Behavior of active species on Pt-Sn/SiO2 catalyst during the dehydrogenation of propane and regeneration

Pt-Sn alloy nanoparticles supported on inert SiO2 were prepared and used in the dehydrogenation of propane. The bulk/surface properties of Pt-Sn alloys during reactions and regeneration reactions and regenerations were investigated by transmission electron microscopy, X-ray diffraction, X-ray absorption fine structure, and X-ray photoelectron spectroscopy. Thermogravimetric analysis showed that small amounts of coke formed on the reacted catalysts, and the Pt-Sn interactions were also weakened during the reaction. Sn enrichment occurred on the catalyst surface after the first and second reaction cycles. Fortunately, a small amount of co-fed H-2 inhibited Sn segregation from Pt-Sn alloys and retained the active structure. The regeneration processes, especially the oxidation-reduction method, strengthened Pt-Sn interactions while concurrently burning off coke, allowing partial recovery of the catalytic performance. This work indicates the key role of the special geometric arrangements of Pt-Sn alloys in the dehydrogenation of propane.