Effect of reduction method on the activity of Pt-Sn/Si02 for dehydrogenation of propane

The effect of reduction method (direct reduction (DR), decomposition in inert gas (DI) and calcinationreduction (CR)) on the catalytic performances of Pt-Sn/Si02 catalyst in the dehydrogenation of propane was investigated. The Pt-Sn/Si02 (DR) showed the highest activity among the catalysts tested. The order of activities of Pt/Si02 and Pt-Sn/Si02 catalysts was Pt/Si02 (DR) Pt-Sn/Si02 (CR) < Pt-Sn/Si02 (DI) < Pt-Sn/Si02 (DR). The results of structural characterization by X-ray diffraction (XRD), CO pulse, transmission electron microscopy (TEM), and Pt L111 and Sn K-edges X-ray absorption fine structure (XAFS) spectroscopy indicated that Pt3Sn alloy nanoparticle was mainly formed on the Pt-Sn/Si02 (DR). In the case of the Pt-Sn/Si02 (CR) catalyst, PtSn alloy particle was mainly dispersed on 5i02. On the other hand, Pt metal particles and highly dispersed 5n02 were present on the Pt-Sn/Si02 (DI). The relationship between activity and structure of platinum-tin catalysts suggested that Pt3Sn alloy acts as active site for dehydrogenation of propane, whereas PtSn alloy shows low or no activity. C) 2013 Elsevier B.V. All rights reserved.