Developing highly efficient, SO2-resistant low-temperature CO oxidation catalysts is crucial for industrial applications. This study optimized Pt–Pd/TiO2 catalysts via TiO2 support precalcination. Precalcination at 600–800 °C significantly enhanced the CO oxidation activity and SO2 tolerance. The sample precalcined at 700 °C (denoted Pt–Pd/TiO2(700)) showed the best performance, achieving complete CO conversion (T100) at 120 °C under a feed gas (0.8% CO, 5% O2, balance N2)─a significant 50 °C reduction compared to the T100 of 170 °C for the unmodified Pt–Pd/TiO2 catalyst. In a 45 h stability test under a wet gas containing 15% H2O and 200 ppm of SO2, Pt–Pd/TiO2(700) maintained >95% CO conversion, outperforming the unmodified Pt–Pd/TiO2 catalyst (74.2%). Characterization revealed that precalcination at 700 °C increased surface Pt/Pd concentration and metallic species proportion, improving activity. Enlarged Pt/Pd particles and pores also inhibited SO2 adsorption and sulfate formation, enhancing the SO2 resistance. The Pt–Pd/TiO2(700) catalyst shows promising potential for industrial CO removal.
Yu et al. (Mon,) studied this question.