Loading Eu2O3 Enhances the CO Oxidation Activity and SO2 Resistance of the Pt/TiO2 Catalyst

Pt/TiO2 and Pt-Eu2O3/TiO2 catalysts were prepared via the impregnation method for catalytic oxidation of CO. The Pt-2Eu2O3/TiO2 catalyst exhibited better CO oxidation activity as well as greater SO2 resistance than the Pt/TiO2 catalyst. For the inlet gas consisting of 0.8% CO, 5% O2, and balanced N2, the lowest complete conversion temperatures (T100) of CO were 120 °C and 140 °C for the Pt-2Eu2O3/TiO2 and Pt/TiO2 catalysts, respectively. During the 72 h SO2-resistance test at 200 °C under an inlet gas composition of 0.8% CO, 5% O2, 15% H2O, 50 ppm SO2, and balanced N2, the CO conversion on the Pt-2Eu2O3/TiO2 catalyst remained >99%, while that on the Pt/TiO2 catalyst gradually decreased to 77.8%. Pre-loading 2 wt% Eu2O3 on TiO2 enhanced the dispersion of Pt, increased the proportion of Pt0, and facilitated the adsorption and dissociation of H2O, all of which promoted CO oxidation. SO2 preferentially occupied the Eu2O3 sites by forming stable sulfates on the Pt-2Eu2O3/TiO2 catalyst, which protected the Pt active sites from poisoning. The OH* species produced from the dissociation of H2O played a significant role in promoting CO oxidation through the formation of COOH* as the key reaction intermediate. The developed Pt-2Eu2O3/TiO2 catalyst has great application potential in terms of the removal of CO from industrial flue gases.