CeVO₄ and CeO₂ crystalline phase in V₂O₅-K₂SO₄-Cs₂SO₄-CeO₂/SiO₂ catalyst These crystalline phases play an important role in redox reaction at low temperature and can increase the available oxygen for the redox reaction. The characterization results also showed that cerium can promote the formation of pyrosulfate, increase the proportion of large macropores, and improve stability of V^V at high temperature. Due to its excellent low-temperature and high-temperature activity, the V₂O₅-K₂SO₄-Cs₂SO₄-CeO₂ /SiO₂ catalyst appears to be more efficient for the conversion of SO₂ in a larger concentration range.