Strong metal support interaction (SMSI) and MoO synergistic effect of Pt-based catalysts on the promotion of CO activity and sulfur resistance.

In industrial applications, Pt-based catalysts for CO oxidation have the dual challenges of CO self-poisoning and SO toxicity. This study used synthetic Keggin-type HPMoO (PMA) as the site of Pt, and the Pt-MoO produced by decomposition of PMA was anchored to TiO to construct the dual-interface structure of Pt-MoO and Pt-TiO, abbreviated as Pt-P&M/TiO. Pt-0.125P&M/TiO with a molar ratio of Pt to PMA of 8:1 showed both good CO oxidation activity and SO tolerance. In the CO activity test, the CO complete conversion temperature T of Pt-0.125P&M/TiO was 113 ℃ (compared with 135 ℃ for Pt/TiO). In the SO resistance test, the conversion efficiency of Pt-0.125P&M/TiO at 170 ℃ remained at 60% after 72 h, while that of Pt/TiO was only 13%. H-TPR and XPS tests revealed that lattice oxygen provided by TiO and hydroxyl produced by MoO increased the CO reaction rate on Pt. According to the DFT theoretical calculation, the electronegative MoO attracted the d-orbital electrons of Pt, which reduced the adsorption energy of CO and SO from - 4.15 eV and - 2.54 eV to - 3.56 eV and - 1.52 eV, respectively, and further weakened the influence of strong CO adsorption and SO poisoning on the catalyst. This work explored the relationship between catalyst structure and catalyst performance and provided a feasible technical idea for the design of high-performance CO catalysts in industrial applications.