Suppressed Strong Metal–Support Interactions in Platinum on Sulfated Titania and Their Influence on the Oxidation of Carbon Monoxide

Strong metal–support interactions (SMSI), which are evidenced by the coverage of Pt by the TiO₂ support under reducing conditions, were suppressed upon loading Pt on sulfated TiO₂ (S-TiO₂), according to controlled CO chemisorption results. Combined X-ray diffraction (XRD) and X-ray absorption near-edge structure (XANES) studies showed that the Pt species interacted more strongly with the sulfur-free TiO₂ surface than with the sulfated TiO₂ surface, which thereby facilitated the formation of SMSIs at low temperatures. Weakened interactions between Pt and S-TiO₂ led to the formation of large Pt clusters with more metallic character. CO oxidation on the Pt/S-TiO₂ and Pt/TiO₂ catalysts revealed that the temperature for 50 % conversion was lower on Pt/S-TiO₂ than on Pt/TiO₂ by more than 50 °C. It was concluded that the metal–support interactions between Pt and TiO₂ could be controlled by S species on TiO₂, and this ultimately influenced the CO oxidation ability of the catalyst.