The sulfur and water resistance improvement of Pt/TiO2 catalyst for CO oxidation reaction by anatase and rutile TiO2 crystal interfaces

Catalytic oxidation is an effective strategy for eliminating CO pollutant. Pt/TiO₂ catalyst are one of the most active catalysts as used, but facing the issue of sulfur and water deactivation. In this study, TiO₂ was synthesized using a sol-gel method, while Pt/TiO₂ was prepared by impregnation method. By varying the calcination temperature of the TiO₂ support, Pt/TiO₂ catalysts with different proportions of anatase and rutile phases were synthesized. At the calcination temperature of 500 °C, the catalysts exhibited approximately equal proportions of anatase and rutile, resulting in exceptional catalytic activity for CO oxidation, as well as improved resistance to sulfur and water in the flue gas. Consequently, the Pt/TiO₂-500 catalyst achieved a CO conversion of 93% at 160 °C. Even under conditions of 8% (vol) H₂O and 0.016% (vol) SO₂ (GHSV = 300000 ml·h⁻¹·g⁻¹), the CO conversion remained above 95% at 220 °C for 46 h. The catalysts were characterized and analyzed using various techniques. The results indicated that anatase-phase TiO₂ exhibited weak CO adsorption capacity but strong SO₂ adsorption capacity, whereas rutile-phase TiO₂ demonstrated strong CO adsorption capacity and weak SO₂ adsorption capacity. The presence of the anatase phase mitigated the CO self-poisoning phenomenon of the catalyst, while the biphase interface reduced the adsorption and oxidation of SO₂ on the catalyst’s surface, significantly inhibiting the deposition of TiOSO₄. Consequently, the Pt/TiO₂-500 catalyst displayed the highest CO catalytic activity along with superior resistance to sulfur and water.