Synergistic roles of Pt0 and Pt2+ species in propane combustion over high-performance Pt/AlF3 catalysts

Catalytic propane combustion was performed on a series of supported Pt/AlF 3 catalysts. These catalysts are very active and stable in the reaction, and the 0.2Pt/AlF 3 catalyst gives the highest specific reaction rate of 207.3 μmol g Pt −1  s −1 at 220 °C. The 1Pt/AlF 3 is much more active than the reference Pt/Al 2 O 3 catalyst, due to its higher content of metallic Pt species than that in the Pt/Al 2 O 3 . Furthermore, turnover frequency (TOF) based on Pt dispersion increases with the surface concentration of metallic Pt 0 in the catalyst, suggesting these species might be the active sites. Furthermore, synergistic roles of metallic and oxidized Pt species are found, as the TOFs calculated based on surface Pt 0 concentration reaches a maximum at the Pt 0 /Pt 2+ molar ratio of about 1. Such optimal Pt 0 /Pt 2+ ratio implies the requirement of Pt 0 Pt 2+ pair in the reaction, probably due to the activation and cleavage of C H bond on metallic Pt atom and the sequential oxidation on the oxidized Pt atoms.