Effects of Synthesis Procedures on Pt–Sn Alloy Formation and Their Catalytic Activity for Propane Dehydrogenation

In this work, we improved the conventional sequential impregnation synthetic method for preparing Pt–Sn/SiO 2 catalysts for propane dehydrogenation. Three different synthesis procedures (Pt calcination (PC), co-calcination (CC) and direct reduction (DR)) were performed and examined for catalytic dehydrogenation of propane. The results shows that the synthesis procedures had a notable influence on the activities of the supported Pt–Sn bimetallic catalysts. Co-calcination method mainly produces Pt 1 Sn 1 alloy nanoparticles over Pt–Sn/SiO 2 _CC, which was totally inactive in propane dehydrogenation. Pt calcination resulted in the coexistence of Pt 0.84 Sn 0.16 , Pt 3 Sn 1 , Pt 1 Sn 1 on SiO 2 . Pt–Sn/SiO 2 _PC exhibited the medium activity. Direct reduction caused the formation of Pt 3 Sn alloy nanoparticle. Pt–Sn/SiO 2 _DR displayed the best catalytic performances among the studied catalysts, with 27% of propane conversion and 99% of selectivity towards propylene. These results in the present work indicated that the beneficial role of Sn requires the suitable catalyst preparation procedures. Direct reduction of Pt–Sn/SiO 2 as prepared can afford more homogenous active Pt 3 Sn 1 alloy on Pt–Sn/SiO 2 _DR. The procedure is simple in operation and much suitable for industrially catalyst preparation. Pt x Sn y (x/y ≥ 3) with face-centered cubic structure are much active than Pt 1 Sn 1 alloy with hexagonal structure. Graphical Abstract